Engine drop test device under large overload impact and gap measurement test method

Abstract

The invention discloses an engine drop test device under large overload impact and a gap measurement test method, and the device comprises a box body which is internally provided with an engine accommodation cavity; the engine is positioned in the engine accommodating cavity, and the engine is provided with an engine rotor and an engine stator casing; the crane is connected with the box body, is suitable for driving the box body to lift and can release the box body; the rotor blade driving mechanism is connected with the engine rotor and is suitable for driving the rotor blades to rotate when the engine is in a non-running state; the blade tip clearance measuring device is arranged on an engine stator casing and is suitable for measuring the clearance between an engine rotor and the engine stator casing when an engine is subjected to an impact load. When the test is carried out, the engine is not started, so that the risk of scraping and friction of the rotor and the stator of the engine caused by reduction of the gap between the rotor and the stator of the engine due to engine operation is avoided, and the possibility of scraping and friction of the rotor and the stator of the engine is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine detection, and particularly relates to an engine drop test device and a clearance measurement test method under large overload impact. Background Art

[0002] The engine drop test is an important test item for obtaining design parameters such as the deformation of the rotating and static parts of the engine and the acceleration response under large overload impact conditions. The existing engine drop test method requires the establishment of a complete engine dynamic load test bench. Under the operating conditions of the engine, a large overload impact is suddenly applied through a loading device to obtain relevant verification data. Since the mass of the test devices such as the test engine and the mounting frame usually reaches more than two tons, this method requires a powerful impact load loading system to achieve the loading, resulting in high construction costs and a complex test system. Moreover, since the test is carried out under the operating conditions of the engine, the tip clearance is already in a small state. Under the action of an external impact load, the clearance will further decrease, increasing the risk of rubbing between the rotating and static parts of the engine and affecting the safe operation of the engine. Summary of the Invention

[0003] In view of this, the present invention provides an engine drop test device and a clearance measurement test method under large overload impact to solve the problem that the current engine drop test method may cause rubbing between the rotating and static parts of the engine.

[0004] In a first aspect, the present invention provides an engine drop test device under large overload impact, including:

[0005] A box body, inside which an engine accommodation cavity is provided;

[0006] An engine, which is positioned in the engine accommodation cavity, and the engine has an engine rotor and an engine stator casing;

[0007] A crane, which is connected to the box body and is suitable for driving the box body to lift and be able to release the box body;

[0008] A rotor blade driving mechanism, which is connected to the engine rotor and is suitable for driving the rotor blades to rotate when the engine is in a non-operating state;

[0009] A tip clearance measurement device, which is arranged on the engine stator casing and is suitable for measuring the clearance between the engine rotor and the engine stator casing when the engine is subjected to an impact load.

[0010] The beneficial effects of the above engine drop test device under large overload impact are as follows: During the test, the engine is not started, there is no fuel combustion process, and there is no high-temperature and high-pressure gas to push the turbine and other moving parts, reducing the deformation and clearance change of the engine rotor and stator caused by thermal expansion, avoiding the risk of rubbing between the engine rotor and stator due to the reduction of the clearance between the engine rotor and stator during engine operation, reducing the possibility of rubbing between the engine rotor and stator, and reducing the test risk. The present invention drives the engine rotor to rotate through the rotor blade driving mechanism and combines with the tip clearance measuring device to effectively measure the clearance between the engine rotor and stator under impact load.

[0011] In an alternative embodiment, the rotor blade driving mechanism includes:

[0012] A motor;

[0013] A transmission shaft, one end of which is connected to the output shaft of the motor, and the other end is connected to the engine rotor through a transmission member, and the transmission member is adapted to convert the rotation of the transmission shaft into the rotation of the engine rotor.

[0014] The beneficial effects of the above technical solution are as follows: The test object, the engine body, is not operating. The motor is used to drive the engine rotor to obtain a certain speed, and in combination with the tip clearance measuring device, the change law of the tip clearance under the action of external impact load can be effectively obtained.

[0015] In an alternative embodiment, a buffer structure is laid below the box body, and the buffer structure can prevent the failure of the load-bearing system such as the engine casing and mounting lugs due to excessive impact when the engine falls.

[0016] In an alternative embodiment, at least one mounting lug is provided on the outer wall of the engine, and the engine is mounted on the engine mounting bracket through the mounting lug, and the engine mounting bracket is fixedly connected to the inner wall of the box body.

[0017] In an alternative embodiment, the tip clearance measuring device includes at least one capacitive gap sensor, and each capacitive gap sensor is arranged on the engine stator casing and is arranged opposite to the tip of the rotor blade of the engine rotor. By converting the capacitance signal into a gap value signal, the change process of the gap value between the rotor and stator with the external load can be obtained.

[0018] In a second aspect, the present invention provides a gap measurement test method, which is based on the above engine drop test device under large overload impact and includes the following steps:

[0019] Lift the box body to a predetermined height by a crane;

[0020] Drive the engine rotor to rotate to the target speed through the rotor blade driving mechanism;

[0021] When the engine rotor rotates to the target speed instantaneously, release the housing, and the housing falls freely, generating an impact load.

[0022] During the time when the load acts, drive the engine rotor to continue running through the rotor blade drive mechanism, and measure the clearance between the engine rotor and the engine stator casing through the tip clearance measuring device.

[0023] In an alternative embodiment, measuring the clearance between the engine rotor and the engine stator casing through the tip clearance measuring device is to measure the tip clearance by detecting the change in capacitance between the tip of the engine rotor blade and the capacitive clearance sensor, including the following specific steps:

[0024] When the engine rotor is running, when each engine rotor blade rotates past the position of the capacitive clearance sensor, an instantaneous capacitance signal is formed between the tip and the engine stator casing. During the time when the external impact load acts, multiple engine rotor blades pass through the position of the capacitive clearance sensor, forming multiple capacitance signals. Convert the capacitance signals into clearance value signals, and then obtain the history of the change in the clearance value between the rotating and stationary parts with respect to the external load.

[0025] In an alternative embodiment, before obtaining the history of the change in the clearance value between the rotating and stationary parts with respect to the external load, perform the equivalence of the real external impact load to the test load: According to the design load and simulation results, carry out the conversion of the equivalent load for the engine test.

[0026] In an alternative embodiment, performing the equivalence of the real external impact load to the test load specifically includes the following steps:

[0027] Analyze the design load spectrum to obtain the peak value a of the impact load acceleration and the corresponding half-sine wave pulse width value s;

[0028] Preset the test spectrum as an impact spectrum with an acceleration peak value a1 and a half-sine wave pulse width value s1;

[0029] Use the impact dynamics method to analyze the deformation and acceleration response of the engine rotating and stationary parts under the design load spectrum, obtain the deformation response of the engine rotating and stationary parts under the impact load, the initial clearance of the engine rotating and stationary parts is d0, and the minimum clearance under the external load is d1. Obtain the maximum clearance change amount Δd = d0 - d1 of the engine rotating and stationary parts under the test spectrum;

[0030] Use the impact dynamics method to analyze the deformation and acceleration response of the engine rotating and stationary parts under the test spectrum, obtain the deformation response of the engine rotating and stationary parts under the impact load, the initial clearance of the engine rotating and stationary parts is d0, and the minimum clearance under the external load is d1'. Obtain the maximum clearance change amount Δd' = d0 - d1' of the engine rotating and stationary parts under the test spectrum;

[0031] By continuously adjusting the peak value of the test spectrum acceleration and the half-sine pulse width, and through iterative analysis, the peak value af of the acceleration of the final test spectrum half-sine waveform and the pulse width sf are determined to ensure that under this load spectrum, Δd = Δd', and at the same time ensure that the peak value af of the test spectrum acceleration is not less than the peak value a of the design spectrum acceleration.

[0032] The beneficial effect of the above equivalent method from the real external impact load to the test load is as follows: Using the half-sine shock wave as the test spectrum as the test equivalent load, with the change amount of the rotor-stator clearance as the target, the peak value of the test spectrum acceleration and the half-sine bandwidth are determined through iterative analysis, and the design load spectrum can be effectively simulated.

[0033] In an optional implementation manner, after determining the peak value af of the acceleration of the final test spectrum half-sine waveform and the pulse width sf, test debugging is carried out, including the following steps:

[0034] Adjust the drop height h of the box body, and / or the buffer structure material and / or thickness, and conduct tests;

[0035] Set load calibration points on the box body and arrange acceleration sensors at the load calibration points. According to the acceleration response spectrum output by the acceleration sensors, compare it with the test spectrum to ensure consistency with the target parameters, that is, the debugging is completed.

[0036] In summary, the technical solution of the present invention has the following advantages:

[0037] The present invention can effectively simulate different half-sine shock spectrum loads and measure the change of the rotor-stator clearance and the acceleration response of the engine under external large overload shocks, while reducing the test cost and test safety risks, and achieving the expected verification effect.

[0038] The present invention can effectively simulate the situation of the engine under external large overload shocks and obtain the change amount of the rotor-stator clearance of the engine under external large overload shocks. The test principle is simple and easy to implement. Compared with the method of using a shock table or a vibration table to carry out tests under the operating conditions of the engine, the cost can be greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required to be used in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0040] Figure 1 It is a schematic structural diagram of the engine drop test device under large overload shocks provided by the present invention;

[0041] Figure 2 Schematic diagram of the method and device for measuring the tip clearance under impact load provided by the present invention;

[0042] Figure 3 Schematic diagram of the design load spectrum for the equivalence of the real external impact load to the test load in the present invention;

[0043] Figure 4 Schematic diagram of the test load spectrum after equivalence in the method for the equivalence of the real external impact load to the test load provided by the present invention;

[0044] Figure 5 Position relationship diagram between the capacitive gap sensor and the rotor blade in the engine drop test device under large overload impact provided by the present invention;

[0045] Figure 6 Schematic diagram of the displacement change of the stator and rotor during the clearance measurement test of the present invention.

[0046] Explanation of reference numerals:

[0047] 1. Engine, 11. Engine rotor, 12. Rotor blade, 13. Mounting node, 14. Engine stator casing, 15. Load calibration point, 2. Engine mounting bracket, 3. Box body, 4. Crane, 5. Rotor blade driving mechanism, 51. Motor, 52. Transmission shaft, 53. Transmission part, 6. Buffer structure, 7. Capacitive gap sensor, 8. Acceleration test equipment. Detailed implementation manners

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0049] When a carrier-based aircraft lands, its descent speed is relatively large. The maximum sinking speed at the moment of landing of a carrier-based aircraft is more than twice that of a shore-based aircraft. Considering that the ship is in motion and the waves will cause the ship's hull to heave, it is difficult to control the landing attitude of the aircraft. Structures such as the fuselage and landing gear must be able to withstand the impact loads during symmetric and asymmetric landings of the aircraft. The "anti-overload" ability is one of the most important technical characteristics of carrier-based aircraft. According to the design requirements, under the condition of large landing overload, the strength of each component of the engine should meet the requirements, and no harmful deformation that affects the engine performance and safety should occur. To obtain the deformation conditions and acceleration responses of the stator and rotor under the action of external impact loads, it is necessary to use experimental means to measure relevant parameters.

[0050] The existing engine drop shock test method requires the establishment of a complete engine dynamic load test bench. Under the operating conditions of the engine, a shock overload spectrum with a predetermined waveform is suddenly applied through a loading device (shock table or vibration table). The deformation and acceleration response data of the engine are obtained through sensors arranged at various positions of the engine.

[0051] Since the mass of test devices such as the test engine and mounting brackets can usually reach more than two tons, this method requires a powerful shock load loading system to achieve loading, resulting in high bench construction costs. The engine is simultaneously subjected to external loads under operating conditions, and the test method is complex. Moreover, since the test is carried out under the operating conditions of the engine, the tip clearance of the working engine blade is already in a relatively small state. Under the action of an external shock load, the clearance will further decrease, increasing the risk of rubbing between the rotating and stationary parts of the engine, and may cause failure risks such as blade breakage, damaging the engine and affecting the safe operation of the engine. Under the operating conditions of the engine, the load-bearing systems such as the compressor casing and mounting lugs bear the working load. Under the sudden application of an external shock load, the load is further increased, increasing the failure risk of the mounting system and the main structure.

[0052] Based on this, the present invention provides an engine drop shock test device under large overload shocks, which can effectively simulate different half-sine shock spectrum loads, measure the change in the clearance between the rotating and stationary parts of the engine under external large overload shocks and the acceleration response, while reducing the test cost and test safety risk, and achieving the expected verification effect.

[0053] According to an embodiment of the present invention, in a first aspect, there is provided an engine drop shock test device under large overload shocks, combined with Figures 1 to 6 As shown, it includes a box body 3, an engine 1, a crane 4, a rotor blade driving mechanism 5, and a tip clearance measuring device. An engine accommodation cavity is provided inside the box body 3. The engine 1 is positioned in the engine accommodation cavity. The engine 1 has an engine rotor 11 and an engine stator casing 14. The crane 4 is connected to the box body 3 through a hook, and is adapted to drive the box body 3 to lift and be able to release the box body 3. The rotor blade driving mechanism 5 is connected to the engine rotor 11 and is adapted to drive the rotor blades 12 to rotate in the non-operating state of the engine. The tip clearance measuring device is arranged on the engine stator casing 14 and is adapted to measure the clearance between the engine rotor 11 and the engine stator casing 14 when the engine 1 is subjected to a shock load.

[0054] The above-mentioned engine drop shock test device under large overload shocks can effectively simulate the situation of the engine under external large overload shocks, and obtain the change amount of the clearance between the rotating and stationary parts of the engine under external large overload shocks. The test principle is simple and easy to implement. Compared with the method of carrying out tests under the operating conditions of the engine by using a shock table or a vibration table, the cost can be greatly reduced.

[0055] During the test, the engine does not start, there is no fuel combustion process, and no high-temperature and high-pressure gas is generated to drive the turbine and other moving parts, reducing the deformation and clearance change of the engine rotor and stator caused by thermal expansion, avoiding the risk of engine rotor and stator rubbing due to the reduction of the engine rotor and stator clearance during engine operation, reducing the possibility of engine rotor and stator rubbing, and reducing the test risk. In this embodiment, the engine rotor is driven to rotate by the rotor blade driving mechanism 5, and combined with the tip clearance measuring device, the measurement of the engine rotor and stator clearance under impact load can be effectively realized.

[0056] To reduce the test risk, the engine does not operate during the test, and a capacitive gap sensor is used to measure the tip clearance, that is, the tip clearance measuring device includes at least one capacitive gap sensor 7, and each capacitive gap sensor 7 is arranged on the engine stator casing 14 and is arranged opposite to the tip of the rotor blade of the engine rotor 11. Since the capacitive method measures the tip clearance by detecting the change in capacitance between the tip of the engine rotor blade and the sensor, and the capacitance change is related to the distance between the rotor and stator at the position of the sensor. To dynamically obtain the clearance value between the rotor blade and the engine stator casing 14, the engine rotor needs to reach a certain speed. When each blade rotates past the sensor position, an instantaneous capacitance signal is formed between the tip and the engine stator casing 14. During the tens of milliseconds under the action of the external impact load, multiple blades pass through the position of the capacitive gap sensor 7, forming multiple capacitance signals. The capacitance signals are converted into clearance value signals, and then the change in the clearance value between the rotor and stator with the external load is obtained.

[0057] Since the test object, the engine body, does not operate in the present invention, in order to effectively obtain the change law of the tip clearance under the action of the external impact load, a method of driving the engine rotor 11 by the motor 51 to obtain a certain speed is adopted. The specific method is as Figure 2 shown. The rotor blade driving mechanism 5 includes a motor 51 and a transmission shaft 52. One end of the transmission shaft 52 is connected to the output shaft of the motor 51, and the other end is connected to the engine rotor 11 through a transmission member 53. The transmission member 53 is adapted to convert the rotation of the transmission shaft 52 into the rotation of the engine rotor 11. The rotation speed of the engine rotor 11 can be accurately controlled by the motor 51 and maintained at a relatively low and stable level.

[0058] The transmission member 53 includes a first transmission gear and a second transmission gear. The transmission shaft 52 is coaxially connected to the first transmission gear, and the second transmission gear is coaxially connected to the engine rotor 11 and meshes with the first transmission gear. Among them, both the first transmission gear and the second transmission gear are bevel gears.

[0059] In some embodiments, a buffer structure 6 is laid below the box body 3. In this embodiment, the free-fall plus buffer pad method is adopted to carry out the engine complete machine drop shock test. The test principle is simple and easy to implement. Compared with the method of carrying out the test under the engine operating conditions by using a shock table or a vibration table, the cost can be greatly reduced, and at the same time, the test risk can be effectively reduced. The buffer structure 6 can prevent the failure of the load-bearing systems such as the engine casing and the mounting lugs due to excessive impact when the engine falls.

[0060] It should be noted that the buffer structure 6 can be a buffer pad, or a hydraulic damping system can be used to replace it.

[0061] Before the test, an acceleration sensor is installed at the engine body load calibration point 15 (as Figure 1 shown), and an acceleration test device 8 is also arranged outside the box body 3. By adjusting the buffer pad thickness, material and drop height, the contact stiffness of the box body and the impact energy are changed. According to the impact load spectrum obtained by testing the acceleration sensor of the engine body and comparing it with the design spectrum, a load spectrum consistent with the preset load is obtained.

[0062] In some embodiments, at least one mounting lug 13 is arranged on the outer wall of the engine 1. The engine 1 is installed on the engine mounting bracket 2 through the mounting lug 13, and the engine mounting bracket 2 is fixedly connected to the inner wall of the box body 3.

[0063] According to an embodiment of the present invention, in a second aspect, a clearance measurement test method is provided. This method is based on an engine drop shock test device under large overload impact and includes the following steps:

[0064] Lift the box body 3 to a predetermined height by a crane 4.

[0065] Drive the engine rotor 11 to rotate to the target speed through the rotor blade driving mechanism 5. Start the motor 51, and the motor 51 drives the engine rotor 11 to rotate above 6000 r / min (revolutions per minute). At the moment when the speed of the engine rotor 11 reaches the target value, release the box body 3, and the box body 3 freely falls onto the buffer pad to generate an impact load.

[0066] During the time when the load acts, drive the engine rotor 11 to continuously operate through the rotor blade driving mechanism 5, and measure the clearance between the engine rotor 11 and the engine stator casing 14 through the tip clearance measurement device, and measure and obtain continuous capacitance signals and clearance values.

[0067] The clearance between the engine rotor 11 and the engine stator casing 14 is measured by a tip clearance measuring device. The tip clearance is measured by detecting the change in capacitance between the tip of the engine rotor blade and the capacitive clearance sensor, including the following specific steps: When the engine rotor 11 is running, when each engine rotor blade rotates past the position of the capacitive clearance sensor, an instantaneous capacitance signal is formed between the tip and the engine stator casing 14. During the time of the external impact load, multiple engine rotor blades pass through the position of the capacitive clearance sensor, forming multiple capacitance signals. The capacitance signals are converted into clearance value signals, and then the change in the clearance value between the rotor and the stator over the external load history is obtained.

[0068] The true external impact load spectrum of the engine in the landing environment is the impact acceleration vs. time history curve ( Figure 3 as shown). Usually, it is difficult for the test device to simulate the entire history, and test load equivalence is required. Therefore, this embodiment provides a method for equivalent impact load, and the specific method is as follows: According to the design load and simulation results, carry out the conversion of the equivalent load for the engine test.

[0069] Perform the equivalence of the true external impact load to the test load, and the specific method is as follows:

[0070] S1. Analyze the design load spectrum to obtain the peak value a of the impact load acceleration and the corresponding half-sine wave pulse width value s, as Figure 3 shown.

[0071] S2. Preset the test spectrum as an impact spectrum with an acceleration peak value a1 and a half-sine wave pulse width value s1, as Figure 4 shown.

[0072] S3. Use the impact dynamics method to analyze the deformation and acceleration response of the engine rotor and stator under the design load spectrum, obtain the deformation response of the rotor and stator under the impact load. The initial clearance between the rotor and stator is d0, and the minimum clearance under the external load is d1. Obtain the maximum clearance change amount Δd = d0 - d1 of the rotor and stator under the test spectrum, as Figure 6 shown.

[0073] S4. Similarly, use the impact dynamics method to analyze the deformation and acceleration response of the engine rotor and stator under the test spectrum, obtain the deformation response of the rotor and stator under the impact load. The initial clearance between the rotor and stator is d0, and the minimum clearance under the external load is d1'. Obtain the maximum clearance change amount Δd' = d0 - d1' of the rotor and stator under the test spectrum. S5. By continuously adjusting the acceleration peak value and half-sine pulse width of the test spectrum, iterative analysis is carried out to determine the final acceleration peak value af and pulse width sf of the half-sine waveform of the test spectrum, ensuring that under this load spectrum, Δd = Δd', and at the same time ensuring that the acceleration peak value af of the test spectrum is not less than the acceleration peak value a of the design spectrum.

[0074] In this step, an iterative analysis method is adopted to determine the acceleration peak value and the half-sine wave pulse width of the test spectrum, ensuring that the maximum change in the stator-rotor clearance under the test spectrum is equal to or close to that under the design load spectrum. This method guarantees the effectiveness and reliability of the test results, while avoiding over-compression or over-stretching of the engine caused by load differences and reducing the risk of stator-rotor contact in the engine.

[0075] S6. After determining the acceleration peak value af and the pulse width sf of the half-sine wave form of the test spectrum, conduct test debugging. By adjusting Figure 1 parameters such as the drop height h of the middle box body and the material and thickness of the buffer pad for testing. According to Figure 1 the acceleration response spectrum output by the acceleration sensor at the load calibration point 15, compare it with the test spectrum to ensure consistency with the target parameters, and thus complete the debugging.

[0076] In summary, the present invention effectively solves the risk of stator-rotor rubbing in the engine by simplifying the test method, precisely controlling the impact load, dynamically monitoring the tip clearance, and optimizing the impact load equivalent method, and provides a safer and more reliable test means. Specifically, it is manifested as follows:

[0077] Cost reduction: Compared with the traditional impact table or vibration table method, the cost of the test device of the present invention is significantly reduced, and the operation is more convenient.

[0078] Risk control: Testing under non-operating conditions and precisely controlling the impact load significantly reduces the risk of stator-rotor rubbing in the engine during the test.

[0079] Data accuracy: Through the capacitive sensor and the motor-driven rotation method, the high-precision measurement of the tip clearance is ensured, making the test data more credible.

[0080] Flexibility: By adopting the method of free fall plus buffer pad, the test parameters can be flexibly adjusted according to different requirements to adapt to various test scenarios.

[0081] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. Engine drop shock test device under large overload impact, characterized in that: include: A box body (3) is provided with an engine accommodating chamber inside; An engine (1) is positioned in an engine accommodating chamber, wherein the engine (1) comprises an engine rotor (11) and an engine stator casing (14); A crane (4) connected to the box (3) and adapted to drive the box (3) to be raised or lowered and to release the box (3); A rotor blade driving mechanism (5) connected to the engine rotor (11) and adapted to drive the rotor blades (12) to rotate when the engine is not in operation; A blade tip clearance measuring device is arranged on an engine stator casing (14) and is suitable for measuring the clearance between an engine rotor (11) and an engine stator casing (14) when an engine (1) is subjected to an impact load.

2. The engine drop shock test device under high overload impact according to claim 1 is characterized in that: The rotor blade driving mechanism (5) comprises: Motor (51); A transmission shaft (52) has one end connected to the output shaft of the motor (51) and the other end connected to the engine rotor (11) via a transmission member (53). The transmission member (53) is suitable for converting the rotation of the transmission shaft (52) into the rotation of the engine rotor (11).

3. The engine drop shock test device under high overload impact according to claim 1 is characterized in that: A buffer structure (6) is provided below the box body (3).

4. The engine drop shock test device under high overload impact according to claim 1 is characterized in that: The outer wall of the engine (1) is provided with at least one mounting joint (13); the engine (1) is mounted on an engine mounting frame (2) via the mounting joint (13); and the engine mounting frame (2) is fixedly connected to the inner wall of the box body (3).

5. The engine drop shock test device under high overload impact according to any one of claims 1 to 4, characterized in that: The blade tip clearance measuring device comprises at least one capacitive clearance sensor (7), each of the capacitive clearance sensors (7) being arranged on an engine stator casing (14) and arranged opposite to a rotor blade tip of the engine rotor (11).

6. A gap measurement test method, characterized in that: The method is carried out based on the engine drop shock test device under high overload impact according to any one of claims 1 to 5, and comprises the following steps: The box (3) is raised to a predetermined height by means of a crane (4); The engine rotor (11) is driven to rotate to a target rotation speed by a rotor blade driving mechanism (5); At the moment when the engine rotor (11) rotates to the target speed, the housing (3) is released, and the housing (3) falls freely, generating an impact load; During the load action time, the engine rotor (11) is driven to continuously operate by the rotor blade driving mechanism (5), and the clearance between the engine rotor (11) and the engine stator casing (14) is measured by the blade tip clearance measuring device.

7. The gap measurement test method according to claim 6, characterized in that: The tip clearance measuring device is used to measure the clearance between an engine rotor (11) and an engine stator casing (14). The tip clearance is measured by detecting the capacitance change between the tip of the engine rotor blade and a capacitive clearance sensor. The method comprises the following specific steps: When the engine rotor (11) is running, when each engine rotor blade rotates and passes the position of the capacitive gap sensor, an instantaneous capacitance signal is formed between the blade tip and the engine stator casing (14). During the time when the external impact load acts, multiple engine rotor blades pass the position of the capacitive gap sensor, forming multiple capacitance signals, which are converted into gap value signals, thereby obtaining the history of the gap value change between the rotor and the stator along with the external load.

8. The gap measurement test method according to claim 7, characterized in that: Before obtaining the change of the clearance value between the rotor and stator along with the external load, the actual external impact load is equivalent to the test load: according to the design load and simulation results, the equivalent load of the engine test is converted.

9. The gap measurement test method according to claim 8, characterized in that: The equivalence of the real external impact load to the test load includes the following steps: Analyze the design load spectrum to obtain the peak value a of the impact load acceleration and the corresponding half-sine wave pulse width s; The test spectrum is preset to the shock spectrum of the acceleration peak value a1 and the half-sine wave pulse width value s1; The impact dynamics method is used to analyze the deformation and acceleration response of the engine rotor and stator under the design load spectrum, and the deformation response of the engine rotor and stator under the impact load is obtained. The initial clearance of the engine rotor and stator is d0, and the minimum clearance under the external load is d1. The maximum clearance change of the engine rotor and stator under the test spectrum is Δd=d0-d1. The impact dynamics method is used to analyze the deformation and acceleration response of the engine rotor and stator under the test spectrum, and the deformation response of the engine rotor and stator under the impact load is obtained. The initial clearance of the engine rotor and stator is d0, and the minimum clearance under the external load is d1′. The maximum clearance change of the engine rotor and stator under the test spectrum is Δd′=d0-d1′. By continuously adjusting the test spectrum acceleration peak value and half-sine pulse width, iterative analysis is performed to determine the final test spectrum half-sine waveform acceleration peak value af and pulse width sf to ensure that under this load spectrum, Δd=Δd′, and at the same time ensure that the test spectrum acceleration peak value af is not less than the design spectrum acceleration peak value a.

10. The gap measurement test method according to claim 9, characterized in that: After determining the final test spectrum half-sine waveform acceleration peak af and pulse width sf, carry out test debugging, including the following steps: Adjust the drop height h of the box (3), and / or the material and / or thickness of the buffer structure (6) to conduct the test; A load calibration point (15) is set on the box (3) and an acceleration sensor is arranged at the load calibration point (15). The acceleration response spectrum output by the acceleration sensor is compared with the test spectrum to ensure that it is consistent with the target parameters, thus completing the debugging.

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