A combined self-tightening seal structure for a thrust chamber head

Abstract

The present application relates to the technical field of rocket engine test device, and particularly relates to a combined self-tight sealing structure for the head of a thrust chamber, which is used for sealing the head of the thrust chamber during testing; the combined self-tight sealing structure comprises a first sealing assembly, a second sealing assembly and a third sealing assembly; the first sealing assembly and the second sealing assembly both form annular sealing surfaces on the head of the thrust chamber, and the sealing surfaces of the first sealing assembly, the second sealing assembly and the third sealing assembly are sequentially arranged from outside to inside, and jointly seal the head of the thrust chamber; the first sealing assembly transmits a test load to the flange of the head of the thrust chamber, the second sealing assembly transmits the test load to the back of the flange of the head of the thrust chamber, and the third sealing assembly transmits the test load to the base of the test device; the high-pressure load during testing acts on the first sealing assembly, the second sealing assembly and the third sealing assembly respectively, thereby improving the safety factor of each sealing assembly and reducing the stress level of the sealing member under high-pressure test conditions.

Description

Technical Field

[0001] This invention relates to the field of rocket engine testing equipment technology, and in particular to a combined self-tightening sealing structure for the thrust chamber head. Background Technology

[0002] The thrust chamber is the core component of a liquid rocket engine, responsible for converting propellant energy into thrust. Developing a thrust chamber requires addressing not only design, materials, and manufacturing processes, but also rigorous testing and verification of the strength and airtightness of its various components.

[0003] Therefore, it is necessary to design and develop a sealing structure for the thrust chamber head, which can be used in conjunction with the thrust chamber throat sealing assembly, the test device base and the installation platform to assess the welding quality and static strength of the thrust chamber weld. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a combined self-tightening sealing structure for the head of a thrust chamber, which is used in conjunction with a thrust chamber throat sealing assembly, a test device base and a mounting platform for testing the thrust chamber.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A combined self-tightening sealing structure for the head of a thrust chamber, used to seal the head of the thrust chamber during testing; comprising a first sealing assembly, a second sealing assembly, and a third sealing assembly;

[0007] The first sealing assembly and the second sealing assembly both form an annular sealing surface at the head of the thrust chamber. The sealing surfaces of the first sealing assembly, the second sealing assembly and the third sealing assembly are arranged sequentially from the outside to the inside, and together they seal the head of the thrust chamber.

[0008] The first sealing assembly transmits the test load force to the thrust chamber head flange, the second sealing assembly transmits the test load force to the back of the thrust chamber head flange, and the third sealing assembly transmits the test load force to the test device base.

[0009] In the aforementioned combined self-tightening sealing structure for the thrust chamber head, the first sealing assembly includes an end face sealing flange, a first connector, a first rubber ring, and a first retaining ring.

[0010] The end face sealing flange has an annular structure and is detachably connected to the thrust chamber head flange through the first connecting piece.

[0011] A first sealing groove is provided on the end face of the end face sealing flange that is in contact with the thrust chamber head flange. The first sealing groove is annular and extends along the entire circumference of the end face sealing flange. A first rubber ring and a first retaining ring are provided inside the first sealing groove.

[0012] In the aforementioned combined self-tightening sealing structure for the thrust chamber head, the first connecting member is a bolt, which passes through the through hole of the end face sealing flange and connects to the threaded hole of the thrust chamber head flange.

[0013] In the aforementioned combined self-tightening sealing structure for a thrust chamber head, the second sealing assembly includes a sealing flange and a first slider.

[0014] The first slider is an annular structure and is located inside the end face sealing flange; an annular outer sealing cavity is formed between the first slider and the inner side of the end face sealing flange; a first sealing ring is provided on the outer side of the first slider and extends into the outer sealing cavity; the first sealing ring is located at the end of the outer sealing cavity near the thrust chamber, and its outer side is in contact with the inner side of the end face sealing flange; a first sealing ring assembly is provided in the outer sealing cavity.

[0015] The sealing flange is located on the side of the end face sealing flange away from the thrust chamber head flange. The sealing flange has an annular structure, with its lower end extending into the outer sealing cavity and abutting against the first sealing ring assembly. The outer side of the lower end of the sealing flange is provided with a first positioning step, which abuts against the end face of the end face sealing flange and fits and positions itself against the inner side of the end face sealing flange.

[0016] The first slider is detachably and fixedly connected to the sealing flange; the sealing flange is detachably connected to the thrust chamber head flange via the first connecting assembly.

[0017] In the aforementioned combined self-tightening sealing structure for the thrust chamber head, the first connecting assembly includes a fixed flange, an adapter, and a second connecting member.

[0018] The fixed flange is a ring structure, and its minimum inner diameter is larger than the outer diameter of the thrust chamber head flange.

[0019] The adapter is an arc-shaped plate with a corresponding central angle of less than or equal to 180°; the inner surface of the adapter is adapted to the shape of the outer and lower sides of the thrust chamber head flange.

[0020] The adapter is located between the thrust chamber head flange and the fixed flange. The fixed flange and the sealing flange are detachably and fixedly connected as one unit through the second connector.

[0021] In the aforementioned combined self-tightening sealing structure for the thrust chamber head, the first sealing ring assembly includes two second rubber rings, with a second retaining ring between the two second rubber rings, and the second retaining ring is annular.

[0022] In the aforementioned combined self-tightening sealing structure for a thrust chamber head, the third sealing assembly includes a second slider and a gland.

[0023] The second slider is located inside the first slider. An annular inner sealing cavity is formed between the outer side of the second slider and the inner side of the first slider. A second sealing ring is provided on the outer side of the second slider, which extends into the inner sealing cavity. The second sealing ring is located at one end of the inner sealing cavity near the thrust chamber, and its outer side is in contact with the inner side of the first slider. A second sealing ring assembly is provided inside the inner sealing cavity.

[0024] The gland is located inside the sealing flange. The outer side of the gland has a third positioning step. The gland abuts against the end face of the sealing flange through the third positioning step and cooperates with and positions the inner side of the sealing flange. The end of the gland facing the second slider is provided with an annular second positioning step. The second positioning step extends into the inner sealing cavity and abuts against the second sealing ring assembly.

[0025] The second slider and the pressure cap are detachably and fixedly connected as one unit; the pressure cap is detachably and fixedly connected to the base of the test device through the second connecting component.

[0026] In the aforementioned combined self-tightening sealing structure for the thrust chamber head, the second sealing ring assembly includes two third rubber rings, with a third retaining ring between the two third rubber rings, the third retaining ring being annular.

[0027] In the aforementioned combined self-tightening sealing structure for the thrust chamber head, the outer diameter of the second sealing ring is adapted to the diameter of the thrust chamber throat.

[0028] In the aforementioned combined self-tightening sealing structure for the thrust chamber head, the second connecting assembly includes a fixed base and a pull rod;

[0029] The gland is provided with multiple third connecting studs, and the fixing base is provided with connecting holes at the corresponding positions of the third connecting studs. The third connecting studs pass through the connecting holes and are connected to the first nut.

[0030] The fixed base is provided with multiple support corner seats, which are evenly and spaced apart in the circumference of the fixed base; one end of the pull rod is connected to the support corner seat through a washer and a third nut, and the other end is installed on the base of the test device.

[0031] The combined self-tightening sealing structure used for the thrust chamber head has the following advantages:

[0032] The high-pressure load during the test was divided into three parts according to the ratio of the force-bearing area of ​​each sealing component, and applied to the first sealing component, the second sealing component and the third sealing component respectively. This improved the safety factor of the threads of each sealing component, reduced the stress level of the seals under high-pressure test conditions, and improved the sealing reliability.

[0033] During the assembly of the second and third sealing components, the second and third rubber rings have no interference fit when they are assembled with the mating surfaces, meaning there is no compression. After assembly, the first and second spare nuts are tightened, causing the second and third rubber rings to expand and be compressed radially. The compression is generally set to about 25%, which reduces the assembly difficulty and increases the compression of the rubber rings, thereby improving the reliability of the sealing structure.

[0034] Based on the principle of fluid dynamics in flat plate gap flow, the fluid leakage rate is inversely proportional to the square of the sealing length. Therefore, through structural design, two rubber rings are used in both the second and third sealing components, which effectively improves sealing reliability. The metal retaining ring increases the sealing length of the sealing groove, and by setting a tightening nut, the compression of the rubber ring is quantitatively controlled, further improving the reliability of the sealing structure. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a structural diagram showing the assembled self-tightening sealing structure and the thrust chamber head.

[0037] Figure 2 yes Figure 1 A magnified view of a portion of area A in the middle;

[0038] Figure 3 This is a structural diagram of the fixed base;

[0039] Figure 4 yes Figure 3 Schematic diagram of the structure of the middle BB section;

[0040] Figure 5 This is a schematic diagram of the gland structure;

[0041] Figure 6 This is a top view of the pressure cap structure;

[0042] Figure 7 This is a schematic diagram of the second slider;

[0043] Figure 8 This is a top view of the second slider.

[0044] In the picture:

[0045] 1-Fixed flange; 2-Adapter seat; 3-End face sealing flange; 4-Sealing flange; 5-First slider; 6-Second slider; 7-First spare nut; 8-Second spare nut; 9-Glander cap; 10-Fixed seat; 11-Pull rod; 12-Gasket; 13-First connector; 14-Second connector; 15-First nut; 16-Second nut; 17-First rubber ring; 18-Second rubber ring; 19-Second rubber ring; 20-Second retaining ring; 21 21-Third rubber ring; 22-Third retaining ring; 23-Third nut; 24-Thrust chamber; 25-First connecting stud; 26-Thrust chamber head flange; 27-First positioning step; 28-Second positioning step; 29-Support angle seat; 30-Connecting hole; 31-First reinforcing member; 32-Second reinforcing member; 33-Third reinforcing member; 34-Third positioning step; 35-Connecting cavity; 36-Third connecting stud; 37-Second connecting stud; 38-Support platform. Detailed Implementation

[0046] The present invention will be further described below with reference to the embodiments.

[0047] A combined self-tightening sealing structure for the head of a thrust chamber 24 is disclosed for sealing the head of the thrust chamber 24 during testing. The combined self-tightening sealing structure includes a first sealing assembly, a second sealing assembly, and a third sealing assembly. The first sealing assembly forms an annular sealing surface at the head of the thrust chamber 24 and transmits the test load force to the threaded hole of the thrust chamber head flange 26 via a first connector 13. The second sealing assembly forms an annular sealing surface at the head of the thrust chamber 24 and transmits the test load force to the back side of the thrust chamber head flange 26 via a second connector 14. The third sealing assembly transmits the test load force to the base of the test device via a tie rod 11. The sealing surfaces of the first, second, and third sealing assemblies are arranged sequentially from the outside to the inside, collectively sealing the head of the thrust chamber. The first, second, and third sealing assemblies are positioned axially within the thrust chamber 24 and are not rigidly connected to each other, thus preventing the transmission of axial force. The split-structure design reduces the stress level of each load-bearing component, minimizing the impact of excess test force on the thrust chamber 24.

[0048] like Figure 1 and Figure 2 As shown, the first sealing assembly includes an end face sealing flange 3, a first connecting piece 13, a first rubber ring 17, and a first retaining ring 18.

[0049] The end face sealing flange 3 is annular in shape and has an inner hole, which is adapted to the shape of the end face of the thrust chamber head flange 26. In use, the end face sealing flange 3 and the thrust chamber head flange 26 are detachably connected as one unit through the first connecting member 13. Preferably, the first connecting member 13 is a bolt, which passes through the through hole of the end face sealing flange 3 and connects to the threaded hole of the thrust chamber head flange 26.

[0050] A first sealing groove is provided on the end face of the end face sealing flange 3 that fits against the thrust chamber head flange 26. The first sealing groove is annular and extends along the entire circumference of the end face sealing flange 3. Figure 2 As shown, a first rubber ring 17 and a first retaining ring 18 are provided in the first sealing groove. The first rubber ring 17 is an O-ring. The first retaining ring 18 is annular and fits completely into the first sealing groove, increasing the sealing length in the leakage channel, improving the reliability of the sealing structure, and reducing the assembly difficulty of the components.

[0051] The second sealing assembly includes a sealing flange 4, a first slider 5, a first connecting assembly, a first sealing ring assembly, and a first tightening nut 7. The first connecting assembly is used to detachably connect the sealing flange 4 to the thrust chamber head flange 26, and includes a fixed flange 1, an adapter 2, a second connecting piece 14, and a second nut 16. The first sealing ring assembly includes two second rubber rings 19 and a second retaining ring 20.

[0052] The first slider 5 is located inside the end-face sealing flange 3, and its outer surface mates with the inner surface of the end-face sealing flange 3 to achieve a seal. The first slider 5 has an annular structure with an inner hole. An annular groove is provided on the side of the first slider 5 facing the thrust chamber 24, which not only reduces weight but also improves the sealing effect. An annular outer sealing cavity is formed between the first slider 5 and the inner surface of the end-face sealing flange 3. A first sealing ring extending into the outer sealing cavity is provided on the outer surface of the first slider 5, and the first sealing ring is positioned close to the thrust chamber 24, with its outer surface fitting against the inner surface of the end-face sealing flange 3. A first sealing ring assembly is provided inside the outer sealing cavity, comprising two second rubber rings 19, with a second retaining ring 20 between the two second rubber rings 19. The second retaining ring 20 is a complete ring, fitting entirely into the outer sealing cavity. The second retaining ring 20 has second rubber rings 19 on both its front and rear sides, increasing the sealing length in the leakage channel and improving the reliability of the sealing structure.

[0053] The sealing flange 4 is located on the side of the end face sealing flange 3 opposite to the thrust chamber head flange 26. The sealing flange 4 has an annular structure and an inner hole; its lower end extends into the outer sealing cavity and abuts against the second rubber ring 19. The outer side of the sealing flange 4 is provided with a first positioning step 27, which abuts against the end face of the end face sealing flange 3 and fits against the inner side of the end face sealing flange 3 to achieve positioning of the sealing flange 4. A first connecting stud 25 is welded onto the first slider 5. The first connecting stud 25 cooperates with the first tightening nut 7 to fix the first slider 5 to the sealing flange 4.

[0054] The fixed flange 1 is a continuous ring structure, with its minimum inner diameter larger than the outer diameter of the thrust chamber head flange 26. Ideally, the minimum inner diameter of the fixed flange 1 is 0.5mm-1mm larger than the outer diameter of the thrust chamber head flange 26, allowing the thrust chamber head flange 26 to pass through the inner hole of the fixed flange 1 during equipment installation, thus reaching the other side of the thrust chamber head flange 26 via the fixed flange 1. Figure 1 In the state shown, the fixed flange 1 is located below the thrust chamber head flange 26.

[0055] The adapter 2 is an arc-shaped plate with a central angle less than or equal to 180°. The inner surface of the adapter 2 fits against the outer and lower surfaces of the thrust chamber head flange 26. In use, the adapter 2 is positioned between the thrust chamber head flange 26 and the fixed flange 1. The fixed flange 1 and the sealing flange 4 are detachably and securely connected as one unit via the second connector 14. The second connector 14 can be made of bolts and used in conjunction with the second nut 16 to achieve a reliable connection between the fixed flange 1 and the sealing flange 4.

[0056] The third sealing assembly includes a second slider 6, a pressure cap 9, a second connecting assembly, a second sealing ring assembly, a second tightening nut 8, and a first nut 15; wherein, the second connecting assembly includes a fixing seat 10, a pull rod 11, a gasket 12, and a third nut 23, for detachably and securely connecting the pressure cap 9 to the base of the test device as a whole; the second sealing ring assembly includes two third rubber rings 21 and a third retaining ring 22.

[0057] The second slider 6 is located inside the first slider 5, as follows: Figure 7 and 8 As shown, the second slider 6 is disc-shaped with a groove on its lower end face for weight reduction. The outer surface of the second slider 6 mates with the inner surface of the first slider 5 to achieve a seal. An annular inner sealing cavity is formed between the inner surfaces of the second slider 6 and the first slider 5. The outer surface of the second slider 6 is provided with a second sealing ring 38 that extends into the inner sealing cavity. The second sealing ring 38 is located at the end of the inner sealing cavity near the thrust chamber 24, and its outer surface is in contact with the inner surface of the first slider 5. The second sealing ring assembly is located inside the inner sealing cavity, and the third retaining ring 22 is located between the two third rubber rings 21. The third rubber ring 21 is preferably an O-ring. The third retaining ring 22 is a complete ring that fits completely into the inner sealing cavity. The third retaining ring 22 has third rubber rings 21 on both its front and rear sides, which increases the sealing length in the leakage channel and improves the reliability of the sealing structure.

[0058] Furthermore, the outer diameter of the second sealing ring 38 is adapted to the diameter of the throat of the thrust chamber 24, that is, the outer diameter of the second sealing ring 38 is approximately equal to the diameter of the throat of the thrust chamber 24. The axial force on the second slider 6 is equal to the axial force on the throat sealing device. At this time, taking the first sealing assembly, the second sealing assembly, and the thrust chamber 24 as the objects of force analysis, the net external force is zero. Therefore, almost no extra force is generated on the thrust chamber 24 as a whole, ensuring that the thrust chamber 24 as a whole does not generate extra axial deformation.

[0059] The gland 9 is located inside the sealing flange 4, such as... Figure 5 and Figure 6 As shown, the outer surface of the gland 9 has a third positioning step 34. The gland 9 abuts against the end face of the sealing flange 4 via the third positioning step 34 and is engaged and positioned with the inner surface of the sealing flange 4. The end of the gland 9 facing the second slider 6 has an annular second positioning step 28, which extends into the inner sealing cavity and abuts against the third rubber ring 21. A second connecting stud 37 is welded onto the second slider 6, and the second connecting stud 37 is connected to the second tightening nut 8 to achieve a fixed connection between the second slider 6 and the gland 9.

[0060] The pressure cap 9 is welded with a third connecting stud 36, such as Figure 3 and Figure 4 The fixed base 10 has a connecting hole 30 at the position corresponding to the third connecting stud 36. The connecting hole 30 is a smooth hole. The third connecting stud 36 passes through the connecting hole 30 and connects to the first nut 15, realizing the fixed connection between the pressure cap 9 and the fixed base 10. The upper end of the fixed base 10 is provided with multiple support corner seats 29, which are evenly and spaced apart in the circumference of the fixed base 10. One end of the pull rod 11 is connected to the support corner seat 29 through the washer 12 and the third nut 23, and the other end is mounted on the base of the test device through the pin.

[0061] Furthermore, in order to increase the strength of the fixing seat 10, the inner cavity of the fixing seat 10 is provided with a first reinforcing member 31, a second reinforcing member 32, and a third reinforcing member 33.

[0062] When the combined self-tightening sealing structure is applied to the thrust chamber 24 test, before installation, check whether the first rubber ring 17, first retaining ring 18, second rubber ring 19, second retaining ring 20, third rubber ring 21, and third retaining ring 22 are cracked, deteriorated, or otherwise damaged; check whether the threads of each component are damaged, and replace or repair them if necessary. During installation, install the first sealing assembly, second sealing assembly, and third sealing assembly in sequence, following these steps:

[0063] a. Assemble the first rubber ring 17 and the first retaining ring 18 according to... Figure 2The first sealing assembly is installed in the first sealing groove as shown; the end face sealing flange 3 is screwed and connected to the threaded hole of the thrust chamber head flange 26 through the first connector 13, and the first sealing assembly is installed; the inner hole of the end face sealing flange 3 can be used as the positioning of the second sealing assembly.

[0064] b. Place the first slider 5 into the inner hole of the end face sealing flange 3, and then arrange the second rubber ring 19 and the second retaining ring 20 according to... Figure 2 Installed into the outer sealing cavity as shown in the diagram;

[0065] The fixed flange 1 is passed through the thrust chamber head flange 26 and fitted onto the outside of the thrust chamber 24;

[0066] The sealing flange 4 is placed above the end face sealing flange 3, and is positioned by engaging with the inner hole of the end face sealing flange 3 through the first positioning step 27;

[0067] Then, the inner side of the adapter 2 is fitted with the outer side of the thrust chamber head flange 26, and the fixed flange 1 is moved to the adapter 2 so that the outer bottom surface of the adapter 2 is fitted with the stepped surface of the fixed flange 1.

[0068] The fixed flange 1 is fixedly connected to the sealing flange 4 via the second connector 14 and the second nut 16. The first slider 5 is fixedly connected to the sealing flange 4 via the first connecting stud 25 and the first tightening nut 7. The first tightening nut 7 can be slightly tightened.

[0069] After the second sealing assembly is installed, the inner hole of the sealing flange 4 can be used as the positioning hole for the third sealing assembly.

[0070] c. Place the second slider 6 inside the first slider 5; the third rubber ring 21 and the third retaining ring 22 are arranged according to... Figure 2 Install it into the inner sealing cavity as shown in the diagram;

[0071] The gland 9 is placed inside the sealing flange 4, and abuts against the end face of the sealing flange 4 through the third positioning step 34 and cooperates with and positions the inner side of the sealing flange 4; the second slider 6 is fixedly connected to the gland 9 through the second connecting stud 37 and the second tightening nut 8, and the second tightening nut 8 can be tightened slightly.

[0072] The fixing seat 10 is placed on the upper side of the pressure cover 9; the pressure cover 9 is fixedly connected to the fixing seat 10 by the third connecting stud 36 and the first nut 15.

[0073] The fixing seat 10 and the tie rod 11 are fixed together by the gasket 12 and the third nut 23, and the installation of the third sealing assembly is completed.

[0074] After installing the first, second, and third sealing components according to the above steps, tighten all fastener threads, including the first and second spare nuts 7 and 8. The second rubber ring 19 and the third rubber ring 21 will then expand, creating a sealing pressure on the surface and ensuring a reliable seal. The combined self-tightening seal installation is now complete. Both the first and second spare nuts 7 and 8 can be commercially available nuts, allowing for a detachable connection with the studs.

[0075] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A combined self-tightening sealing structure for the head of a thrust chamber, used to seal the head of the thrust chamber (24) during testing; characterized in that: It includes a first sealing assembly, a second sealing assembly, and a third sealing assembly; The first sealing assembly and the second sealing assembly both form an annular sealing surface at the head of the thrust chamber (24). The sealing surfaces of the first sealing assembly, the second sealing assembly and the third sealing assembly are arranged sequentially from the outside to the inside, and together they seal the head of the thrust chamber (24). The first sealing assembly transmits the test load force to the thrust chamber head flange (26), the second sealing assembly transmits the test load force to the back of the thrust chamber head flange (26), and the third sealing assembly transmits the test load force to the test device base. The first sealing assembly includes an end face sealing flange (3), a first connector (13), a first rubber ring (17), and a first retaining ring (18). The end face sealing flange (3) has an annular structure and is detachably connected to the thrust chamber head flange (26) as a whole through the first connector (13); The end face sealing flange (3) is provided with a first sealing groove on the end face that fits with the thrust chamber head flange (26). The first sealing groove is annular and extends in the entire circumference of the end face sealing flange (3). The first sealing groove is provided with a first rubber ring (17) and a first retaining ring (18). The second sealing assembly includes a sealing flange (4) and a first slider (5); The first slider (5) is an annular structure and is located inside the end face sealing flange (3); an annular outer sealing cavity is formed between the first slider (5) and the inner side of the end face sealing flange (3); a first sealing ring is provided on the outer side of the first slider (5) and extends into the outer sealing cavity; the first sealing ring is located at one end of the outer sealing cavity near the thrust chamber (24), and its outer side is in contact with the inner side of the end face sealing flange (3); a first sealing ring assembly is provided in the outer sealing cavity; The sealing flange (4) is located on the side of the end face sealing flange (3) away from the thrust chamber head flange (26). The sealing flange (4) has an annular structure, with its lower end extending into the outer sealing cavity and abutting against the first sealing ring assembly. The outer side of the lower end of the sealing flange (4) is provided with a first positioning step (27). The first positioning step (27) abuts against the end face of the end face sealing flange (3) and fits and positions against the inner side of the end face sealing flange (3). The first slider (5) is detachably and fixedly connected to the sealing flange (4); the sealing flange (4) is detachably and fixedly connected to the thrust chamber head flange (26) through the first connecting assembly. The third sealing assembly includes a second slider (6) and a pressure cap (9); The second slider (6) is located inside the first slider (5). An annular inner sealing cavity is formed between the outer side of the second slider (6) and the inner side of the first slider (5). The outer side of the second slider (6) is provided with a second sealing ring (38) that extends into the inner sealing cavity. The second sealing ring (38) is located at one end of the inner sealing cavity near the thrust chamber (24), and its outer side is in contact with the inner side of the first slider (5). A second sealing ring assembly is provided inside the inner sealing cavity. The gland (9) is located inside the sealing flange (4). The outer side of the gland (9) has a third positioning step (34). The gland (9) abuts against the end face of the sealing flange (4) through the third positioning step (34) and cooperates with and positions the inner side of the sealing flange (4). The end of the gland (9) facing the second slider (6) is provided with an annular second positioning step (28). The second positioning step (28) extends into the inner sealing cavity and abuts against the second sealing ring assembly. The second slider (6) and the pressure cap (9) are detachably and fixedly connected as one unit; the pressure cap (9) is detachably and fixedly connected to the base of the test device through the second connecting component.

2. The combined self-tightening sealing structure for the thrust chamber head according to claim 1, characterized in that: The first connector (13) is a bolt that passes through the through hole of the end face sealing flange (3) and connects to the threaded hole of the thrust chamber head flange (26).

3. The combined self-tightening sealing structure for the thrust chamber head according to claim 1, characterized in that: The first connection assembly includes a fixed flange (1), an adapter (2), and a second connector (14). The fixed flange (1) is a ring structure, and its minimum inner diameter is larger than the outer diameter of the thrust chamber head flange (26); The adapter (2) is an arc-shaped plate with a corresponding central angle of less than or equal to 180°; the inner surface of the adapter (2) is adapted to the shape of the outer and lower sides of the thrust chamber head flange (26); The adapter (2) is located between the thrust chamber head flange (26) and the fixed flange (1). The fixed flange (1) and the sealing flange (4) are detachably and fixedly connected as one unit through the second connector (14).

4. A combined self-tightening sealing structure for a thrust chamber head according to claim 1, characterized in that: The first sealing ring assembly includes two second rubber rings (19), and a second retaining ring (20) is provided between the two second rubber rings (19). The second retaining ring (20) is annular.

5. A combined self-tightening sealing structure for a thrust chamber head according to claim 1, characterized in that: The second sealing ring assembly includes two third rubber rings (21), and a third retaining ring (22) is provided between the two third rubber rings (21). The third retaining ring (22) is annular.

6. A combined self-tightening sealing structure for a thrust chamber head according to claim 1, characterized in that: The outer diameter of the second sealing ring (38) is adapted to the diameter of the throat of the thrust chamber (24).

7. A combined self-tightening sealing structure for a thrust chamber head according to claim 1, characterized in that: The second connecting component includes a fixed base (10) and a pull rod (11); The pressure cap (9) is provided with multiple third connecting studs (36), and the fixing seat (10) is provided with connecting holes (30) at the corresponding positions of the third connecting studs (36). The third connecting studs (36) pass through the connecting holes (30) and are connected to the first nut (15). The fixed base (10) is provided with multiple support corner seats (29), which are evenly and spaced apart in the circumference of the fixed base (10); one end of the pull rod (11) is connected to the support corner seat (29) through a washer (12) and a third nut (23), and the other end is installed on the base of the test device.

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