CN106855486B - Rotary air film cooling type temperature gradient thermo-mechanical fatigue test system - Google Patents

Abstract

The invention discloses a rotating air film cooling temperature gradient thermomechanical fatigue test system, which includes: a loading subsystem, a heating subsystem, a power subsystem, an air cooling subsystem and a control subsystem. By improving the existing test equipment, the The temperature gradient field of air film cooling is generated by friction with the air under the rotating condition of the specimen, which ensures that the specimen is rotated and bears the uniaxial tensile load at the same time, which better solves the difficulty of simulating the test environment of the temperature gradient field of the specimen, and the operation method is simple and easy ,low cost. The rotating test piece improves the traditional thermomechanical fatigue test system, truly reproduces the air film cooling temperature gradient field under the working state of the blade, ensures the smooth progress of the thermomechanical fatigue test of the aeroengine turbine blade, and provides a technical basis and safety guarantee for the safe and reliable operation of the aeroengine .

Description

A rotating film cooling temperature gradient thermomechanical fatigue test system

technical field

The invention belongs to the technical field of aerospace engine testing, and relates to a single crystal turbine blade thermomechanical fatigue test system for an aeroengine, in particular to a rotating air film cooling temperature gradient thermomechanical fatigue test system capable of simulating the temperature gradient service environment of a single crystal turbine blade .

Background technique

The thermomechanical fatigue (TMF) performance of single crystal turbine blades is one of the important performance indicators of aeroengines, and is an important factor affecting the service life of turbine blades. The service process of the blade and the air friction produce a film cooling temperature gradient field in the blade structure. The temperature gradient field changes with the engine's working state, directly affecting the mechanical properties of the turbine blade, and even causing material damage. In the laboratory environment, in order to ensure the accuracy of the test, it is necessary to truly reproduce the same film cooling temperature gradient field in the service of the specimen, and the test results in this environment are authentic.

In the existing domestic temperature gradient control systems, quartz tubes are commonly used for infrared radiation heating. This method is simple and easy to implement, and the cost is low. However, the driving power of this system is small and the thermal inertia is large, so the controllability of the temperature field is poor. The heating system in the invention patent 201110460131.4 is composed of a high-frequency induction heating furnace and an induction heating coil. It adopts a double-tube split-half structure, and uses the cooling water inside the copper tube to form the desired temperature by changing the shape of the heating coil and the distance from the turbine blade. Temperature gradient. In the invention patent 201210051835.0, multiple high-energy energy beams are used to heat and scan the structure according to the set trajectory and output power, and the temperature gradient field is formed by adjusting the scanning trajectory and output power in real time through temperature feedback. However, the above-mentioned temperature control system is costly, complicated in process, and poor in cooling effect. It requires the purchase of special test instruments and special personnel to monitor the test process, and the controllability of temperature is poor. In particular, existing test equipment cannot truly reproduce the film-cooled temperature gradient field generated by the test piece due to rotation and air friction. Therefore, simulating the thermal-mechanical fatigue of the specimen under the rotating test conditions and ensuring that the specimen is in a temperature gradient environment under service are important issues to be solved urgently in the study of cooling single crystal turbine blades.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a rotating air film cooling temperature gradient thermomechanical fatigue test system, which improves the existing test equipment so that the air film cooling temperature gradient field is generated by the friction between the test piece and the air under the rotating condition, ensuring that the test While the workpiece rotates, it bears the uniaxial tensile load, which better solves the difficulty of simulating the test environment of the temperature gradient field of the specimen. The operation method is simple and easy, and the cost is low. The rotating test piece improves the traditional thermomechanical fatigue test system, truly reproduces the air film cooling temperature gradient field under the working state of the blade, ensures the smooth progress of the thermomechanical fatigue test of the aeroengine turbine blade, and provides a technical basis and safety guarantee for the safe and reliable operation of the aeroengine .

The present invention adopts following technical scheme:

A rotating film cooling temperature gradient thermomechanical fatigue test system, comprising: a loading subsystem, a heating subsystem, a power subsystem, an air cooling subsystem and a control subsystem, characterized in that the loading subsystem includes a chuck , the collet and the fixture are connected by a thrust bearing, and the fixture is connected with the specimen bolt and the specimen connection key; the heating subsystem is placed horizontally on the specimen and heats it around the specimen; the power subsystem controls the gear rotation through the motor, and the linkage gear The inner connection with the lower fixture drives the lower fixture to rotate; the air-cooling subsystem provides cooling airflow through the air compressor, and the upper hollow chuck is connected by the ventilation pipe, and the cooling air passes through the upper chuck, the upper fixture, the test specimen, the lower fixture and the lower fixture. Outflow after the clamp; the control subsystem is composed of a load controller, a rotameter, a thermocouple and a normally closed solenoid valve, and is connected with the loading subsystem, the air cooling subsystem and the heating subsystem through cables. The invention can be used in thermomechanical fatigue test, and can truly reproduce the gas film cooling temperature gradient field generated by the friction between the test piece and air.

Further, the loading subsystem is composed of a fatigue testing machine, a high temperature-resistant fixture and a thrust bearing, which is used to provide the mechanical load required for the thermomechanical fatigue test. The specimen is connected to the high-temperature fixture with bolts, and the specimen connection key is added to fix it to prevent the bolt from sliding during the rotation process. The fixture is internally fixed on the inner shaft of the thrust bearing, and the self-designed thrust bearing sleeve fixes the bearing to the chuck of the testing machine through rivets. The fatigue testing machine and the thrust bearing are hollow structures, and the material of the fixture is heat-resistant alloy mold steel.

Further, the heating subsystem is an electromagnetic induction heating system, which is used to provide a temperature field for a thermomechanical fatigue test. The induction current is generated in the conductor through the alternating current, which causes the conductor to heat up. The electromagnetic coil is equipped with a graphite ring, and the heat generated by the coil is transmitted to the test piece through the graphite ring to ensure the uniformity of heat radiation. The electromagnetic induction equipment is purchased in the market, and the simulation of the temperature field of the test piece is realized by adjusting the input power.

Further, the power subsystem is composed of a motor and a gear linkage system, which are used to provide rotational power for the system. The lower fixture and the motor are connected through the gear linkage system, and the gear is connected to the fixture. The gear drives the fixture to rotate, providing a controllable constant rotation speed for the fixture and the test piece, and is used to simulate the temperature field generated by the friction between the test piece and the air.

Further, the air-cooling subsystem is composed of an air compressor, a pressure reducing and stabilizing valve, a rotameter, and intake and exhaust pipes, which are connected to each other through pipelines, which are used to provide the cooling airflow required for the thermomechanical fatigue test . The size of the airflow is controlled by a rotameter; chucks, fixtures, specimens, and thrust bearings in the system are all hollow structures to ensure that the cooling airflow passes through the entire system smoothly and to ensure forced cooling inside the specimen.

Further, the control subsystem is composed of a load controller, a rotameter, a thermocouple and a normally closed solenoid valve, which are connected by cables, and are used to synchronously control the tensile load, cooling rate and heating rate of the system. purchase. The load controller is equipped with the existing fatigue testing machine, which can input the mechanical load waveform to control the input load; the rotameter adjusts the cooling rate of the system by controlling the cooling air flow; the normally closed solenoid valve controls the system through the on/off signal and the thermocouple point signal heating rate.

The advantages of the present invention are:

1. Improve the existing test equipment, design the high-temperature fixture as a hollow structure, pass cooling air, and simulate the temperature gradient field of air film cooling; the thermocouple channel is connected by a slider to solve the difficulty of measuring the temperature of the inner wall of the rotating specimen; thrust bearings at both ends of the fixture , through the self-designed bearing sleeve connection, it can not only reliably transmit the mechanical load of the testing machine, but also ensure the mechanical connection between the rotation of the fixture itself and the testing machine; by controlling the output power of the motor to control the rotation speed of the fixture, the air compressor controls the cooling air flow, and the electromagnetic The heating system controls the test temperature field to realize the thermomechanical fatigue test of the specimen under the rotating condition. The manufacturing process of the test equipment is simple, the cost is low, and the feasibility is high.

2. The air compressor is used to provide the cooling air flow, and the rotameter controls the air flow, which can accurately control the cooling air flow of the test piece. The cooling efficiency is high, and the temperature field can be greatly adjusted. The thermocouple channel at the end of the fixture is convenient for measuring the test piece. Internal temperature, the whole test system has high controllability to the temperature field.

Description of drawings

Fig. 1 is the structural representation of thermomechanical fatigue testing machine of the present invention

Fig. 2 is a schematic diagram of the thrust bearing structure of the present invention

Fig. 3 is a schematic diagram of the structure of the inner shaft of the thrust bearing of the present invention

Fig. 4 is a schematic diagram of the structure of the thrust bearing outer shaft of the present invention

Fig. 5 is a schematic diagram of the structure of the bearing sleeve of the thrust bearing of the present invention

Figure 6 is a schematic diagram of the overall structure of the test piece and fixture of the present invention

Figure 7 is a schematic diagram of the partial structure of the test piece and the fixture of the present invention

Fig. 8 is a structural schematic diagram of the electromagnetic heating system of the present invention

Fig. 9 is a schematic structural view of the chuck of the present invention

Figure 10 is a schematic diagram of the local structure of Figure 9

The symbols in the figure are explained as follows:

1: Abutment of fatigue testing machine 18: Thrust bearing inner shaft

2: Lower cooling air duct 19: Thrust bearing outer shaft

3: Motor 20: Self-designed bearing sleeve

4: Lower chuck 21: Specimen

5: Lower thrust bearing 22: Specimen thread

6: Gear linkage system 23: Specimen hole

7: Lower connection fixture gear 24: Specimen connection key

8: Bottom fixture 25: Bottom thread of self-designed locking piece

9: Lower self-designed locking ring 26: Self-designed locking piece connection key

10: Electromagnetic heating coil 27: Thread on self-designed locking piece

11: External electromagnetic heating system 28: Fixture connection key

12: Measure the thermocouple on the outer wall of the specimen 29: Thread on the fixture

13: Upper self-designed locking ring 30: Inner wall thermocouple

14: Graphite ring 31: Upper cooling air duct

15: Upper fixture 32: Slider thermocouple

16: Upper thrust bearing 33: Slide block

17: Upper chuck 34: Slideway

Detailed ways

The present invention is further described below in conjunction with accompanying drawing:

In conjunction with the accompanying drawings, a further description will be given of the technical solution adopted by a rotatable hollow air-cooled temperature gradient test system of the present invention to realize the temperature gradient generated by simulating the rotation of the test piece and the friction of air. The structure of the thermomechanical fatigue testing machine is shown in Figure 1.

Under the test conditions, the mechanical load of the specimen thermomechanical fatigue test system is generated by the fatigue testing machine, and the tensile load is applied through the loading system to control the upper and lower clamps 4 and 17, and is transmitted to the specimen 21 through the high temperature resistant upper and lower clamps 15 and 8. The type is controlled by the thermomechanical fatigue testing machine load spectrum. The upper and lower chucks 4, 17 are internally connected with the upper and lower thrust bearings 5, 16, and are connected with the test piece connection key 24 through inner buckles. The upper and lower thrust bearings 5, 16 are fixed to the upper and lower chucks 4, 17 by rivets through self-designed bearing sleeves 20.

The test pieces and fixtures are shown in Figure 3. The self-designed locking part is connected with the upper thread 29 of the fixture through the lower thread 25 of the self-designed locking part, and the connecting key is added to fix the connecting key 26 of the self-designed locking part and the connecting key 28 of the fixture to prevent the fixture from loosening due to rotation; 22 is connected with screw thread 27 on the self-designed locking part, and a connecting key is added to the test piece connecting key 24 and the self-designed locking part connecting key 26 to prevent the clamp from loosening due to rotation. The rotation power of the system is generated by the motor 3, and the lower fixture 8 is driven to rotate through the gear linkage system 6 and the lower connecting fixture gear 7 to make the test piece 21 and the upper fixture 15 rotate. , 15 and the test piece 21 are rotated, effectively connecting the clamps and chucks 4, 17, and transmitting the tensile load spectrum of the loading system well.

The high temperature of the system is provided by the electromagnetic induction heating system, as shown in Figure 4. Under the test conditions, the thermal induction coil 10 is connected to the electromagnetic induction heating system through the cable 9. The thermal induction coil 10 and the graphite ring 14 surround the test piece 21. By adjusting the input power, the simulation of the high temperature test environment of the test piece is realized to ensure a constant temperature field, laying a high-temperature foundation for simulating the temperature gradient field.

The cooling air flow of the system is provided by an air compressor and a pressure reducing and stabilizing valve. The test chucks, fixtures, and test pieces are all designed as hollow structures. The cooling air enters from the upper cooling air duct 31 and passes through the upper chuck 17, upper fixture 15, Part 21, lower fixture 6, and lower chuck 4 flow out from the lower cooling air duct 2, and the flow of cooling air is controlled by a rotameter to ensure forced cooling inside the test piece, so that there is a temperature difference between the inner and outer walls of the test piece, resulting in a temperature gradient field.

The chuck is shown in Figure 5. The inner wall thermocouple 30 for measuring the internal temperature of the specimen is connected to the slider thermocouple on the upper part of the slider through a metal sheet at the slideway 34 through a slider 33 to ensure stable electrical signal transmission under rotation conditions.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only includes an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (4)

1. A rotary gas film cooled temperature gradient thermo-mechanical fatigue test system comprising: the device comprises a loading subsystem, a heating subsystem, a power subsystem, an air cooling subsystem and a control subsystem, and is characterized in that the loading subsystem comprises a chuck, the chuck is connected with a clamp through a thrust bearing, and the clamp is connected with a test piece bolt through a key; the heating subsystem is horizontally arranged at the part of the test piece and surrounds the test piece to heat the test piece; the power subsystem controls the gear to rotate through the motor, and the gear is connected with the lower end clamp in an inscribed manner to drive the lower end clamp to rotate; the air cooling subsystem provides cooling air flow through an air compressor, is connected with the upper hollow chuck through an air duct, and flows out after passing through the upper chuck, the upper clamp, the test piece, the lower clamp and the lower chuck; the control subsystem consists of a load controller, a rotameter, a thermocouple and a normally closed electromagnetic valve, and is connected with the loading subsystem, the air cooling subsystem and the heating subsystem through cables;

the loading subsystem comprises a fatigue testing machine, a high-temperature-resistant clamp and a thrust bearing and is used for providing mechanical load required by a thermal mechanical fatigue test; the test piece is connected with the high-temperature clamp through bolts, and a test piece connecting key is added for fixing, so that the bolts are prevented from sliding in the rotating process; the fixture is internally connected and fixed on the inner shaft of the thrust bearing, the self-designed thrust bearing sleeve fixes the bearing on the chuck of the testing machine through rivets, the thrust bearing is of a hollow structure, and the fixture is made of heat-resistant alloy die steel;

the heating subsystem is an electromagnetic induction heating system and is used for providing a thermal mechanical fatigue test temperature field; the induction current is generated in the conductor through alternating current, so that the conductor heats, the graphite ring is arranged inside the electromagnetic coil, and heat generated by the coil is transferred to a test piece through the graphite ring, so that the uniformity of heat radiation is ensured.

2. The rotary gas film cooled temperature gradient thermo-mechanical fatigue test system according to claim 1, wherein the power subsystem comprises a motor, a gear linkage system, and a controller, wherein the motor, the gear linkage system and the controller are used for providing system rotation power; the lower end clamp and the motor are connected through the gear linkage system, the clamp is internally connected with the gear, the clamp is driven to rotate through the gear, and controllable constant rotation speed is provided for the clamp and the test piece, so that a temperature field generated by friction between the test piece and air is simulated.

3. The rotary air film cooled temperature gradient thermo-mechanical fatigue test system according to claim 1, wherein the air cooling subsystem comprises an air compressor, a pressure reducing and stabilizing valve, a rotameter, an air inlet pipe and an air outlet pipe, which are connected with each other through pipelines and are used for providing cooling air flow required by the thermo-mechanical fatigue test; controlling the air flow through a rotameter; in the system, the clamping head, the clamp, the test piece and the thrust bearing are all hollow structures, so that cooling air flow smoothly passes through the whole system, and forced cooling inside the test piece is ensured.

4. The rotary gas film cooled temperature gradient thermo-mechanical fatigue test system according to claim 1, wherein the control subsystem comprises a load controller, a rotameter, a thermocouple and a normally closed solenoid valve connected by a cable for synchronously controlling the tensile load, cooling rate and heating rate of the system; the load controller is equipped by the existing fatigue testing machine, can input mechanical load waveform, control the input load; the rotameter adjusts the cooling rate of the system by controlling the flow of the cooling air flow; the normally closed electromagnetic valve controls the heating rate of the system through an on/off signal and a thermocouple point signal.

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