A conveying multi-pass structure for nine-vehicle parallel launch vehicle

Abstract

The application provides a conveying multi-pass structure for a nine-vehicle parallel launch vehicle, which comprises at least a spherical shell, wherein the shell is a hollow structure; an outer surface of the shell is provided with a conveying collection port, N conveying branch ports and M diaphragm box mounting ports, and the conveying collection port, the conveying branch ports and the diaphragm box mounting ports are respectively communicated with the hollow structure inside the shell; wherein N is an integer greater than or equal to 2, M is an integer greater than or equal to 2; and the diaphragm box mounting ports are closer to the conveying collection port than the conveying branch ports. The application provides a conveying multi-pass structure for a nine-vehicle parallel launch vehicle, and by optimizing the layout of the multi-pass structure and mounting the diaphragm box on the multi-pass structure, the overall structural complexity and weight of the engine system are greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of aerospace launch vehicle technology, and in particular to a multi-pass transport structure for a nine-unit parallel launch vehicle. Background Technology

[0002] In nine-engine parallel liquid-propellant launch vehicles, to suppress post-coupling vibration (POGO), an accumulator is typically installed near the engine inlet on the first-stage propellant tank delivery pipeline. The accumulator uses a diaphragm structure as an elastic element. Currently, for rocket stages with one, two, or four engines, the traditional approach is to install two or three diaphragms at each engine inlet. For nine-engine parallel rocket stages, if the conventional layout is followed, up to eighteen diaphragms would be required.

[0003] In existing technologies, these diaphragm boxes are separately arranged from the delivery multi-channel (usually ten or fourteen channels), meaning the diaphragm boxes are distributed and installed on the inlet pipes of each engine. For a rocket stage with nine engines in parallel, this design would require at least eighteen diaphragm boxes. This results in a large number of diaphragm boxes, making the entire accumulator system structurally complex, space-consuming, costly, and heavy, while also reducing sealing reliability.

[0004] Therefore, for nine-unit parallel launch vehicles, there is an urgent need for an integrated multi-pass structure that can reduce the number of diaphragm boxes. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a multi-pass delivery structure for a nine-engine parallel launch vehicle. By optimizing the layout of the multi-pass structure and installing the diaphragm box on the multi-pass structure, the overall structural complexity and weight of the engine system are significantly reduced.

[0006] This invention provides a multi-channel transport structure for a nine-unit parallel launch vehicle, comprising at least a spherical shell, wherein the shell is a hollow structure; the outer surface of the shell is provided with a transport concentrator port, N transport branch ports, and M diaphragm box mounting ports, wherein the transport concentrator port, the transport branch ports, and the diaphragm box mounting ports are respectively connected to the hollow structure inside the shell; wherein N is an integer greater than or equal to 2, and M is an integer greater than or equal to 2; the diaphragm box mounting ports are closer to the transport concentrator port than the transport branch ports.

[0007] In one embodiment, N equals 9 and M equals 4.

[0008] In one embodiment, the conveying confluence port is located at the top of the housing, one of the nine conveying branch ports is located at the bottom of the housing, and the remaining eight conveying branch ports and four membrane box mounting ports are arranged in three staggered layers on the outer surface of the housing; wherein, the four membrane box mounting ports are located near the conveying confluence port at the top layer, the four conveying branch ports are located at the middle layer, and the remaining four conveying branch ports are located at the bottom layer.

[0009] In one embodiment, the top layer is located in the middle between the top and bottom of the housing, and the middle layer and the bottom layer are both located on the sidewall of the lower half of the housing.

[0010] In one embodiment, the axes of the four membrane box mounting ports are perpendicular to the axis of the conveying and collecting port.

[0011] In any of the above embodiments, the transport multi-channel structure for the nine-unit parallel launch vehicle of this embodiment further includes a detachable first sealing member and a second sealing member; the first sealing member can be selectively installed on at least one of the transport branch ports, and the second sealing member is installed on the transport convergence port for sealing it before product assembly.

[0012] In one embodiment, each of the membrane box mounting ports is provided with a flexible graphite sealing flange groove structure for connecting to the membrane box.

[0013] In one embodiment, the conveying and collection port is provided with a flexible graphite sealing flange tenon structure for connection to the storage tank.

[0014] In one embodiment, each of the conveying branch ports is provided with a flexible graphite sealing flange groove structure for connecting to the conveying pipe.

[0015] In one embodiment, the housing is integrally formed and made of an alloy material.

[0016] The present invention provides a multi-channel transport structure for a nine-unit parallel launch vehicle, which has at least one of the following beneficial effects: I. The multi-channel conveying structure and its application accumulator system (diaphragm box) provided by this invention, for nine parallel rocket stages, significantly reduces the number of required diaphragm boxes (from 18 to 4) while ensuring POGO suppression effect, thereby significantly reducing the structural weight and manufacturing cost of the product and simplifying the system layout and installation and maintenance process.

[0017] Second, the present invention adopts a multi-pass structure integrally formed by low-pressure casting, which avoids the problems of high production difficulty and difficulty in ensuring dimensional accuracy caused by dense welds and large welding deformation in the sheet metal forming and flange welding scheme. It also overcomes the defects of high overall machining cost, difficulty in machining thin-walled positions, and 3D printing being limited by materials and size.

[0018] Third, this invention optimizes the spatial layout of each delivery port and diaphragm box installation port on the multi-channel structure, so that the flow of each delivery branch port is as balanced as possible and the flow resistance is basically the same, effectively avoiding cavitation caused by the internal liquid flow, realizing a reasonable flow channel arrangement in a limited space, and ensuring the stability of liquid supply to each engine inlet.

[0019] IV. The membrane box in this invention is installed on the conveying multi-pass structure, and the POGO (longitudinal coupled vibration) suppression requirements can be met by adjusting the PV value.

[0020] Upon reading the detailed embodiments and examining the accompanying drawings, those skilled in the art will recognize additional features and advantages. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments 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.

[0022] Figure 1 This is a three-dimensional structural diagram of the multi-channel conveying structure according to an embodiment of the present invention.

[0023] Figure 2 This is a front view of the multi-channel transport structure according to an embodiment of the present invention.

[0024] Figure 3 This is a bottom view of the multi-channel transport structure according to an embodiment of the present invention.

[0025] Figure 4 This is a three-dimensional structural diagram of the multi-channel conveyor structure after the membrane box is installed according to an embodiment of the present invention.

[0026] Figure 5 This is an assembly diagram of the multi-channel conveying structure according to an embodiment of the present invention.

[0027] Figure 6 The graph shows the pressure curves of the accumulator cavity and the pump inlet pressure obtained during the power system test using the multi-channel conveying structure of this embodiment of the invention.

[0028] Explanation of reference numerals in the attached figures: 1. Housing; 11. Conveying main port; 12. Conveying branch port; 13. Membrane box installation port; 2. Membrane box; 3. Conveying pipe. Detailed Implementation

[0029] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and to exemplify the principles of the present invention, and are not configured to limit the present invention. In addition, the structural components in the drawings are not necessarily drawn to scale. For example, the dimensions of some structural components or regions in the drawings may be enlarged for other structural components or regions to aid in the understanding of the embodiments of the present invention.

[0030] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the embodiments of the present invention. In the description of the present invention, it should be noted that, unless otherwise stated, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0031] Furthermore, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure or component that includes a list of elements includes not only those elements but also other structural elements that are not expressly listed or inherent to the structure or component. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the article or apparatus that includes the element.

[0032] Spatial relation terms such as "below," "under," "under," "low," "above," "on," and "high" are used for descriptive convenience to explain the positioning of one element relative to a second element, indicating that these terms are intended to cover different orientations of the device, in addition to those different from those shown in the figure. Furthermore, phrases such as "one element on / below another element" can indicate that two elements are in direct contact, or that there are other elements between the two elements. In addition, terms such as "first" and "second" are also used to describe individual elements, areas, parts, etc., and should not be considered limiting. Similar terms are used throughout the description to refer to similar elements.

[0033] It will be apparent to those skilled in the art that the present invention can be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention.

[0034] See Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 To address the problems of numerous accumulator diaphragm boxes, high cost, heavy weight, and low reliability in nine-unit parallel launch vehicles, this invention provides a multi-channel transport structure for nine-unit parallel launch vehicles, integrating the diaphragm box installation port, transport convergence port, and transport branch port into a single multi-channel structure.

[0035] See Figure 1 , Figure 2 , Figure 3 and Figure 4 The multi-channel transport structure for a nine-unit parallel launch vehicle of the present invention includes at least a spherical shell 1, wherein the shell 1 is a hollow structure. The outer surface of the shell 1 is provided with a transport concentrator port 11, N transport branch ports 12, and M diaphragm box mounting ports 13. The transport concentrator port 11, transport branch ports 12, and diaphragm box mounting ports 13 are respectively connected to the hollow structure inside the shell 1. Wherein, N is an integer greater than or equal to 2, and M is an integer greater than or equal to 2. In this embodiment, the diaphragm box mounting port 13 is closer to the transport concentrator port 11 than the transport branch ports 12. The diaphragm box mounting port 13 is used to install a diaphragm box 2 (or accumulator diaphragm box). This diaphragm box 2 absorbs or buffers pressure pulsations in the multi-channel structure, thereby suppressing longitudinally coupled vibrations (i.e., POGO oscillations) during rocket flight.

[0036] The multi-channel delivery structure for the nine-unit parallel launch vehicle in this embodiment integrates a delivery hub 11, a delivery branch port 12, and a diaphragm box mounting port 13 on the shell 1. This integrated design significantly reduces the number of connecting pipes and interfaces between the diaphragms, thereby reducing the risk of propellant leakage and improving the system's sealing reliability and safety. Secondly, this integrated design effectively saves limited internal space and reduces overall weight, which is beneficial for improving launch efficiency. Furthermore, by integrating the diaphragm box 2 onto the multi-channel structure, it facilitates pressure equalization and coordinated operation among the diaphragms, making the POGO suppression effect more stable and consistent, avoiding performance fluctuations caused by individual differences, and thus improving overall suppression effectiveness.

[0037] In the above embodiments, the number of membrane box mounting ports 13 and conveying branch ports 12 is designed according to actual needs.

[0038] See Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 In one embodiment, after simulation and power system test, the multi-pass structure of this embodiment is specifically designed as follows: a delivery hub 11, nine delivery branch ports 12, and four diaphragm box mounting ports 13 are provided on the outer surface of the housing 1. That is, the delivery multi-pass structure of this embodiment is a fourteen-pass structure. Specifically, the housing 1 is a spherical hollow structure with an inner diameter of approximately 700 mm and an average thickness of approximately 10 mm. The housing 1 is made of cast aluminum alloy, with a 480 mm diameter delivery hub 11 at the top, one of the nine delivery branch ports 12 located at the bottom of the housing 1, and the remaining eight delivery branch ports 12 and four diaphragm box mounting ports 13 arranged in three staggered layers on the outer surface of the housing 1. Among them, the four diaphragm box mounting ports 13 are located on the top layer near the delivery hub 11, the four delivery branch ports 12 are located in the middle layer, and the remaining four delivery branch ports 12 are located at the bottom layer. In this embodiment, the delivery hub 11 is connected to the propellant tank, and each of the nine delivery branch ports 12 is connected to one of the nine engines (e.g., Figure 4 (As shown).

[0039] In this embodiment, the four diaphragm box mounting ports 13 have the same diameter (size), and one diaphragm box 2 is installed in each diaphragm box mounting port 13. The four diaphragm boxes 2 are set independently, and each diaphragm box 2 is equipped with an inflation switch. During operation, they are filled with helium at the rated pressure to suppress POGO (longitudinal coupled vibration) of the rocket product.

[0040] In this embodiment, the nine delivery branch ports 12 have the same diameter (size), and each delivery branch port 12 is connected to an engine via a delivery pipe 3. During operation, the propellant enters the casing 1 through the delivery collection port 11, and then is delivered to the nine engines through the nine delivery branch ports 12 and the delivery pipe 3. During this process, the diaphragm 2 installed at the diaphragm mounting port 13 always suppresses longitudinal coupling vibration of the rocket.

[0041] See also Figure 1 , Figure 2 , Figure 3 and Figure 4 In one embodiment, the top layer (the layer containing the membrane box mounting port 13) is located in the middle between the top and bottom of the housing 1. Simulation experiments have determined that placing the membrane box 2 in this position optimizes the POGO suppression effect of the membrane box. Furthermore, the middle and bottom layers where the delivery branch ports 12 are located are both on the sidewalls of the lower half of the housing 1. The four delivery branch ports 12 in the middle layer and the four delivery branch ports 12 in the bottom layer are evenly staggered, and the delivery branch ports 12 in the same layer are symmetrically distributed. The remaining delivery branch port 12 is located at the bottom of the housing 1.

[0042] In this embodiment, the axes of the four membrane box mounting ports 13 are perpendicular to the axis of the delivery and collection port 11, thereby further defining the mounting angle of the membrane box 2. This vertical arrangement ensures that the mounting direction of the membrane box 2 is orthogonal to the main propellant flow direction, which is beneficial for each membrane box 2 to uniformly absorb pressure pulsations from the delivery and collection port 11, while avoiding spatial interference between the membrane boxes 2, achieving optimal POGO suppression effect in a compact layout.

[0043] Furthermore, in order to further increase the connection reliability between the diaphragm box 2 and the diaphragm box mounting port 13, a flexible graphite sealing flange groove structure can be provided at each diaphragm box mounting port 13.

[0044] It should be noted that the installation position and number of membrane boxes can be adjusted according to the actual situation. For example, the installation port of the membrane box can be adjusted from the top layer to the bottom layer, and the number can also be increased or decreased appropriately, as long as the required POGO suppression effect can be achieved.

[0045] In one embodiment, the main delivery port 11 is equipped with a flexible graphite sealing flange tenon structure to facilitate a quick and reliable sealing connection with the storage tank. Each delivery branch port 12 is equipped with a flexible graphite sealing flange groove structure to form a tenon-groove sealing connection with the delivery pipe 3, and to deliver propellant to the corresponding engine through the delivery pipe 3. The flexible graphite sealing material has good high and low temperature resistance, corrosion resistance, and self-lubricating properties, which can effectively improve the sealing reliability of the connection. At the same time, the tenon-groove structure facilitates positioning and assembly, reduces the risk of leakage, and improves product reliability.

[0046] The multi-port (14-port) structure in this embodiment has a reasonable layout, fully considering the circumferential distribution and spatial constraints of the engines in a nine-engine parallel launch vehicle. This structure can flexibly adapt to the nine engines located at different positions on the rocket's bottom, ensuring short and smooth docking paths between the propellant delivery pipelines and each engine inlet. The 14-port structure in this embodiment significantly improves the uniformity of propellant supply to the nine delivery branches, avoiding engine thrust deviations caused by flow rate differences. Simultaneously, the structure, with its symmetrical and compact configuration and the diaphragm installed at the diaphragm mounting port, reduces the coupling effect between propellant pulsation excitation and structural modes, enhancing the dynamic stability of the engine system and thus effectively suppressing POGO vibration. Overall, the 14-port structure in this embodiment balances delivery uniformity and vibration suppression, providing crucial support for the reliable flight of the nine-engine parallel launch vehicle.

[0047] Furthermore, to prevent the introduction of foreign matter during production and transportation, the multi-channel conveying structure of this embodiment also includes a detachable first sealing component and a second sealing component. Before product assembly, the first sealing component can be selectively installed on at least one conveying branch port, and the second sealing component can be installed on the conveying convergence port, thereby achieving complete closure of the multi-channel structure of this embodiment and preventing foreign matter from entering the internal cavity of the multi-channel structure.

[0048] In any of the above embodiments, to further reduce structural weight, the housing may be made of an alloy material. For example, the fourteen-way structure in this embodiment is designed as a cast, one-piece product, and its casting material is cast aluminum alloy.

[0049] The multi-channel delivery structure of this invention breaks through the traditional design of installing the accumulator on the engine inlet branch pipe. While significantly reducing the number of diaphragm boxes used, it still maintains or even surpasses the original technology effect (especially the function of suppressing POGO vibration), and at the same time significantly reduces the system size, weight and cost, and simplifies the system composition.

[0050] The multi-channel conveyor structure integrating four diaphragm boxes of the present invention underwent first-stage power system test and flight test.

[0051] The engine using the multi-pass conveyor structure of the present invention was also tested as a first-stage power system; the test results are available here. Figure 6 The pressure curves of the accumulator cavity and the pump inlet pressure during the test run of the primary power system are shown. During the test run, the pressure curve of the accumulator diaphragm cavity changes with the engine inlet pressure in a consistent manner, indicating that the accumulator's pulsation suppression function is normal.

[0052] Three additional units were selected for further pulse frequency analysis, and the results are shown in Tables 1, 2, 3 and 4.

[0053] Table 1 Spectrum Analysis Data Parameters As can be seen from the spectral analysis data in Table 1, the first-order frequency during the test run was not clearly displayed on the spectral curve due to its low level. The second-order frequency was 23.39 Hz, and the third-order frequency was between 47.53 and 49.48 Hz. Meanwhile, there were also relatively distinct frequencies between 4.10 and 4.57 Hz and between 6.56 and 7.9 Hz. Comparative analysis revealed that these frequencies corresponded to the first and second-order longitudinal vibration frequencies of the rocket body structure.

[0054] Table 2 First-order frequency comparison table Table 3 Comparison of Second-Order Frequencies Table 4. Comparison of Third-Order Frequencies As can be seen from Table 2 (first-order frequency comparison), Table 3 (second-order frequency comparison), and Table 4 (third-order frequency comparison), the second and third-order POGO frequencies obtained from the pump inlet pressure simulation analysis match well with the POGO frequencies obtained from the telemetry analysis.

[0055] POGO vibration test conclusion: The accumulator's pulsation suppression function is normal. The diaphragm pressure is normal. The second and third order POGO frequencies obtained from the pump inlet pressure simulation analysis match well with the POGO frequencies obtained from the telemetry analysis. No POGO vibration was observed in the engine, and the POGO system's suppression function is normal.

[0056] Furthermore, during flight testing, the accumulator pressure slowly increased from 0.502 MPa to 0.575 MPa after ignition, consistent with the trend of pump inlet pressure change, indicating that the POGO vibration suppression function was normal.

[0057] Therefore, the series of rigorous power system tests and actual flight verifications completed by this invention are sufficient to prove that, based on conventional design capabilities, those skilled in the art could not have anticipated that the system could still pass all the above tests and maintain its functionality after a significant reduction in the number of diaphragm cartridges and a change in their installation positions. Thus, the design scheme of this invention, which significantly reduces the number of diaphragm cartridges and integrates them into a multi-pass structure, is not a simple reduction in quantity, but rather represents a significant qualitative change and advancement.

[0058] The applicant did not provide measured data for the prior art solution because it was not implemented by the applicant. However, it is well known in the art that reducing the number of diaphragm boxes linearly reduces redundancy, increases the load on individual diaphragm boxes, and leads to leakage risk and stiffness changes. Furthermore, the closer the diaphragm boxes are to the engine inlet, the better the POGO suppression effect. This invention integrates the diaphragm boxes into the multi-pass structure (approximately 2 meters from the engine inlet), and even under the extreme condition of a significant reduction in the number of diaphragm boxes, it still passed the power system test and was verified as effective in actual flight. These data collectively demonstrate that the technical effect of this invention is unpredictable by prior art combined with conventional design capabilities.

[0059] The conveyor multi-port (14-port) structure in this embodiment is integrally formed using a low-pressure casting process. Compared to traditional casting methods, low-pressure casting allows for smooth molten metal filling, thereby reducing the formation of porosity and inclusions within the casting. Filling and crystallization under pressure ensures adequate feeding of the casting through the gating system and risers, preventing shrinkage cavities and porosity defects. The 14-port structure in this embodiment has a thickness allowance to avoid manufacturing errors and ensure product reliability. Furthermore, the flange structures at each opening of the 14-port structure are machined, the inner cavities of the flange structures are hand-polished to ensure surface roughness, and the outer surfaces utilize the naturally formed surface of the casting process.

[0060] The multi-port (14-port) structure provided in this embodiment adopts a low-pressure casting process. Compared with the machining method, the cost of this casting method is only one-third of the former, and compared with the 3D printing method, the cost is only one-quarter of the former. At the same time, the machining accuracy of each interface is high, reaching ±0.5mm. This multi-port structure is made of cast aluminum alloy. Compared with ordinary aluminum alloy, cast aluminum alloy has superior mechanical properties: tensile strength reaches 350MPa, yield strength reaches 300MPa, elongation after fracture is 9%, while the total weight of the structure is only 50kg. To meet the need for further weight reduction, other materials such as titanium alloy can also be used to cast the shell.

[0061] It should be noted that after the diaphragm box is installed at the diaphragm box mounting port of the multi-pass conveyor structure in this embodiment, simulation analysis was conducted using a 3D model. The simulation results show that this design has an excellent effect on suppressing POGO vibration of the rocket body, and its suppression capability is basically equivalent to that of the prior art scheme that places the diaphragm box at the engine inlet. In addition, through further verification through ground power system testing and flight testing, the multi-pass conveyor structure of this embodiment successfully reduces the number of diaphragm boxes from eighteen required by the prior art to only four, thereby significantly reducing the structural weight and manufacturing cost of the engine system, and significantly improving engineering economy while ensuring suppression performance.

[0062] The above embodiments can be combined with each other and have corresponding technical effects.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-pass transport structure for a nine-unit parallel launch vehicle, characterized in that, It includes at least a spherical shell, which is a hollow structure; the outer surface of the shell is provided with a conveying convergence port, N conveying branch ports and M membrane box mounting ports, and the conveying convergence port, the conveying branch ports and the membrane box mounting ports are respectively connected to the hollow structure inside the shell; Wherein, N equals 9 and M equals 4; The conveying convergence port is located at the top of the housing, one of the nine conveying branch ports is located at the bottom of the housing, and the remaining eight conveying branch ports and four membrane box installation ports are arranged in three staggered layers on the outer surface of the housing. Among them, four of the membrane box installation ports are located near the conveying convergence port on the top layer, four of the conveying branch ports are located on the middle layer, and the remaining four of the conveying branch ports are located on the bottom layer. The axes of the four membrane box mounting ports are perpendicular to the axis of the conveying and collecting port.

2. The multi-pass transport structure for a nine-unit parallel launch vehicle according to claim 1, characterized in that, The top layer is located in the middle between the top and bottom of the shell, and the middle layer and the bottom layer are both located on the side wall of the lower half of the shell.

3. The multi-pass transport structure for a nine-unit parallel launch vehicle according to any one of claims 1 to 2, characterized in that, It also includes a detachable first sealing element and a second sealing element; the first sealing element can be selectively installed on at least one of the conveying branch ports, and the second sealing element is installed on the conveying convergence port for sealing it before product assembly.

4. The multi-pass transport structure for a nine-unit parallel launch vehicle according to claim 3, characterized in that, Each of the membrane box mounting ports is provided with a flexible graphite sealing flange groove structure for connecting to the membrane box.

5. The multi-pass transport structure for a nine-unit parallel launch vehicle according to claim 3, characterized in that, The conveying and collection port is equipped with a flexible graphite sealing flange tenon structure for connection with the storage tank.

6. The multi-pass transport structure for a nine-unit parallel launch vehicle according to claim 3, characterized in that, Each of the conveying branch ports is equipped with a flexible graphite sealing flange groove structure for connecting to the conveying pipe.

7. The multi-pass transport structure for a nine-unit parallel launch vehicle according to claim 1, characterized in that, The shell is integrally molded and made of alloy material.

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