Thermal mechanical composite fatigue test equipment for turbine blade in rotating environment

Abstract

The invention belongs to the technical field of aero-engine high-temperature part test, and particularly relates to a thermal mechanical composite fatigue test device in a turbine blade rotation environment, which comprises a high-temperature gas system, a stator system, a rotor system, a support system, a test system, an auxiliary system and a turbine rotor blade test piece, the high-temperature fuel gas system is used for providing a fuel gas environment for a turbine rotor blade test piece and controlling the high-low temperature circulation state of fuel gas, a combustion chamber is arranged at the front end of the high-temperature fuel gas system and provided with a double-oil-way nozzle, a fuel gas flowing system is arranged at the rear end of the high-temperature fuel gas system, and a blade grid structure is designed for the fuel gas flowing system according to the geometrical shape of a turbine rotor blade. And a spray cooling section is arranged at the rear part of the test section. The device is composed of six core systems including a high-temperature fuel gas system, a stator system, a rotor system, a supporting system, a testing system and an auxiliary system, all the systems work cooperatively, and integrated simulation of the high-temperature fuel gas environment, rotating centrifugal loads and heat-force synchronous circulation is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-temperature component test of an aero-engine, and particularly relates to a hot-mechanical combined fatigue test equipment for a turbine blade in a rotating environment. BACKGROUND

[0002] In the technical path of improving the performance of an aero-engine, the increase of the temperature before the turbine is one of the core directions. The temperature before the turbine of the current advanced aero-engine has broken through 1800K and is close to or even exceeds the limit temperature resistance capacity of the turbine rotor blade material; meanwhile, in order to pursue a higher thrust-to-weight ratio, the turbine speed continues to increase, which causes the centrifugal load borne by the rotor blade to reach several hundred MPa, becoming one of the main causes of the failure of the blade. The turbine rotor blade needs to experience complex working conditions such as take-off, cruising, landing and maneuvering flight in the whole life cycle of the engine, and the thermal load and the centrifugal load borne by the blade change periodically: in the take-off stage, the gas temperature rapidly increases to the peak value, and the centrifugal force rapidly increases due to the rapid increase of the rotating speed; in the cruising stage, the load is maintained at a stable level; in the landing stage, the load rapidly falls to the trough. This periodic “thermal-force” coupling is the fundamental reason for the low-cycle fatigue damage of the rotor blade and the final fracture failure. According to the fault statistical data of the aviation industry, about 35% of the aero-engine air stop accidents are directly related to the fatigue failure of the turbine rotor blade, and therefore, it is crucial to carry out accurate hot-mechanical combined fatigue test in the blade development stage. At present, the test methods for the fatigue performance of the turbine rotor blade in the industry mainly include three types, but all have significant defects: Gas environment thermal shock test: this method generates high-temperature gas through a combustion chamber, introduces cooling air into the inner cavity of the blade to simulate the wall temperature distribution, and realizes the thermal stress cycle by periodically adjusting the temperatures of the gas and the cooling air. However, it can only examine the influence of the thermal load on the stator component (such as the guide vane), completely ignores the coupling effect of the centrifugal force on the temperature field distribution of the rotor blade (such as the change of the cooling passage flow caused by the deformation of the blade due to the centrifugal force) and the stress state (the superposition of the centrifugal stress and the thermal stress), and relevant researches show that the amplitude of the centrifugal stress of the rotor blade can reach 3-5 times of the thermal stress, and therefore, this method cannot accurately evaluate the fatigue life of the rotor blade. Local high-temperature static hot-mechanical test: high-frequency induction heating is used to simulate the temperature field of the dangerous section of the blade, and hydraulic tension or weight loading is used to simulate the single-axis centrifugal force. This method has three defects: first, local heating is used to replace the whole gas scouring, which ignores the oxidation, corrosion and aerodynamic force load of the high-temperature gas on the surface of the blade; second, the static loading needs to process an additional force tooling at the blade tip, which changes the original structure and stress distribution of the blade; third, the single-axis loading cannot simulate the gradient distribution of the real centrifugal force (the stress at the blade root is 8-10 times of that at the blade tip) and the bending-torsion coupling effect, which greatly deviates from the actual working condition. Gas environment static thermal mechanical test: although the gas scouring environment can be reproduced, the static loading mode is still used to simulate the centrifugal force, the core problems such as the centrifugal force gradient effect in the rotating state and the influence of the dynamic deformation of the blade on the thermal field are not solved, and the correlation of the test data with the real service state is still weak. In summary, the existing test equipment cannot simultaneously reproduce the real working condition of 'high-temperature gas scouring + rotating centrifugal load + periodic coupling of load', so that the guiding value of the test data for the blade design is limited. Therefore, developing a thermal mechanical composite fatigue tester capable of accurately simulating the real service environment of the turbine rotor blade has become an urgent need in the field of aero-engine development. SUMMARY

[0003] The purpose of the present application is to provide a turbine blade rotating environment thermal mechanical composite fatigue test equipment, which is composed of six core systems of high-temperature gas system, stator system, rotor system, support system, test system and auxiliary system, and each system works cooperatively to realize the integrated simulation of 'high-temperature gas environment + rotating centrifugal load + thermal-power synchronous cycle'.

[0004] The technical scheme adopted by the present application is as follows: A turbine blade rotating environment thermal mechanical composite fatigue test equipment, comprising a high-temperature gas system, a stator system, a rotor system, a support system, a test system, an auxiliary system and a turbine rotor blade test piece, the high-temperature gas system is used to provide a gas environment for the turbine rotor blade test piece and control the high-low temperature cycle state of the gas, a combustion chamber is arranged at the front end of the high-temperature gas system, the combustion chamber is equipped with a double-oil-way nozzle, a gas flow system is arranged at the rear end of the high-temperature gas system, the gas flow system is designed according to the geometric shape of the turbine rotor blade, and a spray cooling section is arranged at the rear part of the test section. The stator system and the rotor system are cooperatively designed and divided into multiple chambers, including a gas sealing chamber, an axial force adjusting chamber and a fulcrum sealing chamber, the gas sealing chamber is connected with normal-temperature high-pressure air to seal the gas leakage into the chamber, the axial force adjusting chamber is connected with normal-temperature high-pressure air to adjust the aerodynamic force acting on the rotating disc, the fulcrum sealing chamber is used to inhibit the leakage of the lubricating oil of the fulcrum bearing, and the stator system cooperates with the determined turbine rotor blade test piece to control the blade tip clearance. The rotor system comprises a shaft system and a rotating disc, the rotating disc is connected with the shaft system through a compression structure, the end part of the shaft system is connected with a high-speed variable frequency motor, and the high-speed variable frequency motor is used to control the rotating speed of the shaft system, thereby realizing the control of the centrifugal force suffered by the turbine rotor blade test piece. The support system is used for supporting the whole tester, and expansion deformation caused by rotating system temperature and static system temperature is considered, the test system includes rotating system test equipment and static system test equipment, the rotating system test equipment includes a slip ring power supply device and a dynamic pressure sensor, and the static system test equipment includes a thermocouple, a pressure transmitter and a flow meter, which are used for testing related parameters in the test process, and the auxiliary system includes a control system, a circulating water system, a fuel system and an exhaust silencer tower, which are used for cooperating with the above system.

[0005] In a preferred scheme, the combustion chamber is designed in series, and the design temperature includes 1000K, 1600K and 1800K, and the corresponding combustion chamber is selected according to the specific requirements of the test.

[0006] In a preferred scheme, the auxiliary oil nozzle of the double-oil-path nozzle adopts an auxiliary oil pump to control the rotating speed of a variable frequency motor to provide continuous adjustment capability, and an electromagnetic valve is used to control the opening and closing, so that the oil pressure is increased to be greater than the main flow pressure to provide ignition oil ignition; the main oil nozzle supply oil path adopts a regulating valve instead of an electromagnetic valve, the high-temperature gas temperature level is determined by the rotating speed of the oil pump and the stroke opening of the regulating valve, and the regulating valve can control the stroke cycle of the regulating valve, so that the transition state cycle time from low temperature to high temperature and from high temperature to low temperature is independently controllable.

[0007] In a preferred scheme, the cascade of the gas flow system is composed of 3-5 blades, the turbine rotor blade test piece is located in the middle of the cascade, and the gas flow system is matched and designed according to the flow field design requirements of the test blade, the parameters of the tip clearance, the inlet angle and the exhaust angle, the temperature and pressure test parameter interfaces are arranged in the inlet section of the test section, and the exhaust test parameter interface is arranged in the exhaust section.

[0008] In a preferred scheme, the design scheme of the rotating disc includes two kinds, scheme one selects metal material, and the strength reserve under the centrifugal load and the disc edge cooling are comprehensively considered; scheme two selects composite material, the composite material is CMC material, the structure design is optimized by using the temperature resistance performance, the diameter of the rotating disc meets the requirement of the rotor test blade, the strength of the rotating disc meets the requirement of high temperature and high speed, and a certain strength reserve is provided.

[0009] In a preferred scheme, the shafting is designed with a support point scheme at a suitable position, and the labyrinth and boss structures are designed on the shafting to meet the sealing and positioning design requirements, and the specific structure of the shafting is determined according to the size of the rotating disc and the rotating speed requirement.

[0010] In a preferred scheme, the high-speed variable frequency motor controls the variable frequency time between high speed and low speed, so that the centrifugal mechanical load is adjustable and controllable.

[0011] In a preferred solution, the test system can also use infrared thermal imager, wall temperature thermocouple testing instruments and meters according to the test state and the specific situation of the test piece.

[0012] In a preferred solution, the high-temperature gas system cooperates with the rotor system to realize synchronous loading of centrifugal force and thermal load, the centrifugal force is controlled by the rotating speed, and the thermal load is controlled by the gas temperature.

[0013] In a preferred solution, the composite load spectrum is divided into four stages of "temperature rise loading (t1) - high temperature load preservation (t2) - temperature drop unloading (t3) - low temperature load preservation (t4)", and the load size, rate and time are adjusted according to the task requirements.

[0014] The technical effects obtained by the present application are: High precision of working condition reproduction: for the first time, the full working condition simulation of "high-temperature gas scouring + rotating centrifugal load + thermal-power synchronous cycle" is realized, the centrifugal force gradient distribution error is less than or equal to 5%, the gas temperature control error is ±10K, the real service environment of the rotor blade is completely reproduced, and the reliability of the test data is improved by more than 60% compared with traditional equipment. Strong flexibility of load adjustment: through the coordinated control of double-oil-way nozzles and high-speed variable frequency motors, the independent adjustment of temperature rise rate (5-20K / min), temperature drop rate (3-15K / min), and rise / drop time (10-60s) can be realized, 10-1000 cycles can be set, different models and different working conditions of turbine blade test requirements can be adapted, and the universality of the equipment is improved by 40%. High running safety: three-stage sealing (gas sealing chamber + axial force adjusting chamber + fulcrum sealing chamber) and spray cooling technology are adopted, the gas leakage rate is less than 0.1%, the bearing working temperature is less than or equal to 80 DEG C, and multiple alarm mechanisms such as over-temperature, over-pressure and low oil level are equipped, and there is no safety accident risk in the test process. Strong comprehensiveness of test data: integrating multi-dimensional test equipment such as slip ring power supply device, infrared thermal imager and dynamic pressure sensor, 18 kinds of parameters such as temperature field, stress field, flow field and rotating speed can be synchronously collected, the data sampling rate is up to 10000Hz, complete data support is provided for blade fatigue life evaluation and design optimization. The engineering application value is remarkable: before the engine whole machine test, the blade design defects can be exposed in advance through the equipment, the test risk and cost are reduced; the test data can be used to verify the rotating heat transfer model, the constitutive model and the life prediction method, promote the design technology of aero-engine high-temperature parts, and shorten the development cycle by more than 30%. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a composite load spectrum diagram of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the present application; Figure 2It is a test device overall design scheme diagram of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the application; Figure 3 It is a combustion chamber schematic diagram of a test device of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the application; Figure 4 It is a double oil path adjusting principle schematic diagram of a test device of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the application; Figure 5 It is a test cascade schematic diagram of a test device of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the application; Figure 6 It is a flow system structure schematic diagram of a test device of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the application; Figure 7 It is a rotor system schematic diagram of a test device of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the application; Figure 8 It is a stator system schematic diagram of a test device of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the application; Figure 9 It is a support system schematic diagram of a test device of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the application; Figure 10 It is a schematic diagram of a combustion chamber of a turbine blade rotating environment thermal mechanical composite fatigue test equipment of the application.

[0016] In the figure: 0-combustion chamber, 1-high temperature gas system, 2-stator system, 3-rotor blade test piece, 4-rotor system, 5-support system, 6-test system. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0018] Please refer to Figures 1-9 The application provides a turbine blade rotating environment thermal mechanical composite fatigue test equipment, which comprises a high temperature gas system 1, a stator system 2, a rotor system 4, a support system 5, a test system 6, an auxiliary system and a turbine rotor blade test piece 3. The high temperature gas system 1 is used for providing a gas environment for the turbine rotor blade test piece 3 and controlling the high and low temperature cycle state of the gas. The front end of the high temperature gas system 1 is provided with a combustion chamber 0, the combustion chamber 0 is equipped with a double oil path nozzle, and the rear end is provided with a gas flow system. The gas flow system is designed to have a cascade structure according to the geometric shape of the turbine rotor blade, and a spraying cooling section is arranged at the rear of the test section. The stator system 2 is designed in cooperation with the rotor system 4, and is divided into a plurality of chambers including a gas sealing chamber, an axial force adjusting chamber and a fulcrum sealing chamber. The gas sealing chamber is connected to the high-pressure air at normal temperature to seal the leakage of the gas into the chamber. The axial force adjusting chamber is connected to the high-pressure air at normal temperature to adjust the aerodynamic force acting on the rotating disc. The fulcrum sealing chamber is used to suppress the leakage of the lubricating oil of the fulcrum bearing. Meanwhile, the stator system 2 cooperates with the determined turbine rotor blade test piece 3 to control the tip clearance. The rotor system 4 includes a shaft system and a rotating disc. The rotating disc is connected to the shaft system through a compression structure. The end of the shaft system is connected to a high-speed variable frequency motor. The high-speed variable frequency motor is used to control the rotating speed of the shaft system, thereby realizing the control of the turbine rotor blade test piece 3 subjected to the centrifugal force. The support system 5 is used to support the whole test device, and the expansion deformation caused by the temperature of the rotating and stationary systems is considered. The test system 6 includes a rotating system test device and a stator test device. The rotating system test device includes a slip ring power supply and a dynamic pressure sensor. The stator test device includes a thermocouple, a pressure transmitter and a flowmeter, which are used to test the related parameters in the test process. The auxiliary system includes a control system, a circulating water system, a fuel system and an exhaust silencer tower, which are used to cooperate with the above systems. The combustion chamber 0 is designed in series. The design temperature includes 1000K, 1600K and 1800K. The corresponding combustion chamber 0 is selected according to the specific requirements of the test. The auxiliary oil nozzle of the double-oil-path nozzle adopts an auxiliary oil pump to provide continuous adjustment capability by controlling the rotating speed of the frequency conversion motor. The opening and closing of the auxiliary oil nozzle are controlled by an electromagnetic valve. The oil pressure is increased to be greater than the main flow pressure to provide the ignition oil ignition. The main oil nozzle supply oil path adopts an adjusting valve to replace the electromagnetic valve. The high-temperature retention temperature level of the gas is determined by the rotating speed of the oil pump and the stroke opening of the adjusting valve. The adjusting valve can control the adjusting valve stroke cycle, so that the transition state cycle time from low temperature to high temperature and from high temperature to low temperature is independently controllable. The cascade of the gas flow system is composed of 3-5 blades. The turbine rotor blade test piece is located in the middle of the cascade. The gas flow system is designed according to the flow field design requirements of the test blade to match the design of the tip clearance, the inlet angle and the exhaust angle parameters. The temperature and pressure test parameter interfaces are arranged in the inlet section of the test section. The exhaust test parameter interface is arranged in the exhaust section. There are two design schemes of the rotating disc. In the first scheme, a metal material is selected. The disc rim cooling and the strength reserve under the centrifugal load are comprehensively considered. In the second scheme, a composite material is selected. The composite material is a CMC material. The structure design is optimized by using the temperature resistance performance of the composite material. The diameter of the rotating disc meets the requirements of the rotor test blade. The strength of the rotating disc meets the requirements of high temperature and high rotating speed, and has a certain strength reserve. The fulcrum scheme is designed at a suitable position of the shaft system. The labyrinth and boss structures are designed on the shaft system to meet the sealing and positioning design requirements. The specific structure of the shaft system is determined according to the size and rotating speed requirements of the rotating disc. The high-speed variable frequency motor realizes adjustable and controllable centrifugal mechanical load by controlling variable frequency time between high rotation speed and low rotation speed. The test system 6 can also use infrared thermal imager and wall temperature thermocouple testing instruments according to the test state and specific conditions of the test piece. The high-temperature gas system 1 cooperates with the rotor system 4 to realize synchronous loading of centrifugal force and thermal load, the centrifugal force is controlled by rotation speed, and the thermal load is controlled by gas temperature. The composite load spectrum is divided into four stages of "temperature rise loading (t1) - high temperature load maintaining (t2) - temperature drop unloading (t3) - low temperature load maintaining (t4)", and the load size, rate and time can be adjusted according to the task requirements.

[0019] In the application, the high-speed rotation of the rotating part is directly driven by the power device, so that the turbine rotor blade itself generates a real and uniformly distributed centrifugal stress field. This provides the most real stress field, and the thermal load is superimposed on the basis, so that the stress state of the rotor blade is highly consistent with the real working state. In the high-temperature environment, the centrifugal force generated by high-speed rotation realizes synchronous loading of centrifugal force and thermal load, the centrifugal force is controlled by rotation speed, and the thermal load is controlled by gas temperature. The composite load spectrum is usually divided into four stages of "temperature rise loading (t1) - high temperature load maintaining (t2) - temperature drop unloading (t3) - low temperature load maintaining (t4)", and the load size, rate and time can be adjusted according to the task requirements.

[0020] The above only describes the preferred embodiments of the application, and it should be pointed out that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the application, and these improvements and refinements should also be considered as the protection scope of the application. The structures, devices and operation methods not specifically described and explained in the application are implemented according to the conventional means in the art, unless otherwise specified and limited.

Claims

1. A hot mechanical composite fatigue test apparatus for a turbine blade in a rotating environment, characterized by: The turbine rotor blade test piece (3) is provided with a combustion chamber (0) at the front end, the combustion chamber (0) is provided with a double-oil-way nozzle, a gas flow system is arranged at the rear end, the gas flow system is designed with a cascade structure according to the geometric shape of the turbine rotor blade, and a spray cooling section is arranged at the rear of the test section; The stator system (2) is cooperatively designed with the rotor system (4) and is divided into a plurality of chambers, including a gas sealing chamber, an axial force adjusting chamber and a fulcrum sealing chamber, the gas sealing chamber is connected with normal-temperature high-pressure air to seal the gas leakage into the chamber, the axial force adjusting chamber is connected with normal-temperature high-pressure air to adjust the aerodynamic force acting on the rotating disc, and the fulcrum sealing chamber is used for inhibiting the lubricating oil leakage of the fulcrum bearing; meanwhile, the stator system (2) cooperates with the determined turbine rotor blade test piece (3) to control the tip clearance. The rotor system (4) includes a shaft system and a rotating disc, the rotating disc is connected with the shaft system through a compression structure, the end of the shaft system is connected with a high-speed variable frequency motor, and the high-speed variable frequency motor is used for controlling the rotating speed of the shaft system, thereby realizing the control of the centrifugal force suffered by the turbine rotor blade test piece (3). The support system (5) is used for supporting the whole test equipment, and the expansion deformation caused by the temperature of the rotating system and the stator system is considered, the test system (6) includes a rotating system test equipment and a stator test equipment, the rotating system test equipment includes a slip ring power supply device and a dynamic pressure sensor, the stator test equipment includes a thermocouple, a pressure transmitter and a flowmeter, which are used for testing the related parameters in the test process, the auxiliary system includes a control system, a circulating water system, a fuel system and an exhaust silencing tower, which are used for cooperating with the above systems, and the test of the test system (6) further includes a composite load spectrum.

2. The apparatus for thermomechanical combined fatigue testing of turbine blade in rotating environment according to claim 1, characterized in that: The combustion chamber (0) is designed in a series, the design temperature includes 1000K, 1600K and 1800K, and the corresponding combustion chamber (0) is selected according to the specific requirements of the test.

3. The apparatus for thermomechanical combined fatigue testing of turbine blade in rotating environment according to claim 2, characterized in that: The auxiliary oil nozzle oil supply path adopts an auxiliary oil pump to provide continuous adjustment capacity by controlling the rotating speed of the frequency conversion motor, and the oil pressure is increased to be greater than the main flow pressure to provide ignition oil ignition by controlling the opening and closing of the electromagnetic valve; the main oil nozzle oil supply path adopts an adjusting valve to replace the electromagnetic valve, the high-temperature maintaining temperature level of the gas is determined by the rotating speed of the oil pump and the stroke opening of the adjusting valve, the adjusting valve can control the adjusting valve stroke cycle, and the transition state cycle time from low temperature to high temperature and from high temperature to low temperature is independently controllable.

4. The apparatus for thermomechanical fatigue testing of turbine blade in rotating environment according to claim 3, wherein: The cascade of the gas flow system is composed of 3-5 blades, the turbine rotor blade test piece is located in the middle of the cascade, and the gas flow system matches the design of the tip clearance, the inlet angle and the exhaust angle parameters according to the flow field design requirements of the test blade, temperature and pressure test parameter interfaces are arranged in the inlet section of the test section, and exhaust test parameter interfaces are arranged in the exhaust section.

5. The apparatus for thermomechanical combined fatigue testing of turbine blade in rotating environment according to claim 4, characterized in that: The design scheme of the rotating disc includes two schemes. In the first scheme, a metal material is selected, and the disc rim cooling and the strength reserve under centrifugal load are comprehensively considered. In the second scheme, a composite material is selected, the composite material is a CMC material, the structure design is optimized by using the temperature resistance of the composite material, the diameter of the rotating disc meets the demand of the rotor test blade, the strength of the rotating disc meets the high-temperature and high-speed strength requirement, and the rotating disc has a certain strength reserve.

6. The apparatus for thermomechanical combined fatigue testing of turbine blade in rotating environment according to claim 5, characterized in that: The shafting is designed with a fulcrum scheme at a suitable position, and the shafting is designed with a labyrinth and a boss structure to meet the sealing and positioning design requirements. The specific structure of the shafting is determined according to the size of the rotating disc and the speed requirement.

7. The apparatus for thermomechanical fatigue testing of turbine blade in rotating environment according to claim 6, wherein: The high-speed variable frequency motor realizes adjustable and controllable centrifugal mechanical load by controlling the variable frequency time between high speed and low speed.

8. The apparatus for thermomechanical combined fatigue testing of turbine blade in rotating environment according to claim 7, characterized in that: The test system (6) can also use an infrared thermal imager and a wall temperature thermocouple according to the test state and the specific condition of the test piece.

9. The apparatus for thermomechanical combined fatigue testing of turbine blade in rotating environment according to claim 8, characterized in that: The high-temperature gas system (1) cooperates with the rotor system (4) to realize synchronous loading of centrifugal force and thermal load. The centrifugal force is controlled by the rotating speed, and the thermal load is controlled by the gas temperature.

10. The apparatus for thermomechanical combined fatigue testing of turbine blade in rotating environment according to claim 9, characterized in that: The composite load spectrum is divided into four stages of "temperature rising loading (t1) - high-temperature load maintaining (t2) - temperature dropping unloading (t3) - low-temperature load maintaining (t4)". The load size, rate and time are adjusted according to the task requirement.

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