Axial flow compressor surge experiment automatic test method

Abstract

This invention discloses an automatic testing method for surge testing of axial compressors, comprising the following steps: First, the process data and predicted surge pressure of the axial compressor stator vane, corresponding exhaust pressure, are preset in the automatic testing system; then, the associated interlock protection logic of the axial compressor is deactivated in the automatic testing system, and the stator vane angle and anti-surge valve opening of the axial compressor are adjusted according to the surge test scheme; next, relevant data of the axial compressor are collected in real time through the automatic testing system; then, the collected data are processed by the automatic testing system to determine whether a surge state has been reached and to trigger a rapid protection action; finally, the relevant data are recorded and displayed in the surge test data table. The entire experimental process automatically completes a stable pressure build-up process, and can immediately release air and pressure at the moment of surge, shortening the duration of the surge phenomenon and reducing labor intensity.

Description

Technical Field

[0001] This invention relates to the field of anti-surge control technology for axial compressors, and specifically to an automatic testing method for surge experiments on axial compressors. Background Technology

[0002] Axial flow compressors are key power equipment in blast furnace ironmaking. To ensure the safe and stable operation of axial flow compressors, their control systems must be equipped with anti-surge control and protection functions. This allows the axial flow compressor to cope with the rapidly changing furnace conditions while simultaneously meeting the needs of continuous blast furnace production, compressor unit safety, and energy conservation. The basis of the anti-surge control and protection function lies in the performance curve of the axial flow compressor, which is a curve plotted with the throat differential pressure of the axial flow compressor as the abscissa and the exhaust pressure as the ordinate, called the surge line. When the operating point of the axial flow compressor is below the surge line, the unit is safe; when the operating point is above the surge line, the unit will experience surge, which can cause serious damage. Therefore, the anti-surge control and protection function usually sets multiple protection lines below the surge line to protect the unit in advance. Thus, determining this performance curve of the axial flow compressor is particularly important.

[0003] However, the actual performance of axial compressors often differs from the theoretically calculated performance, meaning theoretical performance data cannot be directly applied to performance curve plotting. Therefore, it is usually necessary to manually re-measure the actual performance curve of the axial compressor on-site through surge testing. Furthermore, as the service life increases or the unit is modified, the performance of the axial compressor will change, again requiring re-measurement of the actual performance curve. Therefore, surge testing is an unavoidable procedure before commissioning and during long-term use of axial compressors.

[0004] Because surge testing is a destructive test, it requires a smooth experimental process, success at each test point on the first attempt, accurate surge data collection, and immediate air release during surge. This places high demands on the psychological resilience and technical skills of the testing personnel. Current technologies primarily rely on manual control by staff, which is complex and labor-intensive. Therefore, developing an automated surge testing system for axial compressors is crucial. This system should not only ensure accurate data acquisition and rapid air release during surge, but also reduce the psychological and physical stress and workload for testing personnel. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an automated testing method for surge testing of axial compressors.

[0006] The technical solution of this invention to solve the above-mentioned technical problems is as follows: An automatic testing method for surge testing of axial compressors, comprising the following steps:

[0007] S1: In the automatic testing system, preset the experimental angle of the axial compressor stator and the corresponding exhaust pressure process data and predict the surge pressure;

[0008] S2: Subsequently, the interlock protection logic of the axial compressor is released in the automatic test system, and the stationary blade angle and anti-surge valve opening of the axial compressor are automatically adjusted according to the surge test plan;

[0009] S3: Real-time data collection of throat differential pressure, discharge pressure, shaft vibration, inlet temperature, discharge temperature, and main motor current of the axial compressor through an automatic testing system;

[0010] S4: The automatic testing system calculates the data collected in S3 and determines whether a surge state has been reached and initiates a rapid protection action, or automatically releases pressure after the exhaust pressure reaches the predicted surge pressure.

[0011] S5: Record the actual surge time of the axial compressor in S4 or the throat differential pressure, exhaust pressure, compressor inlet temperature, compressor exhaust temperature, and main motor current, and display them in the surge measurement data table.

[0012] Furthermore, in step S1, each stator angle is pressurized by gradually closing the anti-surge valve, and the relevant data of throat differential pressure, exhaust pressure, compressor inlet temperature, compressor exhaust temperature, and main motor current are recorded when each exhaust pressure is reached during the pressurization process. This process is repeated until the predicted surge pressure is reached or actual surge occurs.

[0013] Further, in step S2, the experimental point is first determined, and then the experiment start button is clicked. After the experiment starts, the automatic testing system automatically raises the current surge performance curve and other protection lines of the axial compressor, automatically releases the shaft vibration and displacement interlock shutdown protection of the axial compressor, locks the check valve on the air supply pipe of the axial compressor, and then automatically and gradually adjusts the stationary blade angle of the axial compressor to the corresponding experimental angle according to the surge test plan. When the stationary blade angle is reached, the anti-surge valve is automatically and gradually closed to perform pressure holding operation. When each exhaust pressure process data point is reached, the system automatically pauses for 1 minute to wait for the experimenter to manually record the corresponding throat differential pressure, exhaust pressure, compressor inlet temperature, compressor exhaust temperature, main motor current and other relevant data. After waiting for 1 minute, the anti-surge valve is automatically and gradually closed to perform pressure holding operation again, and so on.

[0014] Furthermore, during the relevant data acquisition in step S3, data is acquired in real time through various transmitter instruments and transmitted to the automatic testing system. The rate of change of throat differential pressure and exhaust pressure of the axial compressor is calculated in real time using the cyclic scanning program of the automatic testing system.

[0015] Furthermore, the automatic testing system calculates the rate of change between the throat differential pressure collected in the current scanning cycle and the throat differential pressure collected and recorded in the previous scanning cycle through a cyclic scanning program, as well as the rate of change between the exhaust pressure collected in the current scanning cycle and the exhaust pressure collected and recorded in the previous scanning cycle. Each cyclic scanning cycle produces two rate of change results.

[0016] Furthermore, in step S4, the combined data of the rate of change of throat differential pressure, the rate of change of exhaust pressure, and the shaft vibration acquisition value are used to determine whether the axial compressor is experiencing surge.

[0017] Furthermore, in step S4, when determining whether a surge state has been reached and a rapid protection action has been initiated, the following steps are included:

[0018] S4.1: Determine whether the rate of change of the differential pressure in the throat is greater than the set value. If the condition is met, immediately execute a fast protection action.

[0019] S4.2: Determine whether the rate of change of throat differential pressure is greater than the set value and at the same time determine whether the shaft vibration acquisition value is greater than the shutdown set value. If the conditions are met, immediately execute a fast protection action.

[0020] S4.3: Determine whether the rate of change of the throat differential pressure is greater than the set value and at the same time determine whether the rate of change of the exhaust pressure is greater than the set value. If the conditions are met, immediately execute a fast protection action.

[0021] Furthermore, in step S5, the maximum value recorded within the first 10 cyclic scanning cycles is used as the surge data measured in the experiment and displayed in a table.

[0022] The present invention has the following beneficial effects: The automatic testing method for surge testing of axial compressors provided by the present invention is convenient to operate, performs well, and is fully automated. It eliminates the need for external pressure gauges connected to the exhaust pipe of the axial compressor and manual button presses by the test personnel, and no longer relies on the technical skills and experience of the test personnel. In this application, after the test personnel select the test point, the entire test process is carried out automatically. The automatic testing system automatically completes the stable pressure build-up process and can immediately release air and pressure at the moment of surge, with a reaction speed faster than manual judgment. This shortens the duration of surge phenomenon, better protects the safety of the unit, and greatly reduces labor intensity. Attached Figure Description

[0023] Figure 1 This is a flowchart of the testing method of the present invention;

[0024] Figure 2 This is a line graph of the measured surge line (AML) and two protection lines, the rapid ventilation line (QRL) and the energy efficiency control line (ECL), plotted according to the experimental data after a surge test in an embodiment of the present invention. Detailed Implementation

[0025] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0026] like Figure 1 As shown, an automated testing method for surge testing of axial compressors is presented. The testing is based on an automated testing system, which includes a controller and a host computer. The controller adopts a Siemens S7-400H series controller + ET200M I / O control substation architecture, and the host computer's display software uses WINCC. The S7-400H series controller + ET200M I / O control substation architecture possesses high-speed computing performance, enabling user program scan cycles to reach millisecond levels. Particularly for the approximately one-second surge period during which axial compressor surge occurs, its rapid data acquisition and processing performance meets the requirements of the automated testing system. The host computer's display software, WINCC, serves as the human-machine interface software, primarily implementing various operations of the axial compressor and displaying and recording data.

[0027] The main steps involved in conducting the test are as follows:

[0028] S1: In the automatic testing system, preset the experimental angle of the axial compressor stator and the corresponding exhaust pressure process data and predict the surge pressure.

[0029] In step S1, the surge test is generally required to be conducted under the condition of 4 to 6 stator vane angles of the axial compressor. At each stator vane angle, the pressure is built up by gradually closing the anti-surge valve, and the relevant data such as throat differential pressure, exhaust pressure, compressor inlet temperature, compressor exhaust temperature, and main motor current are recorded when the exhaust pressure is reached during the pressure building process. This process is repeated until the predicted surge pressure is reached or actual surge occurs.

[0030] To minimize the potential damage to the unit from surge testing, surge test procedures generally have two requirements. One requirement is to continuously pressurize until the axial compressor experiences actual surge; the other requirement is to pressurize only to the exhaust pressure that meets the user's maximum operating conditions, i.e., the predicted surge pressure, without actually experiencing surge.

[0031] S2: Subsequently, the interlock protection logic associated with the axial compressor is released in the automatic testing system, and the stationary blade angle and anti-surge valve opening of the axial compressor are automatically adjusted according to the surge test plan.

[0032] In step S2, the experimental point is first determined, and then the experiment start button is clicked. After the experiment starts, the automatic testing system automatically raises the current surge performance curve and other protection lines of the axial compressor, automatically releases the shaft vibration and displacement interlock shutdown protection of the axial compressor, locks the check valve on the air supply pipe of the axial compressor, and then automatically and gradually adjusts the stationary blade angle of the axial compressor to the corresponding experimental angle according to the surge test plan. When the stationary blade angle is reached, the anti-surge valve is automatically and gradually closed to perform the pressure holding operation. When each exhaust pressure process data point is reached, the system automatically pauses for 1 minute to wait for the experimenter to manually record the corresponding throat differential pressure, exhaust pressure, compressor inlet temperature, compressor exhaust temperature, main motor current and other relevant data. After waiting for 1 minute, the anti-surge valve is automatically and gradually closed to perform the pressure holding operation again, and so on.

[0033] Furthermore, in this step, the automatic testing system automatically modifies the original protection program, increasing the set values ​​of the original surge performance curve and other protection lines. This causes the surge performance curve and other protection lines displayed on the host computer's WINCC screen to move upwards to the top of the screen. Then, the interlock button for the axial compressor's shaft vibration and displacement is set to "cut off" to prevent the axial compressor from shutting down due to excessive vibration or displacement. Subsequently, a forced closure signal is sent to the check valve on the axial compressor's air supply duct to prevent high-pressure gas from leaking into the air supply duct during the pressure build-up process, thus affecting downstream processes. The purpose of this series of operations is to prevent interference from process equipment or logic program issues during the experiment.

[0034] S3: Real-time data collection of throat differential pressure, discharge pressure, shaft vibration, inlet temperature, discharge temperature, and main motor current of the axial compressor through an automatic testing system;

[0035] During step S3, when collecting relevant data, various transmitters are used to collect data in real time and transmit it to the automatic testing system. The automatic testing system's cyclic scanning program then calculates the rate of change of the throat differential pressure and exhaust pressure of the axial compressor in real time. The automatic testing system collects the above data in real time, with a collection cycle in the millisecond range.

[0036] The automated testing system uses an extremely short cyclic scanning procedure to calculate the rate of change between the throat differential pressure collected in the current scan cycle and the throat differential pressure collected in the previous scan cycle, as well as the rate of change between the exhaust pressure collected in the current scan cycle and the exhaust pressure collected in the previous scan cycle. Each cyclic scan cycle produces two rate of change results. The extremely short time can be set to 50 milliseconds, 100 milliseconds, 150 milliseconds, 200 milliseconds, 250 milliseconds, 300 milliseconds, 350 milliseconds, 400 milliseconds, 450 milliseconds, and 500 milliseconds.

[0037] S4: The automatic testing system processes the data collected in S3 and determines whether a surge condition has been reached and initiates a rapid protection action; or automatically releases pressure after the exhaust pressure reaches the predicted surge pressure.

[0038] In step S4, the combined data of the rate of change of throat differential pressure, the rate of change of exhaust pressure, and the shaft vibration acquisition values ​​are used to determine whether the axial compressor is experiencing surge. If surge occurs, the automatic testing system immediately executes a rapid protection action to ensure the safety of the axial compressor. This experiment was successful. For the requirement of only pressurizing to the predicted surge pressure, the automatic testing system continuously judges whether the axial compressor is experiencing surge before the exhaust pressure reaches the predicted surge pressure. When the predicted surge pressure is reached and the unit is not experiencing surge, the automatic testing system automatically and gradually opens the anti-surge valve to release pressure. This experiment was successful.

[0039] Specifically, this combined data comes in three forms, as follows:

[0040] S4.1: Determine whether the rate of change of the differential pressure in the throat is greater than the set value. If the condition is met, immediately execute a fast protection action.

[0041] S4.2: Determine whether the rate of change of throat differential pressure is greater than the set value and at the same time determine whether the shaft vibration acquisition value is greater than the shutdown set value. If the conditions are met, immediately execute a fast protection action.

[0042] S4.3: Determine whether the rate of change of the throat differential pressure is greater than the set value and at the same time determine whether the rate of change of the exhaust pressure is greater than the set value. If the conditions are met, immediately execute a fast protection action.

[0043] Rapid protective actions include immediately opening the anti-surge valve of the axial compressor to the maximum extent and closing the stationary vanes of the axial compressor to achieve rapid pressure relief and prevent unit surge.

[0044] The first combination form (i.e. S4.1) above requires the simultaneous judgment of the following four conditions: the rate of change of laryngeal differential pressure is greater than 0.1; the rate of change of laryngeal differential pressure is greater than 0.2; the rate of change of laryngeal differential pressure is greater than 0.3; the rate of change of laryngeal differential pressure is greater than 0.4, and any one of the conditions is satisfied.

[0045] The first combination form (i.e., S4.2) above requires simultaneous judgment of the following four conditions: the rate of change of throat differential pressure is greater than 0.1 and any vibration value in the shaft vibration acquisition is greater than the shutdown setting value of 100µm; the rate of change of throat differential pressure is greater than 0.2 and any vibration value in the shaft vibration acquisition is greater than the shutdown setting value of 100µm; the rate of change of throat differential pressure is greater than 0.3 and any vibration value in the shaft vibration acquisition is greater than the shutdown setting value of 100µm; the rate of change of throat differential pressure is greater than 0.4 and any vibration value in the shaft vibration acquisition is greater than the shutdown setting value of 100µm. Any one of these conditions is sufficient.

[0046] The first combination form (i.e. S4.3) above requires the simultaneous judgment of the following four conditions: the rate of change of throat differential pressure is greater than 0.2 and the rate of change of exhaust pressure is greater than 0.5; the rate of change of throat differential pressure is greater than 0.2 and the rate of change of exhaust pressure is greater than 1.0; the rate of change of throat differential pressure is greater than 0.2 and the rate of change of exhaust pressure is greater than 2.0. Any one of these conditions is sufficient.

[0047] S5: Record the actual surge time of the axial compressor in S4 or the throat differential pressure, exhaust pressure, compressor inlet temperature, compressor exhaust temperature, and main motor current, and display them in the surge measurement data table.

[0048] When an axial compressor experiences actual surge, in addition to the compressor inlet temperature and compressor discharge temperature, three other data points—throat differential pressure, discharge pressure, and main motor current—will change rapidly. Therefore, the automatic testing system cannot directly record the values ​​at this moment as experimentally measured data. Instead, it records the maximum values ​​within the first 10 cyclic scanning cycles as the experimentally measured surge data.

[0049] Based on experimental data, the measured surge line (AML) was plotted on the WINCC human-machine interface of the Siemens S7-400H series PLC automatic control system. After simple scaling calculations, the rapid ventilation line (QRL) and energy efficiency control line (ECL) were then plotted. Figure 2 As shown. Figure 2 The topmost line is the measured surge line (AML), the middle line is the rapid air release line (QRL), and the bottommost line is the energy efficiency control line (ECL).

[0050] In a specific surge experiment, the experimental data recorded are shown in the table below. The experimental data recorded in the surge experiment are as follows:

[0051] parameter unit 1 2 3 4 5 still leaf angle Spend 35 40 45 50 55 Laryngeal pressure differential kPa 7.28 8.77 10.43 12.46 14.04 Exhaust pressure kPa 480.1 511.3 540.7 566.3 593.6 Inlet temperature ℃ 25.2 25.4 24.9 24.3 24.9 Exhaust temperature ℃ 251.1 256.4 264.8 269.5 275.5 Motor current A 975.8 1095.3 1200 1333.9 1485.8 Notes Panting Panting Panting No panting No panting

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An automatic testing method for surge testing of an axial compressor, characterized in that, Includes the following steps: S1: In the automatic testing system, preset the experimental angle of the axial compressor stator and the corresponding exhaust pressure process data and predict the surge pressure; S2: Subsequently, the interlock protection logic of the axial compressor is released in the automatic test system, and the stationary blade angle and anti-surge valve opening of the axial compressor are automatically adjusted according to the surge test plan; S3: Real-time data collection of throat differential pressure, discharge pressure, shaft vibration, inlet temperature, discharge temperature, and main motor current of the axial compressor through an automatic testing system; S4: The automatic testing system processes the data collected in S3 and determines whether the axial compressor has reached a surge state based on the calculation results. If a surge state is reached, a rapid protection action is executed. Alternatively, if a surge state is not reached, the system checks whether the exhaust pressure has reached the predicted surge pressure. If a surge state is not reached but the exhaust pressure has reached the predicted surge pressure, the system automatically releases pressure. In step S4, the combined data of the throat differential pressure change rate, the exhaust pressure change rate, and the shaft vibration acquisition value are used to determine whether the axial compressor has reached a surge state. The specific criteria for determining whether the axial compressor has reached a surge state and executing a rapid protection action include the following steps: S4.1: Determine whether the rate of change of the throat differential pressure is greater than the set value. If the condition that the rate of change of the throat differential pressure is greater than the set value is met, execute a fast protection action immediately. S4.2: Determine whether the rate of change of throat differential pressure is greater than the set value and at the same time determine whether the shaft vibration acquisition value is greater than the shutdown set value. If the determination that the rate of change of throat differential pressure is greater than the set value and at the same time the determination that the shaft vibration acquisition value is greater than the shutdown set value are both true, then immediately execute a fast protection action. S4.3: Determine whether the rate of change of the throat differential pressure is greater than the set value and at the same time determine whether the rate of change of the exhaust pressure is greater than the set value. If the rate of change of the throat differential pressure is greater than the set value and the rate of change of the exhaust pressure is greater than the set value, then immediately execute a fast protection action. S5: Record the relevant data of throat differential pressure, exhaust pressure, compressor inlet temperature, compressor exhaust temperature, and main motor current when the axial compressor in S4 reaches the surge state or when the exhaust pressure reaches the predicted surge pressure, and display them in the surge measured data table.

2. The automatic testing method for surge testing of axial compressors according to claim 1, characterized in that, In step S1, each stator angle is pressurized by gradually closing the anti-surge valve, and the throat differential pressure, exhaust pressure, compressor inlet temperature, compressor exhaust temperature, and main motor current are recorded when each exhaust pressure is reached during the pressurization process. This process is repeated until the exhaust pressure reaches the predicted surge pressure or the axial compressor reaches the surge state.

3. The automatic testing method for surge testing of axial compressors according to claim 1, characterized in that, In step S2, the experimental point is first determined, and then the experiment start button is clicked. After the experiment starts, the automatic testing system automatically raises the current surge performance curve and other protection lines of the axial compressor, automatically releases the shaft vibration and displacement interlock shutdown protection of the axial compressor, locks the check valve on the air supply pipe of the axial compressor, and then automatically and gradually adjusts the stationary blade angle of the axial compressor to the corresponding experimental angle according to the surge test plan. When the stationary blade angle is reached, the anti-surge valve is automatically and gradually closed to perform the pressure holding operation. When each exhaust pressure process data point is reached, the system automatically pauses for 1 minute to wait for the experimenter to manually record the relevant data of throat differential pressure, exhaust pressure, compressor inlet temperature, compressor exhaust temperature, and main motor current. After waiting for 1 minute, the anti-surge valve is automatically and gradually closed to perform the pressure holding operation again, and so on.

4. The automatic testing method for surge testing of axial compressors according to claim 1, characterized in that, When collecting relevant data in step S3, data is collected in real time through various transmitters and transmitted to the automatic testing system. The cyclic scanning program of the automatic testing system is used to calculate the rate of change of throat differential pressure and the rate of change of exhaust pressure of the axial compressor in real time.

5. The automatic testing method for surge testing of axial compressors according to claim 4, characterized in that, The automatic testing system calculates the rate of change between the throat differential pressure collected in the current scan cycle and the throat differential pressure collected in the previous scan cycle through a cyclic scanning program, as well as the rate of change between the exhaust pressure collected in the current scan cycle and the exhaust pressure collected in the previous scan cycle. Each cyclic scanning cycle produces two rate of change results.

6. The automatic testing method for surge testing of axial compressors according to claim 1, characterized in that, In step S5, the maximum value within the first 10 cyclic scanning cycles is recorded as the surge data measured in the experiment and displayed in the table.

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