JP2002061594A - Optimum load control system for compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optimum load control system for compressors, permitting the use at a high pressure ratio by controlling the loads of stages in the axial direction to be averaged and flattened. SOLUTION: The pressures of the stages of compressors are measured by using wall pressure sensors 1-8 and input to a computer 10 via an amplifier 9. The computer 10 selects the stage having the highest load from these signals and controls the stagger angle of a stationary vane upstream of this stage to be larger (closed) via an actuator 11. Therefore, the load of the selected stage is lowered. With the repetition of the operation in sequence, the loads of the stages in the axial direction can be flattened. The computer raises a pressure ratio in the range of not exceeding a preset estimated limiting value and flattens load distribution in the axial direction, permitting the use at a high pressure ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optimum load control system for a compressor, which avoids surges and can operate at a high pressure ratio to extend the operation range.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view of a conventional axial compressor. In the drawing, reference numeral 50 denotes a casing, around the inner wall of the casing 50, a plurality of stationary blades are provided in each stage, and around the rotating shaft, a plurality of moving blades are mounted in each stage, and these stationary blades are provided. And the rotor blades are alternately arranged in the axial direction. In the example shown in the figure, the compressor is a six-stage compressor. A plurality of struts 51 for forming an inlet are provided around the inlet, and an IGV (inlet guide vane) is provided downstream. The arrangement of each wing is such that the moving blade 1S and the stationary blade 1C are arranged in one stage.
However, the moving blade 2S and the stationary blade 2C are arranged in two stages, and the moving blades 3S to 6S and the stationary blades 3C to 6C are similarly arranged in the subsequent stages. In this example, a six-stage compressor is configured.

In the above-mentioned conventional axial flow compressor, when a pressure ratio (outlet total pressure / inlet total pressure) rises, it is warned that a surge will occur.
Operating at a pressure ratio lower than the expected operating surge operating point. FIG. 6 shows the stage-wise load of the axial compressor. The stage-wise load is determined by the set angle of the blade and the operating condition at that time. When it was determined (when the predicted limit was reached), the pressure ratio was further increased to avoid surge.

[0006] That is, in the example of FIG. 6, the compressor is a six-stage compressor, and a dotted line 18 in the figure indicates a predicted limit value, and a circle indicates a load distribution of each stage. Therefore, in this example, the fourth stage has reached the predicted limit value, indicating that a surge will occur if the pressure rises further. The other stages each have a margin with respect to the prediction limit value 18, and are used without exhibiting the potential boosting ability in these stages.

[0005]

As described above, in the conventional axial flow compressor, the surge is warned when the pressure rises, and the compressor is operated at a pressure ratio lower than the predicted operating surge operating point. . For this purpose, the prediction limit value of each stage is set, and when the prediction limit value is reached, the pressure ratio rise is abandoned, and the operation is performed at a low pressure ratio or the operation is stopped.
For this reason, at a stage where the load is not so high, there is a margin with respect to the prediction limit value, so that there is a margin as a whole and the operation is performed without exhibiting the potential boosting ability.

Therefore, in the present invention, the stagger angle of the vane is adjusted so that the change in the axial load is constant within a predetermined range by averaging the margins in each stage of the vane as independent variable vanes. Another object of the present invention is to provide an optimum load control system for a compressor that can expand the operating range of the compressor.

[0007]

The present invention provides the following means (1) to (3) to solve the above-mentioned problems.

(1) A load control system for a compressor in which variable vanes are configured in multiple stages, wherein a plurality of sensors for measuring the internal pressure of the casing at each stage and a stagger angle of the vanes at each stage are provided. A plurality of actuators for adjusting the actuators, an actuator control device for controlling the driving of the plurality of actuators, and taking in pressure signals from the plurality of sensors, calculating a stagger angle of the vane of each stage and outputting the calculated stagger angle to the actuator control device A computer having the highest pressure ratio (load) among the pressure signals of the respective stages, and setting the stagger angle of the stationary vane upstream of the selected stage by a predetermined angle. A signal is output to the actuator control device, the control device controls the stagger angle to be set, and the control is sequentially repeated. Optimal load control system of the compressor, characterized by controlling so as to set the pressure ratio distribution of each stage within a predetermined range within a preset prediction limit.

(2) A load control system for a compressor in which variable vanes are configured in multiple stages, wherein a plurality of sensors for measuring the internal pressure of the casing at each stage and a casing near each stage are penetrated. A hole is provided, a bleeding pipe connected to each of the holes, a control valve connected to each of the pipes, a valve control device for controlling an opening degree of each of the control valves, and a pressure from the plurality of sensors. A computer that takes in signals and calculates an opening signal of the control valve for setting a pressure ratio (load) in the casing of each stage and outputs the signal to the valve control device; The stage having the highest pressure ratio (load) among the pressure signals is selected, and an opening signal of the control valve for lowering the pressure of the selected stage to a predetermined pressure is output to the valve controller. Reduce the pressure of the selected stage An optimum load control system for a compressor, wherein the pressure fluctuation of each stage is set within a predetermined range within a preset limit value by repeating the control sequentially. .

(3) The piping via the control valve at each stage is as follows:
The optimum load control system for a compressor according to (2), wherein the extracted air is connected so as to flow to a turbine cooling system.

In (1) of the present invention, when the compressor pressure increases, the pressure signals measured by the sensors at each stage are input to a computer, and the computer averages the pressure (load) at each stage based on these pressure signals. Then, a signal is sent to the actuator controller so that the angle of the stator vanes is such that the load in the axial direction is constant, and the variable stator actuators at each stage are driven. That is, the computer selects the stage with the highest pressure ratio (load) from the measured pressure signals, and sets the actuator control device so as to increase (close) the stagger angle of the stationary blade upstream of the selected stage. Control over. Increasing the stagger angle of a given vane reduces the load on the wake, so that the load on the selected stage can be reduced. Such control is sequentially repeated, so that the pressure at the highest pressure (load) stage is reduced, and the fluctuation of the axial load distribution is within a predetermined range, and the control can be performed so as to be flat. Further, the computer has a predicted limit value at which a surge may occur in advance, and the pressure is controlled so as to equalize and increase the pressure ratio within a range where the pressure of each stage does not exceed the predicted limit value. By using the boosting capability of each stage to the maximum, it is possible to operate at a higher pressure ratio than before.

In (2) of the present invention, the pressure signal of each stage is input to the computer, and the computer selects the highest pressure stage from the pressure (load) signals of each stage, and selects the selected stage. A signal to open the control valve at a predetermined angle is sent to the valve control device, and the valve control device opens the control valve of the selected stage by a predetermined angle and bleeds a predetermined amount of air from this stage. This reduces the pressure in this stage. By sequentially repeating such control, the fluctuation of the load (pressure) in the axial direction of each stage can be set within a predetermined range and made uniform. Further, the computer controls the opening of the control valve of each stage through the valve control device, and has a predicted limit value in which a surge may occur in advance, and the pressure of each stage does not exceed the predicted limit value. Since the pressure ratio is controlled to be uniform and increased in the range, the boosting capability of each stage can be used to the maximum and operation at a higher pressure ratio than before can be performed.

In (3) of the present invention, the extracted air flows to the cooling system of the turbine and is used as cooling air, so that the compressed air in the above (2) is not wasted and the efficiency of the compressor is reduced. Can be prevented.

[0014]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a configuration diagram of a compressor optimum load control system according to a first embodiment of the present invention. In the figure, 9 is an amplifier, 10 is a computer, and 11 is an actuator control device. A signal from a sensor is amplified by an amplifier as described later, and input to the computer 10 as a digital signal, and the computer 10 performs an operation. A signal is output to the actuator control device 11 so that an axial load (hereinafter, also referred to as a pressure ratio) of the axial compressor is optimized, and the angle of each variable vane actuator is controlled by the actuator control device 11. is there.

Reference numerals 1 to 8 denote wall pressure sensors for measuring the steady pressure in the casing at each stage. Sensor 1
Is the pressure at the inlet, 2 is the pressure at the inlet of the first stage blade 1S, 3 is the pressure at the inlet of the second stage blade 2S, and similarly the sensors 4, 5, 6,
At 7, the inlet pressure of each of the moving blades 3S, 4S, 5S, 6S is measured, and at the sensor 8, the pressure at the compressor outlet is measured.

Reference numeral 17 denotes an actuator for adjusting the blade angle of the IGV, 16 denotes a variable stationary blade actuator of the one-stage stationary blade 1C,
Similarly, 15, 14, 13, and 12 are variable stationary blade actuators of a two-stage stationary blade 2 </ b> C, a three-stage stationary blade 3 </ b> C, a four-stage stationary blade 4 </ b> C, and a five-stage stationary blade 5 </ b> C.
Is controlled by

In the system having the above structure, when the compressor pressure ratio (outlet total pressure / inlet total pressure) rises, the pressure in each stage is measured by the steady wall pressure sensors 1 to 8 attached to each stage, and the measurement signals are output. Is amplified through an amplifier 9, converted into an appropriate digital signal, and transferred to a computer 10. The computer 10 compares the predetermined predicted limit value with the input measured value, averages the axial load so as to be uniform in each stage, that is, averages the load within a predetermined fluctuation range, The angle of the stationary blade at each stage is calculated so that the result is output to the actuator control device 11. The actuator control device 11 receives these signals, sends signals to the variable vane actuators 12 to 17 at each stage, drives them, and sets an appropriate angle of each vane.

FIG. 2 is a diagram showing the load distribution of each stage when the compressor is operated at a predetermined overall compressor pressure ratio. In the figure, white circles indicate data at a pressure ratio of π1, black squares indicate data at a pressure ratio of π2, and black diamonds indicate data of operating conditions π1 obtained as a result of optimization according to the present invention. is there. The dotted line at the upper limit is the predicted limit value 18, which is a value at which a surge is likely to occur with a load exceeding this limit value.

In FIG. 2, in a compressor operating at a certain pressure ratio π1, the pressure of each stage wall is measured by pressure sensors 1 to 8, and the pressure of each stage is measured by an amplifier 9 as indicated by a white circle in the figure.
Is taken into the computer 10 via the. The computer 10 which has input these data displays the load in each step direction on the display almost in real time using an arbitrary programming language. In addition, the computer 10 inputs and stores a prediction limit value 18 (shown by a dotted line at the upper limit in the figure) in advance.

The computer 10 compares the input pressure of each stage with the prediction limit value 18 and selects the stage 19 having the smallest margin, that is, data 19 of four stages. Experiments so far have revealed that when the stagger angle (the angle θ between the stationary blade C and the rotation axis R shown in FIG. 7) of a given stationary blade is increased (closed), the downstream load decreases. Therefore, the computer 10 increases (closes) the stagger angle of the vane upstream of the stage having the smallest margin. FIG.
In the example, since the four-stage margin is the smallest, the variable stationary blade actuator 14 of the three-stage stationary blade 3C on the upstream side is driven to set the stagger angle of the stationary blade to be larger by a predetermined amount. This operation reduces the four-stage load.

When the above operation is completed, the computer 10
Again compares the predicted set value with the input measured value, selects the stage with the smallest margin, repeats the same operation as above, and repeats this operation until the axial load fluctuates within the , And finally a flat load is obtained as indicated by the dotted line indicated by the black diamond in the figure. After that, if the operation is continued, the load distribution becomes the pressure ratio π2
The above operation is repeated so that the load distribution becomes flat in the same manner since the load distribution rises again and has the distribution again in the axial direction.

FIG. 3 is a control flowchart executed by the computer of the optimum load control system according to the first embodiment described above. In the figure, after the start,
The computer 10 includes wall pressure sensors 1 to 8 for each stage of the compressor.
In step S1, the stage with the highest load in the current load distribution is selected. Next, in S2, a signal for increasing (closing) the stagger angle of the stationary blade on the upstream side of the selected stage by a predetermined angle is output to the actuator control device 11, and the actuator control device 11 controls the corresponding variable stationary blade actuator. Drive to set the stagger angle.

The load of the stage selected by the above operation decreases, and the load distribution of each stage is checked again in S3, and the difference between the load distributions of each stage becomes equal to or less than a preset value, and the fluctuation of the axial load falls within a predetermined range. It is checked whether or not the load is within the range. If the difference in the load is still larger than the predetermined value, the process returns to S1 and the same operation is repeated.

When the change in the axial load falls within a predetermined range,
In S4, it is checked whether or not the load distribution of each stage is equal to or less than the prediction limit value.
It is determined that there is enough room to increase the pressure ratio, the process returns to S1, and the same operation is performed to reduce the load of the stage having the higher pressure ratio (load), thereby performing control to keep the axial load distribution constant. In S4, if the load distribution of each stage matches or exceeds the predicted limit value, the increase in the pressure ratio is stopped in S6.

According to the first embodiment described above,
The compressor is operated by controlling the boosting capacity of each stage to the maximum, and the control is performed so that the pressure ratio rise stops when the predicted limit value is exceeded. It is possible.

FIG. 4 is a configuration diagram of a compressor optimum load control system according to a second embodiment of the present invention. In the figure, in the second embodiment, holes 31 to 36 penetrating the casing 50 are provided in the vicinity of each stage, and pipes via control valves 41 to 46 are connected to the holes, respectively.
46 is opened by a predetermined opening to extract the air in the compressor to adjust the pressure, and the extracted air flows to the turbine cooling system 22 for cooling. Holes 31 to 36 instead of the variable stator blade actuators 12 to 16 of the first embodiment, piping for bleeding and control valves 41 to 4
6 is provided.

In FIG. 1, reference numerals 1 to 8 denote the same wall pressure and pressure sensors as those shown in FIG. 1, which are provided on the walls of the respective stages in the casing 50, and the detection signals of which are input to the computer 10 via the amplifier 9. Reference numerals 31 to 36 denote holes provided through the casing 50, 31 is one step, 32 is two steps, and 33 is 3 steps.
The stage, 34 is provided in the vicinity of each of the four stages, the 35 is provided in the five stages, and the 36 is provided in the vicinity of each of the six stages of the stationary vanes. Piping is connected to each of the holes 31 to 36, and the control valves 41 to 46 are opened to be connected to the turbine cooling system 22. The opening degree of each of the control valves 41 to 46 is controlled by the valve control device 21.

In the second embodiment of the above configuration, the pressure of each stage is detected and input to the computer 10 by the sensors 1 to 8, and as in the first embodiment, the computer 10 A stage having a high pressure ratio (load) is selected, and a signal for opening the corresponding control valve by a predetermined opening to reduce the pressure of this stage to a predetermined value is sent to the valve control device 21. Air is extracted from the stage to reduce pressure and load. The extracted air is sent to a turbine cooling system 22 and is effectively used for cooling blades and a rotor of the turbine.

By controlling the control valves 41 to 46 in each stage as described above, the load distribution in each stage can be kept constant as a variation within a predetermined range. The control valve can be controlled to make full use of the boosting capacity of the valve, and in the event that any one of the loads at each stage exceeds the predicted limit and there is a danger of a surge, the corresponding control valve is opened. Then, the pressure at that stage can be reduced to reduce the load to or below the predicted limit value, so that the boosting capability of each stage can be used to the maximum and operation at a higher pressure ratio than before can be performed.

[0030]

The optimum load control system for a compressor according to the present invention is (1) a load control system for a compressor in which variable vanes are configured in multiple stages, and measures the internal pressure of the casing at each stage. A plurality of sensors, a plurality of actuators for adjusting the stagger angle of the vane of each stage, an actuator control device for controlling the driving of the plurality of actuators,
A computer that takes in pressure signals from the plurality of sensors, calculates a stagger angle of the stator vane of each stage, and outputs the calculated stagger angle to the actuator control device.
The stage having the highest pressure ratio (load) among the pressure signals of the stages is selected, and a signal for setting the stagger angle of the stationary blade upstream of the selected stage to be larger by a predetermined angle is output to the actuator control device. The control device controls the stagger angle to be set, and controls the pressure fluctuation of each stage to be set within a predetermined range within a preset limit value by repeating the control sequentially. Features.

According to the above configuration, it is possible to control the fluctuation of the load distribution in the axial direction to be within a predetermined range and to make the load distribution flat. Further, the computer has a predicted limit value at which a surge may occur in advance, and the pressure is controlled so as to equalize and increase the pressure ratio within a range where the pressure of each stage does not exceed the predicted limit value. By using the boosting capacity of each stage to the maximum, it is possible to operate at a higher pressure ratio than before.

(2) The present invention relates to a load control system for a compressor comprising variable stages in multiple stages, comprising a plurality of sensors for measuring the pressure in the casing of each stage, and a vicinity of each stage. A hole that penetrates the casing, a bleeding pipe connected to each of the holes, a control valve connected to each of the pipes, a valve control device that controls an opening degree of each of the control valves, A computer that takes in a pressure signal from the sensor of the controller and calculates an opening signal of the control valve for setting the pressure in the casing of each of the stages and outputs the signal to the valve control device. Selecting the stage having the highest pressure ratio (load) among the pressure signals of the above, outputting an opening signal of the control valve for reducing the pressure of the selected stage to a predetermined pressure to the valve control device, Reduces the pressure of the selected stage Controlled so as to, it is characterized by controlling so as to set the pressure fluctuation of each stage in the prediction limit value set in advance by sequentially repeating the same control within a predetermined range.

Also in the above-described configuration, the fluctuation of the load distribution in the axial direction of each stage can be set within a predetermined range and made uniform. Further, the computer controls the opening of the control valve of each stage through the valve control device, and has a predicted limit value in which a surge may occur in advance, and the pressure of each stage does not exceed the predicted limit value. Since the pressure ratio is controlled to be uniform and increased in the range, the boosting capability of each stage can be used to the maximum and operation at a higher pressure ratio than before can be performed.

In (3) of the present invention, the extracted air flows into the cooling system of the turbine and is used as cooling air, so that the compressed air in the above (2) is not wasted and the efficiency of the compressor is reduced. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a compressor optimum load control system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a load distribution of each stage during operation to which the optimal load control system for a compressor according to the first embodiment of the present invention is applied.

FIG. 3 is a control flowchart in the compressor optimum load control system according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of an optimal load control system for a compressor according to a second embodiment of the present invention.

FIG. 5 is a general internal sectional view of a compressor.

FIG. 6 is a diagram showing a load distribution of each stage during operation of a conventional compressor.

FIG. 7 is an explanatory diagram showing a stagger angle of a stationary blade.

[Explanation of symbols]

 1-8 Wall pressure sensor 9 Amplifier 10 Computer 11 Actuator control device 12-17 Variable stationary blade actuator 21 Valve control device 31-36 Hole 41-46 Control valve 50 Casing

Claims (3)

[Claims] 1. A load control system for a compressor comprising variable stages of multi-stage vanes, comprising: a plurality of sensors for measuring a pressure in a casing of each stage; and a stagger angle of a vane of each stage. A plurality of actuators to be adjusted, an actuator control device for controlling the driving of the plurality of actuators, and pressure signals from the plurality of sensors are taken in, the stagger angles of the vanes at each stage are calculated and output to the actuator control device. A computer having the highest pressure ratio (load) among the pressure signals of the respective stages.
Is selected, and a signal for setting the stagger angle of the stator blade on the upstream side of the selected stage to be larger by a predetermined angle is output to the actuator control device, and the stagger angle is set by the control device. An optimal load control system for a compressor, wherein the control is performed such that the pressure ratio distribution of each stage is set within a predetermined range within a preset limit value by repeating the same control. 2. A load control system for a compressor comprising variable stages in a multi-stage configuration, comprising: a plurality of sensors for measuring a pressure in a casing of each stage; and a hole penetrating a casing near each stage. Provided, pipes for bleeding respectively connected to the holes, control valves connected to the pipes, a valve control device for controlling the opening of each control valve, and pressure signals from the plurality of sensors And a computer that calculates an opening signal of the control valve for setting the pressure in the casing of each stage and outputs the signal to the valve control device. A stage having a high pressure ratio (load) is selected, an opening signal of the control valve for lowering the pressure of the selected stage to a predetermined pressure is output to the valve control device, and the selected stage is selected by the valve control device. Control to reduce the pressure An optimal load control system for a compressor, wherein the control is performed such that the pressure fluctuation of each stage is set within a predetermined range within a preset limit value by repeating the same control. 3. The optimum load control system for a compressor according to claim 2, wherein a pipe via the control valve of each stage is connected so that the extracted air flows to a turbine cooling system.