A low temperature performance test system for thermal protection materials

Abstract

The application discloses a low-temperature performance test system of a heat protection material, and belongs to the technical field of heat protection material testing; and solves the technical problems of high refrigeration cost and unstable refrigeration of the existing low-temperature test device. The low-temperature performance test system comprises a furnace body, a low-temperature container and a refrigerating machine; the low-temperature container and the refrigerating machine are arranged in the furnace body; the refrigerating machine is communicated with the low-temperature container and can refrigerate the low-temperature container; the low-temperature container is internally provided with an isolation sleeve and a heat conduction sleeve; the isolation sleeve is arranged above the heat conduction sleeve; the top end of the isolation sleeve is in contact with the furnace body; the bottom end of the isolation sleeve is embedded in an annular groove arranged on the top surface of the heat conduction sleeve; the isolation sleeve is communicated with the heat conduction sleeve and coaxially arranged with the heat conduction sleeve; the area inside the heat conduction sleeve forms a sample cavity; a heating element is arranged on the heat conduction sleeve and used for heating the sample cavity. The application can realize stable and low-cost refrigeration of the heat protection material sample.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-temperature testing of thermal protection materials, and particularly relates to a low-temperature performance test system for thermal protection materials. BACKGROUND

[0002] Thermal protection materials refer to coating materials coated on the surface of a base body and capable of isolating the base body from direct contact with an oxidizing atmosphere, such as silicide coatings coated on the surface of a niobium hafnium alloy, silicide coatings coated on the surface of a niobium tungsten alloy, iridium coatings coated on the surface of a rhenium base body, etc. It is of great significance to accurately test the distribution changes of the oxidation resistance of these thermal protection materials with time, space and temperature.

[0003] Existing low-temperature performance test devices have complex structures and high refrigeration costs. SUMMARY

[0004] In view of the above analysis, the present application aims to provide a low-temperature performance test system for thermal protection materials to solve the problem of complicated operation caused by repeated nitrogen injection of existing low-temperature test devices for thermal protection materials.

[0005] The purpose of the present application is mainly achieved by the following technical solutions:

[0006] The present application provides a low-temperature performance test system for thermal protection materials, comprising a furnace body, a low-temperature container and a refrigeration machine; the low-temperature container and the refrigeration machine are both arranged in the furnace body; the refrigeration machine is in communication with the low-temperature container and capable of refrigerating the low-temperature container;

[0007] The low-temperature container is provided with an isolation sleeve and a heat conduction sleeve; the isolation sleeve is arranged above the heat conduction sleeve, the top end of the isolation sleeve is in contact with the furnace body, the bottom end of the isolation sleeve is embedded in an annular groove arranged on the top surface of the heat conduction sleeve, the isolation sleeve is in communication with the heat conduction sleeve and coaxially arranged with the heat conduction sleeve; the area inside the heat conduction sleeve constitutes a sample cavity, and a thermal protection material sample is arranged in the sample cavity; the area between the heat conduction sleeve and the isolation sleeve and the inner wall of the low-temperature container is defined as a first area; the first area is a vacuum environment;

[0008] A heating element is arranged on the heat conduction sleeve, and the heating element is used for heating the sample cavity.

[0009] In a possible design, an annular hole is arranged on the heat conduction sleeve, and the heating element is a resistance wire arranged in the annular hole.

[0010] The low-temperature performance test system further comprises a temperature measuring device arranged in a blind hole on the heat conduction sleeve; the temperature measuring device and the resistance wire are both connected with an external power supply.

[0011] In a possible design, the low-temperature performance test system further comprises a vacuumizing assembly connected with the vacuum joint arranged on the wall of the low-temperature container, and the vacuumizing assembly is capable of vacuumizing the first region.

[0012] In a possible design, the vacuumizing assembly comprises a vacuum pipeline, a vacuum measuring device, a first-stage vacuum device and a second-stage vacuum device; the first-stage vacuum device and the second-stage vacuum device are arranged in series.

[0013] The upper end of the vacuum pipeline is in communication with the vacuum joint, and the lower end of the vacuum pipeline is provided with a tee joint, one end of the tee joint is connected with the vacuum measuring device, and the other end is connected with the first-stage vacuum device and the second-stage vacuum device in sequence.

[0014] The first-stage vacuum device is a mechanical vacuum pump, and the second-stage vacuum device is a turbo molecular pump.

[0015] In a possible design, the refrigeration machine comprises a refrigeration head, a compressor and a temperature control device.

[0016] The refrigeration head is arranged in the low-temperature container, one end of the refrigeration head is in communication with the sample cavity, the other end of the refrigeration head is connected with the compressor, and the temperature control device is used for adjusting the output of the refrigeration machine so that the heat protection material sample reaches a target temperature.

[0017] In a possible design, the low-temperature test system further comprises a sample clamping and moving device, the top of the low-temperature container is provided with a first opening, and the sample clamping and moving device is arranged directly above the sample cavity and penetrates through the first opening.

[0018] The sample moving device comprises a horizontal guide rail and a vertical guide rail; the horizontal guide rail is provided with a horizontal moving slider and a horizontal moving motor; and the vertical guide rail is provided with a vertical moving slider and a vertical moving motor.

[0019] The vertical guide rail is arranged on the horizontal moving slider, and the horizontal moving motor is capable of driving the horizontal moving slider to drive the vertical guide rail to move in the horizontal direction.

[0020] The vertical moving slider is connected with a lifting belt, the lower end of the lifting belt is connected with the connecting end of the sample clamping mechanism, the sample clamping mechanism further comprises a clamping end, and the clamping end clamps the heat protection material sample; and the vertical moving motor is capable of driving the vertical moving slider to drive the heat protection material sample to move in the vertical direction.

[0021] In a possible design, the low-temperature performance test system further comprises a sample weighing device.

[0022] The weighing device comprises a horizontal tray, an electronic balance and a balance lifting hook; the horizontal tray is arranged on the vertical moving slider, the electronic balance is arranged on the horizontal tray, the connecting end of the balance lifting hook is arranged on the bottom surface of the horizontal tray, and the hook end of the balance lifting hook is connected with the connecting end of the lifting belt.

[0023] The electronic balance is connected with the computer through an interface to record the weight of the heat protection material sample in real time.

[0024] In a possible design, the low-temperature test system further comprises a positive-pressure nitrogen input assembly, which comprises a nitrogen source, a blower and an input pipe;

[0025] The nitrogen is input into the sample cavity through the blower and the input pipe.

[0026] In a possible design, the low-temperature test system further comprises a liquid nitrogen input assembly, which comprises a liquid nitrogen tank, a liquid nitrogen delivery pipeline and a liquid nitrogen funnel;

[0027] The liquid nitrogen funnel penetrates through the top of the first region, one end of the liquid nitrogen delivery pipeline is connected with the liquid nitrogen tank, and the other end of the liquid nitrogen delivery pipeline is connected with the input port of the liquid nitrogen funnel.

[0028] When the heat protection material sample is tested at -198℃--100℃, the liquid nitrogen input assembly is used to input liquid nitrogen into the first region for refrigeration;

[0029] When the heat protection material sample is tested at -100℃--50℃, the sample cavity is refrigerated by the refrigerator.

[0030] In a possible design, the furnace body is provided with a furnace body support for supporting the furnace body.

[0031] The low-temperature container is provided with a low-temperature container support body, the top of the low-temperature container support body is provided with a groove matched with the outer side of the low-temperature container, and the bottom of the low-temperature container is located in the groove.

[0032] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0033] (1) The present application adopts the refrigeration mode of combining the refrigeration of the refrigerator and the refrigeration of liquid nitrogen, on the one hand, when the refrigerator or the liquid nitrogen input assembly fails, it can be quickly switched to another refrigeration mode, on the other hand, when the refrigeration temperature is -198℃--50℃, if the refrigerator is used to maintain at this low temperature, it consumes more electricity, resulting in higher refrigeration cost, therefore, when the refrigeration temperature of the present application is -198℃--50℃, liquid nitrogen refrigeration is adopted, which can reduce the refrigeration cost, in addition, liquid nitrogen refrigeration is easy to realize and simple to operate, when the refrigeration temperature is -50℃-0℃, the refrigerator is used for refrigeration, avoiding the complicated operation of repeatedly filling liquid nitrogen required by liquid nitrogen refrigeration, the refrigeration is stable and the safety is high.

[0034] (2) The present application uses the positive-pressure nitrogen input assembly to input positive-pressure nitrogen into the sample cavity, which can discharge air and avoid the pre-cooling frost in the sample cavity.

[0035] (3) The low-temperature container is provided with a vacuum connector on the arm, which is connected with a vacuumizing assembly. When the first area needs to be vacuumized, the vacuumizing assembly is opened to vacuumize the first area. The vacuumizing of the first area can reduce the heat transfer of the gas in the sample cavity. The outer wall of the first area and the inner wall of the low-temperature container are silver-plated or polished to reduce the radiation frequency, so that the radiation heat transfer is reduced as much as possible.

[0036] The technical solutions in the present application can be combined with each other to realize more preferred combination solutions. Other features and advantages of the present application will be described in the following description, and some advantages will become apparent from the description, or will be understood by those skilled in the art through implementation of the present application. The purposes and other advantages of the present application can be realized and obtained through the contents particularly indicated in the description, the embodiments and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0037] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. In the drawings:

[0038] Figure 1 A low-temperature performance test system;

[0039] Figure 2 A structural schematic diagram of a sample weighing, clamping and moving device;

[0040] Figure 3 A state diagram of a thermal protection material sample being clamped.

[0041] Reference signs:

[0042] 1 - furnace body; 2 - low-temperature container; 3 - isolation sleeve; 4 - heat conduction sleeve; 5 - insulation layer; 6 - vacuum connector; 7 - sample cavity; 8 - first area; 9 - temperature measuring device; 10 - low-temperature container support; 11 - furnace body support; 12 - optical window; 13 - annular hole; 14 - cold head; 15 - refrigerator; 16 - compressor; 17 - first opening; 18 - lifting belt; 19 - sample clamp; 20 - thermal protection material sample; 21 - balance hook; 22 - balance tray; 23 - electronic balance; 24 - vertical guide rail; 25 - vertical moving motor; 26 - horizontal guide rail; 27 - horizontal moving motor; 28 - first sheet-shaped high-temperature ceramic; 29 - second sheet-shaped high-temperature ceramic; 30 - threaded hole; 31 - partition plate; 32 - first liquid nitrogen on-off valve; 33 - second liquid nitrogen on-off valve; 34 - third liquid nitrogen on-off valve; 35 - fourth liquid nitrogen on-off valve; 36 - liquid nitrogen on-valve. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present application are described in detail below with reference to the accompanying drawings, in which the drawings constitute a part of this application and illustrate embodiments of the present application together with the principles of the present application, but are not intended to limit the scope of the present application.

[0044] The low-temperature performance test system of the heat protection material provided by the present application comprises a furnace body 1, a low-temperature container 2 and a refrigerator 15; the low-temperature container 2 and the refrigerator 15 are both arranged in the furnace body 1; the refrigerator 15 is in communication with the low-temperature container 2 and can refrigerate the low-temperature container 2; the low-temperature container 2 is internally provided with an isolation sleeve 3 and a heat conduction sleeve 4; the isolation sleeve 3 is arranged above the heat conduction sleeve 4; the top end of the isolation sleeve 3 is in contact with the furnace body 1; the bottom end of the isolation sleeve 3 is embedded in a ring-shaped groove arranged on the top surface of the heat conduction sleeve 4; the isolation sleeve 3 is in communication with the heat conduction sleeve 4 and arranged on the same axis as the heat conduction sleeve 4; the area inside the heat conduction sleeve 4 constitutes a sample cavity 7 (refrigeration area); a heat protection material sample 20 is arranged in the sample cavity 7; the area between the heat conduction sleeve 4 and the isolation sleeve 3 and the inner wall of the low-temperature container 2 is defined as a first area 8; the first area 8 is a vacuum environment; a heating element is arranged on the heat conduction sleeve 4 and used to heat the sample cavity 7.

[0045] As shown in Figure 1 The low-temperature test system provided by the present application comprises a furnace body 1; a low-temperature container 2 and a refrigerator 15 are both arranged in the furnace body 1; the low-temperature container 2 is internally provided with an isolation sleeve 3 and a heat conduction sleeve 4; the isolation sleeve 3 is arranged directly above the heat conduction sleeve 4 and arranged on the same axis as the heat conduction sleeve 4; the top of the isolation sleeve 3 is in contact with the top of the furnace body 1; the bottom of the isolation sleeve 3 is provided with a ring-shaped protrusion; a ring-shaped groove is arranged on the top of the heat conduction sleeve 4; the ring-shaped protrusion of the isolation sleeve 3 is embedded in the ring-shaped groove of the heat conduction sleeve 4; the specifications and shapes of the ring-shaped protrusion and the ring-shaped groove are matched; the bottom of the heat conduction sleeve 4 is a certain distance away from the bottom of the low-temperature container 2; the area inside the heat conduction sleeve 4 forms a sample cavity 7; a heat protection material sample 20 is arranged in the sample cavity 7; the area between the outer wall of the heat conduction sleeve 4 and the inner wall of the low-temperature container 2 and the area between the outer wall of the isolation sleeve 3 and the low-temperature container 2 jointly constitute a first area 8; the first area 8 is a vacuum environment; the sample cavity 7 is equivalent to being arranged in a Dewar container; this can prevent dew and frost from forming in the first area 8 and the sample cavity 7, thereby ensuring the accuracy of the later weighing of the heat protection material sample 20.

[0046] It should be noted that a heating element is arranged on the heat conduction sleeve 4; when it is necessary to increase the temperature inside the sample cavity 7, the heating element on the heat conduction sleeve 4 is used for heating, and the heat conduction sleeve 4 is used for heat conduction, thereby increasing the temperature inside the sample cavity 7, so as to ensure the performance test of the heat protection material sample 20 at low temperature.

[0047] In order to heat the heat protection material sample 20 and record the real-time temperature of the heat protection material sample 20, the heat conduction sleeve 4 is provided with an annular hole 13, and the heating element is a resistance wire arranged in the annular hole 13; the low-temperature performance test system further comprises a temperature measuring device 9 arranged in a blind hole on the heat conduction sleeve 4; the temperature measuring device 9 and the resistance wire are connected with an external power supply.

[0048] Specifically, the annular heating hole is arranged on the heat conduction sleeve 4, and the resistance wire or other heating element is arranged in the annular hole 13, so that the effective heating area is formed in the sample cavity 7 by using the heating element, thereby ensuring that the heat protection material sample 20 can be uniformly heated in the sample cavity 7. In addition, the temperature measuring device 9 of the present application adopts platinum resistance contact type temperature measurement, which can measure the temperature of the heat protection material sample 20 in real time.

[0049] In order to reduce the heat loss in the sample cavity 7, the first area 8 needs to be evacuated, therefore, the low-temperature performance test system of the present application further comprises a vacuum pumping assembly connected with the vacuum joint 6 arranged on the wall of the low-temperature container 2, and the vacuum pumping assembly can evacuate the first area 8.

[0050] Specifically, the low-temperature container 2 is provided with a vacuum connection head connected with the vacuum pumping assembly, and when the first area 8 needs to be evacuated, the vacuum pumping assembly is started to evacuate the first area 8. Evacuating the first area 8 can reduce the heat transfer of the gas in the sample cavity 7, and the outer wall of the first area 8 and the inner wall of the low-temperature container 2 are silver-plated or polished to reduce the radiation frequency, so as to reduce the radiation heat as much as possible.

[0051] In order to meet the vacuum degree requirement of the first area 8, the vacuum pumping assembly of the present application comprises a second vacuum pipeline, a vacuum measuring device, a first-stage vacuum equipment and a second-stage vacuum equipment; the first-stage vacuum equipment and the second-stage vacuum equipment are arranged in series; one end of the vacuum pipeline penetrates through the furnace body 1 and is connected with the vacuum joint 6, and the other end of the vacuum pipeline is provided with a tee pipe, one end of the tee pipe is connected with the vacuum measuring device, and the other end is connected with the first-stage vacuum equipment and the second-stage vacuum equipment in sequence. The first-stage vacuum equipment adopts a mechanical vacuum pump; the second-stage vacuum equipment adopts a turbo molecular pump.

[0052] The advantage of adopting the turbo molecular pump in series with the mechanical vacuum pump is that the vacuum degree of the vacuum pumping assembly can reach 10 -6 Pa without baking, and the vacuum degree can reach 10 -8 Pa after baking; in addition, the vacuum pumping assembly provided by the present application is relatively clean, and can realize oil-free ultra-high vacuum environment.

[0053] It should be noted that the present application adopts two sets of devices to measure the vacuum degree: the resistance gauge is used to measure the low vacuum degree (1x105 ~1×10 -1 Pa); High vacuum measurement is achieved using the BA gauge (10 Pa); 0 ~1×10 -7 Pa), the two connected in series can meet the vacuum requirements in the first region 8.

[0054] In order to cool the sample chamber 7, the refrigeration machine 15 of the present invention includes a cooling head 14, a compressor 16 and a temperature control device; the cooling head 14 is located in the low temperature container 2, one end of the cooling head 14 is connected to the sample chamber 7, and the other end is connected to the compressor 16 through a pulse tube; the temperature control device is used to adjust the output of the refrigeration machine 15 so that the thermal protection material sample 20 reaches the target temperature.

[0055] It should be noted that the advantage of using the refrigerator 15 for refrigeration in this invention is that it is sustainable, stable, and easy to control. Using the refrigerator 15, the temperature can be quickly reduced to the test temperature.

[0056] For ease of observation, a first optical window 12 is provided on the wall of the cryogenic container 2.

[0057] To facilitate the movement of the thermal protection material sample 20, such as Figure 2 and Figure 3 As shown, the low-temperature testing system of the present invention also includes a sample clamping and moving device. The top of the low-temperature container 2 is provided with an insulating layer 5 and a first opening 17. The sample clamping and moving device is located directly above the sample cavity 7 and passes through the first opening 17. The sample moving device includes a horizontal guide rail 26 and a vertical guide rail 24. A horizontal moving slider and a horizontal moving motor 27 are provided on the horizontal guide rail 26. A vertical moving slider and a vertical moving motor 25 are provided on the vertical guide rail 24. The vertical guide rail 24 is located on the horizontal moving slider. The horizontal moving motor 27 can drive the horizontal moving slider to move the vertical guide rail 24 in the horizontal direction. The vertical moving slider is connected to a lifting strap 18. The lower end of the lifting strap 18 is connected to the connecting end of the sample clamping mechanism. The sample clamping mechanism also includes a clamping end, which clamps a heat-protective material sample 20. The vertical moving motor 25 can drive the vertical moving slider to move the heat-protective material sample 20 in the vertical direction.

[0058] It should be noted that the horizontal moving motor 27 and the vertical moving motor 25 of the present invention can be linear motors or stepper motors. Their technical specifications are as follows: Movement mode: automatic; Horizontal movement range: 0~1800mm; Vertical movement range: 0~400mm; Movement speed: ±20mm / s; Position control accuracy: ±1mm.

[0059] The sample clamping mechanism of the present application comprises a first sheet ceramic 28 and a second sheet ceramic 29 which are identical in structure, the top of each of the first sheet ceramic and the second sheet ceramic is provided with a threaded hole 30, the first sheet ceramic 28 and the second sheet ceramic 29 are connected by a screw passing through the threaded holes 30, and the first sheet ceramic 28 and the second sheet ceramic 29 can clamp the thermal protection material sample 20 at the lower end after being aligned.

[0060] In order to obtain the real-time weight of the thermal protection material sample 20, the low-temperature performance test system of the present application further comprises a sample weighing device; the weighing device comprises a horizontal tray, an electronic balance 23 and a balance hook 21, the horizontal tray is arranged on a vertical moving slider, the electronic balance 23 is arranged on the horizontal tray, the connecting end of the balance hook 21 is arranged on the bottom surface of the horizontal tray, and the hook end of the balance hook 21 is connected with the connecting end of the lifting belt 18. It should be noted that the electronic balance 23 is connected with a computer through an interface to record the weight of the thermal protection material sample 20 in real time.

[0061] The low-temperature performance test system of the present application further comprises a sample weighing device; as shown in Figure 1 and Figure 3 The weighing device comprises a horizontal tray, an electronic balance 23 and a balance hook 21, the horizontal tray is arranged on a vertical moving slider, the electronic balance 23 is arranged on the horizontal tray, the connecting end of the balance hook 21 is arranged on the bottom surface of the horizontal tray, and the hook end of the balance hook 21 is connected with the connecting end of the lifting belt 18.

[0062] The electronic balance 23 of the present application is connected with a computer through an interface to record the weight of the thermal protection material sample 20 in real time.

[0063] The electronic balance 23 of the present application adopts a precision electronic analytical balance with a weighing function as a weighing instrument. The electronic balance 23 is connected with a computer through an RS232 interface to record (or print) the weight and weight loss of the thermal protection material sample 20 in real time.

[0064] Table 1 Technical index of the electronic balance 23

[0065]

[0066] In order to prevent the furnace body 1 and the sample cavity 7 from dewing, the low-temperature performance test system of the thermal protection material of the present application further comprises a positive pressure nitrogen input assembly, the positive pressure nitrogen input assembly comprises a nitrogen source, a blower and a nitrogen input pipe; the nitrogen is input into the sample cavity 7 through the blower and the nitrogen input pipe.

[0067] Specifically, the air low-temperature refrigeration needs to overcome the problem of frosting, and the present application inputs the positive pressure nitrogen into the sample cavity 7 by using the positive pressure nitrogen input assembly, so that the air can be discharged and the moisture in the air can be prevented from frosting in the sample cavity 7.

[0068] In order to ensure that the low temperature performance of the heat protection material can be continuously tested, the low temperature test system of the present application further comprises a liquid nitrogen input assembly, which comprises a liquid nitrogen tank, a liquid nitrogen conveying pipeline and a liquid nitrogen funnel; the liquid nitrogen funnel penetrates through the top of the first area 8, one end of the liquid nitrogen conveying pipeline is connected with the liquid nitrogen tank, and the other end of the liquid nitrogen conveying pipeline is connected with the input port of the liquid nitrogen funnel; when the heat protection material sample 20 is tested at -198℃--50℃, the liquid nitrogen input assembly is used to input liquid nitrogen into the first area 8 for rapid refrigeration; when the heat protection material sample 20 is tested at -50℃-0℃, the sample cavity 7 is rapidly refrigerated by the refrigeration machine 15.

[0069] Compared with the prior art, the present application adopts the refrigeration mode of the refrigeration machine 15 and the liquid nitrogen refrigeration in combination, on the one hand, when the refrigeration machine 15 or the liquid nitrogen input assembly fails, the refrigeration mode can be quickly switched to another one; on the other hand, when the refrigeration temperature is -198℃--50℃, if the refrigeration machine 15 is used to maintain at this low temperature, it is relatively power-consuming, thereby resulting in a relatively high cost, therefore, when the refrigeration temperature is -198℃--50℃, the liquid nitrogen refrigeration is adopted in the present application, so that the refrigeration cost can be reduced. When the refrigeration temperature is -50℃-0℃, the refrigeration machine 15 is used for refrigeration, thereby avoiding the complicated operation of repeatedly filling liquid nitrogen in the liquid nitrogen refrigeration.

[0070] It should be noted that the sample cavity is divided into a sample area and a liquid nitrogen buffer area by the partition plate 31; wherein the sample area is arranged above the liquid nitrogen buffer area, the nitrogen gas input pipe extends into the liquid nitrogen buffer area, a plurality of liquid nitrogen switch valves are arranged on the partition plate 31, and the volatilization speed of the liquid nitrogen can be controlled by controlling the opening and closing of the liquid nitrogen switch valves, that is, the flow and flow rate of the liquid nitrogen entering the sample area are controlled, so that the low temperature performance test system has the functions of rapid refrigeration or slow refrigeration.

[0071] In order to further improve the temperature control accuracy of the low temperature performance test system, the bottom of the heat conduction sleeve is provided with a liquid nitrogen guide valve 36, and the liquid nitrogen enters the liquid nitrogen buffer area through the liquid nitrogen guide valve 36. The above-mentioned plurality of liquid nitrogen switch valves comprise a first liquid nitrogen switch valve 32, a second liquid nitrogen switch valve 33, a third liquid nitrogen switch valve 34 and a fourth liquid nitrogen switch valve 35, and the first liquid nitrogen switch valve 32 to the fourth liquid nitrogen switch valve 35 can be controlled individually; when it is needed to sharply reduce the temperature to -198℃, the first liquid nitrogen switch valve 32 to the fourth liquid nitrogen switch valve 35 can be all opened, so as to increase the liquid nitrogen flow and flow rate of the liquid nitrogen entering the sample area from the liquid nitrogen buffer area, that is, the volatilization of the liquid nitrogen is increased, so that the sample can be rapidly cooled to the target temperature.

[0072] It should be noted that when the sample cavity 7 is refrigerated by the refrigerator 15, the first area 8 needs to be vacuumized by the vacuumizing assembly; when the sample cavity 7 is refrigerated by the liquid nitrogen input assembly, the first area 8 does not need to be vacuumized, at this time, liquid nitrogen is injected into the first area 8 by the liquid nitrogen input assembly, and refrigeration in the sample cavity 7 is realized through heat conduction of the heat conduction sleeve 4.

[0073] Compared with the prior art, when the refrigerator 15 is used, the operation is simple in use, and the trouble of repeatedly filling liquid nitrogen for liquid nitrogen refrigeration is saved. Meanwhile, the refrigeration compressor 16 needs to be water-cooled, water cooling circulating water needs to be provided, and the vacuum pump is used to vacuumize the sample chamber.

[0074] In order to support and fix the furnace body 1, the furnace body support 11 is arranged at the bottom of the furnace body 1, and the furnace body support 11 is used to support the furnace body 1; the low-temperature container support body 10 is arranged at the bottom of the low-temperature container 2, the top of the low-temperature container support body 10 is provided with a groove matched with the outer side of the low-temperature container 2, and the bottom of the low-temperature container 2 is located in the groove.

[0075] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A system for testing the low temperature performance of a thermal protection material, characterized by, The low-temperature container and the refrigerator are arranged in the furnace body, and the refrigerator is in communication with the low-temperature container and can refrigerate the low-temperature container; The low-temperature container is internally provided with an isolation sleeve and a heat-conducting sleeve, the isolation sleeve is arranged above the heat-conducting sleeve, the top end of the isolation sleeve is in contact with the furnace body, the bottom end of the isolation sleeve is embedded in an annular groove arranged on the top surface of the heat-conducting sleeve, the isolation sleeve is in communication with the heat-conducting sleeve and arranged on the same axis as the heat-conducting sleeve; the area inside the heat-conducting sleeve constitutes a sample cavity, and a heat protection material sample is arranged in the sample cavity; the area between the heat-conducting sleeve, the isolation sleeve and the inner wall of the low-temperature container is defined as a first area; the first area is a vacuum environment; The heat-conducting sleeve is provided with a heating element, and the heating element is used for heating the sample cavity; The low-temperature test system further comprises a positive pressure nitrogen input assembly, and the positive pressure nitrogen input assembly comprises a nitrogen source, a blower and an input pipe; Nitrogen is input into the sample cavity through the blower and the input pipe; The low-temperature test system further comprises a liquid nitrogen input assembly, and the liquid nitrogen input assembly comprises a liquid nitrogen tank, a liquid nitrogen conveying pipeline and a liquid nitrogen funnel; The liquid nitrogen funnel penetrates the top of the first area, one end of the liquid nitrogen conveying pipeline is connected with the liquid nitrogen tank, and the other end of the liquid nitrogen conveying pipeline is connected with the input port of the liquid nitrogen funnel; When the heat protection material sample is tested at-198℃--100℃, liquid nitrogen is input into the first area by the liquid nitrogen input assembly for refrigeration; When the heat protection material sample is tested at-100℃--50℃, the sample cavity is refrigerated by the refrigerator; The sample cavity is divided into a sample area and a liquid nitrogen buffer area by a partition plate, the sample area is arranged above the liquid nitrogen buffer area, and a plurality of liquid nitrogen on-off valves are arranged on the partition plate; The plurality of liquid nitrogen on-off valves comprise a first liquid nitrogen on-off valve, a second liquid nitrogen on-off valve, a third liquid nitrogen on-off valve and a fourth liquid nitrogen on-off valve, and the first liquid nitrogen on-off valve to the fourth liquid nitrogen on-off valve can be controlled individually.

2. The system for testing low temperature performance of thermal protection materials according to claim 1, wherein The heat-conducting sleeve is provided with an annular hole, the heating element is a resistance wire, and the resistance wire is arranged in the annular hole; The low-temperature performance test system further comprises a temperature measuring device, and the temperature measuring device is arranged in a blind hole on the heat-conducting sleeve; the temperature measuring device and the resistance wire are connected with an external power supply.

3. The system for testing low temperature performance of thermal protection materials according to claim 2, wherein The low-temperature performance test system further comprises a vacuumizing assembly, the vacuumizing assembly is connected with a vacuum joint arranged on the wall of the low-temperature container, and the vacuumizing assembly can vacuumize the first area.

4. The system for testing low temperature performance of thermal protection materials according to claim 3, wherein The vacuumizing assembly comprises a vacuum pipeline, a vacuum measuring device, a first-stage vacuum equipment and a second-stage vacuum equipment; the first-stage vacuum equipment and the second-stage vacuum equipment are arranged in series; The upper end of the vacuum pipeline is in communication with the vacuum joint, the lower end of the vacuum pipeline is provided with a tee joint, one end of the tee joint is connected with the vacuum measuring device, and the other end is connected with the first-stage vacuum equipment and the second-stage vacuum equipment in sequence; The first-stage vacuum equipment adopts a mechanical vacuum pump, and the second-stage vacuum equipment adopts a turbo molecular pump.

5. The system for testing low temperature performance of thermal protection materials according to claim 1, wherein The refrigerating machine comprises a refrigerating head, a compressor and a temperature control device; The refrigerating head is arranged in the low-temperature container, one end of the refrigerating head is communicated with the sample cavity, the other end of the refrigerating head is connected with the compressor, and the temperature control device is used for adjusting the output of the refrigerating machine so that the heat shield material sample reaches a target temperature.

6. The system for testing low temperature performance of thermal protection materials according to claim 1, wherein The low-temperature test system further comprises a sample clamping mechanism and a sample moving device, the low-temperature container is provided with a first opening at the top, and the sample clamping mechanism and the sample moving device are arranged directly above the sample cavity and penetrate through the first opening; The sample moving device comprises a horizontal guide rail and a vertical guide rail, the horizontal guide rail is provided with a horizontal moving slider and a horizontal moving motor, and the vertical guide rail is provided with a vertical moving slider and a vertical moving motor; The vertical guide rail is arranged on the horizontal moving slider, and the horizontal moving motor can drive the horizontal moving slider to move the vertical guide rail in the horizontal direction; The vertical moving slider is connected with a lifting belt, the lower end of the lifting belt is connected with the connecting end of the sample clamping mechanism, the sample clamping mechanism further comprises a clamping end, and the clamping end clamps the heat shield material sample; and the vertical moving motor can drive the vertical moving slider to move the heat shield material sample in the vertical direction.

7. The system for testing low temperature performance of thermal protection materials according to claim 6, wherein The low-temperature performance test system further comprises a sample weighing device; The weighing device comprises a horizontal tray, an electronic balance and a balance lifting hook, the horizontal tray is arranged on the vertical moving slider, the electronic balance is arranged on the horizontal tray, the connecting end of the balance lifting hook is arranged on the bottom surface of the horizontal tray, and the hook end of the balance lifting hook is connected with the connecting end of the lifting belt; The electronic balance is connected with a computer through an interface to record the weight of the heat shield material sample in real time.

8. The system for testing low temperature performance of thermal protection materials according to any one of claims 1 to 7, characterized in that, The furnace body is provided with a furnace body support for supporting the furnace body; The low-temperature container is provided with a low-temperature container support body at the bottom, the top of the low-temperature container support body is provided with a groove matched with the outer side surface of the low-temperature container, and the bottom of the low-temperature container is located in the groove.

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