Fault-removing method of water dynamometer for turboshaft engine ground whole machine test bed

Abstract

The application discloses a troubleshooting method of a hydraulic dynamometer for a turboshaft engine ground whole machine test bench, and belongs to the technical field of fault diagnosis and elimination of turboshaft engine ground test equipment, and the method comprises the following steps: detecting performance output parameters such as power, torque, rotating speed and vibration parameters; when the parameter fluctuation exceeds a preset threshold value, the water inlet pressure stability, the test piece running stability and the vibration abnormality source are determined respectively, and corresponding troubleshooting measures of a water supply system, control mode adjustment and flow field stability adjustment are taken; and the troubleshooting effect is evaluated through a verification step. In the prior art, the troubleshooting of the dynamometer depends on experience, lacks a standardized process and quantifiable criteria, and therefore leads to low troubleshooting efficiency and long troubleshooting period. The application has the advantages of clear determination basis, simple operation, quick recovery of stable operation of the dynamometer and reduction of test driving influence cost.

Description

Technical Field

[0001] This application relates to the field of turboshaft engine testing technology, specifically a troubleshooting method for a hydraulic dynamometer on a ground-based turboshaft engine test bench. Background Technology

[0002] Ground-based engine testing of turboshaft engines is an indispensable and crucial step in the engine development and finalization process. During testing, the engine's output power needs to be absorbed and loaded to assess its performance and verify its stability under different operating conditions. Hydraulic dynamometers, due to their advantages of high power absorption, wide applicable speed range, and high operational reliability, are commonly used as important power absorption devices on ground-based turboshaft engine test benches and are widely applied in turboshaft engine ground testing systems.

[0003] During actual testing, the operating status of the hydraulic dynamometer is affected by various factors, including water supply conditions, valve control strategies, flow field conditions, and the operating status of the test specimen. Because the hydraulic dynamometer operates with a large water flow rate and rapid system pressure changes, and because test benches often experience frequent acceleration and deceleration, rapid switching between operating conditions, and prolonged full-power operation, the dynamometer is prone to malfunctions such as large power fluctuations, large torque fluctuations, large speed fluctuations, and abnormal vibrations. These malfunctions not only affect the accuracy and stability of engine test data but may also lead to test interruptions, prolong the test cycle, increase test costs, and even adversely affect test safety.

[0004] In existing technologies, troubleshooting hydraulic dynamometer malfunctions typically relies on the experience of on-site personnel. This includes checking the water level in the water supply tower, the operating status of the water supply pump, and the operation of the water supply pipeline and valves. Alternatively, adjustments to valve openings and PID parameters may be made to attempt to restore dynamometer stability. However, dynamometer malfunctions are complex, potentially caused by fluctuations in water supply pressure, fluctuations in supply and return valves, or pipeline diversion. They may also be related to factors such as unstable test piece operation, abnormal rotor dynamic balance, resonance of the test bench's natural frequency, and fluid-structure interaction in the water supply. Existing troubleshooting methods lack systematic and standardized analysis processes and quantifiable judgment criteria, easily leading to low troubleshooting efficiency, uncertain results, and even repeated trial and error and long troubleshooting cycles. Therefore, a troubleshooting method for hydraulic dynamometers suitable for ground-based turboshaft engine test benches is needed to achieve rapid identification and effective handling of common dynamometer malfunctions, shorten the troubleshooting cycle, and improve test efficiency and reliability. Summary of the Invention

[0005] This application provides a troubleshooting method for a hydraulic dynamometer on a ground test bench for a turboshaft engine, in order to solve the problems of low troubleshooting efficiency and long troubleshooting cycle of hydraulic dynamometers during ground test runs in the prior art.

[0006] According to one aspect of this application, a method for troubleshooting a hydraulic dynamometer on a ground-based test bench for a turboshaft engine is provided, comprising the following steps:

[0007] The performance output parameters are detected, and the performance output parameters include at least one of power parameters, torque parameters, and speed parameters.

[0008] When the performance output parameters exceed the preset fluctuation threshold, the stability of the inlet water pressure and the operational stability of the test piece are judged, and the stability of the inlet water pressure and / or the operational stability of the test piece are maintained according to the judgment result.

[0009] Determining the stability of the inlet water pressure includes: collecting water level signals from the water supply tower, operating status signals from the water supply pump, pressure signals from the water supply pipeline, valve opening signals from the water supply pipeline, and filter blockage status signals from the water supply pipeline, and determining whether there are abnormal fluctuations in the inlet water pressure based on the signals.

[0010] Maintaining the stability of inlet water pressure includes: when abnormal fluctuations in inlet water pressure are detected, performing troubleshooting and maintenance operations on at least one of the following locations: water supply tower, water supply pump, water supply pipeline seal, water supply pipeline valve, and water supply pipeline filter element.

[0011] Determining the operational stability of the test specimen includes: acquiring the current operating control mode of the hydraulic dynamometer, which includes a position control mode, a torque control mode, and a speed control mode; in the position control mode, determining that the test specimen is unstable when the fluctuations of power parameters, torque parameters, and / or speed parameters exceed a preset fluctuation threshold; in the torque control mode, determining that the test specimen is unstable when the fluctuations of non-torque parameters exceed a preset fluctuation threshold; and in the speed control mode, determining that the test specimen is unstable when the fluctuations of non-speed parameters exceed a preset fluctuation threshold.

[0012] Maintaining the operational stability of the test specimen includes adjusting the dynamometer control mode when the test specimen is determined to be unstable.

[0013] Optionally, it also includes detecting vibration parameters and maintaining the vibration stability of the dynamometer when the vibration parameters exceed a preset fluctuation threshold. Maintaining the vibration stability of the dynamometer includes: performing spectral analysis on the dynamometer vibration signal, determining the vibration type based on the vibration frequency characteristics, and distinguishing between vibrations caused by test piece rotational speed resonance, bench natural frequency resonance, or fluid-structure interaction of the water supply system; when it is determined that the vibration is related to the fluid-structure interaction of the water supply system, monitoring the pressure parameters after the inlet valve, and based on the relationship that the pressure after the inlet valve is negative and its absolute value is positively correlated with the dynamometer vibration amplitude, adjusting the stability of the flow field on the inlet side to reduce the dynamometer vibration amplitude and restore stable operation.

[0014] Optionally, the stability adjustment of the inlet flow field includes at least one of the following methods: increasing the inlet pressure, increasing the diameter of the dynamometer vent, increasing the number of vents on the dynamometer body, changing the arrangement of the vents, and adjusting the opening ratio of the dynamometer supply and return water valves to change the inlet flow rate.

[0015] Optionally, adjusting the dynamometer control method may include adjusting at least one of the following: PID parameters, inlet valve opening, valve initial value, and inlet / outlet valve ratio, in order to reduce the fluctuation amplitude of performance output parameters and restore stable operation.

[0016] Optionally, when it is determined that there is an abnormal fluctuation in the inlet water pressure, the maintenance of inlet water pressure stability also includes: synchronously acquiring the opening signals of the dynamometer supply valve, the return valve, and the pressure signal of the diversion pipeline; when the opening signals of the supply valve and / or the return valve exhibit periodic fluctuations, the inlet water pressure fluctuation is determined to be caused by unstable control of the supply and return valves; when the pressure signal of the diversion pipeline is amplified relative to the pressure signal of the main supply pipeline, the inlet water pressure fluctuation is determined to be a pressure disturbance caused by the diversion.

[0017] Optionally, after completing the stability maintenance, a verification step is also included. The verification step includes: re-detecting the performance output parameters and / or vibration parameters under the same test conditions, and comparing the detection results before and after the maintenance to verify the effectiveness of the maintenance measures in reducing the fluctuation amplitude.

[0018] Optionally, the verification step further includes the following test procedure: after the engine is started, it runs in a ground slow state for a preset time, then in an idle slow state for a preset time, then the engine state is pushed up to the state point where the dynamometer malfunctions and maintained for a preset time to test the effectiveness of the maintenance measures.

[0019] Optionally, when maintenance measures are detected to improve dynamometer operation, the engine status is pushed up to a higher operating condition and maintained for a preset duration; when maintenance measures are detected to fail to improve or worsen the fault, the engine status is pulled down to idle slow state for a preset duration, and then further pulled down to ground slow state for a preset duration before stopping.

[0020] Optionally, after performing spectral analysis on the dynamometer vibration signal, the dominant vibration frequency is obtained and compared with a preset frequency threshold. When the dominant vibration frequency is lower than the preset frequency threshold, a test of the test bench's natural frequency is performed. The test of the test bench's natural frequency includes applying excitation to the test bench and collecting the test bench's response signal to obtain the test bench's natural frequency. When the dominant vibration frequency is consistent with the test bench's natural frequency, the vibration is determined to be caused by resonance of the test bench's natural frequency. When the dominant vibration frequency is inconsistent with the test bench's natural frequency, the vibration is determined to be caused by fluid-structure interaction of the water supply system.

[0021] Optionally, when the dominant vibration frequency is higher than the preset frequency threshold, the rotor dynamic balance test result is obtained, and it is determined whether the vibration is related to the rotor dynamic balance quality based on the dynamic balance test result; when the dynamic balance test result does not meet the preset requirements, the rotor is removed from the platform for dynamic balance maintenance.

[0022] In summary, this application includes at least one of the following beneficial technical effects:

[0023] This solution monitors at least one performance output parameter among power, torque, and speed parameters in real time, using whether it exceeds a preset fluctuation threshold as the trigger condition for troubleshooting, thus providing an objective basis for initiating troubleshooting. When abnormal fluctuations in performance output parameters are detected, the cause of the fault is preferentially diverted into two investigation paths: inlet water pressure stability and test piece operational stability. This avoids the long troubleshooting cycle caused by repeated trial and error based on experience in existing technologies. Specifically, in the inlet water pressure stability determination stage, signals from the water supply tower level, water supply pump operation status, water supply pipeline pressure, water supply pipeline valve opening, and water supply pipeline filter blockage status are collected to determine whether there are abnormal fluctuations in the inlet water pressure. During the maintenance stage, troubleshooting and maintenance are carried out on the water supply tower, water supply pump, water supply pipeline seals, valves, and filter elements. At the same time, fluctuations in the supply and return water valves and pressure fluctuations after diversion are detected to eliminate the source of pressure disturbance. Meanwhile, in the stability assessment of the test specimen, the current operating control mode of the dynamometer is obtained, and the fluctuation characteristics of the performance output parameters under different control modes are used to determine whether the test specimen is unstable. Stable operation is then restored by adjusting the dynamometer control mode. Therefore, this solution enables rapid location and targeted handling of fault causes, reducing ineffective troubleshooting and redundant adjustments, thereby improving troubleshooting efficiency and shortening the troubleshooting cycle.

[0024] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. A further detailed description of this application will be provided below with reference to the figures. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0026] Figure 1 This is a flowchart of this application. Detailed Implementation

[0027] The embodiments of this application are described in detail below with reference to the accompanying drawings; however, this application may be implemented in a variety of different ways as defined and covered below.

[0028] The following provides a further detailed description of this application.

[0029] Reference Figure 1 This application discloses a troubleshooting method for a hydraulic dynamometer on a ground test bench for a turboshaft engine, comprising the following steps:

[0030] The performance output parameters are detected, including at least one of the following: power parameters, torque parameters, and speed parameters.

[0031] When the performance output parameters exceed the preset fluctuation threshold, the stability of the inlet water pressure and the operational stability of the test piece are judged, and the stability of the inlet water pressure and / or the operational stability of the test piece are maintained according to the judgment results.

[0032] Determining the stability of inlet water pressure includes: collecting water level signals from the water supply tower, operating status signals from the water supply pump, pressure signals from the water supply pipeline, valve opening signals from the water supply pipeline, and filter blockage status signals from the water supply pipeline, and judging whether there are abnormal fluctuations in inlet water pressure based on the signals;

[0033] Maintaining the stability of inlet water pressure includes: when abnormal fluctuations in inlet water pressure are detected, troubleshooting and maintenance are performed on the water level of the water supply tower, the working status of the water supply pump, the sealing status of the water supply pipeline, the working status of the valves in the water supply pipeline, and the blockage status of the filter element in the water supply pipeline.

[0034] Determining the operational stability of the test specimen includes: acquiring the current operating control mode of the hydraulic dynamometer, which includes position control mode, torque control mode, and speed control mode; in position control mode, the test specimen is deemed unstable when the fluctuations of power parameters, torque parameters, and / or speed parameters exceed preset fluctuation thresholds; in torque control mode, the test specimen is deemed unstable when the fluctuations of non-torque parameters exceed preset fluctuation thresholds; and in speed control mode, the test specimen is deemed unstable when the fluctuations of non-speed parameters exceed preset fluctuation thresholds.

[0035] Maintaining the operational stability of the test specimen includes adjusting the dynamometer control mode when the test specimen is determined to be unstable.

[0036] The above scheme allows for real-time acquisition of the power, torque, and / or speed parameters of the hydraulic dynamometer via the test bench control system during commissioning. The acquired data is then statistically analyzed within a preset time window to determine if the performance output parameters exceed preset fluctuation thresholds. When abnormal fluctuations in performance output parameters are detected, a troubleshooting process is triggered.

[0037] After the troubleshooting process is initiated, the cause of the fault is preferentially diverted into two paths: one for investigating the stability of the inlet water pressure, and the other for investigating the operational stability of the test specimen. This avoids the prolonged troubleshooting cycle caused by the traditional trial-and-error approach of checking the water supply system, control system, and test specimen status item by item. For determining the stability of the inlet water pressure, signals such as the water level in the water supply tower, the operating status of the water supply pump, the pressure in the water supply pipeline, the valve opening status in the water supply pipeline, and the filter blockage status in the water supply pipeline can be collected simultaneously. The source of inlet water pressure fluctuations can be determined by combining the trend of these signals. For example, fluctuations in the water tower level may lead to insufficient water supply pressure, abnormal operation of the water supply pump may cause unstable output pressure, fluctuations in valve opening may cause disturbances in the water supply flow, and filter blockage may lead to changes in pipeline resistance and cause pressure fluctuations.

[0038] When abnormal fluctuations in inlet water pressure are detected, troubleshooting and maintenance can be performed on the water supply tower, water supply pump, water supply pipeline seals, water supply pipeline valves, and filter cartridges. For example, the water level can be stabilized by adding water or adjusting the water supply conditions, the water supply pump and its drive system can be checked to ensure stable pump output, leaks or air intake can be eliminated by checking pipeline connections, jamming or delayed response can be eliminated by checking valve actuators and valve core movements, and abnormal resistance caused by blockage can be eliminated by cleaning or replacing filter cartridges to remove the source of inlet water pressure disturbance.

[0039] After completing the water supply side investigation or confirming stable inlet water pressure, the operational stability of the test specimen is further assessed. Preferably, the operational stability assessment of the test specimen is combined with the analysis of the current operating control mode of the dynamometer. By analyzing the fluctuation characteristics of performance output parameters under different control modes, it is determined whether there is a control mode mismatch or abnormal operating status of the test specimen, thereby avoiding misjudging output fluctuations caused by control strategy factors as water supply system faults. When the test specimen is determined to be unstable, the performance output parameter fluctuations are reduced and stable operation is restored by adjusting the dynamometer control mode, preventing the fault from continuing to develop and causing the test run to be interrupted. Through the above troubleshooting process, rapid diversion and targeted handling of abnormal performance output parameters can be achieved, thereby improving troubleshooting efficiency and shortening the troubleshooting cycle.

[0040] In one embodiment, the method further includes detecting vibration parameters and maintaining the vibration stability of the dynamometer when the vibration parameters exceed a preset fluctuation threshold. Maintaining the vibration stability of the dynamometer includes: performing spectral analysis on the dynamometer vibration signal, determining the vibration type based on the vibration frequency characteristics, and distinguishing between vibrations caused by test piece rotational speed resonance, test bench natural frequency resonance, or fluid-structure interaction of the water supply system; when it is determined that the vibration is related to the fluid-structure interaction of the water supply system, monitoring the pressure parameters after the inlet valve, and based on the relationship that the pressure after the inlet valve is negative and its absolute value is positively correlated with the dynamometer vibration amplitude, adjusting the stability of the inlet flow field to reduce the dynamometer vibration amplitude and restore stable operation.

[0041] Through the above-described scheme, in addition to potential abnormal fluctuations in performance output parameters such as power, torque, and speed during ground-based whole-machine testing, the dynamometer and its test bench structure may also exhibit abnormal vibration. Abnormal vibration not only affects the stability of the testing process but may also cause fatigue damage to the dynamometer and test bench structural components, and even lead to testing safety risks. Therefore, this embodiment further introduces a vibration parameter detection and vibration stability maintenance path to achieve rapid identification and effective handling of dynamometer vibration faults.

[0042] In practice, vibration sensors can be installed on the dynamometer body, dynamometer support structure, or test bench base to collect vibration parameters in real time. Vibration parameters may include at least one of vibration acceleration, vibration velocity, or vibration displacement, and vibration anomalies can be determined by setting vibration amplitude thresholds or fluctuation thresholds. When vibration parameters exceed the preset fluctuation threshold, a vibration troubleshooting process is triggered to maintain the vibration stability of the dynamometer.

[0043] In the vibration troubleshooting process, vibration frequency characteristics are obtained by performing spectral analysis on the vibration signal, such as extracting the dominant vibration frequency and its frequency distribution characteristics, and the vibration type is distinguished based on the frequency characteristics. In this way, the vibration sources can be classified into test specimen rotational resonance, test bench natural frequency resonance, and vibration caused by fluid-structure interaction of the water supply system, thereby avoiding the problem of low troubleshooting efficiency caused by using a single maintenance method to deal with different types of vibration.

[0044] When vibration is determined to be related to fluid-structure interaction (FSI) in the water supply system, this embodiment further monitors the pressure parameters downstream of the inlet valve. The pressure monitoring point downstream of the inlet valve is preferably located downstream of the inlet valve to reflect changes in the flow field state on the inlet side. Under constant test conditions, the pressure downstream of the inlet valve is typically negative, and the absolute value of this negative pressure is correlated with the dynamometer vibration amplitude: the larger the absolute value of the negative pressure, the more unstable the flow field on the inlet side, and the larger the vibration amplitude; the closer the absolute value of the negative pressure is to zero, the smaller the dynamometer vibration amplitude, and the higher the operational stability. Therefore, this embodiment utilizes the negative value of the pressure downstream of the inlet valve and the positive correlation between its absolute value and the vibration amplitude as the basis for determining and adjusting fluid-structure interaction vibration, and accordingly adjusts the stability of the flow field on the inlet side to reduce the dynamometer vibration amplitude and restore stable operation.

[0045] In one embodiment, the stability adjustment of the inlet flow field includes at least one of the following methods: increasing the inlet pressure, increasing the diameter of the dynamometer vent, increasing the number of vents on the dynamometer body, changing the arrangement of the vents, and adjusting the opening ratio of the dynamometer supply and return water valves to change the inlet flow rate.

[0046] After determining that the dynamometer vibration is related to the fluid-structure interaction of the water supply system, this embodiment proposes to improve the dynamometer's operating state by adjusting the stability of the inlet flow field to reduce instability and suppress vibration amplitude. This stability adjustment is not a single measure, but rather a combination of one or more adjustment methods selected based on the structural configuration and fault characteristics of the test bench's water supply system to achieve better stability improvement.

[0047] In practical implementation, increasing the inlet pressure of the water supply system can reduce the pressure fluctuation amplitude on the dynamometer's inlet side, thereby mitigating flow field instability caused by localized negative pressure changes. Furthermore, adjusting the dynamometer's venting structure, such as increasing the diameter or number of vents, can enhance the internal gas-liquid exchange capacity, improving the local pressure distribution on the inlet side and reducing the absolute value of the negative pressure after the inlet valve. For different test benches and dynamometer structures, the placement of the vents also affects the stability of the internal flow field. Therefore, the vent positions can be adjusted according to the internal flow channel structure of the dynamometer to improve venting efficiency and reduce flow separation. In addition, the opening ratio of the supply and return water valves directly affects the matching relationship between the dynamometer's inlet and return water flow rates. An unreasonable supply and return water valve ratio can lead to flow disturbances or localized backflow, thus exacerbating fluid-structure interaction vibrations. Therefore, in this embodiment, the inlet flow rate can also be changed by adjusting the opening ratio of the supply and return water valves, so as to better match the flow rate on the supply side with the dynamometer's power absorption state, thereby achieving the purpose of stabilizing the flow field on the inlet side.

[0048] In one implementation, adjusting the dynamometer control method includes adjusting at least one of the PID parameters, inlet valve opening, valve initial value, and inlet / outlet valve ratio to reduce the fluctuation amplitude of performance output parameters and restore stable operation.

[0049] During troubleshooting, if it is determined that the fluctuation of performance output parameters is related to the unstable operation of the test piece or the mismatch of the dynamometer control response, the system operating status can be corrected by adjusting the dynamometer control mode, so as to achieve rapid convergence of performance output parameters and restore stable operation.

[0050] In practice, adjusting the control method may include optimizing the PID parameters. PID parameters are used to adjust the response speed and stability of the dynamometer control loop. An excessively large proportional gain may cause control overshoot and fluctuations, while an improperly set integral gain may lead to accumulated errors and oscillations. Insufficient derivative gain may result in a slow system response to disturbances. By adjusting the PID parameters, the dynamic response characteristics of the dynamometer under different operating conditions can be improved, reducing the amplitude of power, torque, or speed fluctuations.

[0051] In one implementation, when abnormal fluctuations in the inlet water pressure are detected, maintaining the stability of the inlet water pressure further includes: synchronously acquiring the opening signals of the dynamometer's water supply valve, the return water valve, and the pressure signal of the diversion pipeline; when the opening signals of the water supply valve and / or the return water valve exhibit periodic fluctuations, the inlet water pressure fluctuations are determined to be caused by unstable control of the water supply and return valves; when the pressure signal of the diversion pipeline exhibits amplified fluctuations relative to the pressure signal of the main water supply pipeline, the inlet water pressure fluctuations are determined to be pressure disturbances caused by diversion.

[0052] During troubleshooting of abnormal fluctuations in inlet water pressure, relying solely on signals such as the water supply pump, water tower level, or filter blockage status may not be sufficient to quickly distinguish whether the pressure fluctuation is caused by unstable valve control or by pressure disturbances caused by pipeline diversion. To improve fault location accuracy, this embodiment further introduces the synchronous acquisition and comparative analysis of supply and return water valve opening signals and diversion pipeline pressure signals to achieve rapid identification of the source of pressure fluctuations.

[0053] In practice, valve opening feedback signals can be collected at the actuators of the dynamometer's supply and return valves. Simultaneously, pressure sensors are placed in the branch lines to collect pressure signals, which are then synchronously compared with the pressure signal from the main supply line. If the supply or return valve opening signals exhibit significant periodic changes, and these changes are consistent with the pressure fluctuations in the main supply line in time, it indicates that the inlet pressure fluctuations may be caused by unstable control of the supply and return valves. For example, delayed response of the valve actuator, control signal oscillations, or mechanical jamming of the valve may lead to repeated adjustments of the valve opening. If the pressure signal in the branch lines shows amplified fluctuations relative to the pressure signal in the main supply line—that is, the amplitude of the branch line pressure fluctuations is significantly greater than that of the main supply line pressure fluctuations—it indicates that the branch structure may introduce additional disturbances, such as unstable flow in the branch lines, sudden changes in local resistance, or backflow, thereby disturbing the pressure in the main supply line and affecting the stability of the dynamometer's inlet pressure.

[0054] In one embodiment, after stability maintenance is completed, a verification step is also included. The verification step includes: retesting the performance output parameters and / or vibration parameters under the same test conditions, and comparing the test results before and after maintenance to verify the effectiveness of the maintenance measures in reducing the fluctuation amplitude.

[0055] After the troubleshooting and maintenance measures are implemented, to avoid judging the effectiveness of the troubleshooting based solely on short-term phenomena, this embodiment further includes a verification step to objectively evaluate the effectiveness of the troubleshooting measures. The core of the verification step is to ensure that the verification process is conducted under the same test conditions as when the fault occurred, thereby guaranteeing the repeatability and reliability of the comparison results.

[0056] In one implementation, the verification steps include the following test procedure: after the engine is started, it runs in a ground slow state for a preset time, then in an idle slow state for a preset time, the engine state is pushed up to the state point where the dynamometer malfunctions and maintained for a preset time, to detect the effectiveness of the maintenance measures.

[0057] To ensure the verification process closely mirrors actual test runs and covers the fault reproduction range, this embodiment preferably employs a phased testing procedure to verify the effectiveness of maintenance measures. This verification process proceeds gradually from low to high engine operating conditions, allowing the dynamometer to approach the fault occurrence condition under different stable states. This enables a more accurate assessment of the maintenance measures' improvement on the dynamometer's stability. Specifically, after engine start-up, the system first runs at ground idle for a preset duration to allow the engine and dynamometer system to achieve initial stabilization. Then, it switches to idle for a preset duration to allow the system to enter a stable phase with higher speeds and higher power consumption. After achieving stable operation at ground idle and idle, the engine state is pushed up to the point where the dynamometer malfunctions, and this state is maintained for a preset duration to observe whether abnormal fluctuations still exist in the dynamometer's power, torque, speed, and vibration parameters at this point after the maintenance measures are implemented.

[0058] In one implementation, when maintenance measures are detected to improve dynamometer operation, the engine state is pushed up to a higher operating condition and maintained for a preset duration; when maintenance measures are detected to have failed to improve the condition or worsened the fault, the engine state is pulled down to idle state for a preset duration, and then further pulled down to ground idle state for a preset duration before stopping.

[0059] To further determine whether maintenance measures can cover operational requirements under higher operating conditions, this embodiment sets up a further push-up or pull-down processing strategy for the verification process, ensuring a controllable safety boundary for the verification process. Specifically, when maintenance measures are detected to improve dynamometer operation—that is, when the fluctuation amplitude of performance output parameters is significantly reduced and vibration parameters return to within the allowable range—the engine state can be pushed up to a higher operating condition and maintained for a preset duration to further verify the stability effect of maintenance measures under higher load conditions. This method confirms whether troubleshooting maintenance is only effective at a specific state point or whether it can improve the dynamometer's operational stability over a wider range of operating conditions. When maintenance measures are detected to have failed to improve the situation or worsened the fault—for example, when the fluctuation amplitude of performance output parameters still exceeds the limit or the vibration amplitude further increases—to prevent the fault from escalating and affecting test run safety, this embodiment adopts a pull-down processing strategy. This involves pulling the engine state down to an idle slow state for a preset duration, allowing the system to gradually unload and enter a stable buffer state. If the abnormality still cannot be eliminated, it is further pulled down to an idle slow state for a preset duration before stopping the test, thereby ensuring the safety of the test bench and dynamometer equipment.

[0060] In one embodiment, after performing spectral analysis on the dynamometer vibration signal, the dominant vibration frequency is obtained and compared with a preset frequency threshold. When the dominant vibration frequency is lower than the preset frequency threshold, a test of the test bench's natural frequency is performed. The test of the test bench's natural frequency includes applying excitation to the test bench and collecting the test bench's response signal to obtain the test bench's natural frequency. When the dominant vibration frequency is consistent with the test bench's natural frequency, the vibration is determined to be caused by resonance of the test bench's natural frequency. When the dominant vibration frequency is inconsistent with the test bench's natural frequency, the vibration is determined to be caused by fluid-structure interaction of the water supply system.

[0061] In troubleshooting vibration anomalies, to avoid deviations in troubleshooting direction due to relying solely on experience to determine the vibration source, this embodiment further proposes a comparative analysis method based on the dominant vibration frequency and the natural frequency of the test bench to improve the accuracy of vibration source determination. This method is particularly suitable for vibration faults with low dominant vibration frequencies. Specifically, after performing spectral analysis on the dynamometer vibration signal, the dominant frequency of the vibration signal is extracted as a vibration characteristic parameter, and compared with a preset frequency threshold. Using the preset frequency threshold, the vibration fault can be initially classified into a low-frequency vibration range, allowing for further analysis of test bench structural factors. When the dominant vibration frequency is lower than the preset frequency threshold, this embodiment performs a test bench natural frequency test. The test bench natural frequency test can be achieved by applying excitation to the test bench and collecting the test bench response signal, for example, by applying transient impact excitation or frequency sweep excitation to the test bench structure and collecting acceleration or displacement response signals, and obtaining the test bench natural frequency through frequency domain analysis. This test can reflect the inherent vibration characteristics of the test bench structure under conditions without external load disturbance. After obtaining the test bench natural frequency, the dominant vibration frequency and the test bench natural frequency are compared and analyzed. If the two are close, it indicates that there is a coupling relationship between the dynamometer vibration and the natural frequency of the test bench, and the vibration may be caused by the resonance of the natural frequency of the test bench; if the two are significantly different, it indicates that the natural frequency of the test bench is not the main source of vibration, and the vibration is more likely to be caused by the coupling between the flow field disturbance of the water supply system and the structural response, that is, the vibration caused by the fluid-structure interaction of the water supply system.

[0062] The preset frequency threshold is set to 40Hz. Specifically, when the dominant vibration frequency obtained from the spectral analysis is below 40Hz, the vibration is considered to be in the low-frequency range, and further bench natural frequency testing is performed to determine whether the vibration is caused by bench natural frequency resonance. When the dominant vibration frequency is inconsistent with the bench natural frequency, the low-frequency vibration can be identified as vibration caused by fluid-structure interaction in the water supply system, thus providing a basis for subsequent troubleshooting and maintenance. Inconsistency means that the difference between the two is less than ±5Hz.

[0063] In one implementation, when the dominant vibration frequency is higher than a preset frequency threshold, the rotor dynamic balance test result is obtained, and it is determined whether the vibration is related to the rotor dynamic balance quality based on the dynamic balance test result; when the dynamic balance test result does not meet the preset requirements, the rotor is removed from the platform for dynamic balance maintenance.

[0064] During the troubleshooting process for abnormal vibrations, when the spectral analysis results indicate that the dominant vibration frequency is higher than a preset frequency threshold, the vibration typically exhibits high-frequency excitation characteristics that vary with the rotational speed. This type of vibration is strongly correlated with the unbalanced state of the rotor system. Therefore, this embodiment further introduces dynamic balance detection results as a basis for determining the source of vibration, in order to improve the accuracy of troubleshooting and location.

[0065] In practice, dynamic balance test results obtained during the processing or assembly stages of the test piece or dynamometer rotor can be acquired, such as dynamic balance reports, balance correction records, or balance grade determination results. By verifying the dynamic balance test results, it can be determined whether the rotor dynamic balance quality meets the preset requirements. If the dynamic balance test results show that the unbalance exceeds the limit, the balance grade does not meet the requirements, or there are obvious correction abnormalities, it can be determined that the current high-frequency vibration is related to the rotor dynamic balance quality. When it is determined that the dynamic balance test results do not meet the preset requirements, a rotor off-stage dynamic balance maintenance operation is performed. The off-stage dynamic balance maintenance operation may include disassembling the test piece or dynamometer rotor assembly and rebalancing it, adjusting the counterweight or removing the weight to make the rotor unbalance meet the requirements, thereby reducing the high-frequency vibration amplitude and restoring the dynamometer's operational stability.

[0066] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A troubleshooting method for a hydraulic dynamometer on a ground-based test bench for a turboshaft engine, characterized in that... Includes the following steps: The performance output parameters are detected, and the performance output parameters include at least one of power parameters, torque parameters, and speed parameters. When the performance output parameters exceed the preset fluctuation threshold, the stability of the inlet water pressure and the operational stability of the test piece are judged, and the stability of the inlet water pressure and / or the operational stability of the test piece are maintained according to the judgment result. Determining the stability of inlet water pressure includes: collecting water level signals from the water supply tower, operating status signals from the water supply pump, pressure signals from the water supply pipeline, valve opening signals from the water supply pipeline, and filter blockage status signals from the water supply pipeline, and judging whether there are abnormal fluctuations in inlet water pressure based on the signals; Maintaining the stability of inlet water pressure includes: when abnormal fluctuations in inlet water pressure are detected, performing troubleshooting and maintenance operations on at least one of the following locations: water supply tower, water supply pump, water supply pipeline seal, water supply pipeline valve, and water supply pipeline filter element. Determining the operational stability of the test specimen includes: acquiring the current operating control mode of the hydraulic dynamometer, which includes a position control mode, a torque control mode, and a speed control mode; in the position control mode, determining that the test specimen is unstable when the fluctuations of power parameters, torque parameters, and / or speed parameters exceed a preset fluctuation threshold; in the torque control mode, determining that the test specimen is unstable when the fluctuations of non-torque parameters exceed a preset fluctuation threshold; and in the speed control mode, determining that the test specimen is unstable when the fluctuations of non-speed parameters exceed a preset fluctuation threshold. Maintaining the operational stability of the test specimen includes adjusting the dynamometer control mode when the test specimen is determined to be unstable.

2. The troubleshooting method for the hydraulic dynamometer on the ground test bench of the turboshaft engine according to claim 1, characterized in that: It also includes detecting vibration parameters and maintaining the vibration stability of the hydraulic dynamometer when the vibration parameters exceed the preset fluctuation threshold; Maintaining the vibration stability of the dynamometer includes: performing spectral analysis on the dynamometer vibration signal, determining the vibration type based on the vibration frequency characteristics, and distinguishing between vibrations caused by test piece rotational speed resonance, bench natural frequency resonance, or fluid-structure interaction of the water supply system; when the vibration is determined to be related to the fluid-structure interaction of the water supply system, monitoring the pressure parameters after the inlet valve, and based on the positive correlation between the absolute value of the pressure after the inlet valve and the dynamometer vibration amplitude, adjusting the stability of the flow field on the inlet side to reduce the dynamometer vibration amplitude and restore stable operation.

3. The troubleshooting method for the hydraulic dynamometer on the ground test bench of the turboshaft engine according to claim 2, characterized in that: Stability adjustment of the inlet flow field includes at least one of the following methods: increasing the inlet pressure, increasing the diameter of the dynamometer vent, increasing the number of vents on the dynamometer body, changing the arrangement of the vents, and adjusting the opening ratio of the dynamometer supply and return water valves to change the inlet flow rate.

4. The troubleshooting method for the hydraulic dynamometer on the ground test bench of the turboshaft engine according to claim 1, characterized in that: Adjusting the dynamometer control method involves regulating at least one of the following: PID parameters, inlet valve opening, valve initial value, and inlet / outlet valve ratio, in order to reduce the fluctuation amplitude of performance output parameters and restore stable operation.

5. The troubleshooting method for the hydraulic dynamometer on the ground test bench of the turboshaft engine according to claim 1, characterized in that: When it is determined that there is an abnormal fluctuation in the inlet water pressure, the maintenance of inlet water pressure stability also includes: synchronously collecting the opening signal of the dynamometer water supply valve, the opening signal of the return water valve, and the pressure signal of the diversion pipeline; When the opening signals of the water supply valve and / or the water return valve exhibit periodic fluctuations, the inlet pressure fluctuations are determined to be caused by unstable control of the water supply and return valves; when the pressure signal of the diversion pipeline exhibits amplified fluctuations relative to the pressure signal of the main water supply pipeline, the inlet pressure fluctuations are determined to be pressure disturbances caused by the diversion.

6. The troubleshooting method for the hydraulic dynamometer on the ground test stand for a turboshaft engine according to claim 2, characterized in that: After completing the stability maintenance, a verification step is also included. The verification step includes: retesting the performance output parameters and / or vibration parameters under the same test conditions, and comparing the test results before and after maintenance to verify the effectiveness of the maintenance measures in reducing the fluctuation amplitude.

7. The troubleshooting method for the hydraulic dynamometer on the ground test stand for a turboshaft engine according to claim 6, characterized in that: The verification steps also include the following test procedure: after the engine is started, it runs in the ground slow state for a preset time, then in the idle slow state for a preset time, then the engine state is pushed up to the state point where the dynamometer malfunctions and maintained for a preset time to test the effectiveness of the maintenance measures.

8. The troubleshooting method for the hydraulic dynamometer on the ground test stand for a turboshaft engine according to claim 7, characterized in that: When maintenance measures are detected to improve dynamometer operation, the engine status is pushed up to a higher operating condition and maintained for a preset duration. When maintenance measures are detected to have failed to improve the condition or worsen the fault, the engine status is pulled down to idle slow state for a preset duration, and then further pulled down to ground slow state for a preset duration before stopping.

9. The troubleshooting method for the hydraulic dynamometer on the ground test bench of the turboshaft engine according to claim 2, characterized in that: After performing spectral analysis on the vibration signal of the dynamometer, the dominant vibration frequency is obtained and compared with a preset frequency threshold. When the vibration dominant frequency is lower than the preset frequency threshold, the test bench natural frequency test is performed. The test bench natural frequency test includes applying excitation to the test bench and collecting the test bench response signal to obtain the test bench natural frequency. When the dominant vibration frequency is consistent with the natural frequency of the test bench, the vibration is determined to be caused by resonance of the natural frequency of the test bench; when the dominant vibration frequency is inconsistent with the natural frequency of the test bench, the vibration is determined to be caused by fluid-structure interaction of the water supply system.

10. The troubleshooting method for the hydraulic dynamometer on the ground test bench of the turboshaft engine according to claim 9, characterized in that: When the dominant vibration frequency is higher than the preset frequency threshold, the rotor dynamic balance test result is obtained, and it is determined whether the vibration is related to the rotor dynamic balance quality based on the dynamic balance test result; when the dynamic balance test result does not meet the preset requirements, the rotor is removed from the platform for dynamic balance maintenance.

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