CN114720143A

CN114720143A - Test method for hailstones swallowed by turbofan type aircraft engine

Info

Publication number: CN114720143A
Application number: CN202210239045.9A
Authority: CN
Inventors: 许光磊; 吴法勇; 张勇健; 王明金; 孙家超; 黄福增; 刘作宏; 桑则林
Original assignee: AECC Shenyang Engine Research Institute
Current assignee: AECC Shenyang Engine Research Institute
Priority date: 2022-03-11
Filing date: 2022-03-11
Publication date: 2022-07-08

Abstract

The application belongs to the field of combustion engines, and particularly relates to a test method for hail swallowing of a turbofan type aircraft engine, which is used for manufacturing spherical hail with cotton wool content of 1% -4%; impacting fan blades of an air inlet channel of the turbofan type aircraft engine by adopting the spherical hail according to a preset condition, and erecting photographic equipment to shoot the fan blades; the length-diameter ratio of the air inlet channel is 1-1.5, and the luminous flux is not lower than 100000 lm; the shooting frame rate of the photographic equipment is not lower than 1000; coating the fan blade with a non-reflective primer; acquiring a film of a fan blade impacted by the spherical hail through the photographic equipment, and establishing a fan blade model through impact dynamics analysis software based on the preset condition and the film; the method and the device have the advantages that the most rigorous test point for examining the turbofan type aero-engine is determined through the fan blade model, and real data of the engine in the ice swallowing test can be truly restored through photographic analysis and simulation analysis of the test process.

Description

Test method for hailstones swallowed by turbofan type aircraft engine

Technical Field

The application belongs to the field of combustion engines, and particularly relates to a hail swallowing test method for a turbofan type aircraft engine.

Background

The hail ingestion test of the engine is an important component of a model state identification test, and researches find that the hail concentration passing through the interior of the engine is obviously increased under the condition of certain flight speed and engine power or thrust combination, and the caused increase of the ingested hail can obviously cause unstable operation of the engine, such as surge, power loss, structural damage and engine flameout. Therefore, a reasonable and feasible hail swallowing test scheme needs to be designed.

At present, the research on the hail swallowing test technology of the military turbofan engine of the three-generation engine is relatively blank, the performance of the engine is tested after the engine is swallowed by the conventional method, the ice swallowing test performance of the engine is further obtained, and the simulation checking calculation is carried out on the deformation of the engine blade after the test. The invention aims to solve the problems and provides a test method for hail swallowing of a turbofan type aircraft engine, which has the advantages that: the equipment debugging and hail manufacturing method is reasonable and feasible, the test conditions are controlled, the test run method is simple and effective, and the one-time success rate of the test is improved.

Disclosure of Invention

In order to solve the above problems, the present application provides 1 a method for testing hail swallowing of a turbofan type aircraft engine, comprising:

the method has the advantages that 1% -4% of spherical hail is made, 1% -4% of cotton wool is added, so that the intensity of the hail encountered by an airplane in high altitude can be better simulated by the made hail, and the cotton wool can enable the hail to be better formed;

impacting fan blades of an air inlet channel of the turbofan type aircraft engine by adopting the spherical hail according to a preset condition, and erecting photographic equipment to shoot the fan blades; the length-diameter ratio of the air inlet channel is 1-1.5, and the luminous flux is not lower than 100000 lm; the shooting frame rate of the photographic equipment is not lower than 1000; coating the fan blade with a non-reflective primer;

acquiring a film of a fan blade impacted by the spherical hail through the photographic equipment, and establishing a fan blade model through impact dynamics analysis software based on the preset condition and the film;

and determining the most rigorous test point for examining the turbofan type aircraft engine through the fan blade model.

Preferably, the spherical hail provides kinetic energy through a launching system and impacts the fan blades, the launching system comprises a control system, a gun barrel, a cartridge case separator, a quick opening mechanism, a gas tank and the like, the spherical hail is filled in the gun barrel through the cartridge case, the control system controls the gas tank to charge compressed air into the quick opening mechanism, when the air pressure in the quick opening mechanism reaches a preset value, the control system controls the quick opening mechanism to act, the compressed air enters the gun barrel to accelerate the cartridge case and the spherical hail, the cartridge case is separated from the spherical hail after reaching the cartridge case separator, and the spherical hail enters an air inlet channel.

Preferably, the central axis of the air inlet channel is provided with a track, a rack for installing the launching system is erected on the track, and the rack slides relative to the track and can be locked at any position of the track.

Preferably, the transmission system has a degree of freedom on the gantry, the degree of freedom including: the degree of freedom of the length of the air inlet channel is not less than 60% in the vertical direction; the degree of freedom of the length of the air inlet is not less than 50% in the horizontal direction.

Preferably, the erection position of the photographic equipment comprises the front face and the front side face of the air inlet and the direction of the tail nozzle of the turbofan type aircraft engine.

Preferably, when the air pressure in the quick opening mechanism reaches a preset value, the control system controls the quick opening mechanism to act, and the preset value obtaining method comprises the following steps: acquiring a plurality of spherical launching speeds and corresponding air pressures; fitting a relation function between the spherical transmitting speed and the air pressure through simulation; determining the preset value based on the relationship function.

Preferably, the sensed part for non-airborne test in the air inlet channel is dismounted, so that the influence of other parts on the test is avoided, and the test device is damaged.

Preferably, the types of the non-reflective primer include: the non-reflective H06-2 epoxy ester white primer enables the camera to better capture the test picture.

Preferably, a time and performance graph of a hail swallowing test of the turbofan type aircraft engine is obtained, and the most rigorous test point for examining the turbofan type aircraft engine is determined based on the film and the fan blade model.

Preferably, the fan blade is coated with a non-reflective primer, which specifically comprises: the fan blade number, the fan blade radius division and the painting eliminate the fan blade quality unevenness.

The advantages of the present application include:

through systematic test design, the test process can be simplified;

real data during the engine ice swallowing test can be truly restored through photographic analysis and simulation analysis of the test process;

by means of photographic analysis and simulation analysis of the test process and combination of the performance of the engine, more accurate experimental data can be obtained.

Drawings

FIG. 1 is a flow chart of an experiment in accordance with a preferred embodiment of the present application;

FIG. 2 is a schematic diagram of a transmit system architecture;

FIG. 3 is an SPH model of global hail;

FIG. 4 is a fan rotor finite element model.

Detailed Description

In order to make the implementation objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all embodiments of the present application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application. Embodiments of the present application will be described in detail below with reference to the drawings.

As shown in fig. 2: debugging of a transmitting system, and working principle of the transmitting system: the launching system mainly comprises a control system, a gun barrel, a quick opening mechanism, a gas tank and the like. In the test, a compressed air cannon is used to accelerate the hail and the hail enters the engine after reaching a specified speed, the control system controls the quick opening mechanism to act after the gas tank is inflated, the compressed air enters the cannon pipe to accelerate the cartridge case and the hail, the cartridge case is separated from the hail after reaching the cartridge case separator, and the hail enters the engine.

Performing a sufficient boresight test before a formal test, determining the relationship between air gun pressure and launching velocity and the air gun efficiency, and performing velocity repeatability confirmation;

b) the scheme design of the gun tube distribution and support structure of the air gun is developed, (the inlet diameter of an engine and the distribution condition of a support plate need to be considered), the center height is required to be adjustable, and the aiming position can be accurately adjusted conveniently;

c) high-speed photographic equipment distribution is carried out, multi-angle shooting (in the direction of the front face, the front side face and the tail nozzle of an engine inlet) is required to be carried out on the local part of an emission process interface, an enough lighting system is configured, and the recommended luminous flux is not lower than 100000 lm;

d) the short-type technology intake duct of preparation (draw ratio 1 ~ 1.5), the photography and shooting of being convenient for, the intake duct should carry out the atress analysis when directly linking with the engine, guarantees reliable intensity deposit.

Spherical hailstones are adopted, the size of the hailstones is mainly guaranteed by a mold, the types of the mold are mainly divided into rubber, plastic and aluminum alloy materials, the molds made of different materials have respective advantages and disadvantages on the hailstones manufacturing effect, see table 1, and the comprehensive consideration suggests that the molds made of the aluminum alloy materials are adopted to manufacture the spherical hailstones;

TABLE 1 manufacture of hailstones by different moulds

Kind of die	Rubber composition	Plastic material	Aluminum alloy-self-made
				Ice hockey size	Is difficult to ensure	Is difficult to ensure	Can ensure that
Density of ice ball	Can not measure	Can not measure	Basic guarantee
				Dyeing	Can be dyed	Can be dyed	Can be dyed
Difficulty of operation	Simple	Simple	Difficult demoulding

Hail density is mainly guaranteed through water material or manufacturing process, and from the preparation degree of difficulty, preferably from the water material angle of screening, consider that hail launch velocity is higher, the gas big gun pressure rises thereupon, and is also high to hail intensity requirement, adopts in the preparation material to add the method of right amount of cotton fibre to improve intensity in the engineering application, can guarantee hail density simultaneously.

The test technical conditions are as follows:

a) intake fan state

The hail swallowing test is used for painting, numbering and dividing the radius of a fan air inlet support plate, an adjustable blade and a 1-level rotor blade, the painting process is uniform and reliable in adhesion, and a non-reflective H06-2 epoxy ester white primer is generally adopted, so that the impact process can be conveniently recorded in a high-speed photography mode, and the damaged blade can be conveniently positioned. After painting, the partial size and the integral unbalance of the air inlet casing and the fan are ensured to have no great adverse effect on the vibration level of the whole machine;

before and after the hail is swallowed and formal test run, the engine flow channel is subjected to hole detection inspection, fan components are heavily inspected, and the hardware states of the engine before and after the hail is swallowed are confirmed and compared.

b) Simulation analysis

In order to guarantee the success rate of the test, necessary numerical simulation calculation is carried out in the test preparation stage, impact dynamics analysis software PAM _ CRASH is adopted to simulate the impact process of the hail according to different host states and flight speeds of the engine, a full-circle blade model is built, impact energy is calculated, and the most severe test point for examining the engine, such as the SPH model of the spherical hail shown in figure 3, is determined. By utilizing the simulation result, the test scheme can only reserve the most rigorous test points under the conditions of limited engine or component resources and permission of customers

c) Safety measures

1) The test run rack should have protection measures, and protection design is generally carried out according to the flying energy of the rotor piece in an uncontained state;

2) swallowing tests are generally carried out on an open-air test bed, dangerous areas need to be marked, and test sites are subjected to closed management;

3) carrying out emergency plan drilling and fire-fighting equipment inspection before testing;

4) the hail test vehicle is used for dismantling the non-airborne test sensed part in the engine flow passage so as to prevent hail from damaging non-engine parts and causing secondary damage in the engine flow passage after falling off to influence an assessment conclusion.

4 trial run scheme

a) The test run scheme is planned to be adjusted, initially calibrated, run in hail and recalibrated;

1) the adjustment test run is mainly used for carrying out function check and performance debugging on the engine and verifying whether the engine meets hail swallowing test conditions;

2) the calibration test run mainly evaluates the performance of the engine and provides data support for evaluation of test results;

3) and (3) a hail swallowing test verifies whether the working characteristics, performance attenuation and mechanical damage of the engine after the hail is swallowed meet the index requirements of the general requirements of development.

b) And (3) converting key links into data forms in the test run process, and monitoring in real time through a data acquisition system. For example: judging conditions for recovering stable work after hail is swallowed;

c) and setting parameter limit values of different stages for various systems (vibration, pulsation and the like) of the engine aiming at different test run items.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A test method for hail swallowing of a turbofan type aircraft engine is characterized by comprising the following steps:

manufacturing spherical hail with cotton wool content of 1% -4%;

and determining a harsh test point for examining the turbofan type aircraft engine through the fan blade model.

2. The method for a hail-swallowing test of a turbofan type aircraft engine as claimed in claim 1, wherein the spherical hail provides kinetic energy and impacts the fan blades through a launching system, the launching system comprises a control system, a barrel, a cartridge case separator, a quick opening mechanism, a gas tank, etc., the spherical hail is filled in the barrel through the cartridge case, the control system controls the gas tank to charge compressed air into the quick opening mechanism, when the pressure in the quick opening mechanism reaches a preset value, the control system controls the quick opening mechanism to act, the compressed air enters the barrel to accelerate the cartridge case and the spherical hail, the cartridge case is separated from the spherical hail after reaching the cartridge case separator, and the spherical hail enters an air inlet channel.

3. The method for hail swallowing test of a turbofan aircraft engine as defined in claim 2, wherein the central axis of the inlet duct has a rail, and the rail is provided with a rack for mounting the launching system, and the rack slides relative to the rail and can be locked at any position of the rail.

4. The turbofan aircraft engine hail swallowing test method of claim 3 wherein the launching system has degrees of freedom on the gantry, the degrees of freedom comprising: the degree of freedom of the length of the air inlet channel is not less than 60% in the vertical direction; the degree of freedom of the length of the air inlet is not less than 50% in the horizontal direction.

5. The method for a hail-swallowing test in a turbofan aircraft engine of claim 1 wherein the camera mounting locations include a front face, a front side face and a direction of the nozzle of the turbofan aircraft engine.

6. The method for hail swallowing test of a turbofan aircraft engine as recited in claim 2, wherein the control system controls the quick opening mechanism to operate when the air pressure in the quick opening mechanism reaches a predetermined value, and the predetermined value is obtained by: acquiring a plurality of spherical launching speeds and corresponding air pressures; fitting a relation function between the spherical transmitting speed and the air pressure through simulation; the preset value is determined based on the relationship function.

7. The turbofan aircraft engine hail swallowing test method of claim 1 wherein the sensed part of the off-board test in the air intake duct is removed.

8. The turbofan aircraft engine hail swallowing test method of claim 1 wherein the type of the non-retroreflective primer comprises: non-reflective H06-2 epoxy ester white primer.

9. The turbofan aircraft engine hail swallowing test method of claim 1 wherein a time and performance map of a turbofan aircraft engine hail swallowing test is obtained and based on the movie and the fan blade model, the most critical test point for the turbofan aircraft engine is determined.

10. The turbofan aircraft engine hail swallowing test method of claim 1 wherein the fan blades are primed with a non-reflective primer, comprising: applying a non-reflective primer based on the fan blade number, applying a non-reflective primer based on the fan blade radius, and applying a non-reflective primer based on the fan blade mass.