JP4625306B2 - Fluid machinery performance diagnostic apparatus and system - Google Patents

Description

  The present invention relates to a fluid machine performance diagnosis apparatus and system for diagnosing the performance of fluid machines such as various fans, compressors, and pumps that pump fluid.

  Conventionally, various data necessary for diagnosing the performance of the pump are measured at the same time as various data necessary for diagnosing the performance of the pump are collected at the same time so that the performance diagnosis of the pump can be easily performed. Measuring instrument with measuring terminal mounted at the required position (suction pressure detector, discharge pressure detector, shaft seal thermometer, pump body bearing thermometer, motor side bearing thermometer, pump body bearing horizontal direction Vibration meter, pump body side bearing part vertical vibration meter, motor side bearing part horizontal vibration meter, motor side bearing part vertical vibration meter, axial vibration meter, flow meter, and monitoring camera) and these measuring instruments There has been proposed one having a performance diagnosis recorder that collects measurement data and stores the collected data for an arbitrarily set time (for example, Patent Document 1).

JP 2003-166477 A (Summary and FIG. 1)

The conventional one simply records the measured data, displays it in a graph, and further analysis is necessary for the engineer to diagnose the performance of the device.
And it mainly measures vibration at each place, and there is a problem that it is difficult to grasp the deterioration of the performance itself due to the corrosion and deterioration of the impeller and impeller.

  The present invention has been proposed to solve such a problem, and provides a fluid machine performance diagnosis apparatus or a fluid machine performance diagnosis system capable of easily evaluating the degree of deterioration of a fluid machine. The purpose is to do.

  The present invention has been made in order to solve the above-described conventional problems, and each of the inventions described in the claims is as a fluid machine performance diagnosis device and system described in (1) to (4) below. Each means described is adopted.

  (1) The fluid machine performance diagnosis apparatus according to the first means is characterized in that the characteristics are made dimensionless for each of a plurality of fluid control amounts from the compression ratio or pressure difference of the fluid machine and the inlet flow rate. An expected performance curve calculator for obtaining a curve indicating the relationship and a measured performance head from the fluid control amount, suction pressure, discharge pressure, suction temperature, compression coefficient, gas average molecular weight, specific heat ratio during operation of the fluid machine, A performance diagnosis computing unit is provided that obtains a predicted performance head from a predicted performance curve, a fluid control amount, and an inlet flow rate, and calculates a performance deterioration degree from a ratio between the predicted performance head and the actually measured performance head.

(2) In the fluid machine performance diagnostic apparatus according to the second means, in the first means, the actually measured performance head is configured such that the suction pressure is Ps, the discharge pressure is Pd, the suction temperature is Ts, the compression coefficient is Z, and the gas When the average molecular weight is Mw, the specific heat ratio is k, and β = (k−1) / k, the actually measured performance head H _real is expressed by the following equation:
H _real = Z · 1 / β · Ts / Mw · {(Pd / Ps) ^β -1}
It is what is calculated | required by.

  (3) The fluid machine performance diagnostic apparatus according to the third means includes a performance change rate calculator that, in the first or second means, calculates the performance deterioration degree change rate by differentiating the performance deterioration degree. It is characterized by that.

  (4) The fluid machine performance diagnosis system according to the fourth means measures or calculates a suction pressure, a discharge pressure, a suction temperature, a compression coefficient, a gas average molecular weight, and a specific heat ratio during operation of the fluid machine, and outputs the data. A monitoring device that stores the data, and a central monitoring computer that receives the data stored in the monitoring device via a network, wherein the central monitoring computer is described in any one of the first, second, and third means. A fluid machine performance diagnostic device is provided.

  Since the invention according to each claim described in the claims employs the means described in (1) to (4) above, it is possible to evaluate the performance deterioration of the device very easily. become.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic diagram of a plant in which a fluid machine performance diagnosis apparatus according to an embodiment of the present invention is employed. FIG. 2 is a circuit configuration diagram of the fluid machine performance diagnosis apparatus according to the embodiment of the present invention. FIG. 3 is a calculation block diagram of the fluid machine performance diagnosis apparatus according to the embodiment of the present invention, FIG. 4 is an example of a display graph by the fluid machine performance diagnosis apparatus according to the embodiment of the present invention, and FIG. It is a figure which shows the basic principle of evaluation of the performance diagnostic apparatus of the fluid machine which concerns on embodiment of this invention.

First, the basic principle of the evaluation of the fluid machine performance diagnostic apparatus according to the embodiment of the present invention will be described.
In the embodiment of the present invention, the basic principle is to make the design performance (or predicted performance) and the measured performance characteristics dimensionless, and compare and evaluate the characteristics.
Furthermore, the change rate (deterioration rate) of actually measured performance is also calculated so that the evaluation can be performed more easily.

That is, the head, which is the work amount per unit flow rate effectively used for increasing the pressure of a compressor or the like, is used as a parameter for performance evaluation.
The head (that is, the predicted performance head H _pred ) under conditions such as a predetermined suction temperature, a specific heat ratio, and a fluid constant can be calculated by the following equation (1).
Formula (1) Expected performance head: H _pred = f _p (N, Qs)
In the above equation, N is the number of rotations as a fluid control amount of a compressor or the like, and Qs is an inlet volume flow rate.

In this case, the relationship between the predicted performance head H _pred and the inlet volume flow rate Qs in the compressor is predicted as the inlet volume flow rate Qs increases at a plurality of fluid control amounts, that is, at each rotational speed, as shown in FIG. The performance head H _pred becomes a decreasing curve.
Note that the expected performance head H _pred increases as the rotational speed N increases to N ₀₁ , N ₀₂ , and N ₀₃ .

Note that the head (that is, the actually measured performance head H _real ) that is the work amount per unit flow rate under conditions such as a predetermined suction temperature and gas physical properties can be calculated by the following equation (2).
Formula (2) Measured performance head: H _real = f _r (Ps, Pd, Ts)
In the above equation, Ps is the suction pressure, Pd is the discharge pressure, and Ts is the suction temperature.

Then, based on the predicted performance head H _pred , the rotation speed N, and the inlet volume flow rate Qs, the dimensionless pressure coefficient μ and flow coefficient φ are calculated by the following formulas (3) and (4) to form a database. .
Formula (3) Pressure coefficient: μ = 2 g · H _pred / u ² = K ₁ · (H _pred / N ² )
Formula (4) Flow coefficient: φ = Qs / (60π · D · b · u) = K ₂ · (Qs / N)
Here, u is the circumferential speed of the impeller of the compressor, D is the outer diameter of the impeller, b is the width of the exit of the impeller, and K ₁ and K ₂ are constants.

At this time, the relationship between the pressure coefficient μ and the flow coefficient φ is a curve in which the pressure coefficient μ decreases after increasing as the flow coefficient φ increases as shown in FIG. 5B.
The database stores a curve indicating the relationship between the pressure coefficient μ and the flow coefficient φ for each of a plurality of fluid control amounts, that is, the rotation speeds N ₀₁ , N ₀₂ , and N ₀₃ .

  Then, the following calculation is performed based on the actually measured actual rotational speed Nx, discharge pressure Pd, suction pressure Ps, suction temperature Ts, inlet volume flow rate Qx, compression coefficient Z, gas average molecular weight Mw, and specific heat ratio k.

First, a curve indicating the relationship between the pressure coefficient μ and the flow coefficient φ at the actual rotational speed Nx is linearly interpolated by the following equations (5) and (6) as shown by the dotted line in FIG. Is estimated.
Formula (5) Pressure coefficient: μ = {f ₁ (N ₀₂ , φ) −f ₁ (N ₀₁ , φ)} / (N ₀₂ −N ₀₁ ) · (N−N ₀₁ ) + f ₁ (N ₀₁ , φ )
Formula (6) Flow rate coefficient: φ = {f ₂ (N ₀₂ , μ) −f ₂ (N ₀₁ , μ)} / (N ₀₂ −N ₀₁ ) · (N−N ₀₁ ) + f ₂ (N ₀₁ , μ )

The pressure coefficient μ and the flow coefficient φ at the actual rotational speed Nx described above are substituted into the formulas (3) and (4) and back-calculated, and the following formulas (7) and (8) are used to calculate FIG. ) _Shows a curve indicating the relationship between the predicted performance head H _pred and the inlet volume flow rate Qs at the actual rotational speed Nx shown by the dotted line.
Formula (7) Expected performance head: H _pred = 1 / K ₁ · Nx ² · μ
Formula (8) Inlet volume flow rate: Qs = 1 / K ₂ · Nx · φ

Then, the actually measured inlet volume flow rate Qx is corrected to the inlet volume flow rate Qx under predetermined conditions based on the actually measured discharge pressure Pd, suction pressure Ps, and suction temperature Ts, and the expected performance head H shown in FIG. _{From the} curve indicating the relationship between _pred and inlet volume flow rate Qs, the expected performance head H _pred x at the actual rotational speed Nx is obtained.

On the other hand, the actually measured performance head _Hreal can be obtained by the following equation (9).
Formula (9) _Hreal = Z · 1 / β · Ts / Mw · {(Pd / Ps) ^β- 1}
However, the compression coefficient is Z, the gas average molecular weight is Mw, k is the specific heat ratio, and β is (k−1) / k).

Then, the head ratio (performance degradation degree) α = measured performance head H _real / predicted performance head H _pred x is calculated from the calculated expected performance head H _pred x and the actually measured performance head H _real, and the equipment is used as the performance degradation degree. Evaluate the performance.
This head ratio (performance degradation degree) α can be quantitatively evaluated in the entire operation region.

Next, an outline of a plant in which the fluid machine performance diagnostic apparatus according to the embodiment of the present invention using the above-described principle is employed will be described with reference to FIG.
A thermal power plant and other various plants are provided with a large number of fluid machines 1a, 1b, and 1c such as various fans, compressors, and pumps.
The case where the fluid machine 1a is a compressor will be described. The compressor 3 is driven by a variable speed turbine 2.
The rotation speed of the turbine 2 is controlled by a governor (not shown), and a tachometer 4 for detecting the actual rotation speed Nx is connected to the turbine 2.

The discharge pipe 9 of the compressor 3 is provided with a discharge-side pressure gauge 5 that detects the discharge pressure Pd.
Further, the suction pipe 10 of the compressor 3 includes a suction side pressure gauge 6 for detecting the suction pressure Ps, a suction side thermometer 7 for detecting the suction temperature Ts of the fluid flowing through the suction pipe 10, and an inlet volume flow rate Qx of the fluid. A flow meter 8 for measurement is also provided.
Then, the actual rotational speed Nx detected by the tachometer 4, the discharge pressure Pd detected by the discharge side pressure gauge 5, the suction pressure Ps detected by the suction side pressure gauge 6, and the suction pressure detected by the suction side thermometer 7 The temperature Ts and the inlet volume flow rate Qx detected by the flow meter 8 are respectively transmitted to the monitoring device 11.

In addition, the physical property value of the fluid flowing in the suction pipe 10 is separately input and stored in the monitoring device 11 or the central monitoring computer 13 or the like.
The actual rotational speed Nx, the discharge pressure Pd, the suction pressure Ps, the suction temperature Ts, the inlet volume flow rate Qs, the gas physical properties (compression coefficient Z, gas average molecular weight Mw, and specific heat ratio k) input to each monitoring device 11 Each measured value for a predetermined period such as) is stored in a storage device in each monitoring device 11 together with the identification code and the measurement date of each fluid machine 1a, 1b, 1c.
Each identification code, measurement date, time, and measurement value stored in the storage device are transmitted to the central monitoring computer 13 through the network 12 periodically or in response to a request from the central monitoring computer 13.

As a method for inputting, calculating, estimating, and storing physical property values, there are the following methods.
As an example 1, the gas composition is periodically measured by a gas analyzer (not shown), and the gas composition is input to the monitoring device 11 or the central monitoring computer 13 (for example, nitrogen in the case of air; 79%, oxygen 21 The gas property values (gas compression coefficient Z, specific heat ratio k, gas average molecular weight Mw) are estimated and stored in the monitoring device 11 or the central monitoring computer 13 from the reference pressure and the reference temperature.
As an example 2, when the gas compression coefficient Z and the specific heat ratio k are almost constant with respect to the variation of the gas composition among the gas property values, the molecular weight of the gas is measured by a gas hydrometer (gas specific gravity with respect to air) (not shown). Only Mw is measured periodically, and only the gas molecular weight is used as fluctuation data.
In Example 3, the gas composition is measured off-line with a gas analyzer (not shown), and the gas property values (gas compression coefficient Z, specific heat ratio k, gas average molecular weight Mw) are estimated using the measured gas property estimation program. These are input to the monitoring device 11 or the central monitoring computer 13 and used.

As shown in FIG. 2, the central monitoring computer 13 includes an operation data collector 20, a shared memory 21, a performance diagnosis calculator 22, various data input devices 23, an expected performance curve calculator 24, a performance diagnosis database 25, a performance A change rate calculator 26, a history database 27, and a display 28 are provided.
Each of these arithmetic units is usually in the form of a computer program or a sequence block, but is not limited to this, and includes those configured by individual electric arithmetic circuit units. .

Next, with reference to FIG. 3, the processing content in each of these arithmetic units will be described.
First, the operation data collector 20 initializes communication (step S01).
The timer counts the time, and periodically sends a data transmission request signal to each monitoring device 11 (step S02).
When the identification codes of the fluid machines 1a, 1b, and 1c, the measurement date and time, and the measurement values for a predetermined period are input from each monitoring device 11 (step S03), the data is stored in the shared memory. 21 is copied (step S04).
Thereafter, the timer is reset and the process returns to the time counting by the timer (step S02).

On the other hand, the capacity, performance, etc. of each fluid machine 1a, 1b, 1c are input from the various data input devices 23 for each identification code.
The input capacity, performance, etc. are made dimensionless by the expected performance curve calculator 24 according to the above formulas (3) and (4), for each predetermined number of revolutions, for example, as shown in FIG. Thus, a curve indicating the relationship between the pressure coefficient μ and the flow coefficient φ of the three rotation speeds N ₀₁ , N ₀₂ and N ₀₃ is obtained.
A curve indicating the relationship between the obtained pressure coefficient μ and flow coefficient φ is stored in the performance diagnosis database 25 together with the identification code of each fluid machine 1a, 1b, 1c and the name of the apparatus.

In the performance diagnosis computing unit 22, first, the performance diagnosis program is initialized (step S11).
Time is counted by a timer (step S12), and periodically measured data of the fluid machine (identification code, measurement date / time, actual rotational speed Nx, discharge pressure Pd, suction pressure Ps, suction temperature Ts, inlet Volume flow rate Qs, compression coefficient Z, gas average molecular weight Mw, specific heat ratio k, etc.) are obtained from shared memory 21 (step S13).
Based on these input data, the actually measured performance head H _real is calculated by the above-described equation (9).

On the other hand, based on the actually measured actual rotational speed Nx, discharge pressure Pd, suction pressure Ps, suction temperature Ts, inlet volume flow rate Qx, compression coefficient Z, gas average molecular weight Mw, and specific heat ratio k, the above formulas (5) to ( 8) and the predicted performance head H _pred x at the actual rotational speed Nx of the fluid machine at the time of measurement are calculated from the curve showing the relationship between the predicted performance head H _pred and the inlet volume flow rate Qs in FIG.

Then, the head ratio (performance degradation degree) α = measured performance head H _real / predicted performance head H _pred x is calculated (step S14) and output to the history database 27 (step S15).
Thereafter, the timer is reset, and the process returns to the time counting by the timer (step S12).

  Further, the performance change rate calculator 26 receives the head ratio α from the history database 27, obtains the change rate by differentiation, and stores the obtained change rate in the history database 27.

In the display device 28, first, the screen display program is initialized (step S21).
Then, the head ratio α and the change rate of the head ratio α are obtained from the history database 27, screen data is created (step S22), and a graph as shown in FIG. 4 is displayed on the screen (step S23).

As shown in FIG. 4, the graph displayed on this screen is a transition of the head ratio (performance degradation degree) α (or the actually measured performance head H _real ) and the change rate of the head ratio α with the horizontal axis as time. Thus, the performance of the compressor 3 can be easily evaluated.
And it becomes possible to evaluate the performance deterioration of the apparatus very easily, predict the maintenance period, and avoid trouble beforehand.

Further, the above is a case where the fluid machine is driven by a prime mover (motor such as a gas turbine, a steam turbine, and an electric motor) whose rotation speed is variable, and the rotation speed is controlled. Yes.
However, the control of the fluid amount is not limited to this.
For example, the rotational speed of the fluid machine is fixed, an inlet guide vane (IGV, inlet guide vane) or a flow control valve is provided at the inlet of the fluid machine, and the opening of the vane or valve is controlled as a fluid control amount. It is possible to respond to what you do.

  As mentioned above, although the embodiment of the present invention has been described for the performance diagnosis in the case of the compressor, the present invention can be applied to other fans, pumps, etc., and the present invention is not limited to the above embodiment, and the present invention. It goes without saying that various modifications may be made to the specific structure within the scope of.

1 is a schematic view of a plant in which a fluid machine performance diagnosis apparatus according to an embodiment of the present invention is employed. It is a circuit block diagram of the performance diagnosis apparatus of the fluid machine which concerns on embodiment of this invention. It is a calculation block diagram of the performance diagnosis apparatus of the fluid machine which concerns on embodiment of this invention. It is an example of the display graph by the performance diagnosis apparatus of the fluid machine which concerns on embodiment of this invention. It is a figure which shows the basic principle of evaluation of the performance diagnosis apparatus of the fluid machine which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b, 1c Fluid machine 2 Turbine 3 Compressor 4 Tachometer 5 Discharge side pressure gauge 6 Suction side pressure gauge 7 Suction side thermometer 8 Flow meter 9 Discharge pipe 10 Suction pipe 11 Monitoring device 12 Network 13 Central monitoring computer 20 Operation data Collector 21 Shared memory 22 Performance diagnostic computing unit 23 Various data input unit 24 Expected performance curve computing unit 25 Performance diagnostic database 26 Performance change rate computing unit 27 History database 28 Display unit

Claims (4)

An expected performance curve calculator for obtaining a curve indicating the relationship between the pressure coefficient and the flow coefficient by making the characteristics dimensionless for each of a plurality of fluid control amounts from the compression ratio or pressure difference of the fluid machine and the inlet flow rate;
The measured performance head is obtained from the fluid control amount, suction pressure, discharge pressure, suction temperature, compression coefficient, gas average molecular weight and specific heat ratio during operation of the fluid machine, and predicted from the predicted performance curve, fluid control amount and inlet flow rate. A fluid machine performance diagnosis apparatus comprising: a performance diagnosis computing unit that obtains a performance head and calculates a performance deterioration degree from a ratio of an expected performance head to an actual performance head. The measured performance head is
When the suction pressure is Ps, the discharge pressure is Pd, the suction temperature is Ts, the compression coefficient is Z, the gas average molecular weight is Mw, the specific heat ratio is k, and β = (k−1) / k, the measured performance head H _real is formula,
H _real = Z · 1 / β · Ts / Mw · {(Pd / Ps) ^β -1}
The fluid machine performance diagnosis apparatus according to claim 1, wherein the performance diagnosis apparatus is obtained by:   3. The fluid machine performance diagnosis apparatus according to claim 1, further comprising a performance change rate calculator that differentiates the performance deterioration level to calculate a performance deterioration rate change rate. 4. A monitoring device for measuring or calculating suction pressure, discharge pressure, suction temperature, compression coefficient, gas average molecular weight, specific heat ratio during operation of the fluid machine and storing the data;
A central monitoring computer that receives the data stored in the monitoring device via a network;
4. The fluid machine performance diagnosis system according to claim 1, wherein the central monitoring computer includes the fluid machine performance diagnosis apparatus according to claim 1.