Method for testing the crashworthiness of an aeroengine swallowing test

Abstract

The application provides a kind of aviation engine swallowing test anti-collision ability test method, comprising: step one, the installation calibration of high-speed camera system and the speed debugging of impact object target shooting;Step two, determine the effective field of view of high-speed camera in high-speed camera system The closest speed measuring point M to the engine, measure the horizontal distance L4 between speed measuring point M and air gun muzzle;Step three, calculate the speed of speed measuring point M and engine inlet under fitting curve, and establish the speed relationship of speed measuring point M and engine inlet under target shooting debugging;Step four, according to step three, the average speed of impact object is calculated and used as the impact speed of impact object at engine inlet.The application solves the problem of difficult measurement of impact object speed caused by change of impact object posture and the problem of unable to measure the impact object speed of engine inlet cross section caused by shielding of flow guide basin, and improves the speed measurement accuracy of impact object impacting engine.

Description

TECHNICAL FIELD

[0001] The present specification relates to the technical field of aero-engine, in particular to a method for testing the anti-collision capability of aero-engine swallowing test. BACKGROUND

[0002] In the aero-engine swallowing test, the impact object speed is usually measured by three methods: coil target, light curtain target and high-speed camera. The coil target measurement method has large measurement error due to factors such as inaccurate target distance measurement, timer error, and time delay of target surface fine wire breakage. In the light curtain target measurement method, the light path of the light curtain is well aligned, and is less affected by vibration. The main spatial error is that the reference line and the object motion direction are not completely parallel, and the speed measurement error is about 0.6%. The speed measurement error of the high-speed camera mainly comes from the error of the motion distance judgment, and the speed measurement error is about 0.4%. Therefore, it is recommended to use a high-speed camera to measure the speed in the engine swallowing test.

[0003] Although the above-mentioned high-speed camera speed measurement method has high precision, it measures the average speed of the air gun muzzle and the engine inlet. However, in the actual running process of the impact object, the running speed displacement of the impact object gradually decreases due to air resistance. At the same time, due to the shielding of the engine inlet guide basin, the field of view range of the high-speed camera cannot reach the impact object impact section of the engine inlet, but has a certain distance from the impact section. Therefore, the calculated speed of the impact object cannot represent the real impact speed of the impact object. SUMMARY

[0004] Therefore, the embodiment of the present specification provides a method for testing the anti-collision capability of aero-engine swallowing test, which provides more accurate data support for effectively evaluating the anti-collision capability of aero-engine.

[0005] The technical solution of the present application is: a method for testing the anti-collision capability of aero-engine swallowing test, comprising: step one, installation and calibration of high-speed camera system and speed debugging of impact object target shooting; step two, determining the nearest speed measurement point M in the effective field of view of the high-speed camera in the high-speed camera system to the engine, and measuring the horizontal distance L4 between the speed measurement point M and the air gun muzzle; step three, calculating the speed of the speed measurement point M and the engine inlet under the fitting curve, and establishing the speed relationship between the speed measurement point M and the engine inlet under the target shooting debugging; step four, calculating the average speed of the impact object according to step three and taking it as the impact speed of the impact object at the engine inlet.

[0006] Further, the step one comprises: determining the installation position of the high-speed camera according to the distance L1 between the air gun muzzle and the blade leading edge of the engine inlet, and the field of view range of the high-speed camera should contain the air gun muzzle to the blade leading edge of the engine inlet; setting a horizontal scale and a vertical scale on the calibration plate according to the distance L1 between the air gun muzzle and the blade leading edge of the engine inlet, and making the length L2 of the horizontal scale greater than the distance L1 between the air gun muzzle and the blade leading edge of the engine inlet, and making the width L3 of the vertical scale greater than the diameter D of the engine inlet; fixing the calibration plate on the opposite side of the high-speed camera, making the calibration plate parallel to the air gun barrel axis, and making the horizontal scale of the calibration plate on the horizontal line calibrated by the laser level, and the air gun muzzle to the engine inlet in the calibration range of the calibration plate.

[0007] Further, after fixing the calibration plate on the opposite side of the high-speed camera, making the calibration plate parallel to the air gun barrel axis, and making the horizontal scale of the calibration plate on the horizontal line calibrated by the laser level, and the air gun muzzle to the engine inlet in the calibration range of the calibration plate, the method further comprises: taking a picture of the calibration plate by the high-speed camera; and determining the pixel coefficient K for calculating the impact object speed according to the horizontal scale and the pixel relationship corresponding to the high-speed camera in the calibration range of the calibration plate.

[0008] Further, the speed debugging of the impact object in the step one comprises: installing a calibration target at the engine inlet, and performing the target shooting debugging by the impact object, and recording the running track of the impact object under different working pressures of the air gun by the high-speed camera; selecting a set of feature points H of the impact object as the impact object points from the impact object photographed by the high-speed camera, and automatically identifying the pixel coordinates of the feature points H in each frame of picture; extracting the pixel coordinates of the feature points H in the picture according to the set frame interval, and calculating the displacement coordinates Xi of the impact object relative to the muzzle in the running process by combining the pixel coefficient K, wherein i is the frame number of the photographed picture relative to the air gun muzzle; calculating the instantaneous speed Vi of the impact object in the running process according to the displacement coordinates Xi and the shooting frame rate I of the high-speed camera; and performing the quadratic curve fitting on the discrete data of the instantaneous speed Vi and the displacement Xi according to Vi=a*Xi2+b to obtain the relationship Vi=f(Xi), wherein a and b are the fitted coefficients.

[0009] Further, the speed debugging of the impact object in the step one comprises: installing a calibration target at the engine inlet, and performing the target shooting debugging by the impact object, and recording the running track of the impact object under different working pressures of the air gun by the high-speed camera; selecting a set of feature points H of the impact object as the impact object points from the impact object photographed by the high-speed camera, and automatically identifying the pixel coordinates of the feature points H in each frame of picture; extracting the pixel coordinates of the feature points H in the picture according to the set frame interval, and calculating the displacement coordinates Xi of the impact object relative to the muzzle in the running process by combining the pixel coefficient K, wherein i is the frame number of the photographed picture relative to the air gun muzzle; calculating the instantaneous speed Vi of the impact object in the running process according to the displacement coordinates Xi and the shooting frame rate I of the high-speed camera; and performing the quadratic curve fitting on the discrete data of the instantaneous speed Vi and the displacement Xi according to Vi=a*Xi2+b to obtain the relationship Vi=f(Xi), wherein a and b are the fitted coefficients.

[0010] Further, the method further comprises removing the calibration target and installing the engine test guide basin before the step two.

[0011] Further, the step three is specifically: according to the multiple fitting curve relations Vi=fj(Xi), L1 and L4, a speed relation of the measuring point M and the engine inlet under the targeting debugging is established, VFj=g(VMj), wherein, VFj is the engine inlet speed, and VMj is the measuring point M speed.

[0012] Further, the step three further includes: a relation of the impactor speed and displacement Vi=h(Xi) is obtained, the impactor speed VZm of the measuring point M is calculated, and the impactor speed VZh=h(L1) of the engine inlet is extrapolated.

[0013] Further, the step four is specifically: according to the relation VFj=g(VMj), the calculated impactor speed VZg=g(VZm) is obtained, and the average value VZ=(VZh+VZg) / 2 of the extrapolated impactor speed VZh and the calculated impactor speed VZg is taken as the final impactor speed of the engine inlet.

[0014] Compared with the prior art, the above at least one technical solution adopted by the embodiment of the present application can achieve the beneficial effects at least including: the present application effectively solves the problems of the impactor speed being difficult to measure due to the change of the impactor posture and the impactor speed of the engine inlet section being unable to be measured due to the shielding of the flow guide basin, and greatly improves the speed measurement accuracy of the impactor hitting the engine. Accurate and effective data support is provided for the verification of the swallowing test of the aero-engine whole machine and fan components. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1 is a flowchart of the embodiment of the present application. DETAILED DESCRIPTION

[0017] The embodiments of the present application will be described in detail below with reference to the drawings.

[0018] Following, the embodiments of the present application are described through specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details in the specification without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0019] As shown in the figure, the embodiment of the present application provides a collision resistance test method for an aviation engine swallowing test, comprising: Figure 1

[0020] Step one, installation and calibration of a high-speed camera system and speed adjustment of a target impact object;

[0021] Step two, determining the closest speed measurement point M in the effective field of view of the high-speed camera in the high-speed camera system to the engine, and measuring the horizontal distance L4 between the speed measurement point M and the muzzle of the air gun;

[0022] Step three, calculating the speed of the speed measurement point M and the engine inlet under the fitting curve, and establishing the speed relationship between the speed measurement point M and the engine inlet under the target impact adjustment;

[0023] Step four, calculating the average speed of the impact object as the impact speed of the impact object at the engine inlet according to the step three.

[0024] The present application effectively solves the problems of difficulty in measuring the speed of the impact object due to the change of the attitude of the impact object and the problem of being unable to measure the speed of the impact object at the engine inlet section due to the shielding of the flow guide basin, greatly improving the speed measurement accuracy of the impact object impacting the engine. It provides accurate and effective data support for verifying the swallowing test of the aviation engine and fan components.

[0025] The step one comprises:

[0026] According to the distance L1 between the muzzle of the air gun and the blade leading edge of the engine inlet, the installation position of the high-speed camera is determined, and the field of view range of the high-speed camera should include the muzzle of the air gun to the blade leading edge of the engine inlet; it is ensured that the high-speed camera can measure the speed of the impact object at the engine inlet during the target impact adjustment.

[0027] An illumination light source is installed on the side of the high-speed camera, and the illumination degree of the light source should meet the requirements; it is ensured that the position of the impact object can be clearly identified in the photos taken by the high-speed camera. ​

[0028] According to the distance L1 between the muzzle of the air gun and the leading edge of the blade of the engine inlet, a calibration plate is designed and manufactured, a horizontal scale and a vertical scale are arranged on the calibration plate, the length L2 of the horizontal scale is greater than the distance L1 between the muzzle of the air gun and the leading edge of the blade of the engine inlet, and the width L3 of the vertical scale is greater than the diameter D of the engine inlet; the calibration plate is used for the high-speed camera system to determine the position of the impactor and to prepare for the calculation of the speed of the impactor.

[0029] The calibration plate is fixed on the opposite side of the high-speed camera, the calibration plate is parallel to the axis of the air gun barrel, the horizontal scale of the calibration plate is located on the horizontal line calibrated by the laser level, and the air gun muzzle to the engine inlet is within the calibration range of the calibration plate as viewed from the high-speed camera.

[0030] The calibration plate is fixed on the opposite side of the high-speed camera, the calibration plate is parallel to the axis of the air gun barrel, the horizontal scale of the calibration plate is located on the horizontal line calibrated by the laser level, and the air gun muzzle to the engine inlet is within the calibration range of the calibration plate as viewed from the high-speed camera.

[0031] The calibration plate is photographed by the high-speed camera, which is used for the high-speed camera system to determine the position of the impactor.

[0032] Within the calibration range of the calibration plate, the pixel coefficient K for calculating the speed of the impactor is determined according to the relationship between the horizontal scale and the pixels of the corresponding high-speed camera. The pixel coefficient K is associated with the displacement, so as to calculate the running distance of the impactor.

[0033] The calibration plate is removed, and the fixed wall on the opposite side of the high-speed camera is processed to ensure that the impactor has strong contrast with the wall surface, and at the same time, the wall surface cannot have a reflection phenomenon. This is used to improve the recognition degree of the camera system for the impactor in the running.

[0034] The speed adjustment of the impactor in step one includes:

[0035] The calibration target is installed at the engine inlet, the impactor is used for target shooting adjustment, and the high-speed camera is used to record the running track of the impactor under different working pressures of the air gun.

[0036] In the camera processing software, a set of feature points H on the impactor photographed by the high-speed camera are selected as the mass points of the impactor, and the camera processing software is used to automatically identify the pixel coordinates of the feature points H in each frame of photograph; the feature points H are used to replace the entire impactor, so as to facilitate the calculation of the speed of the impactor.

[0037] According to the set frame interval, the pixel coordinates of the feature points H in the photograph are extracted, and the pixel coefficient K is combined to calculate the displacement coordinates Xi of the impactor relative to the muzzle in the running process, wherein i is the frame number of the photographed photograph relative to the muzzle of the air gun.

[0038] According to the displacement coordinate Xi and the shooting frame rate I of the high-speed camera, the instantaneous speed Vi of the impactor in the running process is calculated;

[0039] The discrete data of the instantaneous speed Vi and the displacement coordinate Xi are subjected to quadratic curve fitting according to Vi=a*Xi+b, to obtain a relationship Vi=f(Xi), wherein a and b are fitting coefficients. 2 +b, to obtain a relationship Vi=f(Xi), wherein a and b are fitting coefficients.

[0040] The speed adjustment of the impactor shooting is repeatedly performed to obtain a plurality of fitting curve relationships Vi=fj(Xi), wherein j is the number of shooting adjustment.

[0041] Before the step two, it further comprises:

[0042] The calibration target is disassembled and the engine test flow guide basin is installed.

[0043] The step three specifically comprises: under the real swallowing test condition, determining the speed measurement point M closest to the engine in the effective field of view of the high-speed camera, and measuring the horizontal distance L4 between the speed measurement point M and the muzzle of the air cannon.

[0044] According to the curve relationship Vi=fj(Xi) and the distance L1 and the horizontal distance L4, the speed relationship between the speed measurement point M and the engine inlet in the shooting adjustment is established, VFj=g(VMj), wherein VFj is the engine inlet speed and VMj is the speed of the speed measurement point M. The speed of the impactor at the engine inlet cross section after being shielded by the flow guide basin is facilitated to be calculated.

[0045] The step three further comprises:

[0046] The relationship Vi=h(Xi) between the impactor speed and the displacement is obtained, the impactor speed VZm of the speed measurement point M is calculated, and the impactor speed VZh=h(L1) of the engine inlet is extrapolated.

[0047] The step four specifically comprises:

[0048] According to the relationship VFj=g(VMj), the calculated impactor speed VZg=g(VZm) is obtained, and the average value VZ=(VZh+VZg) / 2 of the extrapolated impactor speed VZh of the engine inlet and the calculated impactor speed VZg is taken as the final impactor speed of the engine inlet.

[0049] The average impactor speed obtained by using the two extrapolation methods can reduce the calculation error and further improve the calculation accuracy of the impactor speed.

[0050] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any changes or replacements within the technical scope disclosed by the present application can be easily conceived by the person skilled in the art, and 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 of testing the crashworthiness of an aeroengine swallow test, characterized in that, The method comprises the following steps: Step 1, installation calibration of high-speed camera system and speed debugging of impactor; Step 2, determining the effective field of view of the high-speed camera in the high-speed camera system, and measuring the horizontal distance L4 between the measuring point M closest to the engine and the muzzle of the air gun; Step 3, calculating the speed of the measuring point M and the engine inlet under the fitting curve, and establishing the speed relationship between the measuring point M and the engine inlet under the target debugging; Step 4, calculating the average speed of the impactor according to the speed relationship between the measuring point M and the engine inlet under the target debugging, and taking the average speed as the impact speed of the impactor at the engine inlet; The speed adjustment of the impactor in the step one comprises: installing a calibration target at the inlet of the engine, using the impactor to perform a calibration, using a high-speed camera to record the running track of the impactor under different working pressures of the air gun; selecting a set of feature points H on the impactor recorded by the high-speed camera as impactor points, automatically identifying the pixel coordinates of the feature points H in each frame of the photo; extracting the pixel coordinates of the feature points H in the photo according to a set frame interval, calculating the displacement coordinates Xi of the impactor relative to the muzzle in the running process in combination with a pixel coefficient K, wherein i is the frame number of the photo relative to the muzzle of the air gun; calculating the instantaneous speed Vi of the impactor in the running process according to the displacement coordinates Xi and the shooting frame rate I of the high-speed camera; performing a quadratic curve fitting on the discrete data of the instantaneous speed Vi and the displacement coordinates Xi according to Vi=a*Xi 2 +b, to obtain a relationship Vi=f(Xi), wherein a and b are the fitted coefficients; Repeating the speed debugging of the impactor to obtain a plurality of fitting curve relationships Vi=fj(Xi), wherein j is the number of target debugging; Before the step 2, further comprising the steps of removing the calibration target and installing the engine test guide basin; The step 3 specifically comprises the steps of: according to the plurality of fitting curve relationships Vi=fj(Xi), the distances L1 and L4 between the muzzle of the air gun and the blade leading edge of the engine inlet, establishing the speed relationship between the measuring point M and the engine inlet under the target debugging VFj=g(VMj), wherein VFj is the engine inlet speed, and VMj is the speed of the measuring point M; The step 3 further comprises the steps of: obtaining the relationship Vi=h(Xi) between the impactor speed and the displacement, calculating the impactor speed VZm of the measuring point M, and simultaneously extrapolating the impactor speed VZh of the engine inlet VZh=h(L1); The step 4 specifically comprises the steps of: obtaining the calculated impactor speed VZg=g(VZm) according to the relationship VFj=g(VMj), and taking the average value VZ=(VZh+VZg) / 2 of the extrapolated impactor speed VZh of the engine inlet and the calculated impactor speed VZg as the final impact speed of the impactor at the engine inlet.

2. The test method of claim 1, wherein, The step 1 comprises the steps of: According to the distance L1 between the muzzle of the air gun and the blade leading edge of the engine inlet, determining the installation position of the high-speed camera, and the field of view of the high-speed camera should contain the muzzle of the air gun to the blade leading edge of the engine inlet; According to the distance L1 between the muzzle of the air gun and the blade leading edge of the engine inlet, setting a horizontal scale and a vertical scale on the calibration plate, and making the length L2 of the horizontal scale greater than the distance L1 between the muzzle of the air gun and the blade leading edge of the engine inlet, and making the width L3 of the vertical scale greater than the diameter D of the engine inlet; Fixing the calibration plate on the opposite side of the high-speed camera, making the calibration plate parallel to the air gun barrel axis, making the horizontal scale of the calibration plate on the horizontal line calibrated by the laser level, and making the air gun muzzle to the engine inlet in the calibration range of the calibration plate.

3. The test method of claim 2, wherein, Fixing the calibration plate on the opposite side of the high-speed camera, making the calibration plate parallel to the air gun barrel axis, making the horizontal scale of the calibration plate on the horizontal line calibrated by the laser level, and making the air gun muzzle to the engine inlet in the calibration range of the calibration plate. Taking a photo of the calibration plate by using the high-speed camera; In the calibration range of the calibration plate, determining the pixel coefficient K for calculating the impactor speed according to the horizontal scale and the pixel relationship corresponding to the high-speed camera.

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