CN102147385B - Multi-phase flow measuring methods based on single-section impedance long-waist internal cone sensor - Google Patents

Abstract

The invention belongs to the technical field of fluid measurement, and relates to multi-phase flow measuring methods based on a single-section impedance long-waist internal cone sensor. The adopted sensor comprises a cone throttling piece, a systolic pressure drop differential pressure transmitter, a permanent pressure loss differential transmitter and an electrical sensitive sensor. According to the difference of properties of continuous phases, the invention provides two measuring methods which have the same inventive concept and respectively comprise the following steps of: collecting two pairs of differential signals generated by the cone throttling piece; collecting electrical signals by utilizing the electrical sensitive sensor; calculating the total mass flow rate, the mass flow rate of each phase and the mass content of each phase according to a double-differential model of a single throttling piece; selecting a corresponding electrical method according to whether the continuous phases are conductive, and calculating the section content of each phase; and selecting a corresponding calculating model, and calculating the procedure parameters of an oil phase, a gas phase and an aqueous phase. The multi-phase flow measuring method is characterized by high measuring precision, high reliability, capability of obtaining more measurement information, low cost and the like, and can be widely applied in the industries of petroleum, chemical engineering, energy power, metallurgy and the like.

Description

Multiphase flow measurement method based on the long waist inner cone of single cross section impedance type sensor

Technical field

The invention belongs to the fluid measurement technical field, be specifically related to a kind of measuring method that merges differential pressure measurement principle and electrical measurement principle, be used for confirming that external phase is that each phase component of polyphasic flow of conductive phase or non-conductive phase contains parameters such as rate, flow velocity and flow.The present invention is measured as description object with oil/gas/water multiphase, but is not limited in this application, and measuring method of the present invention still is suitable in other industrial processs and chemical reaction.

Technical background

Polyphasic flow is often referred to and has flowing of two or more material simultaneously, comprises biphase gas and liquid flow, Dual-Phrase Distribution of Gas olid, liquid fixed double phase flow, liquid-liquid diphasic flow and gas-liquid liquid and gas-liquid-solid multiphase flow etc.Polyphasic flow often appears in modern project field such as power, nuclear energy, chemical industry, oil, refrigeration, metallurgy, pipeline transportation, aerospace, medicine, food and the equipment, as not realizing just can't guaranteeing the accurate measurement of its flow process parameter the reliable design and the safe operation of relevant devices in the pipeline.The popularity that polyphasic flow exists in nature and industrial process and the importance of application make it in national economy and daily life, occupy crucial status.Along with power industry and petrochemical industry develop rapidly, and, impel the work of polyphasic flow area research to develop rapidly, become at present and give the front subject greatly paid close attention to both at home and abroad the pay attention to day by day of environmental protection.

Because each alternate interfacial effect and relative velocity of existing of polyphasic flow, phase interface all is random variation on time and space, causes the flow characteristics of polyphasic flow complicated more than single-phase flow, and characteristic parameter is also many than single-phase flow.The oil gas water three phase flow measuring method can be divided into two aspects at present: 1, regard polyphasic flow as measurement that biphase gas and liquid flow carries out flow.2, each phase component in the polyphasic flow is contained the measurement of rate.The method of wherein regarding polyphasic flow as gas-liquid two-phase flow measurement flow mainly contains: correlation method, volumetric method, flow limit method, turbine type detection method, laser Doppler method, PIV particle imaging velocimetry, hot line hot film anemometer, process tomographic imaging technology, nuclear magnetic resonance method and Coriolis method etc.; This several method has wide range of applications, but needs other subsidiary means (like densitometer etc.) to measure void fraction.The measuring method of phase content has two kinds, and the one, indirect method promptly returns through experiment or theoretical derivation draws the phase content calculating formula that physical parameter and technological parameter with the gas-liquid two-phase medium are function; The 2nd, the measurement mechanism direct method of measurement is like Electromagnetic Wave Detection method, conductance method, capacitance method, calorifics method, microwave method, γ component table method and nuclear magnetic resonance method etc.In actual measurement, generally adopt the measurement mechanism direct method of measurement to confirm phase content.

Using that traditional single-phase flow measurement instrument combines with two-phase flow auxiliary parameter measurement means is a kind of main thought that solves topic between the polyphasic flow procedure parameter is measured in the pipeline.Differential pressure flowmeter like orifice plate, Venturi tube, nozzle and inner cone flow meter etc., is to use maximum online flow measurement instruments of a kind of industry at present, and is also commonplace in the research of polyphasic flow procedure parameter field of measurement.Wherein inner cone flow meter notion that the fluid throttling is retracted to pipeline center's near axis fundamentally change into utilize the coaxial cone that is installed in pipeline center with fluid gradually throttling be retracted to inner-walls of duct, confirm fluid flow through differential pressure before and after measuring cone.Interior cone flow meter can be under shorter straight length condition; With wideer range ratio clean or dirty fluid is realized more accurate, more effective flow measurement; But also there are some shortcomings in himself design feature: there is pulsation in the pressure signal to exist the whirlpool district to cause here at the cone afterbody; Measuring accuracy and repeatability are reduced, and whole crushing is bigger, like the flow performance according to polyphasic flow inner cone flow meter is done malformation; Like inner venturi tube, spindle flowmeter and Shuttle Type Flow Meter etc., can effectively improve its precision and stability in multiphase flow measurement.Based on the multiphase flow measurement method of the responsive principle of electricity existing theory and application foundation preferably; Electrical parameter (electrical impedance, specific inductive capacity etc.) through the measuring channel inner fluid changes the measurement that each phase component of realization polyphasic flow contains rate, and this method is divided into mode such as condenser type, conductance type according to the difference of measurement parameter.If adopt multi-modal sensor and multi-operation mode (excitation measurement strategies) combined method, utilize the measurement advantage of each mode, can realize the comprehensive extraction of polyphasic flow procedure parameter through Combinatorial Optimization, and the acquisition all-sidedly and accurately of flowing information.

Patent CN99257650.4, CN200420093532.6, CN200420061026.9 have announced a kind of special-shaped Venturi tube, spindle flowmeter, Shuttle Type Flow Meter that is used for restriction device respectively, be overcome in the cone flow meter some shortcomings design.The interior relatively cone flow meter of special-shaped Venturi tube is at waist; Increase the equal diameter section; Form annular free air space, help to improve the stability of efflux coefficient, but it is short and angle is big that kinetic energy is converted into the conical diffuser of outlet of potential energy; Fluid produces whirlpool through separating after the cone, and the interior relatively cone flow meter of permanent crushing does not have obvious improvement.Spindle flowmeter and Shuttle Type Flow Meter are very approaching; Only difference to some extent on appearance profile: the throttling element of spindle flowmeter is fairshaped spindle; And the fusiformis body that the throttling element of Shuttle Type Flow Meter is made up of precentrum, middle equal diameter segment body and posterior pyramids; Throttling element is installed along conduit axis, and the centre has one section sufficiently long equal diameter section, and forms uniform circular passage between the inner-walls of duct.These two kinds of deformable bodys are in efflux coefficient stability; Anti-interference fluidity and low pressure loss property all are superior to interior cone flow meter; But throttling element long (4 times to internal diameter of the pipeline); When caliber is big, seeming, comparison is heavy, and it is single relatively to measure the polyphasic flow procedure parameter, needs to cooperate the measurement that other flowmeters could the complete process parameters.

Patent CN86207384, CN200810151346.6, CN03234526.7 have announced " mixer+double-venturi tube " moisture measuring device that Venturi tube restriction device and throttle orifice plate apparatus combination, inner cone restriction device and the combination of Venturi tube restriction device, the combination of two inner cone restriction device and Britain Solartron company propose respectively; Adopt two differential pressure methods to measure gas-liquid two phase contents and flow, i.e. two kinds of similar or inhomogeneous restriction device multiple measurement biphase gas and liquid flow procedure parameters.Utilize the homogeneous flow model; The differential pressure signal that obtains on the restriction device to the different flow coefficient is handled; Obtain the gas phase quality and contain rate, obtain gas-liquid separate phase flow rate in the fluid-mixing by the total mass flow calculation of fluid-mixing then, simultaneously the gas-liquid flow is carried out the temperature and pressure compensation.This combined method only is applicable to measure mixes two-phase fluid uniformly; And two restriction devices fit together the consistance that can not guarantee on the space; Therefore two-phase flow flow pattern and procedure parameter in flow process is difficult to be consistent; Run counter to easily that combined type measures precondition---promptly there is original reason error in the constant principle of its basic parameter when two-phase fluid flows through each ingredient.

Patent US 5485743, US 5130661, US 6857323, US 6940286, CN99209502.6, CN200680055193.4 etc. have announced employing process tomographic imaging technology measurement polyphasic flow procedure parameter.Process tomographic imaging is made up of the sensor space array, data acquisition and the processing unit that obtain the measured object field information, image reconstruction and thing field parameter extraction unit; The sensor array is set up responsive successively in measurement space under certain mode of operation; Through data acquisition and processing unit the signal that reflects detected material field dielectric distribution in the different sensitizing ranges is gathered and handled; Use image algorithm to reconstruct the image of reflection dielectric distribution then, adopt certain information processing method to extract required parameter on this basis.Yet chromatography imaging technique is unmet industrial application requirements still at aspects such as real-time, measuring accuracy and picture qualities; And the quick variation characteristic of polyphasic flow conflicts with the complicacy of tomography image reconstruction algorithm, may cause result of calculation to exist than mistake.

Summary of the invention

The objective of the invention is deficiency to above-mentioned prior art existence; Two kinds of polyphasic flow procedure parameter measuring methods of measuring to heterogeneity external phase are provided; Two kinds of measuring methods realize that according to each sensor own characteristic the signal between sensor is complementary and redundant respectively, realize measuring optimized multiphase flow measurement method.Two kinds of measuring methods that the present invention proposes; A kind of long waist inner cone restriction device and a kind of single cross section electricity sensitive sensor is combined; Do not carry out pre-separation or mixing to measuring fluid; Realize that external phase is the polyphasic flow procedure parameter of conductive phase or non-conductive phase, like the accurate measurement of a minute phase content (cross section phase content, quality phase content), phase-splitting flow velocity, volumetric flow rate and mass rate.Technical scheme of the present invention is following:

A kind ofly be used for the multiphase flow measurement method that external phase is non-conductive phase based on the long waist inner cone of single cross section impedance type sensor; The sensor that adopts comprises segment of cone stream part, contraction pressure drop differential pressure transmitter, permanent crushing differential pressure transmitter; The electricity sensitive sensor; Described cone throttling element is a kind of long waist inner cone restriction device; By the leading portion cone, constitute for three sections,, form annular free air space with the tube wall of pipeline through the coaxial pipeline center of being fixed in of support as stage casing column, the back segment cone of cone waist; Two pressure ports of described contraction pressure drop differential pressure transmitter, one is arranged on cone throttling element upstream end, and another is arranged on annular free air space place or cone afterbody; Two pressure ports of described permanent crushing differential pressure transmitter are separately positioned on recovery place of cone throttling element upstream and downstream pressure; Described electricity sensitive sensor comprises one group of electrode that is distributed in annular free air space and is in pipeline same cross-sectional position; This group electrode is made up of electrode in one or more and one or more external electrode; Interior electrode is cone throttling element or the electrode that is fixed on cone waist surface, and external electrode is fixed on inner-walls of duct; When one in the electrode in the gating with external electrode in one during as an electrode pair, two electrodes of this of gating, one is exciting electrode and potential electrode, one is ground-electrode, this measuring method comprises the following steps:

1) gathers two pairs of differential pressure signals that produce by the cone throttling element: shrink pressure drop differential pressure signal Δ p and permanent crushing differential pressure signal δ p;

2) utilize the electricity sensitive sensor to gather electric signal;

3), obtain total mass flow rate, each phase mass rate, each phase quality and contain the relational expression between rate and the phase content according to two differential pressure models of following single throttling element:

A. according to formula

With

Calculate equivalent mass flow W _Mtp1, W _Mtp2, in the formula, ε is an expansibility factor, C ₁For shrinking pressure drop Δ p is efflux coefficient, the C that differential pressure signal calibrates ₂For permanent crushing δ p is the efflux coefficient that differential pressure signal calibrates, A ₀Be the circulation area of annular free air space, A is the pipeline circulation area, and β is the equivalent diameter ratio of flow area, ρ _gBe density of gas phase;

B. with formula

Compare, calculate L-M parameter χ, in the formula,

Be two-phase flow multiplier, W _MgBe gas phase mass flow, a ₁, b ₁, a ₂, b ₂Be the rating test parameter;

C. according to formula

Obtain that the gas phase quality contains rate x, the liquid phase quality contains rate 1-x and cross section oil content α _o, cross section water percentage α _w, void fraction α _gBetween relational expression, in the formula,

Be two-phase flow multiplier, ρ _gBe density of gas phase, ρ ₁Be density of liquid phase,

α _oBe cross section oil content, α _wBe cross section water percentage, α _gBe void fraction, ρ _oBe oil phase density, ρ _wBe water density;

D. according to formula

Calculate gas phase mass flow W _g, liquid phase mass rate W _l, total mass flow rate W _mWith cross section oil content α _o, cross section water percentage α _w, void fraction α _gBetween relational expression;

4) calculate the procedure parameter of oil-gas-water three-phase flow according to following computation model:

A. the voltage signal of gathering according to the electricity sensitive sensor, the DIELECTRIC CONSTANTS of calculating fluid-mixing _m

B. in the polyphasic flow with cross section oil content α _o, cross section water percentage α _w, void fraction α _gEquivalence contains rate, known oil phase DIELECTRIC CONSTANTS for the volume of Oil, Water, Gas respectively _o, the water DIELECTRIC CONSTANTS _wAnd gas phase DIELECTRIC CONSTANTS _g, according to formula

And φ _o+ φ _w+ φ _g=1 calculates the oil phase volume contains rate φ _o, the water volume contains rate φ _wContain rate φ with gaseous phase volume _g, ρ in the formula _o, ρ _w, ρ _gBe oil phase density, water density, density of gas phase;

C. will go up a step and obtain to such an extent that each phase cross section c step of containing rate substitution step 3) goes on foot determined two relational expressions with d, calculating total mass flow rate, each phase mass rate and each phase quality contain rate;

D. according to formula

Calculate the total volumetric flow rate Q of fluid-mixing _v, in the formula, ρ _mBe the fluid hybrid density;

E. according to formula

Calculate the oil phase volume flow Q _Vo, the water volume flow Q _VwWith gas phase volume flow rate Q _Vg

F. according to formula

Calculate oil phase flow velocity V _o, aqueous phase flow rate V _wWith gas phase flow velocity V _g, in the formula, A ₀Be the circulation area of annular free air space, α _oBe cross section oil content, α _wBe cross section water percentage, α _gBe void fraction.

The present invention provides a kind of multiphase flow measurement method based on the long waist inner cone of single cross section impedance type sensor that external phase is conductive phase that is used for simultaneously, and the measurement mechanism that is adopted is identical with said apparatus, and this measuring method comprises the following steps:

1) gathers two pairs of differential pressure signals that produce by the cone throttling element: shrink pressure drop differential pressure signal Δ p and permanent crushing differential pressure signal δ p;

2) utilize the electricity sensitive sensor to gather electric signal;

3), obtain total mass flow rate, each phase mass rate, each phase quality and contain the relational expression between rate and the phase content according to two differential pressure models of following single throttling element:

E. according to formula

With

Calculate equivalent mass flow W _Mtp1, W _Mtp2, in the formula, ε is an expansibility factor, C ₁For shrinking pressure drop Δ p is efflux coefficient, the C that differential pressure signal calibrates ₂For permanent crushing δ p is the efflux coefficient that differential pressure signal calibrates, A ₀Be the circulation area of annular free air space, A is the pipeline circulation area, and β is the equivalent diameter ratio of flow area, ρ _gBe density of gas phase;

F. with formula

Compare, calculate L-M parameter χ, in the formula,

Be two-phase flow multiplier, W _MgBe gas phase mass flow, a ₁, b ₁, a ₂, b ₂Be the rating test parameter;

G. according to formula

Obtain that the gas phase quality contains rate x, the liquid phase quality contains rate 1-x and cross section oil content α _o, cross section water percentage α _w, void fraction α _gBetween relational expression, in the formula,

Be two-phase flow multiplier, ρ _gBe density of gas phase, ρ ₁Be density of liquid phase,

α _oBe cross section oil content, α _wBe cross section water percentage, α _gBe void fraction, ρ _oBe oil phase density, ρ _wBe water density;

H. according to formula Calculate gas phase mass flow W _g, liquid phase mass rate W _l, total mass flow rate W _mWith cross section oil content α _o, cross section water percentage α _w, void fraction α _gBetween relational expression;

4) calculate the procedure parameter of oil-gas-water three-phase flow according to following computation model:

A. the voltage signal of gathering according to the electricity sensitive sensor, the conductivity of calculating fluid-mixing _m

B. known water conductivity _w, according to formula

α _l+ α _g=1 draw

Calculate cross section oil content α _o, cross section water percentage α _wWith void fraction α _g, in the formula, σ _mBe profit gas mixed conductivity;

C. will go up a step and obtain to such an extent that each phase cross section c step of containing rate substitution step 3) goes on foot determined two relational expressions with d, calculating total mass flow rate, each phase mass rate and each phase quality contain rate;

D. according to formula

Calculate the total volumetric flow rate Q of fluid-mixing _v, in the formula, ρ _mBe the fluid hybrid density;

E. according to formula Calculate the oil phase volume flow Q _Vo, the water volume flow Q _VwWith gas phase volume flow rate Q _Vg

F. according to formula

Calculate oil and calculate oil phase flow velocity V _o, aqueous phase flow rate V _wWith gas phase flow velocity V _g

Beneficial effect of the present invention and advantage are following:

1, the annular free air space of cone throttling element and duct wall formation carries out rectification to the multiphase flow fluid-mixing; Flow in the circular passage of formation standard; Channel inner pressure is stablized and pressure is linear decline along axis, makes the repeatability of measurement and accuracy raising become possibility; Reliable mounting structure flexibly can be changed the cone throttling element of different-diameter ratio based on the different measuring object, with the scope of application of expansion measurement.

2, the polyphasic flow fluid-mixing flows through the cone throttling element and in annular free air space, produces and shrink pressure drop Δ p; And in the cone downstream pressure recovery place of certain distance produces permanent crushing δ p; Adopt contraction pressure drop Δ p to make differential pressure signal with permanent crushing δ p; Comprised flowing information more fully, the capable of using pair of differential pressure model obtains procedure parameters such as flow and the phase content of polyphasic flow simultaneously.

3, the form of electricity sensitive sensor can be diversified; Like ring electrode, arc-shaped electrode etc.; Adopting arc-shaped electrode can be the form of many measurement space combinations with the average measurement characteristic changing of ring electrode, has improved the local measurement susceptibility, and then improves overall measurement accuracy; The energisation mode variation of electricity sensitive sensor, like voltage drive and current excitation etc., internal and external electrode all can be used as exciting electrode.

Description of drawings

Following accompanying drawing has been described embodiment chosen of the present invention, is exemplary drawings and non exhaustive or restricted, wherein:

The long waist inner cone of the single cross section impedance type multiphase flow measurement device front view that Fig. 1 measuring method of the present invention adopts;

The long waist inner cone of the single cross section impedance type multiphase flow measurement device lateral cross section view that Fig. 2 measuring method of the present invention adopts;

The long waist inner cone of the single cross section impedance type multiphase flow measurement device front view that Fig. 3 measuring method of the present invention adopts;

Fig. 4 (a) is vertical C-C cross section view of first kind of sensor of measuring method employing of the present invention; (b) be the vertical view of cone; (c) be the horizontal B-B cross section view of cone;

The transverse cross sectional view of second kind of sensor that Fig. 5 measuring method of the present invention adopts: interior electrode is a ring electrode, the very single cross section of dispatch from foreign news agency 8 arc-shaped electrodes;

The transverse cross sectional view of the third sensor that Fig. 6 measuring method of the present invention adopts: internal and external electrode is single cross section 8 arc-shaped electrodes;

The computing unit structural drawing that Fig. 7 adopts for the present invention;

Signal in Fig. 8 computing unit takes place and the mode selection module structural drawing;

Signal condition modular structure figure in Fig. 9 computing unit;

AD in Figure 10 computing unit gathers and the signal pre-processing module structural drawing;

Figure 11 apparatus of the present invention measurement by capacitance method flow diagram;

Figure 12 apparatus of the present invention conductance type measuring method process flow diagram;

Label declaration among the figure: the different cross section electrode is used a respectively, and b distinguishes, and a among the label 16-21, b represent the 16-21 of different cross section electrode.

Embodiment

Below describing manufacturing in detail and operate step of the present invention, be intended to describe as embodiments of the invention, is not to be should be comprised within the scope of the invention other embodiment that can realize identical function by unique form of making or utilizing yet.

Specify the preferred embodiments of the present invention below in conjunction with Figure of description.

With reference to accompanying drawing 1-4; The measurement mechanism that measuring method of the present invention adopts comprises that two ends have the pipeline 1 of flange 2; 7, three pressure ports of a cone throttling element: upper reaches pressure port 3, middle pressure port 4,5, two transmitters of downstream pressure port: shrink pressure drop differential pressure transmitter 24, permanent crushing differential pressure transmitter 25; Be installed in the electricity sensitive sensor on annular free air space 12 corresponding pipelines 1 and the cone waist 9: external electrode 17, interior electrode 16, computing unit 27 and other accessory structures.Cone throttling element 7 be on the basis of traditional inner cone with throat downstream equal diameter lengthening form cone waist 9 and get; Cone throttling element 7 is through support 11 and the support fixture splice 6 coaxial pipe centerline places that are installed in; And the cone 7 that can change different throttling ratios according to measured matter and operating mode is with the expansion measurement range, and cone throttling element 7 is included in constant cone waist 9 and the diameter of entrance 8, diameter that the flow direction diameter increases gradually and is decreased to zero outlet section 10 gradually, when polyphasic flow fluid-mixing 13 flows through this cone throttling element 7; One of circulation area experience is dwindled gradually; And the process that enlarges gradually after in certain distance, stablizing, during polyphasic flow fluid-mixing 13 process cone entrances 8, circulation area reduces reposefully; Speed is increased regularly; Static pressure is corresponding to be reduced, and along with circulation area reduces, the rate of change of speed is big more; When fluid flows through cone waist 9 places, owing to inertia effect continues to quicken, can adjust the fluid that continues to quicken because of the rectified action of cone throttling element 7 again, flowed in its circular passage that forms standard at annular free air space 12 places.Cone throttling element 7 adopts resistant material (high performance metal material, industrial ceramics or other corrosion-resistant materials) in case the fluid corrosion.At cone throttling element 7 upper reaches, annular free air space 12 and the corresponding tube wall of downstream pressure recovery place be provided with pressure port; Because cone throttling element 7 is coaxially installed in the pipeline 1;, fluid-mixing 13 can produce contraction pressure drop Δ p with middle pressure port 4 by pressure port 3 when flowing through at the upper reaches of cone throttling element 7; Pressure port 3 produces permanent crushing δ p with pressure recovery place downstream pressure port 5 at the upper reaches; Shrink pressure drop transmitter 24 and gather these two pairs of differential pressure signals through pressure guiding pipe 23, the electrical quantity signal that produces is transferred to computing unit 27 through transducer signal line 26 with permanent crushing transmitter 25.

Be embedded in cone waist 9 in apparatus of the present invention and can in annular free air space 12, form symmetrical electric field with electricity sensitive sensor on the pipeline 1, through measurement fluid electrical parameter (as electricity lead, electric capacity, specific inductive capacity etc.) confirm that each phase (component) contains rate.Interior electrode 16 is embedded in cone waist 9 top layers, and external electrode 17 is embedded in pipeline 1 inwall top layer, and electrode and the corresponding top layer that is embedded into body maintain an equal level, and promptly electrode can not produce disturbance to polyphasic flow fluid-mixing 13.Interior electrode 16 is the circular metal electrode of same widths and thickness with external electrode 17; Through terminals separately: interior electrode terminal 18; External electrode terminals 19 and signal wire: interior electrode signal line 20; External electrode signal wire 21 links to each other with computing unit 27, and wherein interior electrode signal line 20 is through linking to each other with computing unit 27 at cone throttling element 7 and support 11 inner signal wire passages 22.External electrode 17 is as exciting electrode in the present embodiment, and energisation mode is a current excitation, insulation and ground connection between interior electrode 16 and the cone throttling element 7; Measure the voltage signal between internal and external electrode; Measuring-signal is transferred to computing unit 27 through signal wire 20,21, with above-mentioned differential pressure signal simultaneous; Obtain the polyphasic flow procedure parameter according to computation model; Like a minute phase content (cross section phase content, quality phase content), phase-splitting flow velocity, volumetric flow rate and mass rate, will export signal 28 then and show perhaps teletransmission to the Long-distance Control interface, the measurement of completion total system.Measurement mechanism of the present invention is installed in the actual pipeline through flange, and the diameter of concrete pipeline and length is border situation and deciding factually.

Single cross section electrode form and array mode in apparatus of the present invention have diversified characteristics, are 0 ° to 180 ° like electrode center of circle angular region; Electrode width scope 0mm is to cone throttling element waist length L; Internal and external electrode can be that identical shaped electrode can be a difformity electrode etc. also, so the electrode structure of this device has various ways, Fig. 2, Fig. 5, Fig. 6 have described wherein three kinds of typical array modes.

Fig. 2 has described first kind of sensor that measuring method of the present invention adopts: internal and external electrode is the device lateral cross section view (electrode structure of preferred embodiment) of the ring electrode of same widths; One in the internal and external electrode as another ground connection of exciting electrode, and energisation mode is current excitation or voltage drive.

Fig. 5 has described second kind of sensor that measuring method of the present invention adopts: the very single cross section of dispatch from foreign news agency 8 circular arc electrodes 17, interior electrode is the device lateral cross section view of same widths ring electrode 16.The structure of electrode, fixed form, signal wire etc. are consistent with interior electrode shown in Figure 2 in this array configuration; Each circular arc electrode 17 all is connected computing unit 27 through terminals 19 separately with signal wire 21.The preferred central angle of external electrode is 11 °, can know according to experiment conclusion, 4 °-40 ° of single cross section 8 circular arc electrode central angle ranges of choice, and circular arc number of poles variable (central angle changes thereupon).One in the internal and external electrode as another ground connection of exciting electrode.Energisation mode is current excitation or voltage drive.

Fig. 6 has described the third sensor that measuring method of the present invention adopts: the very single cross section of dispatch from foreign news agency 8 circular arc electrodes 17, interior electrode are the device lateral cross section view of the single cross section of same widths 8 circular arc electrodes 16.The internal and external electrode number is consistent in this array configuration; And the position is corresponding one by one; Each circular arc electrode 16,17 is through terminals (interior electrode terminal 18, external electrode terminals 19) and signal wire (interior electrode signal line 20, external electrode signal wire 21) link to each other with computing unit 27 separately.The inside and outside preferred central angle of circular arc electrode is 11 °, can know 4 °-40 ° of single cross section 8 circular arc electrode central angle ranges of choice, and circular arc number of poles variable (central angle changes thereupon) according to experiment conclusion.One in the internal and external electrode as another ground connection of exciting electrode.Energisation mode is current excitation or voltage drive.

More than be three kinds of typical combination modes, other array configurations can make up as the basis.When being 0 ° (electrodeless) like the external electrode central angle, duct wall ground connection, the form of interior electrode can be ring electrode or a plurality of arc-shaped electrode, interior electrode structure, fixed form, signal wire etc. are consistent with above typical combination mode implementation method; When being 0 ° (electrodeless) like interior electrode central angle, cone throttling element ground connection, the form of external electrode can be ring electrode or a plurality of arc-shaped electrode, external electrode structure, fixed form, signal wire etc. are consistent with above typical combination mode implementation method.

Computing unit of the present invention is shown in accompanying drawing 7～10: mainly be made up of signal generation and mode selection module, signal condition module, AD collection and signal pre-processing module, computer bus and CPU or computing machine, shown in accompanying drawing 7.Wherein:

Signal generation and mode selection module concrete structure mainly are made up of circuit such as computer bus, logic control circuit, signal generation apparatus, constant voltage or constant current source and electrode channel selections shown in accompanying drawing 8.Computer bus is mainly accomplished communicating by letter and data transmission of data acquisition system (DAS) and CPU or computing machine; The logic control circuit major function is the working forms that circuit takes place to select with electrode channel control signal, realizes the selection of system incentive strategy and mode of operation, and and signal condition module and AD collection and signal pre-processing module between co-ordination; It is the pumping signal of the controlled various ways of realization frequency that signal generating circuit selects major function, for example single, double polarity pulse signal and sinusoidal signal etc.; Constant voltage or constant-current source circuit adopt voltage control voltage source (VCVS) or voltage control current source (VCCS) scheme, and the pumping signal that mainly signal generating circuit is produced converts amplitude and adjustable constant voltage or the current signal of phase place into; Electrode channel selects circuit to adopt the digital simulation switch chip, transmits passage according to working method and policy logic control circuit foundation excitation with measuring-signal.

Signal condition module concrete structure mainly is made up of electrode drive circuit, logic control circuit and signal amplification circuit shown in accompanying drawing 9.Electrode drive circuit adopts the analog drive circuit technology, improves wearing loading capability and reducing the influence of spurious signals such as contact resistance, electric capacity and inductance to measured signal of system; Amplifying circuit is made up of high-precision meter operational amplifier or programmable amplifier chip, but the induced signal that electrode (adjacent electrode) is upward small in the pair cross-section and the transmission signal of differential pressure transmitter amplify the raising signal to noise ratio (S/N ratio).The setting of the logical address of logic control circuit realization amplifying circuit and the selection output of enlargement factor, and the logic communication between responsible and AD collection and signal pre-processing module and signal generation and the mode selection module.

AD collection and signal pre-processing module structure are shown in accompanying drawing 10.Mainly form by AD converter array, digital signal processing and logic control circuit, data storage computer bus etc.The AD converter array circuit adopts the AD conversion chip to constitute, and can convert tested simulating signal and the differential pressure signal passed back through the signal condition module to digital signal.Digital signal processing and logic control circuit realize digital signal filtering, separate and be in harmonious proportion function such as storage control, and the data after will handling are transferred to CPU or computer module through computer bus.

The data acquisition system (DAS) course of work that the present invention adopts: at first CPU or computer module carry out initialization operation through computer bus to signal generation and mode selection module; Comprise the exciting current selection; Excitation frequency is selected and excitation/measurement strategies selection etc., and is realized by logic control circuit.Pumping signal is set up responsive in the cross section, circular passage; Change the differential pressure signal that electrode voltage changes and differential pressure transmitter is passed back that causes by dielectric distribution in the field and pass through the cable parallel transfer to the signal condition module; Electric signal after the conditioning gets into AD and gathers and signal pre-processing module; Accomplish analog to digital conversion and the digital signal after the conversion is carried out processing such as filtering and demodulation by digital signal processing and logic control circuit control AD chip; Effective information after the processing is conveyed into CPU or computing machine through the computer bus interface, combines to carry out the analysis and the processing of measurement data with measurement model.Describe in the face of multiphase flow measurement method of the present invention down: measuring method is divided into two kinds according to the difference of external phase:

First kind of measuring method:

External phase is non-conductive in the known polyphasic flow; The electricity sensitive sensor of measurement mechanism adopts first kind of sensor shown in Figure 2, is used to measure the specific inductive capacity of fluid-mixing, in order to distinguish mutually with second kind of measuring method; In measuring method, be referred to as capacitance type sensor.

1. gather two pairs of differential pressure signals that produce by the cone throttling element: shrink pressure drop differential pressure signal Δ p and permanent crushing differential pressure signal δ p;

2. utilize the electricity sensitive sensor to gather electric signal;

3. utilize and shrink pressure drop Δ p and the two differential pressure measurement models of permanent crushing δ p formation single-unit stream device, draw the relational expression between total mass flow rate, each phase mass rate, each phase quality phase content and the phase content.

Under the phase-splitting flow model; Suppose that promptly each phase-splitting of polyphasic flow is distinct incompressible fluid, and two-phase flow to go out coefficient identical, the pressure drop that the pressure drop when each flows through throttling element mutually equals fluid-mixing when flowing through throttling element; In flow process, do not undergo phase transition and expand; Polyphasic flow fluid-mixing pressure drop expression formula does, is example with oil-gas-water three-phase flow under the low pressure operating mode, regards oil-water two-phase flow as liquid phase:

$\sqrt{\frac{\mathrm{\Δp}}{\mathrm{\Δ}{p}_g}}=\sqrt{\frac{\mathrm{\Δ}{p}_l}{\mathrm{\Δ}{p}_g}}+1---\left(1\right)$

In the formula, Δ p _lWith Δ p _gRepresent that respectively the contraction pressure drop that produces when liquid and gas in the oil-gas-water three-phase flow flow through restricting element separately with total volumetric flow rate, Δ p are the contraction pressure drop that three-phase stream potpourri produces when flowing through throttling element.Can obtain the two-phase flow calculating formula under the phase-splitting flow model through derivation and corresponding correction:

In the formula:

ε is an expansibility factor, for incompressible fluid ε=1;

X contains rate for the gas phase quality;

W _mTotal mass flow rate for fluid-mixing;

C ₁For shrinking pressure drop Δ p is the efflux coefficient that differential pressure signal calibrates;

β is the equivalent diameter ratio of flow area,

A ₀Be the circulation area of annular free air space,

D is the diameter of cone waist; D is an internal diameter of the pipeline;

is the two-phase flow multiplier, and χ is Lockhart-Martinelli (L-M) parameter;

ρ _gBe density of gas phase, ρ ₁Be density of liquid phase;

Directly use the phase-splitting flow model and tend to cause bigger error; The present invention carries out measurement model according to Bizon calculating formula

and derives, and wherein a, b are and cone shape, the relevant parameter in pressure position.Can obtain for two kinds of different differential pressure signals:

Wherein:

Be the two-phase flow multiplier; W _Mtp1, W _Mtp2Be defined as the equivalent mass flow, its size is shunk pressure drop Δ p for supposition and is all produced the flow value that calculates, W by gas phase with permanent crushing δ p _MgBe gas phase mass flow, subscript 1 and 2 is represented respectively and is utilized contraction pressure drop Δ p to bring the formula result calculated into permanent crushing δ p.Hence one can see that:

$W_{\mathrm{mtp}1}=\frac{\mathrm{\ϵ}{C}_1{A}_0}{\sqrt{1-{\mathrm{\β}}^4}}\sqrt{2\mathrm{\Δp}{\mathrm{\ρ}}_g};$ $W_{\mathrm{mtp}2}=\frac{\mathrm{\ϵ}{C}_{2}A}{\sqrt{1-{\mathrm{\β}}^4}}\sqrt{2\mathrm{\δp}{\mathrm{\ρ}}_g}---\left(4\right)$

In the formula:

C ₁For shrinking pressure drop Δ p is the efflux coefficient that differential pressure signal calibrates, C ₂For permanent crushing δ p is the efflux coefficient that differential pressure signal calibrates;

A ₀Be the circulation area of annular free air space, A is the pipeline circulation area;

Above parameter is known or obtains through demarcating, and can calculate equivalent mass flow W according to formula (4) _Mtp1, W _Mtp2Two formulas in the formula (3) are compared, and obtained characteristic parameter a through calibration experiment ₁, b ₁, a ₂, b ₂So, can obtain L-M parameter χ, and then obtain that the gas phase quality contains rate x, the liquid phase quality contains rate 1-x, gas phase mass flow W _g, liquid phase mass rate W _l, total mass flow rate W _mWith cross section oil content α _o, cross section water percentage α _w, void fraction α _gBetween relational expression:

$x=\frac{\sqrt{\frac{{\mathrm{\ρ}}_g}{{\mathrm{\ρ}}_l}}}{(\frac{b_1{W}_{\mathrm{mtp}2}-b_2{W}_{\mathrm{mtp}1}}{a_2{W}_{\mathrm{mtp}1}-a_1{W}_{\mathrm{mtp}2}}+\sqrt{\frac{{\mathrm{\ρ}}_g}{{\mathrm{\ρ}}_l}})}---\left(5\right)$

$W_{\mathrm{mg}}=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\sqrt{2\mathrm{\&Delta;p}{\mathrm{\&rho;}}_g}}{a_1\frac{1-x}{x}\sqrt{{\mathrm{\&rho;}}_g/{\mathrm{\&rho;}}_l}+{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="HDA0000048289480000022.png,HDA0000048289480000023.png"\; state="\{\{state\}\}">b</figure-callout>}}_1}$

$W_{\mathrm{ml}}=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\sqrt{2\mathrm{\&Delta;p}{\mathrm{\&rho;}}_g}}{a_1\sqrt{{\mathrm{\&rho;}}_g/{\mathrm{\&rho;}}_l}+b_1\frac{x}{1-x}}---\left(6\right)$

$W_m=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\sqrt{2\mathrm{\&Delta;p}{\mathrm{\&rho;}}_g}}{a_1(1-x)\sqrt{{\mathrm{\&rho;}}_g/{\mathrm{\&rho;}}_l}+b_{1}x}$

In the formula:

a ₁, b ₁For being the test parameters that sample data is demarcated to shrink pressure drop Δ p;

ρ _lHybrid density for liquid phase under the working condition;

Under the low pressure operating mode, the fluid hybrid density ρ of oil-gas-water three-phase flow _mCan be expressed as:

ρ _m＝α _oρ _o+α _wρ _w+α _gρ _g≈α _oρ _o+α _wρ _w＝(1-α _g)ρ _l (7)

In the formula:

ρ _o, ρ _w, ρ _g, ρ _lBe oil phase density, water density, density of gas phase and density of liquid phase;

α _o, α _w, α _gBe cross section oil content, cross section water percentage, void fraction;

So under the low pressure operating mode, the hybrid density ρ of liquid phase _lCan be expressed as:

${\mathrm{\&rho;}}_l=\frac{{\mathrm{\&alpha;}}_o}{1-{\mathrm{\&alpha;}}_g}{\mathrm{\&rho;}}_o+\frac{{\mathrm{\&alpha;}}_w}{1-{\mathrm{\&alpha;}}_g}{\mathrm{\&rho;}}_w---\left(8\right)$

Utilize this pair differential pressure model can calculate total mass flow rate, each phase mass rate, each phase quality phase content and the cross section oil content α of fluid-mixing _o, cross section water percentage α _w, void fraction α _gRelational expression, then the total volumetric flow rate of fluid-mixing can be expressed as:

$Q_v=\frac{W_m}{{\mathrm{\&rho;}}_m}---\left(9\right)$

In the formula:

Q _vTotal volumetric flow rate for fluid-mixing;

ρ _mHybrid density for fluid under the working condition;

The total volumetric flow rate formula is put out the expression formula of the total volumetric flow rate of fluid in order in differential pressure signal through differential pressure flowmeter and the pipeline:

$Q_v=\frac{\mathrm{\&epsiv;}\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HDA0000048289480000022.png,HDA0000048289480000023.png"\; state="\{\{state\}\}">C</figure-callout>}}_1}{\sqrt{1-{\mathrm{\&beta;}}^4}}{A}_0\sqrt{\frac{2\mathrm{\&Delta;p}}{{\mathrm{\&rho;}}_m}}---\left(10\right)$

Simultaneous formula (7), (9), (10) obtain hybrid density ρ _mAnd shrink the expression formula between the differential pressure Δ p:

${\mathrm{\&alpha;}}_o{\mathrm{\&rho;}}_o+{\mathrm{\&alpha;}}_w{\mathrm{\&rho;}}_w+{\mathrm{\&alpha;}}_g{\mathrm{\&rho;}}_g=\frac{W_m^2(1-{\mathrm{\&beta;}}^4)}{2{(\mathrm{\&epsiv;}\&CenterDot;C_1{A}_0)}^2\mathrm{\&Delta;p}}---\left(11\right)$

For the gas of oil product, water and known static pressure and the temperature confirmed, can think the oil phase density p _o, the water density p _wAnd density of gas phase ρ _gFor known, and known

α _o+α _w+α _g＝1 (12)

Therefore wherein contain rate and can draw fluid hybrid density ρ in the cross section of a certain phase if record oil gas water three phase _m

4. utilize electric method to calculate each phase content.

Introduce electrical parameter measuring method measurement cross section and contain rate; Concrete principle is following: the electrical quantity of fluid 13 (as electricity lead, electric capacity, specific inductive capacity etc.) depend on each mutually shared ratio of fluid-mixing; And can set up each phase content and the relation of mixing electrical quantity through some computation models, as the electrical quantity in the Boyle model can through in the fluid-mixing each minute the phase fluid specific inductive capacity function representation.Discrete phase 15 is to be distributed in the liquid phase of being made up of profit two phase fluid-mixings in the continuous gas phase 14, and then the specific inductive capacity of fluid-mixing 13 can use H-B (H-Bnon) formula to calculate:

$\sqrt{{\mathrm{\&epsiv;}}_m}={\mathrm{\&phi;}}_g\sqrt{{\mathrm{\&epsiv;}}_g}+(1-{\mathrm{\&phi;}}_g)({\mathrm{\&phi;}}_w\sqrt{{\mathrm{\&epsiv;}}_w}+{\mathrm{\&phi;}}_o\sqrt{{\mathrm{\&epsiv;}}_o})---\left(13\right)$

In the formula:

ε _o, ε _w, ε _g, ε _mBe respectively the specific inductive capacity of oil phase, water, gas phase, fluid-mixing;

φ _o, φ _w, φ _gThe volume that is respectively oil phase, water, gas phase contains rate;

The polyphasic flow middle section contains rate α and is difficult to direct measurement, and the average external volume of general available measuring section contains rate φ and replaces.Wherein the specific inductive capacity of oil phase and water can obtain through tabling look-up or demarcating; Because the fluid-mixing specific inductive capacity is proportional to the electric capacity between internal and external electrode; And the electric capacity between internal and external electrode is proportional to the voltage magnitude between internal and external electrode; Therefore through measuring the specific inductive capacity that voltage signal between internal and external electrode can calculate fluid-mixing, through simultaneous formula (11), (12), (13), and then the cross section that obtains oil gas water three phase contains rate α _o, α _w, α _gAnd total volumetric flow rate Q _v, the total mass flow rate, each phase mass rate and each the phase quality that calculate fluid-mixing according to formula (5), (6) contain rate.

The definition that contains rate according to volume can calculate each phase volume flow of oil gas water:

Q _vo＝φ _oQ _v

Q _vw＝φ _wQ _v (14)

Q _vg＝φ _gQ _v

In the formula:

φ _o, φ _w, φ _gFor oil phase, water, gaseous phase volume contain rate;

Q _Vo, Q _Vw, Q _Vg, Q _vBe oil phase, water, gas phase volume flow rate and total volumetric flow rate;

Each phase content is according to the phase velocity definition:

$V_o=\frac{Q_{\mathrm{vo}}}{{\mathrm{\&alpha;}}_o{A}_0}$

$V_w=\frac{Q_{\mathrm{vw}}}{{\mathrm{\&alpha;}}_w{A}_0}---\left(15\right)$

$V_g=\frac{Q_{\mathrm{vg}}}{{\mathrm{\&alpha;}}_g{A}_0}$

In the formula:

V _o, V _w, V _gBe oil phase flow velocity, aqueous phase flow rate, gas phase flow velocity;

α _o, α _w, α _gBe cross section oil content, cross section water percentage, void fraction.

Second kind of measuring method

External phase conduction in the known polyphasic flow, the measurement mechanism that is adopted on the example, in hardware with before a kind of measuring method identical, adopt first kind of sensor shown in Figure 2 equally, be used to measure the fluid-mixing conductivity.In order to distinguish mutually, in this measuring method, be referred to as conductive sensor with first kind of measuring method.

Additive method is all identical with first kind of measuring method in the measuring method; Difference is that electricity sensitive sensor measuring-signal is different; When the water percentage in the fluid-mixing 13 was too high, the use of capacitance method received certain limitation, but electricity consumption this moment is led as tested electrical quantity.Because the gas phase conductivity is approximately zero, and liquid phase is a conducting medium, so the fluid mixed conductivity volume that depends primarily on liquid phase contains rate and distribution mutually.According to Maxwell resistivity approximation theory, then the conductivity of fluid-mixing 13 is:

${\mathrm{\&sigma;}}_m=\frac{2{\mathrm{\&alpha;}}_l}{3-{\mathrm{\&alpha;}}_l}\frac{2{\mathrm{\&alpha;}}_w}{3-{\mathrm{\&alpha;}}_w}{\mathrm{\&sigma;}}_w---\left(16\right)$

In the formula:

α _l, α _wBe liquid holdup and cross section water percentage;

σ _m, σ _wBe respectively oil gas water mixed conductivity and water conductivity;

Because the voltage magnitude between mixed conductivity and internal and external electrode is inversely proportional to, therefore, can calculates the conductivity of fluid-mixing and then obtain cross section water percentage α through measuring the voltage signal between internal and external electrode _wThrough simultaneous formula (11), (12), (16), and then the cross section that obtains oil gas water three phase contains rate α _o, α _w, α _gAnd total volumetric flow rate Q _v, the total mass flow rate, each phase mass rate and each the phase quality that calculate fluid-mixing according to formula (5), (6) contain rate.

Other procedure parameters of polyphasic flow can calculate according to the method among the embodiment 1.

Claims (2)

1. multiphase flow measurement method based on the long waist inner cone of single cross section impedance type sensor; Be used for the multiphase flow measurement that external phase is non-conductive phase; The sensor that adopts comprises segment of cone stream part, contraction pressure drop differential pressure transmitter, permanent crushing differential pressure transmitter; Electricity sensitive sensor, described cone throttling element are a kind of long waist inner cone restriction device, by the leading portion cone, constitute for three sections as stage casing column, the back segment cone of cone waist; Through the coaxial pipeline center of being fixed in of support, form annular free air space with the tube wall of pipeline; Two pressure ports of described contraction pressure drop differential pressure transmitter, one is arranged on cone throttling element upstream end, and another is arranged on annular free air space place or cone afterbody; Two pressure ports of described permanent crushing differential pressure transmitter are separately positioned on recovery place of cone throttling element upstream and downstream pressure; Described electricity sensitive sensor comprises one group of electrode that is distributed in annular free air space and is in pipeline same cross-sectional position; This group electrode is made up of electrode in one or more and one or more external electrode; Interior electrode is cone throttling element itself or the electrode that is fixed on cone waist surface, and external electrode is fixed on inner-walls of duct; When one in the electrode in the gating with external electrode in one during as an electrode pair, two electrodes of this of gating, one is exciting electrode and potential electrode, one is ground-electrode, this measuring method comprises the following steps:

1) gathers two pairs of differential pressure signals that produce by the cone throttling element: shrink pressure drop differential pressure signal Δ p and permanent crushing differential pressure signal δ p;

2) utilize the electricity sensitive sensor to gather electric signal;

3), obtain total mass flow rate, each phase mass rate, each phase quality and contain the relational expression between rate and the phase content according to two differential pressure models of following single throttling element:

A. according to formula $W_{\mathrm{Mtp}1}=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\sqrt{2\mathrm{\&Delta;\; p}{\mathrm{\&rho;}}_g}$ With $W_{\mathrm{Mtp}2}=\frac{\mathrm{\&epsiv;}{C}_{2}A}{\sqrt{1-{\mathrm{\&beta;}}^4}}\sqrt{2\mathrm{\&delta;\; p}{\mathrm{\&rho;}}_g},$ Calculate equivalent mass flow W _Mtp1, W _Mtp2, in the formula, ε is an expansibility factor, C ₁For being the efflux coefficient that differential pressure signal calibrates to shrink pressure drop differential pressure signal Δ p, C ₂For being the efflux coefficient that differential pressure signal calibrates with permanent crushing differential pressure signal δ p, A ₀Be the circulation area of annular free air space, A is the pipeline circulation area, and β is the equivalent diameter ratio of flow area, ρ _gBe density of gas phase;

B. with formula

Compare, calculate L-M parameter χ, in the formula,

Be two-phase flow multiplier, W _MgBe gas phase mass flow, a ₁, b ₁, a ₂, b ₂Be the rating test parameter;

C. according to formula

Obtain that the gas phase quality contains rate x, the liquid phase quality contains rate 1-x and cross section oil content α _o, cross section water percentage α _w, void fraction α _gBetween relational expression, in the formula,

Be two-phase flow multiplier, ρ _gBe density of gas phase, ρ ₁Be density of liquid phase,

α _oBe cross section oil content, α _wBe cross section water percentage, α _gBe void fraction, ρ _oBe oil phase density, ρ _wBe water density;

D. according to formula $\begin{array}{c}{W}_{\mathrm{Mg}}=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\sqrt{2\mathrm{\&Delta;\; p}{\mathrm{\&rho;}}_g}}{a_1\frac{1-x}{x}\sqrt{{\mathrm{\&rho;}}_g/{\mathrm{\&rho;}}_l}+b_1}\\ W_{\mathrm{Ml}}=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\sqrt{2\mathrm{\&Delta;\; p}{\mathrm{\&rho;}}_g}}{a_1\sqrt{{\mathrm{\&rho;}}_g/{\mathrm{\&rho;}}_l}+b_1\frac{x}{1-x}}\\ W_m=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\sqrt{2\mathrm{\&Delta;\; p}{\mathrm{\&rho;}}_g}}{a_1(1-x)\sqrt{{\mathrm{\&rho;}}_g/{\mathrm{\&rho;}}_l}+b_{1}x}\end{array}$ Calculate gas phase mass flow W _Mg, liquid phase mass rate W _M1, total mass flow rate W _mWith cross section oil content α _o, cross section water percentage α _w, void fraction α _gBetween relational expression;

4) calculate the procedure parameter of oil-gas-water three-phase flow according to following computation model:

A. the voltage signal of gathering according to the electricity sensitive sensor, the DIELECTRIC CONSTANTS of calculating fluid-mixing _m

B. in the polyphasic flow with cross section oil content α _oCross section water percentage α _w, void fraction α _gEquivalence contains rate, known oil phase DIELECTRIC CONSTANTS for the volume of Oil, Water, Gas respectively _o, the water DIELECTRIC CONSTANTS _wAnd gas phase DIELECTRIC CONSTANTS _g, according to formula

$\sqrt{{\mathrm{\&epsiv;}}_m}={\mathrm{\&phi;}}_g\sqrt{{\mathrm{\&epsiv;}}_g}+(1-{\mathrm{\&phi;}}_g)({\mathrm{\&phi;}}_w\sqrt{{\mathrm{\&epsiv;}}_w}+{\mathrm{\&phi;}}_o\sqrt{{\mathrm{\&epsiv;}}_o}),{\mathrm{\&alpha;}}_o{\mathrm{\&rho;}}_o+{\mathrm{\&alpha;}}_w{\mathrm{\&rho;}}_w+{\mathrm{\&alpha;}}_g{\mathrm{\&rho;}}_g=\frac{W_m^2(1-{\mathrm{\&beta;}}^4)}{2{(\mathrm{\&epsiv;}\&CenterDot;C_1{A}_0)}^2\mathrm{\&Delta;\; p}}$ With

φ _o+ φ _w+ φ _g=1 calculates the oil phase volume contains rate φ _o, the water volume contains rate φ _wContain rate φ with gaseous phase volume _g, ρ in the formula _o, ρ _w, ρ _gBe oil phase density, water density, density of gas phase;

C. will go up the c step that each phase cross section of obtaining of step contains rate substitution step 3) goes on foot determined two relational expressions with d, and calculating total mass flow rate, each phase mass rate and each phase quality contain rate;

D. according to formula

Calculate the total volumetric flow rate Q of fluid-mixing _v, in the formula, ρ _mBe the fluid hybrid density;

E. according to formula $\begin{array}{c}{Q}_{\mathrm{Vo}}={\mathrm{\&phi;}}_o{Q}_v\\ Q_{\mathrm{Vw}}={\mathrm{\&phi;}}_w{Q}_v\\ Q_{\mathrm{Vg}}={\mathrm{\&phi;}}_g{Q}_v\end{array}$ Calculate the oil phase volume flow Q _Vo, the water volume flow Q _VwWith gas phase volume flow rate Q _Vg

F. according to formula $\begin{array}{c}{V}_o=\frac{Q_{\mathrm{Vo}}}{{\mathrm{\&alpha;}}_o{A}_0}\\ V_w=\frac{Q_{\mathrm{Vw}}}{{\mathrm{\&alpha;}}_w{A}_0}\\ V_g=\frac{Q_{\mathrm{Vg}}}{{\mathrm{\&alpha;}}_g{A}_0}\end{array}$ Calculate oil phase flow velocity V _o, aqueous phase flow rate V _wWith gas phase flow velocity V _g, in the formula, A ₀Be the circulation area of annular free air space, α _oBe cross section oil content, α _wBe cross section water percentage, α _gBe void fraction.

2. multiphase flow measurement method based on the long waist inner cone of single cross section impedance type sensor; Be used for the multiphase flow measurement that external phase is conductive phase; The sensor that adopts comprises segment of cone stream part, contraction pressure drop differential pressure transmitter, permanent crushing differential pressure transmitter; Electricity sensitive sensor, described cone throttling element are a kind of long waist inner cone restriction device, by the leading portion cone, constitute for three sections as stage casing column, the back segment cone of cone waist; Through the coaxial pipeline center of being fixed in of support, form annular free air space with the tube wall of pipeline; Two pressure ports of described contraction pressure drop differential pressure transmitter, one is arranged on cone throttling element upstream end, and another is arranged on annular free air space place or cone afterbody; Two pressure ports of described permanent crushing differential pressure transmitter are separately positioned on recovery place of cone throttling element upstream and downstream pressure; Described electricity sensitive sensor comprises one group of electrode that is distributed in annular free air space and is in pipeline same cross-sectional position; This group electrode is made up of electrode in one or more and one or more external electrode; Interior electrode is cone throttling element itself or the electrode that is fixed on cone waist surface, and external electrode is fixed on inner-walls of duct; When one in the electrode in the gating with external electrode in one during as an electrode pair, two electrodes of this of gating, one is exciting electrode and potential electrode, one is ground-electrode, this measuring method comprises the following steps:

1) gathers two pairs of differential pressure signals that produce by the cone throttling element: shrink pressure drop differential pressure signal Δ p and permanent crushing differential pressure signal δ p;

2) utilize the electricity sensitive sensor to gather electric signal;

3), obtain total mass flow rate, each phase mass rate, each phase quality and contain the relational expression between rate and the phase content according to two differential pressure models of following single throttling element:

A. according to formula $W_{\mathrm{Mtp}1}=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\sqrt{2\mathrm{\&Delta;\; p}{\mathrm{\&rho;}}_g}$ With $W_{\mathrm{Mtp}2}=\frac{\mathrm{\&epsiv;}{C}_{2}A}{\sqrt{1-{\mathrm{\&beta;}}^4}}\sqrt{2\mathrm{\&delta;\; p}{\mathrm{\&rho;}}_g},$ Calculate equivalent mass flow W _Mtp1, W _Mtp2, in the formula, ε is an expansibility factor, C ₁For shrinking pressure drop Δ p is efflux coefficient, the C that differential pressure signal calibrates ₂For permanent crushing δ p is the efflux coefficient that differential pressure signal calibrates, A ₀Be the circulation area of annular free air space, A is the pipeline circulation area, and β is the equivalent diameter ratio of flow area, ρ _gBe density of gas phase;

B. with formula

Compare, calculate L-M parameter χ, in the formula,

Be two-phase flow multiplier, W _MgBe gas phase mass flow, a ₁, b ₁, a ₂, b ₂Be the rating test parameter;

C. according to formula

Obtain that the gas phase quality contains rate x, the liquid phase quality contains rate 1-x and cross section oil content α _oCross section water percentage α _w, void fraction α _gBetween relational expression, in the formula,

Be two-phase flow multiplier, ρ _gBe density of gas phase, ρ ₁Be density of liquid phase,

α _oBe cross section oil content, α _wBe cross section water percentage, α _gBe void fraction, ρ _oBe oil phase density, ρ _wBe water density;

D. according to formula $\begin{array}{c}{W}_{\mathrm{Mg}}=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\sqrt{2\mathrm{\&Delta;}{\mathrm{P\&rho;}}_g}}{a_1\frac{1-x}{x}\sqrt{{\mathrm{\&rho;}}_g/{\mathrm{\&rho;}}_l}+b_1}\\ W_{\mathrm{Ml}}=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\sqrt{2\mathrm{\&Delta;\; p}{\mathrm{\&rho;}}_g}}{a_1\sqrt{{\mathrm{\&rho;}}_g/{\mathrm{\&rho;}}_l}+b_1\frac{x}{1-x}}\\ W_m=\frac{\mathrm{\&epsiv;}{C}_1{A}_0}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\sqrt{2\mathrm{\&Delta;\; p}{\mathrm{\&rho;}}_g}}{a_1(1-x)\sqrt{{\mathrm{\&rho;}}_g/{\mathrm{\&rho;}}_l}+b_{1}x}\end{array}$ Calculate gas phase mass flow W _g, liquid phase mass rate W _l, total mass flow rate W _mWith cross section oil content α _o, cross section water percentage α _w, void fraction α _gBetween relational expression;

4) calculate the procedure parameter of oil-gas-water three-phase flow according to following computation model:

A. the voltage signal of gathering according to the electricity sensitive sensor, the conductivity of calculating fluid-mixing _m

B. known water conductivity _w, according to formula

α _l+ α _g=1 draw

Calculate cross section oil content α _o, cross section water percentage α _wWith void fraction α _g, in the formula, σ _mBe profit gas mixed conductivity;

C. will go up the c step that each phase cross section of obtaining of step contains rate substitution step 3) goes on foot determined two relational expressions with d, and calculating total mass flow rate, each phase mass rate and each phase quality contain rate;

D. according to formula

Calculate the total volumetric flow rate Q of fluid-mixing _v, in the formula, ρ _mBe the fluid hybrid density;

E. according to formula $\begin{array}{c}{Q}_{\mathrm{Vo}}={\mathrm{\&alpha;}}_o{Q}_v\\ Q_{\mathrm{Vw}}={\mathrm{\&alpha;}}_w{Q}_v\\ Q_{\mathrm{Vg}}={\mathrm{\&alpha;}}_g{Q}_v\end{array}$ Calculate the oil phase volume flow Q _Vo, the water volume flow Q _VwWith gas phase volume flow rate Q _Vg

F. according to formula $\begin{array}{c}{V}_o=\frac{Q_{\mathrm{Vo}}}{{\mathrm{\&alpha;}}_o{A}_0}\\ V_w=\frac{Q_{\mathrm{Vw}}}{{\mathrm{\&alpha;}}_w{A}_0}\\ V_g=\frac{Q_{\mathrm{Vg}}}{{\mathrm{\&alpha;}}_g{A}_0}\end{array}$ Calculate oil and calculate oil phase flow velocity V _o, aqueous phase flow rate V _wWith gas phase flow velocity V _g

Images