CN110596417A - Wind speed on-line monitoring method - Google Patents
Wind speed on-line monitoring method Download PDFInfo
- Publication number
- CN110596417A CN110596417A CN201910770159.4A CN201910770159A CN110596417A CN 110596417 A CN110596417 A CN 110596417A CN 201910770159 A CN201910770159 A CN 201910770159A CN 110596417 A CN110596417 A CN 110596417A
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- Prior art keywords
- pressure
- vortex
- pipeline
- wind speed
- cleaning
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
- G01F1/32—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
- G01F15/12—Cleaning arrangements; Filters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/01—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by using swirlflowmeter
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Measuring Volume Flow (AREA)
Abstract
The invention relates to an on-line wind speed monitoring method, which comprises the following steps: introducing a vortex signal into a pressure-inducing pipeline, wherein the vortex signal is vibration or local pressure change generated by a vortex generating body; introducing cleaning gas which is opposite to the vortex signal generated in the pressure-inducing pipeline; the vortex signal detection device receives signals generated by the vortex generating body, calculates the release frequency of the vortex and further obtains the wind speed of the wind channel. When the wind speed of the air channel is measured, cleaning air flow is added in the pressure guide pipeline, the cleaning air flow is introduced from the high-pressure air source inlet, and the high-pressure air flow is reduced to proper flow through the pressure reducing valve. The synchronous operation of measurement and cleaning can be realized; the problem of the pressure pipeline anti-blocking effect that leads to of current monitoring method is poor is solved.
Description
Technical Field
The invention relates to the technical field of primary and secondary wind monitoring of power plants, in particular to an online wind speed monitoring method.
Background
The primary air and secondary air on-line monitoring of a power plant is important monitoring equipment for optimizing combustion and reducing energy consumption of a boiler, and most of the primary air and secondary air on-line measuring devices in the prior art adopt a differential pressure type (also called throttling type) measuring mode, and flow measurement is realized by utilizing pressure difference generated when fluid flows through a throttling device.
Because the primary air pipe and the secondary air pipe contain a large amount of coal powder, the differential pressure type measurement mode is difficult to block by dust. The current methods for solving dust blockage mainly comprise 2 methods: 1) and an intermittent cleaning mode, namely, cleaning is not carried out during normal measurement, and a timing mode is adopted to disconnect the measurement gas path and connect the measurement gas path into cleaning gas flow. Although the intermittent cleaning mode can realize larger cleaning airflow, the cleaning cannot be carried out during the measurement, the measurement must be stopped during the cleaning, meanwhile, control equipment such as an electromagnetic valve and the like also needs to be added, and the cleaning frequency is higher; 2) adopt self-oscillation ash removal device, increase multisection thin metal chain in getting the pressure pipe, thereby utilize multisection thin metal chain to constantly strike along with the swing of wind speed and get the pressure pipe and reach abluent purpose, nevertheless this cleaning performance receives the wind speed restriction, and cleaning performance can worsen gradually along with time lapse, can't guarantee cleaning performance when the dust is great, and blocking phenomenon still exists.
Disclosure of Invention
The invention aims to provide an online wind speed monitoring method, which is used for solving the problem of poor anti-blocking effect of a pressure-leading pipeline caused by the existing monitoring method.
In order to solve the technical problems, the technical scheme of the invention is as follows:
the invention provides an online wind speed monitoring method, which comprises the following steps:
1) introducing a vortex signal into a pressure-inducing pipeline, wherein the vortex signal is vibration or local pressure change generated by a vortex generating body;
2) introducing cleaning gas which is opposite to the vortex signal generated in the pressure-inducing pipeline;
3) the vortex signal detection device receives signals generated by the vortex generating body, calculates the release frequency of the vortex and further obtains the wind speed of the wind channel.
The invention has the beneficial effects that:
the method is characterized in that cleaning airflow is added in the pressure guiding pipeline while the air speed of the air duct is measured, the cleaning airflow can prevent dust from entering the pressure guiding pipeline, and the flowing of the cleaning airflow does not influence the propagation of sound waves, so that the measurement is not influenced; thereby realizing the synchronous operation of measurement and cleaning; the problem of the pressure pipeline anti-blocking effect that leads to of current monitoring method is poor is solved.
Furthermore, the method also comprises the step of adjusting the pressure of the cleaning gas at the other end of the pressure guiding pipeline according to the pressure of the air channel to be detected at one end of the pressure guiding pipeline, so that the pressures at the two ends of the pressure guiding pipeline are equal; the accuracy of detecting the vortex signal is improved.
Further, the vortex signal detection device is an electret and is used for collecting vortex signals.
Drawings
FIG. 1 is a flow chart of an online wind speed monitoring method according to the present invention;
FIG. 2 is a schematic diagram of an apparatus according to a first embodiment of the present invention;
FIG. 3 is a schematic view of an apparatus according to a second embodiment of the method of the present invention;
FIG. 4 is a schematic view of an apparatus according to a third embodiment of the method of the present invention;
in the figure: 1-vortex generating body, 2-pressure leading pipeline, 3-electret, 4-pressure regulating valve, 101-vortex generating body, 102-first pressure leading pipeline, 103-second pressure leading pipeline, 104-bidirectional electret, 105-pressure regulating valve, 106-isolating layer, 201-vortex generating body, 202-pressure leading pipeline, 203-electret and 204-pressure regulating valve.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.
The basic principle of the invention is as follows:
increase the washing air current in drawing the pressure pipeline when measuring the wind speed in wind channel according to the vortex street principle, the washing air current is introduced by the washing branch road and is drawn the pressure pipeline, and the washing air current can block the dust and get into and draw the pressure pipeline to prevent to draw the pressure pipeline by the dust jam, solved current monitoring devices and lead to drawing the problem of pressing the pipe jam when carrying out the wind speed monitoring. The method provided by the invention mainly monitors primary air and secondary air of the power plant, wherein the primary air refers to the part of air which conveys pulverized coal into a hearth through a pipeline, and the primary air has the function of maintaining a certain concentration of air-powder mixture so as to be convenient for transportation and provide enough oxygen for fuel in the initial combustion stage. The secondary air refers to hot air which is sent into a hearth through a single channel of the burner and is gradually mixed with the primary air after entering the hearth. The secondary air provides oxygen for the combustion of carbon, can strengthen the disturbance of airflow, promotes the backflow of high-temperature flue gas and the mixing of combustible and oxygen, and provides conditions for complete combustion. A large amount of dust is carried in the primary air and the secondary air, so that the problem that the dust blocks a detection pipeline is considered when the wind speed is detected.
The basic flow of the invention is as shown in fig. 1, a vortex signal is introduced into a pressure-inducing pipeline, and the vortex signal is vibration or local pressure change generated by a vortex column generated by a vortex generating body; the cleaning gas which generates convection phenomenon with the vortex signal is introduced into the pressure-inducing pipeline, the vortex signal detection device receives the signal generated by the vortex generating body, the release frequency of the vortex is calculated, and the air speed of the air channel is further obtained.
When the wind speed of the air channel is measured, cleaning airflow is introduced in the opposite direction in the pressure introduction pipeline, the cleaning airflow is introduced from the high-pressure air source inlet, and the high-pressure airflow is reduced to the proper flow through the pressure reducing valve.
The key point of the invention is that the vortex signal is introduced into the pressure-leading pipeline, and the cleaning gas which generates convection with the vortex signal is introduced into the pressure-leading pipeline, and the cleaning gas prevents dust from entering the pressure-leading pipeline or blows out the dust entering the pressure-leading pipeline, so that the dust in an air duct is reduced or even isolated from entering the pressure-leading pipeline, and the blockage of the pressure-leading pipeline is avoided.
The first embodiment of the method of the invention:
the wind speed on-line monitoring device suitable for the embodiment is shown in fig. 2, and comprises a probe air duct, so that the probe air duct is generally consistent with the extending direction of an air duct to be measured in order to facilitate measurement. The vortex generating body 1 is arranged in the probe air channel, a pressure guide pipeline 2 is arranged on the downstream of the vortex generating body 1 and the probe air channel, the pressure guide pipeline 2 is connected with an electret 3 (namely a vortex signal detection element), the tail end of the pressure guide pipeline is connected with a cleaning branch, and a pressure regulating valve 4 is arranged on the cleaning branch.
When monitoring is carried out, according to the principle of karman vortex street generation, vortex rows with certain frequency are generated at the downstream of the vortex generating body 1, when vortices are generated, pressure near the vortices changes, the pressure guiding pipeline 2 transmits the pressure change caused by the vortex rows to the electret 3, the electret 3 is connected with a signal processing module (not shown in the figure, a computer is adopted in the embodiment), the signal processing module acquires the collected signals, and the frequency of the vortex rows, namely the release frequency of the vortices is obtained according to the signal waveform. The inlet end of the pressure regulating valve 4 is introduced with cleaning air flow, and the high-pressure cleaning air flow is reduced to a proper flow rate through the pressure regulating valve 4.
The purpose of the pressure regulating valve 4 is to conveniently regulate the pressure and flow of the purge gas stream without having to be regulated on the source side.
For adjusting the flow rate of the pressure regulating valve 4, different ways can be used depending on the form of the pressure regulating valve 4. For example, for a manual pressure regulating valve, a manual regulation mode can be adopted; for an electrically controlled pressure regulating valve, such as an electromagnetic valve, automatic control can be realized by using a control system, and the realization mode comprises the following steps: the pressure regulating valve 4 is controlled by an outlet end control connection pressure regulating valve 4 of a processor (not shown in the figure, such as an MCU).
The advantage of adopting automatic control lies in that, can also set up pressure sensor in the probe wind channel, detect the pressure in probe wind channel, then according to probe wind channel pressure control above-mentioned pressure-regulating valve 4, produce the purge air current, the pressure that is equal basically in the exit end of pressure-regulating valve 4 and the pressure pipeline entry end (the wind channel that awaits measuring) of vortex generating body 1, draw pressure pipeline 2 and be in the constant voltage state promptly, this constant voltage state can not have the influence to the transmission of vortex signal, therefore the transmission of vortex signal and purge air current can be in parallel in drawing pressure pipeline 2 simultaneously, can realize measuring and abluent synchronization going on. For example, assuming that the pressure formed when the vortex is generated is Δ P, when there is no pressure in the pipeline (i.e. when there is no purge gas flow), the pressure of the vortex passing region in the pipeline is still Δ P, and is still maintained after being transferred to the outlet; when a certain pressure P is applied to the pipeline (namely when cleaning airflow exists), when the vortex is transmitted in the pipeline, the pressure of a vortex passing area is P +. DELTA.P, when the pressure is detected to be P +. DELTA.P-P when the pressure is transmitted to the outlet, the pressure DELTA P generated by the vortex is still maintained, so that whether the cleaning airflow is added in the pipeline or not has no influence on the detection of the vortex.
When the release frequency f of the vortex is obtained, the frequency is calculated according to the following formula:
wherein f is the release frequency of the vortex in Hz; v is the average velocity of the fluid flowing through the vortex generator 1 in m/s; d is the characteristic width of the vortex generator 1, and the unit is m; stIs a strouhal number, dimensionless, related to the reynolds number Re, generally having a value in the range of 0.14 to 0.27; when Reynolds number Re is 102To 105Inner, stAbout 0.2.
The average velocity v of the fluid flowing through the vortex generator 1 can be obtained from the above equation:
q＝vA
the flow rate q is determined, where A is the cross-sectional area of the fluid flowing through the vortex generator 1.
As another embodiment, when the pressure line cannot be ensured to be in a constant pressure state, the detection of the vortex signal can still be realized, and therefore, it is also possible to manually control the pressure regulating valve 4.
Embodiment two of the method of the invention:
the difference between the second embodiment and the first embodiment is that the device in the second embodiment adopts two pressure-guiding pipelines. When only one pressure leading pipeline is adopted, the waveform of the signal detected by the electret is poor. Therefore, two pressure leading pipelines which are symmetrically arranged relative to the electret are adopted. When two pressure leading pipelines are adopted, the electrets cannot seal up the whole space, so that the electrets are communicated up and down, and the detected signal effect can be enhanced. The signals transmitted by the two pressure leading pipelines are alternated, because the vortex generated by the vortex generating body is alternated, and the vortex is generated to the two pressure leading pipelines alternately.
The device suitable for the method of the embodiment is shown in fig. 3, a first pressure-leading pipeline 102 and a second pressure-leading pipeline 103 are symmetrically arranged on the wall of the probe air channel at the downstream of the vortex generating body 101, a first branch of the first pressure-leading pipeline 102 is connected with a first opening end of a bidirectional electret 104, a first branch of the second pressure-leading pipeline 103 is connected with a second opening end of the bidirectional electret 104, and an isolation layer 106 is arranged in the middle of the bidirectional electret 104, so that signals detected by the two opening ends can be prevented from interfering with each other, and the reliability of a detection result can be improved; the signal processing module collects pressure signals received by the bidirectional electret 104. The second branches (two cleaning branches) of the first pressure guiding pipeline 102 and the second pressure guiding pipeline 103 are converged into one branch (cleaning main) to be connected with the outlet end of the pressure regulating valve 105, and cleaning gas is introduced into the inlet end of the pressure regulating valve 105. The processor controls the connection pressure regulating valve 105 and controls the pressure regulating valve 105.
The bidirectional electret collects a first vortex signal transmitted by the first pressure leading pipeline 102 through the first opening end, collects a second vortex signal transmitted by the second pressure leading pipeline 103 through the second opening end, converts the release frequency of the vortex into an electric signal through the detection element, and obtains the specific analysis and calculation mode of the wind speed according to the release frequency calculation, which is the same as that in the first embodiment and is not repeated herein.
Embodiment three of the method of the present invention:
the difference between the present embodiment and the first embodiment is that in the first embodiment, the cleaning pipeline is connected to the end of the pressure-inducing pipeline; in the embodiment, the cleaning pipeline is connected between the inlet end of the pressure-inducing pipeline and the vortex signal detection element. That is, if the direction of the solid arrow in fig. 2 is defined as the downstream direction, the cleaning line is upstream of the electret in the present embodiment. In one embodiment, the purge line is downstream of the electret.
As shown in fig. 4, a vortex generator 201 is disposed in the probe air duct, a pressure-leading pipeline 202 is disposed on the probe air duct downstream of the vortex generator 201, the pressure-leading pipeline 202 has two branches, a first branch is connected to an electret 203, and a second branch is connected to an outlet end (i.e., a cleaning branch) of a pressure-regulating valve 204. The gas entering the pressure leading pipeline is dedusted by the cleaning branch and then detected by the electret. The processor is also provided with a pressure regulating valve 204 which is controlled and connected by the processor and controls the pressure regulating valve 204.
The specific detection process and the specific signal analysis and calculation method are the same as those in the first embodiment, and are not described again.
This embodiment has adopted a pressure pipeline of drawing, then will wash the pipeline setting in electret 203's downstream, and like the same, when adopting two pressure pipelines of drawing, also can set up the washing pipeline in the upstream of electret. That is, the cleaning line in the second embodiment may be disposed upstream of the electret 104 on the basis of the second embodiment.
As other embodiments, a throat structure (namely a device for reducing the inner diameter of the pipeline arranged at the connection part in the figure) is added at the connection part of the electret and the pressure-leading pipeline, so that the influence of noise on vortex signal measurement can be effectively eliminated, and the accuracy of the device is improved.
In the above embodiment, the vortex signal detecting element is an electret. As other embodiments, other detection devices known to those skilled in the art may be used for detection.
The method provided by the invention can be realized by the device in the embodiment to detect the wind speed of the primary wind and the secondary wind.
Claims (3)
1. An online wind speed monitoring method is characterized by comprising the following steps:
1) introducing a vortex signal into a pressure-inducing pipeline, wherein the vortex signal is vibration or local pressure change generated by a vortex generating body;
2) introducing cleaning gas which is opposite to the vortex signal generated in the pressure-inducing pipeline;
3) the vortex signal detection device receives signals generated by the vortex generating body, calculates the release frequency of the vortex and further obtains the wind speed of the wind channel.
2. The on-line wind speed monitoring method according to claim 1, further comprising adjusting the pressure of the cleaning gas at the other end of the pressure-leading pipeline according to the pressure of the air duct to be tested at one end of the pressure-leading pipeline, so that the pressures at the two ends of the pressure-leading pipeline are equal.
3. The on-line wind speed monitoring method according to claim 1 or 2, wherein the vortex signal detection device comprises an electret.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910770159.4A CN110596417A (en) | 2019-08-20 | 2019-08-20 | Wind speed on-line monitoring method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910770159.4A CN110596417A (en) | 2019-08-20 | 2019-08-20 | Wind speed on-line monitoring method |
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| CN110596417A true CN110596417A (en) | 2019-12-20 |
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| CN201910770159.4A Withdrawn CN110596417A (en) | 2019-08-20 | 2019-08-20 | Wind speed on-line monitoring method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113714518A (en) * | 2021-08-30 | 2021-11-30 | 威斯坦(厦门)实业有限公司 | High-temperature smoke and dust discharge system for 3D printer |
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| CN1673689A (en) * | 2005-04-22 | 2005-09-28 | 浙江大学 | Pipe wall differential pressure type vortex frequency detecting method and apparatus for vortex street flowmeter |
| CN201508201U (en) * | 2009-09-21 | 2010-06-16 | 北京菲波安乐仪表有限公司 | Differential pressure detection type vortex street flowmeter for measuring differential pressure on one-sided pipe wall |
| CN102252715A (en) * | 2011-04-15 | 2011-11-23 | 王荣虎 | Europa sensor and flow measurement control system |
| US20160222941A1 (en) * | 2015-01-30 | 2016-08-04 | General Electric Company | Vortex generator for a rotor blade |
| CN109580982A (en) * | 2018-11-22 | 2019-04-05 | 国网天津市电力公司电力科学研究院 | A kind of fired power generating unit band powder air-flow block-proof type speed-measuring method |
-
2019
- 2019-08-20 CN CN201910770159.4A patent/CN110596417A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1673689A (en) * | 2005-04-22 | 2005-09-28 | 浙江大学 | Pipe wall differential pressure type vortex frequency detecting method and apparatus for vortex street flowmeter |
| CN201508201U (en) * | 2009-09-21 | 2010-06-16 | 北京菲波安乐仪表有限公司 | Differential pressure detection type vortex street flowmeter for measuring differential pressure on one-sided pipe wall |
| CN102252715A (en) * | 2011-04-15 | 2011-11-23 | 王荣虎 | Europa sensor and flow measurement control system |
| US20160222941A1 (en) * | 2015-01-30 | 2016-08-04 | General Electric Company | Vortex generator for a rotor blade |
| CN109580982A (en) * | 2018-11-22 | 2019-04-05 | 国网天津市电力公司电力科学研究院 | A kind of fired power generating unit band powder air-flow block-proof type speed-measuring method |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113714518A (en) * | 2021-08-30 | 2021-11-30 | 威斯坦(厦门)实业有限公司 | High-temperature smoke and dust discharge system for 3D printer |
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Application publication date: 20191220 |