Method for correcting center loading of test stand thrust measurement system to parallel loading

Abstract

The application belongs to the field of aero-engine test, and particularly relates to a correction method for center loading to parallel loading of a test stand thrust measurement system. The method comprises the following steps: step one, center loading calibration is performed on the test stand thrust measurement system to obtain a center loading calibration curve, and a center loading calibration model is fitted according to the center loading calibration curve; parallel loading calibration is performed on the test stand thrust measurement system to obtain a parallel loading calibration curve, and a parallel loading calibration model is fitted according to the parallel loading calibration curve; step two, a correction value of center loading calibration to parallel loading calibration of each load calibration point is calculated, and a correction coefficient of center loading calibration to parallel loading calibration is determined according to the correction values; and step three, the parallel loading calibration model is corrected according to the center loading calibration model and the correction coefficient to obtain a corrected parallel loading calibration model. The application improves the calibration and measurement accuracy of the test stand thrust measurement system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aero-engine test, and particularly relates to a method for correcting parallel loading by center loading of a test stand thrust measurement system. BACKGROUND

[0002] Parallel loading is a calibration method commonly used for a thrust measurement system of a test stand, as shown in FIG. 1. Parallel loading calibrates the test stand thrust measurement system using a loading device on the static frame of the test stand. The loading device and the force work sensor of the test stand are located in the same plane and above the center axis of the engine (hanger). Parallel loading can eliminate system errors caused by elastic force of flexible components, drag force of pipelines and test lines connected to the engine, and output characteristics of the work sensor. Parallel loading calibration does not require installation and removal of related equipment, and is simple to operate. Moreover, parallel loading calibration can be performed after the engine is installed. Figure 1 Center loading can accurately simulate the test of thrust in engine testing. In center loading, the simulated load is transmitted to the simulated engine, the moving frame and the thrust work sensor through the center loading system, and the loading point is located on the center line of the engine to be tested. The center loading device is shown in FIG. 2. The advantage of center loading is that the transmission path of the simulated load is consistent with the actual transmission path of the thrust generated by the engine in the actual test, and can truly reflect the actual use of the force measurement system of the test stand, so that the calibration result is more accurate. When the engine test requires high calibration accuracy of the thrust measurement system, center loading calibration is usually used.

[0003] Figure 2 After the engine is installed on the test stand, the test stand thrust measurement system needs to be calibrated before testing. Since the center loading calibration device has a large structure size, the installation requires a ground reserved foundation. During the construction stage of the test stand, most test stands do not have the ability of center loading calibration, and the calibration of the test stand thrust measurement system is mainly parallel loading calibration. In parallel loading calibration, the loading device and the force work sensor of the test stand are located in the same plane and above the center axis of the engine (hanger). Although parallel loading can eliminate system errors caused by elastic force of flexible components, drag force of pipelines and test lines connected to the engine, and output characteristics of the work sensor, the transmission path of the parallel loading is not consistent with the actual transmission path of the thrust generated by the engine in the actual test. The bending moment caused by the height difference cannot be eliminated, which affects the measurement accuracy of the thrust parameters. Since the transmission path of the parallel loading is different from the transmission path of the engine in the actual test, the parallel loading result needs to be corrected by center loading. New test stands reserve the installation foundation of the center loading device, and can perform center loading calibration of the thrust measurement system. The differences between the center loading device and the parallel loading calibration are compared, but there is no unified and effective correction method.

[0004] Center loading can accurately simulate the test of thrust in engine testing. In center loading, the simulated load is transmitted to the simulated engine, the moving frame and the thrust work sensor through the center loading system, and the loading point is located on the center line of the engine to be tested. The center loading device is shown in FIG. 2. The advantage of center loading is that the transmission path of the simulated load is consistent with the actual transmission path of the thrust generated by the engine in the actual test, and can truly reflect the actual use of the force measurement system of the test stand, so that the calibration result is more accurate. When the engine test requires high calibration accuracy of the thrust measurement system, center loading calibration is usually used.

[0005] ​Therefore, it is desirable to have a technical solution to overcome or at least alleviate at least one of the aforementioned deficiencies of the prior art. SUMMARY

[0006] The purpose of the present application is to provide a test bed thrust measurement system center loading to parallel loading correction method to solve at least one problem existing in the prior art.

[0007] The technical solution of the present application is:

[0008] A test bed thrust measurement system center loading to parallel loading correction method, comprising:

[0009] Step one,

[0010] Calibrate the test bed thrust measurement system for center loading, obtain the center loading calibration curve, and fit the center loading calibration model according to the center loading calibration curve;

[0011] Calibrate the test bed thrust measurement system for parallel loading, obtain the parallel loading calibration curve, and fit the parallel loading calibration model according to the parallel loading calibration curve;

[0012] Step two, calculate the correction value of each load calibration point center loading calibration to parallel loading calibration, and determine the correction coefficient of center loading calibration to parallel loading calibration according to each correction value;

[0013] Step three, according to the center loading calibration model and the correction coefficient, correct the parallel loading calibration model to obtain the corrected parallel loading calibration model.

[0014] In at least one embodiment of the present application, in step one, the test bed thrust measurement system is calibrated for center loading, the center loading calibration curve is obtained, and the center loading calibration model is fitted according to the center loading calibration curve, comprising:

[0015] Install and adjust the center loading calibration device, load and calibrate the load step by step according to the calibration procedure, obtain the center loading calibration curve, and fit the center loading calibration model according to the center loading calibration curve:

[0016] F=k1xv+b1

[0017] Where F is the measured thrust value, k1 is the center loading calibration curve coefficient, v is the sensor output value, and b1 is a constant.

[0018] In at least one embodiment of the present application, in step one, the test bed thrust measurement system is calibrated for parallel loading, the parallel loading calibration curve is obtained, and the parallel loading calibration model is fitted according to the parallel loading calibration curve, comprising:

[0019] The parallel loading calibration device is used to load calibration loads step by step according to a calibration regulation to obtain a parallel loading calibration curve, and a parallel loading calibration model is fitted according to the parallel loading calibration curve:

[0020] F=k2x v+b2

[0021] Wherein, F is a measured thrust value, k2 is a parallel loading calibration curve coefficient, v is a sensor output value, and b2 is a constant.

[0022] In at least one embodiment of the present application, in step two, the correction value of the center loading calibration to the parallel loading calibration of each load calibration point is calculated, and a correction coefficient of the center loading calibration to the parallel loading calibration is determined according to each correction value, which comprises:

[0023] The correction value α of the center loading calibration to the parallel loading calibration of each load calibration point is calculated i ;

[0024] The average value of each correction value is taken as the correction coefficient of the center loading calibration to the parallel loading calibration, and the correction coefficient is:

[0025]

[0026] Wherein, α i is the correction value of the center loading calibration to the parallel loading calibration of the corresponding load calibration point, and n is the number of load calibration points.

[0027] In at least one embodiment of the present application, in step three, the parallel loading calibration model is corrected according to the center loading calibration model and the correction coefficient to obtain a corrected parallel loading calibration model, which comprises:

[0028] The parallel loading calibration model is corrected according to the center loading calibration model and the correction coefficient, and:

[0029]

[0030]

[0031]

[0032] The corrected parallel loading calibration model is:

[0033]

[0034] In at least one embodiment of the present application, the correction of the center loading calibration to the parallel loading calibration is performed once every 1-2 years.

[0035] The present application has at least the following beneficial technical effects:​

[0036] The center loading correction method for test stand thrust measurement system of the application solves the influence of the bending moment formed by the height difference between the action line of the parallel loading calibration device and the action line of the thrust generated by the engine during the test on the calibration accuracy of the thrust parameter, and improves the calibration and measurement accuracy of the test stand thrust measurement system. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a parallel loading calibration schematic diagram of the test stand thrust measurement system;

[0038] Figure 2 is a center loading calibration schematic diagram of the test stand thrust measurement system;

[0039] Figure 3 is a center loading calibration load-sensor output curve schematic diagram of one embodiment of the application;

[0040] Figure 4 is a parallel loading calibration load-sensor output curve schematic diagram of one embodiment of the application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the application clearer, the technical scheme of the embodiments of the application will be described in more detail below in combination with the drawings of the embodiments of the application. In the drawings, the same or similar notations represent the same or similar elements or elements with the same or similar functions throughout. The described embodiments are part of the embodiments of the application, not all of the embodiments. The embodiments described below by reference to the drawings are exemplary and are intended to explain the application, and cannot be understood as a limitation on the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application. The embodiments of the application will be described in detail below in combination with the drawings.

[0042] In the description of the application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the scope of protection of the application.

[0043] The embodiments of the application will be described in detail below in combination with the drawings. Figures 3 to 4 The application will be described in further detail.

[0044] The application provides a correction method for center loading of a test bench thrust measurement system to parallel loading, comprising the following steps:

[0045] Step one,

[0046] Calibrate the test bench thrust measurement system for center loading, obtain a center loading calibration curve, and fit a center loading calibration model according to the center loading calibration curve;

[0047] Calibrate the test bench thrust measurement system for parallel loading, obtain a parallel loading calibration curve, and fit a parallel loading calibration model according to the parallel loading calibration curve;

[0048] Step two, calculate the correction value of the center loading calibration to the parallel loading calibration of each load calibration point, and determine the correction coefficient of the center loading calibration to the parallel loading calibration according to the correction values;

[0049] Step three, correct the parallel loading calibration model according to the center loading calibration model and the correction coefficient to obtain a corrected parallel loading calibration model.

[0050] Thrust is the most core technical index of an aero-engine, and pre-test calibration of a test bench thrust measurement system is very important to ensure the measurement accuracy of thrust parameters. There are mainly two methods for calibration of the test bench thrust measurement system: parallel loading calibration and center loading calibration. The parallel loading calibration is to calibrate the test bench thrust measurement system by using a parallel loading calibration device on a static frame of the test bench, the parallel loading calibration device and a force work sensor of the test bench are located in the same plane, and the parallel loading calibration process does not need to install and remove related equipment, so the operation is simple, and the parallel loading calibration can be performed after the engine is installed. The center loading calibration needs to install an additional center loading calibration device, the calibration load is transmitted to the simulated engine, the moving frame and the thrust work sensor through the center loading calibration device, and the loading point is located on the center line of the measured engine. The calibration load of the center loading is consistent with the transmission path of the thrust generated by the engine during the test, can truly reflect the actual use of the force measurement system of the test bench, and makes the calibration result more accurate.

[0051] Based on the above status, the correction method for center loading of the test bench thrust measurement system to parallel loading of the application first calibrates the center loading and the parallel loading according to the specific conditions of the test bench.

[0052] During the center loading calibration of the test bench thrust measurement system, the center loading calibration device is installed and adjusted, the calibration load is loaded step by step according to the calibration procedure, the output signal of the thrust measurement sensor of the test bench thrust measurement system, the calibration curve is as shown in Figure 3 The fitted curve obtains the expression of the center loading calibration model:

[0053] F=k1×v+b1

[0054] Where F is the measured thrust value, k1 is the central loading calibration curve coefficient, v is the sensor output value, and b1 is a constant.

[0055] When the test stand thrust measurement system is calibrated in parallel loading, the parallel loading calibration device is used, and the calibration load is loaded step by step according to the calibration procedure. The output signal of the thrust measurement sensor of the test stand thrust measurement system is shown in the calibration curve as shown in FIG. 1, the fitting curve is obtained, and the expression of the parallel loading calibration model is as follows: Figure 4

[0056] F = k2 x v + b2

[0057] Where F is the measured thrust value, k2 is the parallel loading calibration curve coefficient, v is the sensor output value, and b2 is a constant.

[0058] After calibration, the fitted calibration curve coefficient is written into the test stand measurement program to calculate the measured thrust value in the test. From Figure 3 and Figure 4 It can be found that the k value in the calibration curve fitting formula obtained after central loading calibration and parallel loading calibration is different, k1 > k2, that is, the measured thrust value calculated by the central loading calibration coefficient is greater than the parallel loading calibration result. After calculation, this difference is usually between 0.05% and 0.2% of the measured value. For engine performance recording tests, correction is required.

[0059] The engine test stand thrust measurement system has high linearity, usually better than 0.02%. Although the parallel loading calibration and the central loading calibration have different load application positions, the elastic elements connected between the dynamic frame and the static frame have good repeatability, and the repeatability of the test stand thrust measurement system is also better than 0.02%. In engine tests, performance data of each state need to be recorded, so the correction of central loading to parallel loading should also consider each loading calibration point. Table 1 calculates the correction value a of central loading calibration to parallel loading calibration for each load calibration point i .

[0060] Table 1

[0061] Standard load (%) Center load (mv) Parallel load (mv) Correction value 0 0 0 10 V 11 ]]> V 21 ]]> a1 = V 11 / 21 <!-- 4 -->]]> 30 V 12 ]]> V 22 ]]> a2 = V 12 / 22 ]] 50 V 13 ]]> V 23 ]]> a3 = V 13 / 23 ]] 60 V 14 ]]> V 24 ]]> a4 = V 14 V 24 ]]> 70 V 15 ]]> V 25 ]]> a5 = V 15 / 25 ]] 80 V 16 ]]> V 26 ]]> a6 = V 16 / 26 ]] 90 V 17 ]]> V 27 ]]> a7 = V 17 / 27 ]] 100 V 18 ]]> V 28 ]]> a8 = V 18 / 28 ]]

[0062] To facilitate the use of correction values in the test stand data acquisition program, the average value of each correction value is used as the correction coefficient of central loading calibration to parallel loading calibration, and the calculation formula is as follows:

[0063]

[0064] Where a i is the correction value of central loading calibration to parallel loading calibration for the corresponding load calibration point, and n is the number of load calibration points.​

[0065] For convenience of calculation, in the correction of the center loading calibration to the parallel loading calibration before the functional debugging test bench or the non-reference performance recording test, the ratio of the k value in the fitting formula of the center loading calibration to the parallel loading calibration can be approximately used as the correction coefficient, and the following equation is obtained:

[0066]

[0067]

[0068]

[0069] The corrected parallel loading calibration model is:

[0070]

[0071] Considering the good repeatability and stability of the engine test bench thrust measurement system, the correction of the center loading calibration to the parallel loading calibration can be performed once every 1-2 years.

[0072] The center loading calibration to the parallel loading calibration method of the test bench thrust measurement system of the present application corrects the influence of the bending moment formed by the height difference between the action line of the parallel loading calibration device and the action line of the thrust generated by the engine during the test on the calibration accuracy of the thrust parameter, and realizes the correction of the daily parallel loading calibration result to the center loading calibration state through the correction coefficient, thereby improving the calibration and measurement accuracy of the test bench thrust measurement system.

[0073] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.​

Claims

1. A method for correcting the effect of center loading on parallel loading in a test bench thrust measurement system, characterized in that, include: Step 1 The thrust measurement system of the test stand is calibrated by center loading to obtain the center loading calibration curve, and the center loading calibration model is obtained by fitting the center loading calibration curve. Parallel loading calibration is performed on the test bench thrust measurement system to obtain the parallel loading calibration curve, and a parallel loading calibration model is obtained by fitting the parallel loading calibration curve. Step 2: Calculate the correction value of the center loading calibration to the parallel loading calibration for each load calibration point, and determine the correction coefficient of the center loading calibration to the parallel loading calibration based on each correction value; Step 3: Based on the central loading calibration model and the correction coefficient, the parallel loading calibration model is corrected to obtain the corrected parallel loading calibration model. In step one, the process of performing center loading calibration on the test bench thrust measurement system, obtaining a center loading calibration curve, and fitting a center loading calibration model based on the center loading calibration curve includes: Install and adjust the center loading calibration device, apply the calibration load step by step according to the calibration procedure, obtain the center loading calibration curve, and fit the center loading calibration curve to obtain the center loading calibration model: F = k1 × v + b1 Where F is the measured thrust value, k1 is the coefficient of the center loading calibration curve, v is the sensor output value, and b1 is a constant; In step one, the parallel loading calibration of the test bench thrust measurement system is performed to obtain a parallel loading calibration curve. A parallel loading calibration model is then fitted based on the parallel loading calibration curve, including: A parallel loading calibration device is used to apply calibration loads step by step according to the calibration procedure, and parallel loading calibration curves are obtained. A parallel loading calibration model is then obtained by fitting the parallel loading calibration curves. F = k² × v + b² Where F is the measured thrust value, k2 is the coefficient of the parallel loading calibration curve, v is the sensor output value, and b2 is a constant; In step two, the calculation of the correction value for the center loading calibration to the parallel loading calibration at each load calibration point, and the determination of the correction coefficient for the center loading calibration to the parallel loading calibration based on each correction value, includes: Calculate the correction value α for the center loading calibration to the parallel loading calibration at each load calibration point. i ; The average of all correction values ​​is used as the correction factor for the center-load calibration to the parallel-load calibration, and the correction factor is: Where, α i The correction value for parallel loading calibration is applied to the center of the corresponding load calibration point, where n is the number of load calibration points; In step three, the process of correcting the parallel loading calibration model based on the central loading calibration model and the correction coefficient to obtain the corrected parallel loading calibration model includes: Based on the central loading calibration model and the correction coefficient, the parallel loading calibration model is corrected by setting: have to: The corrected parallel loading calibration model is as follows:

2. The method for correcting the center loading of the test bench thrust measurement system for parallel loading according to claim 1, characterized in that, The correction of the parallel loading calibration to the center loading calibration should be performed every 1 to 2 years.

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