A gas film cooling type temperature gradient mechanical property test chamber and experimental method

Abstract

An air film cooling type temperature gradient mechanical property test chamber and experimental method of the present invention belong to the technical field of mechanical property testing of high-temperature structural materials; it includes a test chamber, a tensile loading device, a heating module, a cooling module, a heat insulation device and a temperature measuring device; a test piece with air film holes passes through the test chamber, and its two ends extend out from both ends of the test chamber and are connected to the tensile loading device; the inner cavity of the test chamber is divided into an independent high-temperature area and a cooling area by the heat insulation device and the test piece, and the heat insulation device and the test piece are connected as a whole; the heating module is communicated with the high-temperature area, and the cooling module is communicated with the cooling area, so that the temperatures required for the temperature gradient environment are reached in both areas; the temperature measuring devices are distributed on both side surfaces of the test piece with air film holes and are used to monitor the temperatures on both sides of the test piece. The present invention combines tensile loading with air film cooling, and realizes the mechanical property test of high-temperature materials under temperature gradient through the gradient temperature adjustment of the heating module and the cooling module.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical property testing of high-temperature structural materials, and particularly relates to a gas film cooling type temperature gradient mechanical property test chamber and an experimental method. Background Art

[0002] High thrust-to-weight ratio, high efficiency and long life have always been the goals constantly pursued in the research field of aero-engines. Increasing the turbine inlet gas temperature can directly improve the comprehensive performance of aero-engines. The temperature of high-temperature gas has exceeded the heat resistance limit of the materials used in the hot-end components such as the combustion chamber, turbine blades and tail nozzles in current aero-engines. In actual applications, in order to ensure the safe operation of aero-engines, it is necessary to cool the high-temperature components of aero-engines.

[0003] At present, gas film cooling technology is generally used for cooling the hot-end components of aero-engines. Since the walls of hot-end components such as the combustion chamber, turbine blades and tail nozzles are relatively thin and the cooling system is relatively complex, there is an obvious temperature difference between the inner wall and the outer wall of the hot-end components, and this temperature difference also exists at the gas film cooling holes. The hot-end components are actually in a temperature gradient field during operation, and this temperature gradient can reach dozens to hundreds of °C / mm. The mechanical behavior of high-temperature materials under a temperature gradient is significantly different from that under a uniform temperature field. Therefore, it is not possible to study the mechanical properties of the gas film hole structure materials only by using the test data of the gas film hole structure materials in an isothermal environment, and it is also necessary to consider the influence of the temperature gradient field on the mechanical properties of the gas film hole structure materials. At present, the existing test systems mainly carry out the mechanical property tests of materials in an isothermal environment, and it is still necessary to carry out the mechanical property tests of high-temperature materials in a gas film cooling type temperature gradient field to study the mechanical properties of high-temperature structural materials under the coupling of thermal stress and external load. Therefore, it is necessary to design and prepare a mechanical property test system with a gas film cooling type temperature gradient function, so as to carry out the mechanical property test research work of high-temperature gas film hole structure materials and provide technical support for the application of high-temperature gas film hole structure materials in the hot-end components of aero-engines.

[0004] Journal of Aerospace Power, Vol. 27, No. 2, 2012, pp. 255-259. Tensile property tests of simulated specimens of DD6 single crystal air-cooled blades at high temperatures, in which the loading method uses an electric heating furnace for heating, and tensile tests are carried out at temperature conditions of 850 °C and 980 °C respectively, but this method cannot carry out the research on the mechanical properties of high-temperature materials in a gas film cooling type temperature gradient field. Summary of the Invention

[0005] Technical Problems to be Solved

[0006] In order to avoid the deficiencies of the prior art, the present invention provides a gas film cooling type temperature gradient mechanical property test chamber and an experimental method, which adopt a combination of tensile loading and gas film cooling, and realize the mechanical property test of high-temperature materials under temperature gradient by adjusting the gradient temperature change of the heating module and the cooling module.

[0007] The technical solution of the present invention is: a gas film cooling type temperature gradient mechanical property test chamber, which is characterized in that it includes a test chamber, a tensile loading device, a heating module, a cooling module, a heat insulation device and a temperature measuring device; a test piece with gas film holes passes through the test chamber, and both ends thereof extend out from both ends of the test chamber and are connected to the tensile loading device;

[0008] The inner cavity of the test chamber is divided into an independent high-temperature area and a cooling area by the heat insulation device and the test piece, and the heat insulation device and the test piece are connected as a whole; the heating module is communicated with the high-temperature area, and the cooling module is communicated with the cooling area, so that the temperatures required for the temperature gradient environment are reached in both areas;

[0009] The temperature measuring device is distributed on both side surfaces of the test piece with gas film holes and is used to monitor the temperatures on both sides of the test piece.

[0010] A further technical solution of the present invention is: the heating module includes a heater, an air compressor, and a high-temperature air inlet hole and a high-temperature exhaust hole opened on the side wall of the high-temperature area of the test chamber; the heater and the air compressor are communicated with the high-temperature air inlet hole through a pipeline, and high-temperature gas is introduced into the high-temperature area to heat one side surface of the test piece with gas film holes, and the gas enters the heater and the air compressor through the high-temperature exhaust hole and the pipeline for cyclic heating and pressurization.

[0011] A further technical solution of the present invention is: both the high-temperature air inlet hole and the high-temperature exhaust hole are circumferentially and uniformly distributed on the side wall of the high-temperature area of the test chamber, and the high-temperature exhaust hole is located above the high-temperature air inlet hole.

[0012] A further technical solution of the present invention is: the cooling module includes a water cooling box, an air compressor, and a cooling air inlet hole and a cooling exhaust hole opened on the side wall of the cooling area of the test chamber; the water cooling box and the air compressor are communicated with the cooling air inlet hole through a pipeline, and cooling gas is introduced into the cooling area to cool the other side surface of the test piece with gas film holes, and the gas enters the water cooling box and the air compressor through the cooling exhaust hole and the pipeline for cyclic cooling and pressurization.

[0013] A further technical solution of the present invention is: both the cooling air inlet hole and the cooling exhaust hole are circumferentially and uniformly distributed on the side wall of the cooling area of the test chamber, and the cooling exhaust hole is located above the cooling air inlet hole.

[0014] A further technical solution of the present invention is that: the test chamber is a hollow cylindrical structure; the test piece with air film holes penetrates along the center line of the test chamber, and its two ends are integrally connected to the heat insulation devices respectively, dividing the interior of the test chamber into two semi-cylindrical cavities; the number of high-temperature air inlet holes, high-temperature air outlet holes, cooling air inlet holes, and cooling air outlet holes provided on the outer peripheral surface of the test chamber is 3 each.

[0015] A further technical solution of the present invention is that: the heat insulation device includes a heat insulation wall surface and a filling body. The heat insulation wall surface in the high-temperature area is a high-temperature heat insulation wall surface, and the heat insulation wall surface in the cooling area is a low-temperature heat insulation wall surface. The filling body is filled between the high-temperature heat insulation wall surface and the low-temperature heat insulation wall surface;

[0016] Two groups of heat insulation devices are respectively connected to the two side extension directions of the test piece with air film holes and are installed in the inner wall of the test chamber, closely cooperating with the test piece as a partition board between the high-temperature area and the cooling area to prevent the high-temperature gas and the cooling air flow from mixing with each other and affecting the effect of the temperature gradient generated.

[0017] A further technical solution of the present invention is that: the heat insulation wall surface is made of a ceramic material with high temperature resistance and oxidation resistance; the filling body is made of asbestos with low thermal conductivity.

[0018] A further technical solution of the present invention is that: the temperature measuring device includes 4 thermocouples, which are respectively fixedly installed on the two side surfaces of the test piece with air film holes to monitor the temperatures on both sides of the test piece with air film holes.

[0019] An experimental method for a temperature gradient mechanical property test chamber with air film cooling is characterized in that the specific steps are as follows:

[0020] Step 1: Heat and pressurize the air through a heater and a compressor, and introduce the high-temperature gas into the high-temperature area of the test chamber through the high-temperature air inlet hole to heat one side surface of the test piece with air film holes; measure the temperature of this side surface of the test piece by the thermocouple located in the high-temperature area;

[0021] Step 2: When the surface temperature of the test piece with air film holes is stable, introduce the cooling gas into the cooling air inlet hole through a water cooling box and an air compressor to cool the other side surface of the test piece with air film holes, and at the same time open the cooling air outlet hole to discharge the heated gas; measure the temperature of this side surface of the test piece by the thermocouple located in the cooling area;

[0022] Step 3: When the temperature is stable, start the mechanical property testing machine, and apply loads to both ends of the test piece with air film holes through a tensile loading device, so as to realize the mechanical property test of the air film hole structure under the temperature gradient field condition.

[0023] Beneficial effects

[0024] The beneficial effects of the present invention are as follows: The mechanical property test chamber applying the technical solution of the present invention realizes the mechanical property test of high-temperature materials under temperature gradient through the combination of tensile loading and gas film cooling; the high-temperature gas and the cooling gas are respectively introduced into two regions of the test chamber through the high-temperature and cooling air inlets, and the high-temperature gas and the cooling gas are discharged from the test chamber through the high-temperature and cooling exhaust holes; a temperature gradient environment is constructed by the flow of the high-temperature gas and the cooling gas on both sides of the test piece.

[0025] In addition, the temperature measuring device measures the temperatures of both sides of the flat plate with gas film holes, and the temperature gradient is controlled and adjusted by controlling the flow rates of the high-temperature gas and the cold air. The difficulty of the present invention lies in ensuring the uniformity and stability of the gas flow temperature when heating and cooling the test piece by uniformly arranging the air inlets and exhaust holes on the wall surface of the box body. Brief Description of the Drawings

[0026] Figure 1 is a schematic diagram of the overall structure of the gas film cooling type temperature gradient mechanical property test chamber according to the present invention;

[0027] Figure 2 is a sectional view of the gas film cooling type temperature gradient mechanical property test chamber along the radial direction of the gas film hole and the axial direction of the box body according to the present invention;

[0028] Figure 3 is a sectional view of the gas film cooling type temperature gradient mechanical property test chamber along the radial direction of the box body according to the present invention;

[0029] Figure 4 is a sectional view of the gas film cooling type temperature gradient mechanical property test chamber along the gas film hole and the axial direction of the box body according to the present invention;

[0030] Description of the reference numerals: 1. Tensile loading device; 2. Test piece with gas film holes; 3. High-temperature exhaust hole; 4. Test chamber; 5. High-temperature air inlet; 6. Cooling exhaust hole; 7. Cooling air inlet; 8. Gas film hole; 9. Heat insulation device; 10. Inner wall of the box; 11. Cooling area; 12. High-temperature area; 13. Heat insulation wall surface; 14. Filler; 15. Temperature measuring device. Detailed Embodiments

[0031] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0032] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0033] Referring to the attached Figures 1-4 As shown, this embodiment provides a gas film cooling type temperature gradient mechanical property test chamber, which includes a test chamber 4, a tensile loading device 1, a heating module, a cooling module, a heat insulation device 9 and a temperature measuring device 15; the test chamber 4 is a hollow cylindrical structure; 2, and its two ends are integrally connected with the heat insulation device respectively, dividing the interior of the test chamber into an independent high temperature area and a cooling area; the heating module is communicated with the high temperature area, and the cooling module is communicated with the cooling area, so that the temperatures required for the temperature gradient environment are reached in both areas;

[0034] The test piece with gas film holes tested in this embodiment is determined by the gas film hole structure to be tested, and the number, aperture and arrangement mode of the gas film holes can be changed according to needs. In this embodiment, a test piece with 14 gas film holes, an aperture of 1 mm and a three-row arrangement mode is taken as an example. The air in the high temperature area and the cooling area flows through the gas film holes, so that a gas film cooling type temperature gradient field is generated on the surface of the test piece.

[0035] The heating module includes a heater, an air compressor, and a high temperature air inlet hole 5 and a high temperature exhaust hole 3 opened on the side wall of the high temperature area of the test chamber; the heater and the air compressor are communicated with the high temperature air inlet hole 5 through pipelines, and high temperature gas is introduced into the high temperature area to heat one side of the test piece 2 with gas film holes. The gas enters the heater and the air compressor through the high temperature exhaust hole 3 and the pipeline for cyclic heating and pressurization. The high temperature air inlet hole 5 and the high temperature exhaust hole 3 are both circumferentially uniformly distributed on the side wall of the high temperature area of the test chamber, and the number of both is 3, and the high temperature exhaust hole 3 is located above the high temperature air inlet hole 5.

[0036] The cooling module includes a water-cooled box, an air compressor, a cooling air inlet hole 7 and a cooling air outlet hole 6 opened on the side wall of the cooling area of the test chamber; the water-cooled box and the air compressor are communicated with the cooling air inlet hole 7 through pipelines to introduce cooling gas into the cooling area, cool the other side of the test piece 2 with air film holes, and the gas enters the water-cooled box and the air compressor through the cooling air outlet hole 6 and the pipeline for cyclic cooling and pressurization. The cooling air inlet hole 7 and the cooling air outlet hole 6 are both circumferentially distributed on the side wall of the cooling area of the test chamber, and the number of both is 3, and the cooling air outlet hole is located above the cooling air inlet hole.

[0037] The heat insulation device 9 mainly includes a heat insulation wall surface 13 and a filler 14. The heat insulation wall surface 13 is made of a ceramic material with high temperature resistance and oxidation resistance, and the filler 14 is made of asbestos with low thermal conductivity. The high-temperature heat insulation wall surface and the low-temperature heat insulation wall surface are located in the middle of the test chamber and are connected to the test piece 2 to separate the high temperature and the cooling area. The filler is filled between the high-temperature heat insulation wall surface and the low-temperature heat insulation wall surface. The heat insulation device 9 is embedded on the inner wall 10 of the box body and is closely matched with the test piece 2 with air film holes to prevent the mixing of high-temperature gas and cooling gas.

[0038] The temperature measuring device 15 mainly includes 4 thermocouples 15-1, 15-2, 15-3, 15-4, measures the surface temperatures on both sides of the test piece 2 with air film holes, and ensures the controllability and stability of the temperature of the specimen to be tested by adjusting the high-temperature air flow and the cooling air flow. At the same time, the temperature gradient in the thickness direction of the test piece 2 with air film holes is controlled by adjusting the flow rates of the high-temperature and cooling gases.

[0039] The tensile loading device 1 includes two clamping members, which are respectively connected to the two ends of the test piece 2; the mechanical property testing machine loads the test piece 2 through the clamping members to realize the testing of mechanical properties.

[0040] Working principle: Three air inlet holes and three air outlet holes are evenly distributed on the circumferential surfaces on both sides of the test chamber 4. Among them, the air holes 5-1, 5-2, and 5-3 are high-temperature gas inlet holes, and the air holes 3-1, 3-2, and 3-3 are high-temperature gas outlet holes. The air holes 7-1, 7-2, and 7-3 are cooling gas inlet holes, and the air holes 6-1, 6-2, and 6-3 are cooling gas outlet holes. The high-temperature inlet holes 5-1, 5-2, and 5-3 are connected to the heater and the air compressor through pipelines to ensure that high-temperature gas with appropriate pressure and flow rate is provided to the high-temperature area 12 of the test chamber 4. The high-temperature outlet holes 3-1, 3-2, and 3-3 discharge the heated gas into the heater and the air compressor through pipelines for cyclic heating and pressurization. The cooling inlet holes 7-1, 7-2, and 7-3 are connected to the water-cooled box and the air compressor through pipelines to ensure that cooling gas with appropriate pressure and flow rate is provided to the cooling area 11 of the test chamber 4. The cooling outlet holes 6-1, 6-2, and 6-3 discharge the cooling gas into the cooling box and the air compressor through pipelines for cyclic cooling and pressurization. Therefore, based on the cooling structure design principle of the gas film holes and through the coordinated operation of the heating device and the cooling device, a stable temperature gradient field is formed in the thickness direction of the test piece 2 with gas film holes, so as to realize the mechanical property test of the gas film hole structure under the condition of the temperature gradient field.

[0041] Test method: Before testing the mechanical properties of the test piece, first, heat and pressurize the air through the heater and the compressor, and introduce the high-temperature gas into the high-temperature inlet holes 5-1, 5-2, and 5-3 to heat one side surface of the test piece. Measure the surface temperature of the test piece through the thermocouples on the surface of the test piece. Fix the heat insulation device 9 at the junction of the high-temperature area 12 and the cooling area 11 to ensure a sealed state between the two. Pass the test piece 2 with gas film holes through the heat insulation device 9 and connect it to the fixture of the mechanical property testing machine. Fit the heat insulation device 9 and the test piece 2 with gas film holes tightly. After the surface temperature of the test piece 2 with gas film holes is stable, turn on the cooling air compressor, introduce the cooling gas into the cooling inlet holes 7-1, 7-2, and 7-3, and open the cooling outlet holes 6-1, 6-2, and 6-3 to discharge the heated gas to cool the other side surface of the test piece. Measure the surface temperatures of both sides of the test piece through the thermocouples 15-1, 15-2, 15-3, and 15-4 on the surface of the test piece. After the temperature is stable, start the mechanical property testing machine and apply a load to the test piece 2 with gas film holes, so as to realize the mechanical property test of the gas film hole structure under the condition of the temperature gradient field. If it is necessary to simulate the mechanical property test of the hot end components of an aeroengine under different temperature gradient conditions, the temperature gradient in the thickness direction of the test piece can be changed by adjusting the pressure and flow rate of the high-temperature gas and the cooling gas.

[0042] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A gas film cooling type temperature gradient mechanical property test chamber, characterized in that: It includes a test chamber, a tensile loading device, a heating module, a cooling module, a heat insulation device and a temperature measuring device; the test piece with film holes penetrates through the test chamber, and both ends thereof extend out from both ends of the test chamber and are connected to the tensile loading device; The interior of the cavity of the test chamber is separated into an independent high-temperature area and a cooling area by the heat insulation device and the test piece, and the heat insulation device and the test piece are connected as a whole; the heating module communicates with the high-temperature area, and the cooling module communicates with the cooling area, so that the temperatures required for the temperature gradient environment are reached in both areas; The temperature measuring device is distributed on both side surfaces of the test piece with film holes and is used to monitor the temperatures on both sides of the test piece; The heating module includes a heater, an air compressor, a high-temperature air inlet hole and a high-temperature exhaust hole opened on the side wall of the high-temperature area of the test chamber; the heater and the air compressor are communicated with the high-temperature air inlet hole through a pipeline, and high-temperature gas is introduced into the high-temperature area to heat one side surface of the test piece with film holes, and the gas enters the heater and the air compressor through the high-temperature exhaust hole and the pipeline for cyclic heating and pressurization; Both the high-temperature air inlet hole and the high-temperature exhaust hole are circumferentially uniformly distributed on the side wall of the high-temperature area of the test chamber, and the high-temperature exhaust hole is located above the high-temperature air inlet hole; The cooling module includes a water-cooling box, an air compressor, a cooling air inlet hole and a cooling exhaust hole opened on the side wall of the cooling area of the test chamber; the water-cooling box and the air compressor are communicated with the cooling air inlet hole through a pipeline, and cooling gas is introduced into the cooling area to cool the other side surface of the test piece with film holes, and the gas enters the water-cooling box and the air compressor through the cooling exhaust hole and the pipeline for cyclic cooling and pressurization; Both the cooling air inlet hole and the cooling exhaust hole are circumferentially uniformly distributed on the side wall of the cooling area of the test chamber, and the cooling exhaust hole is located above the cooling air inlet hole.

2. The gas film cooling type temperature gradient mechanical property test chamber according to claim 1, wherein: The test chamber is a hollow cylindrical structure; the test piece with film holes penetrates along the center line of the test chamber, and both ends thereof are integrally connected to the heat insulation device respectively, dividing the interior of the test chamber into two semi-cylindrical cavities; the number of the high-temperature air inlet holes, the high-temperature exhaust holes, the cooling air inlet holes and the cooling exhaust holes provided on the outer peripheral surface of the test chamber is 3 each.

3. The gas film cooling type temperature gradient mechanical property test chamber according to claim 1, characterized in that: The heat insulation device includes a heat insulation wall surface and a filler. The heat insulation wall surface in the high-temperature area is a high-temperature heat insulation wall surface, and the heat insulation wall surface in the cooling area is a low-temperature heat insulation wall surface. The filler is filled between the high-temperature heat insulation wall surface and the low-temperature heat insulation wall surface; Two groups of heat insulation devices are respectively connected to the extending directions on both sides of the test piece with film holes and are embedded in the inner wall of the test chamber, and are closely matched with the test piece as the partition plates between the high-temperature area and the cooling area to prevent the high-temperature gas and the cooling air flow from mixing with each other and affecting the effect of generating the temperature gradient.

4. The gas film cooling type temperature gradient mechanical property test chamber according to claim 3, characterized in that: The heat insulation wall surface is made of a ceramic material with high temperature resistance and oxidation resistance; the filler is made of asbestos with low thermal conductivity.

5. The gas film cooling type temperature gradient mechanical property test chamber according to claim 1, wherein: The temperature measuring device includes 4 thermocouples, which are respectively fixedly installed on both side surfaces of the test piece with film holes to monitor the temperatures on both sides of the test piece with film holes.

6. An experimental method for the gas film cooling type temperature gradient mechanical property test chamber according to any one of claims 1-5, characterized in that The specific steps are as follows: Step 1: Heat and pressurize the air through a heater and a compressor, and introduce the high-temperature gas into the high-temperature area of the test chamber through the high-temperature air inlet hole to heat one side surface of the test piece with gas film holes; measure the temperature of this side surface of the test piece by the thermocouple located in the high-temperature area. Step 2: After the surface temperature of the test piece with gas film holes is stable, introduce the cooling gas into the cooling air inlet hole through the water cooling box and the air compressor to cool the other side surface of the test piece with gas film holes, and at the same time open the cooling exhaust hole to discharge the heated gas; measure the temperature of this side surface of the test piece by the thermocouple located in the cooling area. Step 3: After the temperature is stable, start the mechanical property testing machine, and apply loads to both ends of the test piece with gas film holes through the tensile loading device, so as to realize the mechanical property test of the gas film hole structure under the condition of the temperature gradient field.

Images