A liquid hydrogen temperature zone moving part friction force test system and method

Abstract

A liquid hydrogen temperature zone moving part friction force test system and method, comprising: a testing machine, the center connecting rod of the testing machine is connected with a measured valve core, and a force sensor for measuring the friction force of the valve core is installed on the center connecting rod; the testing machine is used for driving the measured valve core to reciprocate through the center connecting rod; the friction force test device comprises a support, a heat conduction column, a low-temperature cavity, a weight, and a bearing rod; the low-temperature cavity is used for accommodating the measured valve core and sleeve; the support is used for supporting the measured sleeve and connecting with the motion crossbeam of the testing machine through the bearing rod; the heat conduction column is connected with the support and the measured sleeve at one end and connected with the low-temperature cavity at the other end, and is used for conducting cold quantity to the valve core and the sleeve; the weight is connected with the measured sleeve through a steel wire and is used for providing a lateral force in the reciprocating process of the measured valve core; a refrigeration system is used for providing a low-temperature environment for the low-temperature cavity, the measured valve core and the sleeve; and a temperature control system is used for controlling the refrigeration system.

Description

TECHNICAL FIELD

[0001] The application relates to a liquid hydrogen temperature zone moving part friction force test system and method, and belongs to the field of liquid hydrogen temperature zone tests. BACKGROUND

[0002] The valve guide matching pair is a gap matching, and the existence of the guide gap causes a small angle deflection of the valve core during action and return. With the change of the guide gap, the deflection angle of the valve core also changes, and the generated friction force affects the action and return of the valve core. Under the action of the spring force and the air pressure, the lateral force is generated at the interface of the guide matching pair after the deflection of the valve core. The change rule of the friction force of the guide matching pair under the action of the lateral force is difficult to obtain, and therefore the size of the guide gap and the size of the lateral force of the matching pair become the key parameters restricting the performance of the guide matching pair.

[0003] The force-heat characteristics of materials under the liquid hydrogen temperature zone are significantly different from those under the normal temperature condition, which makes the friction characteristics of the guide matching pair matched by different materials under the deep low temperature condition also significantly different from those under the normal temperature condition. Therefore, for the deep low temperature valve, the material matching form and the working temperature also become the key parameters restricting the friction and wear performance of the guide matching pair.

[0004] In summary, it is necessary to construct a liquid hydrogen temperature zone moving part friction force test system to carry out research on different guide matching pair structure forms and material matching, different guide gaps and lateral forces and deep low temperature use conditions. SUMMARY

[0005] The technical problem to be solved by the application is to overcome the shortcomings of the prior art and solve the liquid hydrogen temperature zone moving part friction force test problem.

[0006] The purpose of the application is achieved by the following technical solutions.

[0007] A liquid hydrogen temperature zone moving part friction force test system comprises:

[0008] A testing machine is connected with the measured valve core through a center connecting rod, and a force sensor for measuring the friction force borne by the valve core is installed on the center connecting rod; and the testing machine is used to drive the measured valve core to reciprocate through the center connecting rod.

[0009] The friction force test device comprises a support, a heat conduction column, a low temperature cavity, a weight and a bearing rod; the low temperature cavity is used to accommodate the measured valve core and sleeve; the support is used to support the measured sleeve and is connected with the motion cross beam of the testing machine through the bearing rod; the heat conduction column is connected with the support and the measured sleeve at one end and is connected with the low temperature cavity at the other end, and is used to conduct cold energy to the valve core and the sleeve; and the weight is connected with the measured sleeve through a steel wire and is used to provide a lateral force during the reciprocating motion of the measured valve core.

[0010] A refrigeration system for providing a low-temperature environment for a low-temperature chamber, a valve core to be measured and a sleeve;

[0011] A temperature control system for controlling the refrigeration system.

[0012] Preferably, the center link penetrates into the low-temperature chamber to drive the valve core to reciprocate.

[0013] Preferably, the friction testing device is located in a testing machine, and the weight is located in the low-temperature chamber.

[0014] Preferably, the low-temperature chamber is filled with helium.

[0015] Preferably, the heat-conducting column is connected to the sleeve to be measured through a hinge, so that the sleeve to be measured can be offset when subjected to a lateral force.

[0016] Preferably, the friction testing device further comprises a sealing ring for dynamic sealing between the center link and the low-temperature chamber.

[0017] Preferably, the friction testing device further comprises a vacuum heat insulation layer for heat preservation of the low-temperature chamber.

[0018] Preferably, the size of the lateral force during reciprocation of the valve core is changed by adjusting the weight of the weight.

[0019] Preferably, the testing system further comprises a vacuumizing device and a gas source, the vacuumizing device being used for gas replacement of the low-temperature chamber, and the vacuumizing device and the gas source being used together to provide a predetermined gas pressure.

[0020] A method for testing the friction of a liquid-hydrogen temperature zone moving part, using the above-mentioned friction testing system, comprising:

[0021] Assemble the friction testing device, keep normal temperature, temporarily do not install the valve core to be measured and the weight, and fill the low-temperature chamber with helium; measure the friction generated by reciprocation of the center link at the dynamic sealing place as an initial friction;

[0022] Replace the low-temperature chamber by vacuumizing, fill with helium and cool down, and measure the friction generated by reciprocation of the center link at the dynamic sealing place as a test friction;

[0023] Subtract the initial friction from the test friction, and the friction of the moving part is obtained.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] (1) The present application can measure the friction of uniform-speed reciprocation by adopting the mode of connecting the valve core to the center link and connecting the sleeve to the cross beam;

[0026] (2) The test system can be replaced and matched according to the structure form and material of different guide matching pairs, and the friction force measurement test under different guide clearances and lateral forces can be carried out, and the comprehensive analysis of various influencing factors can be realized;

[0027] (3) The test system can carry out the friction force measurement between the valve core and the sleeve at any temperature from room temperature to 20K.

[0028] (4) The test system comprehensively considers various factors affecting the movement of the valve core, including deep low-temperature environment, structure form and material matching of different guide matching pairs, different guide clearances and lateral forces, etc. Through the system, the above factors can be researched to obtain the friction force change between the reciprocating valve core and the sleeve, provide basic data for low-temperature rocket valve design and state analysis, and improve the stability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a material low-temperature mechanical property test platform schematic diagram.

[0030] Figure 2 It is a partial schematic diagram of the motion part friction force test system. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0032] Example 1:

[0033] The liquid hydrogen temperature zone motion part friction force test system mainly consists of the following parts: a microcomputer control electronic universal testing machine 1 (referred to as a testing machine) which is installed with a center connecting rod 12 (connected to a force sensor located at the top of the testing machine); a friction force test device 2; a temperature control system 3; a refrigeration system 4 (i.e. a G-M refrigerator); a force sensor 5. The friction force test device includes: a bracket 8; a heat conducting column 9; a low-temperature cavity 10; a weight 11; a bearing rod 13; a sealing ring 14, a vacuum heat insulation layer, as shown in Figure 2 Based on the basic platform of the testing machine, the refrigeration mode of the G-M refrigerator is used to provide a 20K low-temperature environment, as shown in Figure 1 The temperature control system is used to stably control the temperature at 20K±1K. The vacuum heat insulation layer is located outside the low-temperature cavity 10 for heat preservation.

[0034] The main working principle of the friction test device is that the valve core 6 is connected with the center connecting rod 12 of the testing machine, the force sensor 5 is installed at the top of the center connecting rod, and the friction force borne by the valve core can be directly measured. The sleeve 7 and the support 8 are connected with the motion crossbeam of the testing machine through four bearing rods 13, and uniform speed reciprocating motion is realized during the experiment. The lateral force during the motion of the sleeve is stably applied through the steel wire rope and the gravity of the weight 11, and different lateral force working conditions can be simulated by replacing the weight. The gap between the valve core and the sleeve and the material can be replaced according to the research object. The valve core, the sleeve and the support are placed in the low-temperature cavity of the low-temperature test system, and the cavity is filled with 0.02 MPa helium gas during the experiment. The dynamic seal between the low-temperature cavity 10 and the center connecting rod is realized through the sealing ring 14. The heat conduction column 9 connects the low-temperature cavity and the sleeve 7, realizes the rapid conduction of cold energy to the valve core and the sleeve, and accelerates the cooling speed. The temperature control system is used to adjust and control the temperature of the test piece, so that the whole system reaches a stable state.

[0035] A specific embodiment of a liquid hydrogen temperature zone moving part friction test system and method is as follows:

[0036] 1) Install the friction test system on the testing machine, and install the force sensor on the top of the connecting rod. The support is connected with the motion crossbeam of the material testing machine through four bearing rods, and the parts of the test system except the valve core are sequentially installed. The low-temperature cavity is filled with 0.02 MPa helium gas after replacement. The initial friction force generated by the reciprocating motion of the center rod at the dynamic seal is measured. The measured result in the subsequent test is subtracted from the initial friction force of the dynamic seal to obtain the real friction force between the valve core and the sleeve.

[0037] 2) Determine the structure form and material matching of the matching pair for this test, install the valve core and the sleeve. The valve core is connected with the center connecting rod, and the sleeve is connected with the support. The weight is connected with the sleeve through the steel wire rope, and the lateral force is set by adding the weight. At this time, the cavity of the valve core is inflated with helium, vacuumized and replaced multiple times, and finally the helium pressure in the cavity is 0.02 MPa. Perform operations in the control computer software, realize the uniform speed reciprocating motion of the valve core through the material testing machine, and measure the friction force under the normal temperature condition.

[0038] 3) The vacuum insulation layer in the test system is vacuumized to reach 1×10 -4 Pa. At this time, the test system is cooled, the temperature control instrument, the temperature acquisition system and the G-M refrigerator are opened, and the test can be carried out after the temperature reaches 20K.

[0039] 4) Measure the friction force of the valve core under the reciprocating motion condition under the liquid hydrogen temperature zone environment. After the test is finished, the refrigerator is closed, and after the system is warmed up, different test conditions can be replaced, and the test can be continued.

[0040] Example 2:

[0041] A liquid hydrogen temperature zone moving part friction force test system, comprising:

[0042] A test machine, a center connecting rod of the test machine is connected with the measured valve core, and a force sensor for measuring the friction force borne by the valve core is installed on the center connecting rod; and the test machine is used to drive the measured valve core to reciprocate through the center connecting rod;

[0043] The friction force test device comprises a support, a heat conduction column, a low-temperature cavity, a weight, and a bearing rod; the low-temperature cavity is used to accommodate the measured valve core and sleeve; the support is used to support the measured sleeve and is connected with the moving beam of the test machine through the bearing rod; the heat conduction column is connected with the support and the measured sleeve at one end and is connected with the low-temperature cavity at the other end, and is used to conduct cold energy to the valve core and the sleeve; the weight is connected with the measured sleeve through a steel wire and is used to provide a lateral force during reciprocation of the measured valve core.

[0044] A refrigeration system is used to provide a low-temperature environment for the low-temperature cavity, the measured valve core, and the sleeve.

[0045] A temperature control system is used to control the refrigeration system.

[0046] Preferably, the center connecting rod penetrates into the low-temperature cavity to drive the measured valve core to reciprocate.

[0047] Preferably, the friction force test device is located in the test machine, and the weight is located in the low-temperature cavity.

[0048] Preferably, the low-temperature cavity is filled with helium.

[0049] Preferably, the heat conduction column is connected with the measured sleeve through a hinge, so that the measured sleeve can be offset when subjected to a lateral force.

[0050] Preferably, the friction force test device further comprises a sealing ring for dynamic sealing between the center connecting rod and the low-temperature cavity.

[0051] Preferably, the friction force test device further comprises a vacuum insulation layer for heat preservation of the low-temperature cavity.

[0052] Preferably, the weight of the weight is adjusted to change the size of the lateral force during reciprocation of the valve core.

[0053] Preferably, the test system further comprises a vacuumizing device and a gas source, the vacuumizing device is used to replace gas in the low-temperature cavity, and the vacuumizing device and the gas source are used to provide a predetermined gas pressure.

[0054] A liquid hydrogen temperature zone moving part friction force test method, using the above-mentioned friction force test system, comprising:

[0055] Assemble the friction test device, keep normal temperature, temporarily do not install the measured valve core and the weight, fill helium in the low temperature cavity; measure the friction force generated by the reciprocating motion of the center connecting rod at the dynamic seal as the initial friction force;

[0056] Replace the low temperature cavity with vacuum, fill helium and reduce temperature, measure the friction force generated by the reciprocating motion of the center connecting rod at the dynamic seal as the test friction force;

[0057] Subtract the initial friction force from the test friction force, and the friction force of the moving part is obtained.

[0058] The contents not described in detail in the specification of the present application are the known technology of the person skilled in the art.

[0059] Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not depart from the technical solutions of the present application, belongs to the protection scope of the technical solutions of the present application.

Claims

1. A liquid hydrogen warm-temperature moving component friction test system, comprising: The test machine connects its center link with the valve core to be tested, and the force sensor for measuring the friction force on the valve core is installed on the center link; and the valve core to be tested is driven to reciprocate by the center link. The friction force testing device comprises a support, a heat-conducting column, a low-temperature cavity, a weight, and a load-bearing rod; the low-temperature cavity is used for accommodating the valve core to be tested and the sleeve; the support is used for supporting the sleeve to be tested and connecting the load-bearing rod with the moving beam of the test machine; the heat-conducting column is connected with the support and the sleeve to be tested at one end and connected with the low-temperature cavity at the other end, and is used for conducting cold energy to the valve core and the sleeve; the weight is connected with the sleeve to be tested by a steel wire and is used for providing a lateral force during the reciprocating movement of the valve core to be tested. A refrigeration system is used for providing a low-temperature environment for the low-temperature cavity, the valve core to be tested, and the sleeve. A temperature control system is used for controlling the refrigeration system. The heat-conducting column is connected with the sleeve to be tested through a hinge, so that the sleeve to be tested can be deviated when subjected to the lateral force. The weight of the weight is adjusted to change the size of the lateral force during the reciprocating movement of the valve core. The center link penetrates into the low-temperature cavity to drive the valve core to be tested to reciprocate.

2. The test system of claim 1, wherein, The friction force testing device is located in the test machine, and the weight is located in the low-temperature cavity.

3. The test system of claim 1, wherein, The low-temperature cavity is filled with helium.

4. The test system of claim 1, wherein, The friction force testing device further comprises a sealing ring for dynamic sealing between the center link and the low-temperature cavity.

5. The test system of claim 1, wherein, The friction force testing device further comprises a vacuum thermal insulation layer for heat preservation of the low-temperature cavity.

6. The test system of claim 1, wherein, The test system further comprises a vacuumizing device and a gas source, the vacuumizing device is used for gas replacement of the low-temperature cavity, and the vacuumizing device and the gas source are used together for providing a predetermined gas pressure.

7. The test system of claim 1, wherein, The friction force testing system according to any one of claims 1 to 7, comprising:

8. A method of testing the friction of moving parts in the cryogenic temperature range of liquid hydrogen, characterized in that Assemble the friction force testing device, keep normal temperature, temporarily do not install the valve core to be tested and the weight, fill the low-temperature cavity with helium; measure the friction force generated at the dynamic sealing place during the reciprocating movement of the center link as the initial friction force; Replace the low-temperature cavity by vacuumizing, fill with helium and cool down, measure the friction force generated at the dynamic sealing place during the reciprocating movement of the center link as the test friction force; Subtract the initial friction force from the test friction force to obtain the friction force of the moving part. ​

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