CN113310701B

CN113310701B - Complete machine tester for mechanical system of military turbofan engine

Info

Publication number: CN113310701B
Application number: CN202110660496.5A
Authority: CN
Inventors: 尉询楷; 赵雪红; 何秀然; 周磊; 张生良; 杨立; 冯悦; 鲁旭红
Original assignee: 93208 Troops Of Chinese Pla
Current assignee: 93208 Troops Of Chinese Pla
Priority date: 2021-06-15
Filing date: 2021-06-15
Publication date: 2022-06-10
Anticipated expiration: 2041-06-15
Also published as: CN113310701A

Abstract

The invention relates to a complete machine tester of a mechanical system of a military turbofan engine, which constructs a complete machine-level simulation service environment of the mechanical system by adaptively modifying a typical active military turbofan engine, more truly simulates service conditions and environments of mechanical system components such as a main bearing, a transmission gear, a bearing, a lubricating system and the like, and axial loads of the main bearing, supports and develops failure rule research of typical faults of the key bearing/gear, the lubricating system and the like of the mechanical system, weak fault signal transmission and characterization of the main bearing, a transmission casing bearing and the like under a complex vibration transmission path of the service environment, state monitoring and failure early warning technology research of the key component/system faults of the mechanical system, development of a health monitoring technology of a traction engine and landing application, and uses safe driving protection for military aviation equipment.

Description

Complete machine tester for mechanical system of military turbofan engine

Technical Field

The invention relates to a complete machine tester for a mechanical system of a military turbofan engine, which can more truly simulate the service working conditions and environments of mechanical system components and systems such as a main bearing, a transmission gear, a bearing, a lubricating system and the like, and the axial load of the main bearing, and provides a key support for improving the health diagnosis capability of the mechanical system of the military aero-engine.

Background

The aeroengine mechanical system is recognized as a system with frequent failures of military aeroengines at home and abroad, and particularly, bearing failure is one of leading causes of aerial parking and single-aircraft-level accidents caused by engine mechanical reasons. The power device of the third generation main warfare aircraft in China has the prominent serious fault problems of sudden failure of a five-fulcrum main bearing (intermediate bearing) and the like, so that the shaft seizing and breaking of a multi-engine are caused, and the loss is huge. The development of onboard health diagnosis technology of the main bearing is very urgent.

The bearing tester is an important platform for the development of the engine health monitoring technology, and main bearing test systems with different complexity degrees are built in units such as FAG company, NASA and Akron. The main bearing tester constructed by FAG simulates the installation and supporting mode of a main bearing on an engine, and the lubricating and loading environment, and the simulation working condition of the bearing test is closer to the actual condition. The intermediary bearing test system jointly built by the university of NASA and Akron is used for supporting the intelligent bearing system project of the NASA intelligent engine and adopts an air turbine to drive a high-speed shaft.

Compared with foreign countries, the main bearing test system developed in China basically has three types: the single bearing tester for the ball bearing is mainly used for life and performance tests of a main bearing of an aircraft engine, the inner diameter of the test bearing is 70-180mm, the highest rotating speed is 20000RPM, and the test bearing tester has a computer automatic measurement and control function. The double-sleeve rotating high-speed bearing tester is mainly used for a double-sleeve rotating life test or a performance test of an intermediate main bearing of an aero-engine, and can also bear the main bearing of a general aero-engine, wherein the inner diameter of the test bearing is 75-210mm, and the highest rotating speed is 20000 RPM. The bearing tester is provided with two main shafts which rotate at high speed simultaneously, is suitable for bearing tests with inner and outer rings rotating simultaneously, has the characteristics of large test load, high test bearing temperature and the like, and has the function of automatic measurement and control of a computer. The double-shaft shafting tester is provided with a complete set of engine main bearing for examination, and can be used for simultaneously carrying out durability and service life tests, oil cut tests, slipping tests, fault reappearance tests, overspeed tests, large load tests, special measurement parameter tests and the like on five sets of main bearings of high-pressure and low-pressure rotors of one engine. The inner diameter of the test bearing is 50-180mm, the maximum rotating speed is 12000RPM, and the ambient temperature is 200 ℃. The industrial computer is adopted to realize the automatic control of the load spectrum, the velocity spectrum and the temperature spectrum, realize the automatic measurement of the main parameters of the test, realize the on-line monitoring and the fault diagnosis of the bearing fault and realize the automatic recording and the automatic alarm shutdown. The three types of testers belong to component-level testers, have large difference between the simulation truth of the engine service environment and the actual condition, and particularly do not have the simulation capability of the service environment such as a vibration acoustic transmission path from a main bearing to an external casing under the engine environment.

In general, the engine health monitoring technology is mature, high-fidelity simulation of typical relevant environments of the engine cannot be left, a current component-level tester is mainly used for design verification of a supporting component or performance, strength or service life test assessment of the component, the engine service environment simulation capability of the component is weak, particularly for a main bearing and the like, the tester does not have the capability of simulating service conditions such as a complex vibration transmission path, a supporting relationship and a complete and real lubricating system working condition of the main bearing of the engine, and the application verification requirements of key technologies such as lubricating oil debris monitoring and high-frequency vibration monitoring are difficult to support. Considering that the mechanical system is an engine fault multi-generation system and has large damage in failure, the turbofan engine is modified, and the complete machine level simulation environment of the mechanical system is constructed, so that the mechanical system has important value for accelerating the maturity of the engine health monitoring technology.

Disclosure of Invention

The invention aims to meet the development requirements of engine health monitoring common technologies of three generations, four generations, five generations and the like of our army, and takes the typical fault mode of a mechanical system of a turbofan engine of our army as an object, a complete machine-level simulation service environment test platform comprising a main bearing and a transmission chain bearing gear is established, failure rule research of typical faults of a key bearing/gear, a lubricating system and the like of the mechanical system is supported and developed, weak fault signals of the main bearing, a transmission case bearing and the like under a complex vibration transmission path of the service environment are transmitted and represented, the state monitoring and failure early warning technology research of the key component/system fault of the mechanical system is realized, the health monitoring technology of a traction engine is developed and is applied to the ground, and safe driving protection is used for military aviation equipment.

The method takes the most common military turbofan engine as an object, and realizes the functions of analyzing the vibration transmission path of the whole engine, modeling and supporting the whole machine coupling dynamics of main bearing faults, simulating the gear faults of a transmission link bearing, truly simulating nonlinear characteristics, simulating the unbalance mechanism of the whole engine, balancing simulation and the like according to the design principle of minimizing structural change, simulating the aerodynamic load with high fidelity and completely keeping the vibration and lubricating environment as far as possible, thereby providing the whole machine level high-fidelity simulation service verification environment for the health monitoring of a mechanical system.

The complete machine level tester is formed by a turbofan engine modification main body, a mounting bracket, a high-low pressure rotor driving system, a lubricating oil supply and return oil system, a lubricating oil heating system, a measurement and control system, a monitoring system and the like, and is shown in figure 1.

The improved engine is arranged on an engine mounting bracket, and a high-power motor and a speed increasing box are adopted, and a flexible coupling is adopted to drive a high-pressure/low-pressure rotor of the engine to rotate. The rotor driving system is fixed on the concrete base through foundation bolts, the engine is installed on a specially designed support to simulate installation on an airplane, and the installation support is fixed on the concrete base through the foundation bolts.

(1) High-low pressure rotor driving system

The rated power of the driving motor is not lower than 315KW, and a high-reliability durable mature goods shelf product is adopted.

The gear box has enough rigidity, meets the requirement of 18000rpm of the highest output rotating speed of the high-low pressure rotor, and has no critical rotating speed in the whole working range. In order to lubricate the bearing in the non-interference test, the gear box adopts an independent hydraulic lubrication system to provide good lubrication for the gear box; to monitor the gearbox operating conditions, the internal bearing temperature, the lubricant temperature, and the body vibration should be monitored.

The gear speed increasing box and the driving motor are connected by adopting an elastic diaphragm coupling, so that the gear speed increasing box has the advantages of large bearing capacity, high transmission precision and high transmission efficiency, and has certain deflection and skew compensation quantity. The gear speed increasing box is connected with the high-low pressure rotor of the engine through a flexible shaft of the engine. The rotating speed of the rotor of the engine can be independently controlled, and the co-rotation and counter-rotation are supported.

(2) Engine host transformation

The main engine is reformed mainly to relate to the power input interface of high-low pressure rotor, blade excision and polishing, fuel annex disconnection power output, the required pressurization chamber design transformation of simulation pneumatic axial force, the lubricating oil of lubricating system heats and supplies oil pressure, each supply line flow control transformation, the supporting pipeline of system and interface transformation such as air seal pressure boost, and monitored control system installs the design transformation of sensor mounted position, fixed bolster additional.

1) And transforming a high-low pressure rotor driving interface. The low-pressure rotor is provided with a detachable fairing, a front support point oil return pump and a transmission shaft thereof, and a reformed front support point lubricating oil supply nozzle, and a front journal of the low-pressure rotor is used as a power input interface of the low-pressure rotor; the engine starter is used for starting a power transmission link, the transmission flexible shaft is used for driving the engine box, and the high-pressure rotor is driven to run through central transmission.

2) And (5) blade modification. Because the single-stage acting power of the engine reaches megawatt, the single-stage acting power can not be realized by the motor, the blades of the compressor and the turbine rotor and stator are cut and polished from the root parts on the basis of keeping the vibration characteristic of a rotor system to the maximum extent, dynamic balance is developed, and the influence of the unbalance of the blades on the vibration of the whole machine is reduced.

3) And (5) reforming a fuel accessory. The whole machine tester does not need to burn and transmit power to the outside, so the aircraft-attached engine box is cancelled, all accessories related to the fuel system on the engine-attached engine box are separated, in order to simulate the vibration characteristic of the engine-attached engine box as much as possible, all accessories of the fuel system are required to be reserved to be arranged on the engine-attached engine box, namely, spline sections on transmission shafts of a main pump, a booster pump and a plunger pump are cut off, and the main pump, the booster pump and the plunger pump are disconnected from the engine-attached engine box in a power connection mode.

4) And (3) simulating modification of a pneumatic axial force pressurizing cavity. Because the working blade of the engine is removed, the ball bearings of the second and the fourth fulcrums of the engine do not bear the pneumatic axial force any more and are not consistent with the actual working load direction of the engine. In order to simulate the actual working stress of the ball bearing as much as possible, a method of pressurizing different disk cavities of a low-pressure rotor and a high-pressure rotor is adopted to apply axial force to the ball bearing. Considering that the axial force of the high-pressure rotor is always forward in the forward direction during the working process of the turbofan engine, the maximum state axial force is 2000Kgf, and the forward maximum value of the axial force is 1000Kgf when the axial force of the low-pressure rotor is N2< 91%; at N2 ≧ 91%, the maximum rearward axial force is 1000 Kgf. The axial force loading realizes the change of the structure by minimizing, avoids changing the rotating piece as far as possible, designs a structural member to separate the front disk cavity of the rear low-pressure turbine of the high-pressure turbine, respectively pressurizes the two separated cavities and the rear disk cavity of the low-pressure turbine to realize the loading, and realizes the loading through the regulation and control of the pressure of the pressurized air.

5) And (5) modifying the pipeline. The improvement of the heating capacity of return oil of the lubricating oil at 250 ℃ increases the overall dimension of the lubricating oil tank, and the pipeline interface of the lubricating oil tank needs to be subjected to adaptive improvement when the lubricating oil tank is assembled; in order to improve the capability of subsequently simulating the rich oil, the lack oil and the oil-cut working state of the bearing gears of each main bearing and the accessory case, the oil supply pipelines of each main bearing and the accessory case are modified, and the pipeline joints are designed and processed.

6) And (5) modifying the interface of the fulcrum sealing system. The fulcrum pressurization system has the function of ensuring the directional pressure difference from the pressurization cavity to the lubricating oil cavity and preventing lubricating oil and lubricating oil steam from entering a gas-air channel of the engine. When the engine normally works, the pressurization sealing of each pivot is used for leading air from the outer duct (when the rotating speed is low before starting, the leading air comes from the seventh stage after the high-pressure compressor; when the N2 reaches 78% -84%, and the pressure difference is more than 0.049Mpa, the leading air is switched to the leading air from the outer duct). Because the complete machine tester blade is cut off, the fulcrum pressure boost can not be provided by the engine again, needs external pressurized air, design transformation pressurized air interface.

7) And (5) adding a monitoring sensor for modification. The method comprises the following steps that a reserved vibration acceleration sensor is required to be modified to have a mounting measuring point position and a mounting support structure at a fan casing, an intermediate casing, an onboard measuring point, a turbine support (mounting edge, in a culvert), a mixer outer casing mounting edge, a generator casing and the like; a reserved lubricating oil metal chip sensor mounting interface and a fixed support structure are designed on a main oil return pipeline, a rear fulcrum oil return pipeline and an engine box oil return pipeline of the engine; and reserving and processing an MEMS sensor fixing groove at a bearing seat and the like, and designing a sensor output signal lead scheme.

(3) Lubrication system

And a lubricating oil system of the engine is adopted for lubricating a transmission system, a main bearing and the like.

1) An oil supply system. The lubricating oil tank, the lubricating oil accessories, the lubricating oil filter, the fuel-lubricating oil heat exchanger, the conversion valve, the guide pipe, the nozzle and other parts of the engine oil supply system are reserved. The lubricating oil accessory is driven by the power of the engine attachment casing in a distributed transmission mode, and lubricating oil with certain pressure is guaranteed to be conveyed to each supporting point of the engine, the engine attachment casing and the like.

2) An oil return system. Since the front pivot scavenge pump position is occupied by the N1 input shaft, the front pivot scavenge pump is eliminated and external scavenge pump lube is substituted. And a middle fulcrum oil return pump and a rear fulcrum oil return pump are reserved, the lower oil return pump is changed into an external oil return pump with strong pumping capacity, and the rear fulcrum external oil return pump is added and returns oil together with the original rear fulcrum oil return pump.

3) And simulating the transformation of a fuel-lubricating oil heat dissipation system. Because no fuel oil cooling source is provided, water is used as a medium, fuel oil inlets and outlets of two original (parallel) fuel-lubricating oil radiators of the engine are connected with an external distilled water cooling system, the fuel oil is simulated to dissipate heat of the lubricating oil through water circulation cooling, and a measurement and control system performs integrated control on water flow and the like according to the state requirements of the engine to provide required heat dissipation capacity.

4) A lubricating oil heating system. In order to simulate the lubricating oil supply and return temperature under the actual working condition of the engine, the lubricating oil is heated by winding a heating belt on a lubricating oil tank or by utilizing the internal structure of the lubricating oil tank in a 'quick heating' mode, and a heat-insulating layer is laid outside the heating belt, so that the lubricating oil heating device has the heating capacity of 250 ℃, and provides required high-temperature lubricating oil for a test bearing according to the requirement of the engine. The test lubrication system can be accurately controlled according to the oil supply and return temperatures of lubricating oil.

5) And (5) simulating a fulcrum lubrication state. The oil supply paths such as the accessory case, the front cavity, the middle cavity and the rear cavity are adaptively modified, the oil supply amount and the on-off control capability of the oil supply path are increased, and the lubricating states such as oil shortage and oil cut of a lubricating system are simulated.

(4) Measurement and control system

The measurement and control system adopts a frequency converter and a PLC to realize automatic closed-loop control of two main motors, oil supply pressure/flow, a lubricating oil heater, a pressurized air pressure source and the like according to a test load spectrum. In order to ensure the operation safety of the tester, the tester can realize the test and record of parameters such as the total oil supply pressure of the lubricating oil, the total oil return temperature of the lubricating oil, the rotating speeds of high-pressure and low-pressure rotors, the rotating speed, the voltage and the current of a driving motor, the bearing temperature of a gear speed increasing box, the temperature and the vibration of the lubricating oil, the water circulation pressure and the flow, and the like, and reserve channel parameters such as the lubricating oil flow (pressure) of each oil supply branch, a pressurized air system, 3-path simulated axial force pressurized air pressure, 1-path fulcrum sealing pressurized air pressure and the like. The system of the measurement and control software has complete functions, friendly interactive interface and convenient operation, supports personalized parameters and display configuration, and can realize the functions of automatic alarm and shutdown of the test board when the system fails or equipment fails.

(6) Health monitoring system

The engine health monitoring system is used for monitoring health information such as vibration, lubricating oil metal chips, lubricating oil quality and the like of an engine, an accessory casing and the like, and state parameters such as the rotating speed of an engine rotor and the temperature and pressure of oil supply and return of a lubricating system, and supporting and developing research of related fault diagnosis technologies.

(5) Charge air system and pressure regulating system

Establishing a uniform pressurized air source, wherein the output air pressure is not lower than 1.0Mpa, and the flow is not lower than 20m³And min, automatically controlling the required pressure according to the pressure requirement of each pressurized air loop, and realizing the sealing and axial force simulation of the whole lubricating oil system.

Drawings

FIG. 1(a) is a general scheme and composition of the present invention

Wherein each part is as follows: 1. the device comprises a cast iron platform, 2, a square steel frame, 3, a driving system, 4, a fulcrum casing, 5, a supporting main body, 6, a radial loading bearing, 7, an axial loading bearing, 8, a basic load applying system, 9, an impact loading sensor and 10, and an axial loading electric cylinder.

FIG. 1(b) is a system configuration diagram of the overall scheme of the present invention

FIG. 2 is a low voltage rotor power input interface

FIG. 3 is a low pressure rotor power input adapter

FIG. 4 is a cross-sectional view of a low pressure rotor input shaft modification

FIG. 5 is a blade line cut

FIG. 6(a) is a cut-off of a splined section on the drive shaft of the main fuel pump

FIG. 6(b) is a view showing a spline section cut off from a thrust-applied fuel pump drive shaft

FIG. 6(c) is a view showing the spline section on the drive shaft of the plunger pump cut off

FIG. 7 shows the modification of the axial force loading structure of the high-low pressure rotor

FIG. 8 is a pressurized air loading implementation for each chamber

FIG. 8a shows a low conductance and outer ring

FIG. 8b is a schematic view of the loading of Chamber A

FIG. 8c is a schematic view of the loading of the B-chamber

FIG. 8d is a schematic view of C-chamber loading

FIG. 9 is a view of a fulcrum pressurized seal air access point

FIG. 10a shows a high and low pressure rotor drive system scheme

Wherein each part is as follows: 11. high pressure rotor actuating system, 12, low pressure rotor actuating system, 13, mounting platform, 14, concrete foundation.

FIG. 10b is a low pressure rotor drive system scheme

Wherein each part is as follows: 15. the low-pressure rotor motor comprises a low-pressure rotor motor base/adjusting plate 16, a low-pressure rotor driving motor 17, a low-pressure rotor metal diaphragm coupler 18, a low-pressure rotor gear speed increasing box 19 and a low-pressure rotor flexible shaft.

FIG. 10c is a high pressure rotor drive system scheme

Wherein each part is as follows: 20. the high-pressure rotor motor comprises a high-pressure rotor motor base/adjusting plate 21, a high-pressure rotor driving motor 22, a high-pressure rotor diaphragm coupler 23, a high-pressure rotor speed increaser 24, a high-pressure rotor flexible shaft 25 and a high-pressure rotor speed increaser base/adjusting plate.

FIG. 11 is a gear increasing gear box

Wherein each part is as follows: 26. output shaft, 27, input shaft, 28, lubricating oil outlet, 29, lubricating oil inlet.

FIG. 12 is a schematic view showing the connection between the output of the speed increasing box and the flexible shaft of the engine rotor

Wherein each part is as follows: 30. the gearbox output shaft 31, the connector 32, the flexible shaft 33, the connector 34, the auxiliary supporting bearing 35, the low-pressure rotor connecting shaft 36 and the low-pressure rotor.

FIG. 13 aeroengine vibration acceleration sensor layout

Detailed Description

1. Engine host transformation

(1) Low pressure rotor drive interface

The low-pressure rotor adopts a high-power motor and a gear speed increasing box to rotate, and the power transmission path is the high-power motor → the speed increasing box → a transmission flexible shaft → a tail handle → an adapter → a front shaft neck of the low-pressure rotor.

The engine needs to be correspondingly modified as follows:

1) removing the fairing, the front support point oil return pump and the transmission shaft thereof, and modifying a front support point lubricating oil supply nozzle, wherein a front shaft neck of a low-pressure rotor is used as a power input interface of the low-pressure rotor, as shown in figure 2;

2) as shown in fig. 3, the adaptor is designed and processed to connect the low pressure rotor front journal with the engine case gear;

3) cutting teeth of the engine box gear, and processing 8 bolt holes, wherein the bolt holes are matched with the 8 bolt holes of the adapter;

4) designing and manufacturing a front fulcrum support shell to replace a fairing to seal a front lubricating oil cavity and support a front end bearing of a gear;

5) a supporting plug cover is additionally arranged on the engine tail rod sealing device, and a tail handle supporting bearing of an engine box connected with a low-pressure rotor transmission flexible shaft is arranged on the plug cover;

the low-pressure rotor input shaft is modified as shown in fig. 4, and it can be seen that engine parts are reserved as far as possible and are matched with engine part modification parts and redesigned machining parts for use.

(2) High pressure rotor drive interface

The high-pressure rotor is driven by a high-power motor, the power input utilizes an engine starter to start a power transmission link, the engine attachment box is driven by the transmission flexible shaft, the high-pressure rotor is driven to run through central transmission, and the power input path is the high-power motor → the speed increasing box → the transmission flexible shaft → the engine attachment box → the central transmission → the high-pressure rotor.

(3) Compressor blade modification

Under the normal working condition, the single-stage working power of the compressor reaches megawatt, the existing motor cannot meet the requirement of belt-rotating power, the complexity of an engine rotor system is considered, in order to furthest reserve the working characteristics of the high-low pressure rotor system of the engine, the rotor blade of the engine can be cut at the root part of the blade, and the tenon of the blade is arranged on the rotor of the compressor. Therefore, all the blades of the high-pressure compressor and the low-pressure compressor are dismantled, the dismantled blades are subjected to line cutting according to the graph shown in figure 5, in addition, the tenons of all the cut blades are installed back in the mortises of the rotors of the high-pressure compressor and the low-pressure compressor in consideration of the influence of the friction resistance of air flow and the like in the high-speed rotation process of the rotors, and the surfaces of blade roots are ground.

(4) Turbine blade modification

In the same consideration as the improvement of the gas compressor, all the blades of the high-pressure turbine and the low-pressure turbine are dismantled, the dismantled blades are subjected to linear cutting, tenons of all the cut blades are installed back in mortises of the high-pressure turbine rotor and the low-pressure turbine rotor, and the surfaces of blade roots are polished.

(5) Fuel system accessory modification

Because the complete machine tester does not need to burn and transmit power to the outside, the aircraft-attached casing is cancelled, all accessories related to the fuel system on the engine-attached casing are separated, in order to simulate the vibration characteristic of the engine-attached casing as much as possible, all accessories of the fuel system are required to be reserved to be installed on the engine-attached casing, namely, spline sections on a main fuel pump, a boosting fuel pump and a plunger pump transmission shaft are cut off, and the spline sections are disconnected from the engine-attached casing, and the engine-attached casing is disconnected from power, as shown in figure 6.

(6) Modification of pressurization cavity simulating pneumatic axial force

Because the working blade of the engine is removed, the aerodynamic force originally caused by the rotation of the blade disappears, and the ball bearings of the second and the fourth fulcrums of the engine do not bear the aerodynamic axial force any more and are not consistent with the actual working load direction of the engine. In order to simulate the actual working stress of the ball bearing as much as possible, a special process structural member is designed to separate the front disk cavity of the rear low-pressure turbine of the high-pressure turbine, and as shown in fig. 7, the two separated cavities and the rear disk cavity of the low-pressure turbine are pressurized respectively to realize loading.

Referring to fig. 7, 8(a) and 8(b), the high scroll and the low scroll are divided into A, B cavities, and a sealed comb gear ring K originally integrated with the low pressure rotor is cut off from the low pressure rotor and is connected with an added partition into a whole, wherein the partition is a black part between A, B fonts in fig. 7:

by pressurizing the cavity A, forward axial force of the high-pressure rotor can be formed;

by pressurizing the cavity B, a backward axial force of the low-pressure rotor can be formed;

-by pressurizing the C-chamber, a forward axial force of the low pressure rotor is formed.

The low guide vanes and the outer ring form a ring cavity, and the ring cavity can be divided into an upper semi-ring cavity and a lower semi-ring cavity or a left semi-ring cavity and a right semi-ring cavity. The cavities of the low guide vanes are respectively communicated with the cavity A and the cavity B of the graph 7, and the cavities are loaded by the pressurized air in a mode shown in the graph 8.

1) Axial loading of high pressure rotor

When the turbofan engine for the tester works, the axial force of the high-pressure rotor is always forward. The pressure of the cavity A is improved by connecting compressed air, so that the aim that the high-pressure rotor bears forward axial force, namely, the No. 4 bearing is axially loaded is fulfilled. Assuming that the maximum axial force of the No. 4 bearing is 2000Kgf, 1.18Kg/cm needs to be added into the A cavity through calculation²Compressed air (relative pressure).

2) Axial loading of low pressure rotor

When the axial force of the low-pressure rotor of the engine is N2< 91%, the axial force is forward, and the maximum value is 1000 Kgf. At N2 ≧ 91%, the axial force was rearward, with a maximum value of 1000 Kgf.

Low pressure rotor forward axial force

Referring to fig. 8(c), compressed air is supplied from the turbine support branch plate hole to the clamping cavity between the low pressure turbine disc and the turbine support, so that the purpose of forward axial force of the low pressure rotor, namely forward axial loading of the bearing No. 2 is achieved. The maximum forward axial force of No. 2 bearing is 1000Kgf, and 0.96Kg/cm needs to be added into the C cavity through calculation²Compressed air (relative pressure).

Axial force of low pressure rotor backwards

The pressure of the cavity B is improved by connecting compressed air, so that the axial force of the low-pressure rotor is backward, and the purpose of backward axial loading of the No. 2 bearing is achieved. The backward axial force of No. 2 bearing in the maximum state is 1000Kgf, and 0.99Kg/cm needs to be added into the cavity B after calculation²Compressed air (relative pressure).

The upper computer adjusts the pressure of the pressurized air through the pressure adjusting valve according to the following logical relation, and the pressurization of the given cavity is realized.

The high-pressure rotor is loaded, and the pressurizing pressure of the cavity A in the maximum state is 1.18Kg/cm²The remaining states are adjusted approximately linearly according to the pressure.

The highest value of the low-pressure rotor is 1000Kgf when N2 is less than 91%, and the rest states are approximately linearly adjusted according to the pressure; when N2 is more than or equal to 91%, the axial force is backward, the maximum value is 1000Kgf, and the rest states adjust the pressure approximately according to the linear relation.

(7) Pipeline transformation

In order to meet the requirement of 250 ℃ heating capacity of return oil of lubricating oil, a heating belt is wound on a lubricating oil tank, and a heat-insulating layer is laid on the outer side of the heating belt for modification, or an internal interface of the lubricating oil tank is utilized, heating is carried out in a 'quick-heating' mode, and the pipeline interface of the lubricating oil tank needs to be modified adaptively; in addition, in order to simulate the working state capacities of rich oil, poor oil and oil cut-off of the bearing gears of the main bearings and the accessory casings, oil supply pipelines of the main bearings and the accessory casings are modified, machining pipeline joints are designed, and electromagnetic valves and bypass oil return pipelines are connected.

(8) Fulcrum supercharging system interface modification

The fulcrum pressurization system has the function of ensuring the directional pressure difference from the pressurization cavity to the lubricating oil cavity and preventing lubricating oil and lubricating oil steam from entering a gas-air channel of the engine. When the engine normally works, the pressurizing seal of each pivot conducts air by the outer duct (when the rotating speed is low before starting, the air is from the seventh stage after the high-pressure compressor; when N2 reaches 78% -84%, and the pressure difference is larger than 0.049Mpa, the air is conducted by the outer duct).

As the blades of the compressor are cut off, the fulcrum pressurization can not be provided by the engine any more, and high-pressure air (see the dotted line part of figure 9) needs to be externally connected at the original fulcrum pressurization pipeline for simulation pressurization, so that the external and internal pressure difference of the graphite sealing ring is ensured to be 0.3 +/-0.1 kg/cm²And considering leakage and other factors, designing and modifying a pressurized air interface at A.

2. High-low pressure rotor driving system

The scheme of the high-low pressure rotor driving system is shown in fig. 10(a), and mainly comprises a concrete base 14, a mounting platform 13, a low pressure rotor driving system 12 and a high pressure rotor driving system 11. The mounting platform 13 is a cast iron platform and is connected with the equipment foundation through a ground anchor; the low pressure rotor system 12 and the high pressure rotor speed increasing system 11 are mounted on a mounting platform 13. The structure of the low-pressure rotor driving system is shown in fig. 10(b), the structure of the high-pressure rotor driving system is shown in fig. 10(c), and the high-pressure rotor driving system mainly comprises a driving motor, a gear speed increasing box and a coupler, wherein the motor is connected with an input shaft of a gear box by adopting an elastic diaphragm coupler, and the speed increasing box is connected with an input shaft of an engine by adopting a flexible shaft.

1) Driving motor

Through calculation, the rated power of the driving motor is to be selected to be 315KW (50Hz) and 350KW (60Hz), the highest output rotating speed is 3600rpm, and the efficiency is as follows: 0.95(50Hz full load), rated torque 1008N m.

2) Speed increasing gear box

The gear box is shown in fig. 11, and the gear box is in a horizontal structure, and has a single-shaft input and a single-shaft output. The whole box body has enough rigidity, the input rotating speed is 200-3600 rpm, the speed increasing ratio is 5, the requirement of 18000rpm of the highest output rotating speed can be met, and the rotor has no critical rotating speed in the whole working range; an independent hydraulic lubricating system is configured, the amount of lubricating oil is more than or equal to 35L/min, and good lubrication can be provided for the gear box. The temperature and vibration sensor is arranged, the temperature of the inner bearing, the temperature of lubricating oil and the vibration of the main body of the gear speed increaser in the running process can be monitored, and the shutdown protection value of the temperature and the vibration is set through the computer monitoring system.

When the tester runs, a computer sends out an instruction signal according to a software program, the start and stop of the motor and the change of the rotating speed are controlled by the frequency converter, the actual rotating speed value is measured by the rotating speed sensor and fed back to the computer for regulation, closed-loop control is formed, and the rotating speed control error is +/-0.3% FS.

The gear speed increasing box is connected with the driving motor by adopting an elastic diaphragm coupler, and the elastic diaphragm coupler has the advantages of large bearing capacity, high transmission precision and high transmission efficiency and also has certain deflection and skew compensation quantity. The gear speed increasing box is connected with the high-pressure rotor and the low-pressure rotor of the engine through flexible shafts, and the flexible shafts are shown in figure 12.

3) Speed regulating system

The speed regulating system consists of an intelligent frequency converter and a variable frequency motor, and meets the test requirements. The variable frequency motor operates stably and reliably at high speed, the motor is operated by a control signal of a given frequency converter, the actual rotating speed value of the motor is fed back to a computer by a rotating speed sensor through a transmitter, and the computer performs PID (proportion integration differentiation) adjustment on the control quantity of the rotating speed and then outputs D/A (digital/analog) to form closed-loop control of the system.

3. Lubrication system

1) Oil supply system

The lubricating oil tank, the lubricating oil accessories, the lubricating oil filter, the fuel-lubricating oil heat exchanger, the conversion valve, the guide pipe, the nozzle and other parts of the engine oil supply system are reserved.

The lubricating oil accessories are driven by the engine box in a power distribution mode, and lubricating oil with certain pressure is guaranteed to be delivered to each pivot of the engine and the engine box.

2) Oil return system

Since the front pivot scavenge pump position is occupied by the N1 input shaft, the front pivot scavenge pump is eliminated and external scavenge pump lube is substituted. A middle supporting point oil return pump and a rear supporting point oil return pump are reserved, the lower oil return pump is changed into an external oil return pump with strong pumping capacity, and a rear supporting point external oil return pump is added (the external oil return pump and the original rear supporting point oil return pump return oil together).

3) Simulated fuel-lubricating oil heat dissipation system

The cooling of fuel oil is simulated through water circulation cooling, the kerosene inlet and outlet of two original (parallel) fuel-lubricating oil radiators of the engine are connected with an external distilled water cooling system, a water circulation system is configured, the lubricating oil is simulated to be radiated through the fuel oil, and the measurement and control system performs integrated control on water flow and the like according to the state requirement of the engine to provide required radiating capacity.

4) Lubricating oil heating system

In order to simulate the oil supply and return temperatures of lubricating oil under the actual working condition of an engine, a lubricating oil heating mode that a heating resistance wire and a heat preservation layer are arranged outside a lubricating oil tank is adopted, or a heating mode of 'quick heating' is adopted by utilizing the existing structure of the lubricating oil tank, and the heating temperature is controlled to realize the simulation of the oil supply or return temperature.

The test lubricating system has the capability of accurately controlling the oil supply and return temperature of lubricating oil. In order to improve the temperature control precision, a special temperature control instrument is adopted to take charge of a heating control scheme. The temperature control target value is set for the temperature controller through the computer, the temperature controller controls the on-off of the solid relay according to the actual temperature of the lubricating oil and the set temperature control target value in a PID control mode according to the set temperature control target value, the power supply power for driving the heating element is adjusted, and the automatic control of the oil temperature is realized. The temperature sensor, the temperature controller, the solid-state relay and the heater form a lubricating oil temperature heating closed-loop control system.

5) And (5) simulating a fulcrum lubrication state. In order to simulate the working states of rich oil, lean oil, oil cut and the like of the bearing gear of the accessory casing and the main bearing of each fulcrum of the engine, the oil supply quantity and the on-off of four oil supply paths of the accessory casing, the intermediate casing, the front casing of the low-pressure compressor, the turbine support and the like need to be automatically controlled.

(5) Charge air system and pressure regulating system

Because the whole lubricating oil system is sealed and has axial forceSimulating the condition that the pressure of the air is needed to be increased, establishing a unified pressure-increasing air source, wherein the output air pressure is not lower than 1.0Mpa, and the flow is not lower than 20m³And/min, the required pressure can be automatically controlled according to the pressure requirement of each pressurized air loop.

4. Measurement and control system

The measurement and control system adopts a PLC control framework to realize the control of two main motors, and the oil supply pressure/flow, the lubricating oil heater, the pressurized air pressure source and the like realize automatic closed-loop control according to a test load spectrum.

The tester monitors parameter acquisition, is responsible for the normal operating of detection tester, and the parameter of test and record includes at least: the method comprises the steps of testing and recording parameters such as total oil supply pressure of lubricating oil, total oil return temperature of the lubricating oil, high-pressure rotor rotating speed, low-pressure rotor rotating speed, driving motor rotating speed, voltage and current, gear speed increasing box bearing temperature, lubricating oil temperature and vibration, water circulation pressure and flow and the like, reserving channel parameters such as lubricating oil flow (pressure) of each oil supply branch, and simulating axial force supercharging air pressure in 3 paths and fulcrum sealing supercharging air pressure in 1 path of a large-flow supercharging air system.

The system of the measurement and control software has complete functions, friendly interactive interface and convenient operation, supports personalized parameters and display configuration, and can realize the functions of automatic alarm and shutdown of the test board when the system fails or equipment fails.

All analog signals enter the PLC analog input module through the isolation transmitter in a 4-20mA signal mode to be subjected to D/A conversion, and numerical values are transmitted to an upper computer (a computer) through a network port to be displayed and processed. The PLC is used as a core to build an electrical test unit, is placed in a special test cabinet and mainly comprises a CPU, an analog input module, a direct current power supply for a sensor and an interface module IM360 for interfacing with a drive control cabinet.

5. Monitoring system

The engine health monitoring system is used for monitoring health information such as vibration, lubricating oil metal chips and lubricating oil quality of an engine and an accessory casing, the rotating speed of an engine rotor and state parameters such as the temperature and pressure of oil supply and return of a lubricating system, a vibration sensor (see figure 13) is laid on a vibration transmission path of the engine, and related fault diagnosis technical research is supported and developed.

(1) Airborne sensor

The original engine lubricating oil pressure, lubricating oil temperature, airborne vibration, lubricating oil metal chip annunciator (switching signal) and high-low pressure rotor speed sensor are connected to a mechanical system health monitoring system.

(2) High-frequency vibration acceleration sensor

The high-frequency vibration sensor is arranged at an engine fulcrum bearing seat, a fan casing, an intermediate casing, an onboard measuring point, a turbine support (an installation edge, in a culvert), a mixer outer casing installation edge, an engine-attached casing and the like.

(3) Lubricating oil metal chip sensor

And a lubricating oil metal chip online sensor is arranged at the positions of a main oil return pipeline, a fault multiple oil return cavity oil return pipeline, an accessory engine box oil return pipeline and the like.

(4) MEMS sensor

MEMS vibration and temperature sensors are arranged on the main bearing seat and the like, and lead wires are led out through an air pipeline of the casing support plate.

Finally, it should be noted that: the above-mentioned embodiments are only used for illustrating the technical solution of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A military turbofan engine mechanical system complete machine tester is composed of a military turbofan engine, an engine accessory casing, a high-power high-low pressure rotor driving system, a load environment simulation system, a measurement and control system, an engine health diagnosis system, a mounting bracket and a foundation, and is characterized in that the military turbofan engine specially modified is adopted to simulate the complete machine service environment of the engine, and pressurized air is used to simulate the complete machine axial aerodynamic force load environment of the engine; the high-power motor and the gear speed increasing box are adopted, the transmission flexible shaft drives the high-low pressure rotor of the engine, the low-pressure rotor adopts the high-power motor and the gear speed increasing box, the transmission flexible shaft rotates, the power transmission path is the high-power motor → the gear speed increasing box → the transmission flexible shaft → the tail handle → the adapter → the front shaft neck of the low-pressure rotor, the high-pressure rotor is driven by the high-power motor, the power input utilizes the engine starter to start a power transmission link, the engine accessory casing is driven by the transmission flexible shaft, the high-pressure rotor is driven to rotate by central transmission, and the power input path is the high-power motor → the gear speed increasing box → the transmission flexible shaft → the engine accessory casing → the central transmission → the high-pressure rotor; cutting the compressor and turbine rotor blades of the engine from the blade root, mounting blade tenons back to the compressor and the turbine, and polishing the surface of the blade root;

cutting off the power output of the fuel accessory, cutting off spline sections on transmission shafts of a main pump, a booster pump and a plunger pump, so that the main pump, the booster pump and the plunger pump are disconnected from the power connection with an engine accessory casing and are kept to be installed on the engine accessory casing;

changing a lower oil return pump into an external oil return pump with strong pumping capacity, adding a rear supporting point external oil return pump, returning oil together with the original rear supporting point oil return pump, and moving a front supporting point oil return pump to the outside for returning oil;

simulating fuel oil cooling through water circulation cooling, connecting fuel oil inlets and outlets of two original parallel fuel-lubricating oil radiators of the engine with an external distilled water cooling system, and performing integrated control on water flow;

the method comprises the following steps of measuring the temperature of oil supply and return of lubricating oil by adopting a high-precision temperature control instrument, and heating the lubricating oil by arranging a heating resistance wire and a heat insulation layer outside the lubricating oil tank or adopting a lubricating oil heating mode of 'quick heating' inside the lubricating oil tank;

the oil supply quantity and the on-off of each oil supply way are automatically controlled;

externally connecting high-pressure air at the original fulcrum pressurization pipeline to simulate the air-entraining pressurization of an external duct, and establishing the directional pressure difference from a pressurization cavity to a lubricating oil cavity;

the disc cavity behind the high-pressure turbine and in front of the low-pressure turbine is divided into two cavities, and the two cavities after the division and the disc cavity behind the low-pressure turbine are respectively subjected to pressurization control.

2. The military turbofan engine mechanical system whole machine tester of claim 1 wherein engine structural integrity is unchanged.

3. The military turbofan engine mechanical system complete machine tester of claim 1 wherein oil return capability is increased.

4. The military turbofan engine mechanical system complete machine tester of claim 1 wherein fuel to oil heat dissipation is simulated.

5. The military turbofan engine mechanical system complete machine tester of claim 1, wherein closed loop control of engine supply and return oil temperatures is achieved.

6. The military turbofan engine mechanical system complete machine tester of claim 1, wherein the test machine is capable of simulating the working conditions of rich oil, lean oil and oil cut-off of oil supply of engine accessory case bearing gears and engine fulcrum main bearings.

7. The military turbofan engine mechanical system complete machine tester of claim 1, wherein the graphite seal ring external and internal differential pressure is guaranteed to be 0.3 ± 0.1kg/cm²And the pressurization and sealing of the lubricating system are realized.

8. The military turbofan engine mechanical system complete machine tester of claim 1, wherein simulation of high and low pressure rotor ball bearing axial force under engine operating conditions is achieved.

9. The military turbofan engine mechanical system complete machine tester of claim 1, wherein the measurement and control system adopts a PLC control architecture to realize automatic closed-loop control of two main motors, oil supply pressure/flow, oil heater, and boost air pressure according to a test load spectrum.

10. The military turbofan engine mechanical system complete machine tester of claim 1, wherein an engine health diagnosis system is provided, and high frequency vibration sensors are provided at an engine fulcrum bearing seat, a fan casing, an intermediate casing, an on-board measuring point, a mounting edge in an outer duct at a turbine support, a mixer outer casing mounting edge, and an engine accessory casing, and lubricating oil metal chip sensors are provided at an engine lubricating oil middle cavity, a rear cavity, and oil return pipelines of the accessory casing, so as to realize condition monitoring and health diagnosis of a main bearing, a transmission gear and a bearing, and a high-low pressure rotor.