Test method of liquid propellant test bed

Abstract

The invention discloses a test method of a liquid propellant test bed, and relates to the technical field of large liquid propellant test piece ground tests, the test bed and a tested piece are subjected to three-dimensional modeling, and the three-dimensional model of the tested piece is assembled on the three-dimensional model of the test bed; and a propellant supply connecting pipeline and a propellant discharge connecting pipeline are drawn according to the three-dimensional model, and then a solid pipe fitting is machined. According to the method, the test process is optimized, design and processing of a propellant supply connecting pipeline and a propellant discharge connecting pipeline are preposed, firstly, a tested piece is assembled on a test bed on a computer, and secondly, the propellant supply connecting pipeline and the propellant discharge connecting pipeline between corresponding pipe orifices between the test bed and the tested piece are designed; processing the pipeline according to the design; after a tested piece is placed on the platform, the propellant supply connecting pipeline and the propellant discharge connecting pipeline are assembled to corresponding positions, so that the test period is shortened, material statistics is facilitated, and work such as structure and fluid simulation can be carried out in advance.

Description

Technical Field

[0001] The invention relates to the technical field of ground testing of large liquid propellant test pieces, and in particular to a testing method of a liquid propellant test bench. Background Art

[0002] Large liquid propellant test benches are generally divided into two types: one is to test the same test piece specifically. When the test piece is replaced, only the factory number is different, but the structural type is exactly the same; the other is to test new types of test pieces from time to time. The test piece structure is different, and the test piece and the test bench interface do not match. For the latter, it is necessary to redesign and manufacture several pipes connecting the test bench and the test piece. The current implementation method is that after a new type of test piece is put on the bench, the designer actually measures the relative position and other relationships between the end flange of the test bench pipeline and the corresponding pipe mouth of the test piece, designs a new route, and then hands it over to the implementation personnel to manufacture the new pipeline. This implementation method has the disadvantages of long demand cycle and is not conducive to statistical materials. Summary of the invention

[0003] The purpose of the present invention is to provide a test method for a liquid propellant test bench to solve the problems existing in the above-mentioned prior art, optimize the test process, and pre-place the design and processing of the propellant supply connecting pipeline and the propellant discharge connecting pipeline, thereby saving time and being conducive to counting materials, and carrying out structure and fluid simulation in advance.

[0004] To achieve the above object, the present invention provides the following solution: The present invention provides a test method for a liquid propellant test bench, comprising the following steps:

[0005] Step 1: 3D modeling of the test bench;

[0006] Step 2: Performing three-dimensional modeling on the test piece, and assembling the three-dimensional model of the test piece onto the three-dimensional model of the test bench;

[0007] Step 3: Draw a propellant supply connection pipe and a propellant discharge connection pipe connected to corresponding nozzles of the test piece and the test bench according to the three-dimensional model of the test piece and the three-dimensional model of the test bench;

[0008] Step 4: Processing the solid pipe fittings according to the data of the propellant supply connection pipe and the propellant discharge connection pipe drawn in the three-dimensional modeling;

[0009] Step 5: Assemble the test piece onto the test bench, and install the processed propellant supply connecting pipe and propellant discharge connecting pipe to the corresponding positions.

[0010] In one embodiment, the test bench includes a platform load-bearing steel structure and a steel structure platform, the first end of the platform load-bearing steel structure is installed on the foundation, and the second end of the platform load-bearing steel structure is equipped with a test piece; the front end of the platform load-bearing steel structure is provided with the steel structure platform, and the propellant supply pipeline test bench end flange and the propellant discharge pipeline test bench end flange are respectively arranged on both sides of the test bench.

[0011] In one embodiment, the first end of the platform load-bearing steel structure is connected to the foundation by means of anchor bolts; the second end of the platform load-bearing steel structure is a docking base, and the test piece is assembled on the docking base by bolts.

[0012] In one embodiment, the test piece is installed on the second end face of the platform load-bearing steel structure through a load-bearing frame, and the propellant supply port of the test piece is connected to the propellant supply pipeline test bench end flange through a propellant supply connecting pipe; the propellant discharge port of the test piece is connected to the propellant discharge pipeline test bench end flange through a propellant discharge connecting pipe.

[0013] In one embodiment, a three-dimensional laser scanning method is used to scan the test bench and establish a three-dimensional model of the test bench, and the dimensional accuracy of the three-dimensional model of the test bench and the actual size of the test bench is ≤3 mm.

[0014] In one embodiment, the dimensional accuracy of the three-dimensional model of the test piece and the actual size of the test piece is ≤1.5 mm.

[0015] In one embodiment, the propellant supply connection pipe and the propellant discharge connection pipe are both provided with metal hoses.

[0016] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0017] The test method of the liquid propellant test bench in the present invention optimizes the test process, and puts the design and processing of the propellant supply connecting pipe and the propellant discharge connecting pipe in advance. First, the test piece is assembled on the test bench on a computer using a virtual digitization method, and then the propellant supply connecting pipe and the propellant discharge connecting pipe between the corresponding pipe openings between the test bench and the test piece are designed, and then the pipes are processed according to the design; after the test piece is on the test bench, the propellant supply connecting pipe and the propellant discharge connecting pipe are installed at the corresponding positions, thereby saving time and being conducive to counting materials and conducting structure and fluid simulation in advance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a schematic diagram of the overall structure of the liquid propellant test bench;

[0020] Figure 2 It is a schematic diagram of the structure of the test piece assembled on the test bench;

[0021] Figure 3 It is a schematic diagram of the assembly of the propellant supply connection pipeline and the propellant discharge connection pipeline;

[0022] Figure 4 This is a schematic diagram of the installation state of the metal hose (i.e., the normal temperature pipeline working state);

[0023] Figure 5 It is a schematic diagram of the working state of the low-temperature pipeline of the metal hose;

[0024] Figure 6 This is a schematic diagram of the metal hose compensation calculation method;

[0025] Figure 7 The test method flow chart for the liquid propellant test bench;

[0026] Among them, 1. the flange at the end of the first propellant supply pipeline test bench; 2. the steel structure platform; 3. the flange at the end of the first propellant leakage pipeline test bench; 4. the flange at the end of the second propellant leakage pipeline test bench; 5. the test bench foundation; 6. the connection between the load-bearing steel structure of the platform and the foundation; 7. the flange at the end of the second propellant supply pipeline test bench; 8. the docking base between the load-bearing steel structure of the platform and the tested equipment; 9. the load-bearing steel structure of the platform; 10. the load-bearing frame of the tested piece; 11. the first leakage outlet of the tested piece; 12. the first supply outlet of the tested piece; 13. the tested piece; 14. the second supply outlet of the tested piece; 15. the second leakage outlet of the tested piece; 16. the docking base between the tested piece and the load-bearing steel structure of the platform; 17. the first propellant supply connecting pipeline; 18. the metal hose of the first propellant supply connecting pipeline; 19. the first propellant leakage connecting pipeline; 20. the second propellant leakage connecting pipeline; 21. the second propellant supply connecting pipeline; 22. the metal hose of the second propellant supply connecting pipeline. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The purpose of the present invention is to provide a test method for a liquid propellant test bench to solve the problems existing in the above-mentioned prior art, optimize the test process, and pre-place the design and processing of the propellant supply connecting pipeline and the propellant discharge connecting pipeline, thereby saving time and being conducive to counting materials, and carrying out structure and fluid simulation in advance.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1-Figure 7 As shown, the present invention provides a test method for a liquid propellant test bench, comprising the following steps:

[0031] (1) 3D modeling of the test bench;

[0032] (2) When a new device is to be tested, a three-dimensional model of the new device is first obtained; at this time, the physical device has not yet arrived or been assembled on the test bench due to the test plan;

[0033] (3) Assemble the three-dimensional model of the test piece 13 onto the three-dimensional model of the test bench in advance;

[0034] (4) Pre-design the propellant supply connection pipeline and the propellant discharge connection pipeline;

[0035] (5) Pre-processing the real propellant supply connection pipe and the propellant discharge connection pipe;

[0036] (6) According to the test plan, after the test piece 13 is physically assembled on the test bench, the pre-processed pipes are installed in the corresponding positions.

[0037] The test bench (already equipped with the test piece and the connecting pipeline) includes: a platform load-bearing steel structure 9, a test piece 13, a first propellant supply pipeline test bench end flange 1, a second propellant supply pipeline test bench end flange 7, a first propellant discharge pipeline test bench end flange 3, a second propellant discharge pipeline test bench end flange 4, a first propellant supply connecting pipeline 17, a second propellant supply connecting pipeline 21, a first propellant discharge connecting pipeline 19, and a second propellant discharge connecting pipeline 20, wherein the first end of the platform load-bearing steel structure 9 is connected to the foundation 5 in some way, and the second end is connected to the test piece 13, and is used to fix and bear the test piece 1 3 The force and moment generated during the test; the load-bearing frame 10 of the test piece 13 is connected to the second end of the platform load-bearing steel structure 9, the first supply port 12 of the test piece is connected to the first end of the first propellant supply connecting pipe 17, the second supply port 14 of the test piece is connected to the first end of the second propellant supply connecting pipe 21, the first discharge port 11 of the test piece is connected to the first end of the first propellant discharge connecting pipe 19, the second discharge port 15 of the test piece is connected to the first end of the second propellant discharge connecting pipe 20, the propellant supply port of the test piece 13 is used to receive the test bench propellant, and the propellant discharge port of the test piece 13 is used to discharge the test bench propellant.

[0038] In an optional embodiment, the first end of the platform load-bearing steel structure 9 is connected to the foundation 5 by means of anchor bolts, and its maximum load-bearing capacity is greater than the force and torque generated when the test piece 13 is tested; the second end is a docking base 8, which is connected to the test piece 13, specifically connected to the load-bearing frame 10 of the test piece 13, and the connection type is a bolt connection to facilitate the replacement of the test piece 13; the maximum load-bearing capacity of the bolt is greater than the force and torque generated when the test piece 13 is tested.

[0039] In an optional embodiment, the test piece 13, its load-bearing frame 10 is connected to the second end of the platform load-bearing steel structure 9, specifically to the docking base 8, its first supply port 12 of the test piece is connected to the first end of the first propellant supply connecting pipe 17, its second supply port 14 of the test piece is connected to the first end of the second propellant supply connecting pipe 21, its first discharge port 11 of the test piece is connected to the first end of the first propellant discharge connecting pipe 19, and its second discharge port 15 of the test piece is connected to the first end of the second propellant discharge connecting pipe 20; the connection method is flange connection.

[0040] In an optional embodiment, the first end of the first propellant supply connecting pipe 17 is connected to the first supply port 12 of the test piece, the first end of the second propellant supply connecting pipe 21 is connected to the second supply port 14 of the test piece, the second end of the first propellant supply connecting pipe 17 is connected to the first propellant supply pipe test bench end flange 1, and the second end of the second propellant supply connecting pipe 21 is connected to the second propellant supply pipe test bench end flange 7; the connection method is flange connection.

[0041] In an optional embodiment, the first end of the first propellant discharge connecting pipe 19 is connected to the first discharge port 11 of the test piece, the first end of the second propellant discharge connecting pipe 20 is connected to the second discharge port 15 of the test piece, the second end of the first propellant discharge connecting pipe 19 is connected to the first propellant discharge pipe test bench end flange 3, and the second end of the second propellant discharge connecting pipe 20 is connected to the second propellant discharge pipe test bench end flange 4; the connection method is flange connection.

[0042] In an optional embodiment, the first propellant supply pipeline test bench end flange 1 is connected to the first propellant supply connecting pipeline 17, and the second propellant supply pipeline test bench end flange 7 is connected to the second propellant supply connecting pipeline 21, and the test bench propellant is supplied to the test piece 13 through the pipeline.

[0043] In an optional embodiment, the first propellant discharge pipe test bench end flange 3 is connected to the first propellant discharge connecting pipe 19, and the second propellant discharge pipe test bench end flange 4 is connected to the second propellant discharge connecting pipe 20, and the propellant of the test piece 13 is discharged to the test bench through the pipe.

[0044] In an optional embodiment, a three-dimensional laser scanning device is used to scan the test bench, and the main performance parameters of the device are: a measuring range of 0.6 to 80 m, a ranging accuracy of ≤2 mm, and a single site scanning time of 2 to 3 min; the advantages are rapid scanning and high accuracy; an accurate three-dimensional model of the test bench is established based on the scanning data after post-processing, and the model at least includes the first propellant supply pipeline test bench end flange 1, the second propellant supply pipeline test bench end flange 7, the first propellant discharge pipeline test bench end flange 3, the second propellant discharge pipeline test bench end flange 4, the platform body load-bearing steel structure 9, and objects that may interfere with the connecting pipelines; the modeling accuracy is controlled to ≤3 mm.

[0045] In an optional embodiment, the three-dimensional model of the test equipment is virtually installed. First, the three-dimensional model of the test piece 13 is obtained in advance. The three-dimensional model of the test piece 13 can be obtained by inverse analysis from the real object, or the three-dimensional model of the test piece 13 can be designed first and then processed into the real object; the accuracy of the test piece model and the real object is controlled to be ≤1.5mm.

[0046] In an optional embodiment, the first propellant supply connection pipe 17, the second propellant supply connection pipe 21, the first propellant discharge connection pipe 19 and the second propellant discharge connection pipe 20 are virtually designed. Under the premise of considering interference, the pipeline route is reasonably arranged and the pipeline is designed; metal hoses are used for compensation, and the radial and axial compensation capabilities of the metal hoses are fully utilized. The compensation is divided into two cases: (1) for normal temperature propellant pipelines, the connection error is compensated, and the connection error includes the error between the three-dimensional model of the test bench and the actual object and the error between the three-dimensional model of the test piece and the actual object; (2) for low-temperature propellant pipelines, the connection error and the cold shrinkage of the pipeline working condition are compensated; the connection flange uses a slip-on connection flange.

[0047] In an optional embodiment, the first propellant supply connecting pipe 17, the second propellant supply connecting pipe 21, the first propellant discharge connecting pipe 19 and the second propellant discharge connecting pipe 20 are actually processed and manufactured, and the pipes are actually welded and processed according to the virtual design dimensions; welding deformation is considered, welding allowance is left, and the final accuracy is ≤1.5mm.

[0048] In an optional implementation, the test piece 13 is physically installed on the test bench, and its orientation is consistent with the virtual assembly pipe opening; the connecting pipes are finally connected and installed.

[0049] The embodiment of the present invention provides a test method for a liquid propellant test bench. First, the test bench is scanned by a three-dimensional laser scanning device to establish a three-dimensional model of the test bench. Secondly, the model of the test piece 13 is virtually assembled to the test bench model, and the propellant supply connecting pipe and the propellant discharge connecting pipe are virtually designed. Under the premise of considering interference, the pipeline route is reasonably arranged and the pipeline is designed. The propellant supply connecting pipe and the propellant discharge connecting pipe are designed to be truly welded and processed. The radial and axial compensation capabilities of the metal hose are fully utilized to compensate for the connection error and the shrinkage that may be caused by the working conditions of the low-temperature pipeline. Finally, the test piece 13 is physically assembled to the test bench, and the propellant supply connecting pipe and the propellant discharge connecting pipe can be directly installed.

[0050] The present invention is mainly used in the ground test process of large liquid propellant test pieces, and can achieve the purpose of rapid testing; before the test piece 13 is assembled to the test bench, the propellant supply connecting pipe and the propellant discharge connecting pipe are prefabricated in advance, and after the test piece 13 is assembled to the test bench, the propellant supply connecting pipe and the propellant discharge connecting pipe are installed to the corresponding positions, thereby saving time and being conducive to counting materials, carrying out structure and fluid simulation in advance, and the like.

[0051] Embodiment 1

[0052] According to an embodiment of the present invention, a test method embodiment of a liquid propellant test bench is provided. Figure 1 is a schematic diagram of the test bench structure according to an embodiment of the present invention, such as Figure 1 As shown, the test bench includes: a first propellant supply pipeline test bench end flange 1, a steel structure platform 2, a first propellant release pipeline test bench end flange 3, a second propellant release pipeline test bench end flange 4, a test bench foundation 5, a connection between the platform body load-bearing steel structure and the foundation 6, a second propellant supply pipeline test bench end flange 7, a docking base 8 between the platform body load-bearing steel structure and the test piece, and a platform body load-bearing steel structure 9.

[0053] like Figure 1 As shown, the first end of the platform load-bearing steel structure 9 is connected to the test bench foundation 5 by means of anchor bolts, and its maximum load-bearing capacity is greater than the force and torque generated when the test piece 13 is tested; the second end of the platform load-bearing steel structure 9 is connected to the test piece 13 by docking with the base, specifically connected to the load-bearing frame 10 of the test piece 13, and the connection type is a bolt connection, so as to facilitate the replacement of the test piece 13; the maximum load-bearing capacity of the bolt is greater than the force generated when the test piece 13 is tested.

[0054] The test bench is scanned using a 3D laser scanning device. The main performance parameters of the device are: measuring range of 0.6-80m, ranging accuracy ≤2mm, and scanning time of a single station of 2-3min; the advantages are fast scanning and high accuracy; based on the scanning data, an accurate 3D model of the test bench is established after post-processing, such as Figure 1 As shown, the model at least includes a first propellant supply pipeline test bench end flange 1, a second propellant supply pipeline test bench end flange 7, a first propellant discharge pipeline test bench end flange 3, a second propellant discharge pipeline test bench end flange 4, a platform load-bearing steel structure 9, and a steel structure platform 2 that may interfere with the connecting pipeline; the modeling accuracy is controlled at ≤3mm.

[0055] like Figure 2 As shown: a load-bearing frame 10 of the test piece, a first discharge port 11 of the test piece, a first supply port 12 of the test piece, a test piece 13, a second supply port 14 of the test piece, a second discharge port 15 of the test piece, and a docking base 16 for the test piece and the load-bearing steel structure of the platform; a three-dimensional model of the test piece 13 is virtually installed by the load-bearing frame 10 to dock the platform load-bearing steel structure 9 with the base 8, and the three-dimensional model of the test piece 13 is first obtained in advance. The three-dimensional model of the test piece 13 can be obtained by inverse calculation from the real object, or the three-dimensional model of the test piece 13 can be designed first and then processed into the real object; the accuracy of the test piece model and the real object is controlled to be ≤1.5mm.

[0056] like Figure 3As shown: a first propellant supply connecting pipe 17, a first propellant supply connecting pipe metal hose 18, a first propellant discharge connecting pipe 19, a second propellant discharge connecting pipe 20, a second propellant supply connecting pipe 21, and a second propellant supply connecting pipe metal hose 22; the first propellant supply connecting pipe 17, the second propellant supply connecting pipe 21, the first propellant discharge connecting pipe 19, and the second propellant discharge connecting pipe 20 are virtually designed, and the pipeline routes and pipelines are reasonably arranged and designed under the premise of considering the interference of the steel structure platform 2; the first propellant supply connecting pipe metal hose 18 and the second propellant supply connecting pipe metal hose 22 are used for compensation, and the radial and axial compensation capabilities of the metal hoses are fully utilized to compensate for the connection errors and the cold shrinkage that may be caused by the working conditions of the low-temperature pipelines; the connecting flanges use slip-on connecting flanges.

[0057] The first propellant supply connecting pipe 17, the second propellant supply connecting pipe 21, the first propellant discharge connecting pipe 19, and the second propellant discharge connecting pipe 20 are actually processed and manufactured, and the pipes are actually welded and processed according to the virtual design dimensions; welding deformation is considered and welding allowance is left, and the final accuracy is ≤1.5mm; the test piece 13 is actually installed on the test bench, and the orientation is consistent with the virtual assembly pipe mouth; the connecting pipes are finally connected and installed.

[0058] like Figure 4 , 5 As shown, compensation is divided into two cases, such as Figure 4 As shown, for normal temperature propellant pipelines, the installation state is the working state, and the connection error is compensated. The compensation capacity of the metal hose is ≥ the connection error; Figure 5 As shown, for cryogenic propellant pipelines, the connection error and the shrinkage of the pipeline under working conditions are compensated, and the compensation capacity of the metal hose is ≥ connection error + shrinkage compensation under working conditions; the connection flange uses a slip-on connection flange; Δt is the extreme value of the model connection error.

[0059] like Figure 6 As shown, the compensation principle of the metal hose, the schematic diagram of the hose compensation calculation method of the embodiment of the present invention, and the compensation capacity calculation formula are as follows;

[0060] L=2(π·R·θ / 180+K·DN) (1)

[0061]

[0062]

[0063] In the formula: L is the length of the metal hose; R is the design bending radius, 10DN; θ is the bending angle of the workpiece, generally between 30° and 45°; K is the straight segment coefficient, ≥1.5; DN is the diameter of the metal hose; Δε is the radial compensation of the hose; Δδ is the axial compensation of the hose.

[0064] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0065] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A test method for a liquid propellant test bench, characterized in that: The following steps are involved: Step 1: 3D modeling of the test bench; Step 2: Performing three-dimensional modeling on the test piece, and assembling the three-dimensional model of the test piece onto the three-dimensional model of the test bench; Step 3: Draw a propellant supply connection pipe and a propellant discharge connection pipe connecting the test piece and the corresponding nozzles on the test bench according to the three-dimensional model of the test piece and the three-dimensional model of the test bench; Step 4: Processing the solid pipe fittings according to the data of the propellant supply connection pipe and the propellant discharge connection pipe drawn in the three-dimensional modeling; Step 5: Assemble the test piece onto the test bench, and install the processed propellant supply connecting pipe and propellant discharge connecting pipe to the corresponding positions.

2. The test method of the liquid propellant test bench according to claim 1, characterized in that: The test bench comprises a load-bearing steel structure and a steel structure platform, wherein the first end of the load-bearing steel structure is installed on the foundation, and the second end of the load-bearing steel structure is equipped with a test piece; the steel structure platform is arranged at the front end of the load-bearing steel structure, and the propellant supply pipeline test bench end flange and the propellant discharge pipeline test bench end flange are respectively arranged on both sides of the test bench.

3. The test method of the liquid propellant test bench according to claim 2, characterized in that: The first end of the platform load-bearing steel structure is connected to the foundation by means of anchor bolts; the second end of the platform load-bearing steel structure is a docking base, and the test piece is assembled on the docking base by means of bolts.

4. The test method of the liquid propellant test bench according to claim 2, characterized in that: The test piece is assembled on the second end face of the load-bearing steel structure of the platform through a load-bearing frame, and the propellant supply port of the test piece is connected to the flange at the end of the propellant supply pipeline test platform through a propellant supply connecting pipeline; the propellant discharge port of the test piece is connected to the flange at the end of the propellant discharge pipeline test platform through a propellant discharge connecting pipeline.

5. The test method of the liquid propellant test bench according to claim 1, characterized in that: The test bench is scanned by a three-dimensional laser scanning method and a three-dimensional model of the test bench is established. The dimensional accuracy of the three-dimensional model of the test bench and the actual object of the test bench is ≤3mm.

6. The test method of the liquid propellant test bench according to claim 1, characterized in that: The dimensional accuracy of the three-dimensional model of the test piece and the actual object of the test piece is ≤1.5mm.

7. The test method of the liquid propellant test bench according to claim 1, characterized in that: The propellant supply connecting pipe and the propellant discharge connecting pipe are both provided with metal hoses.

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