Surface tension tank with convex septum

Abstract

The present invention provides a surface tension tank with an upward convex septum, comprising a tank pressure shell, the tank pressure shell comprising an upper shell, a column section and a lower shell connected in sequence, an upward convex septum provided inside the tank pressure shell, the septum dividing the tank into an upper cabin and a lower cabin, an air nozzle provided at the top of the upper shell, a liquid nozzle provided at the bottom of the lower shell, a vent screen provided at the top of the septum, and a septum screen provided on the septum; during the trajectory change ignition, pressurized gas enters the upper cabin through the air nozzle, and the propellant in the upper cabin enters the lower cabin through the septum screen, a liquid film is provided in both the septum screen and the vent screen and can prevent the pressurized gas from entering the lower cabin before the propellant is exhausted, and the gas in the lower cabin is discharged to the upper cabin through the vent screen. The present invention requires a smaller septum size to separate the lower cabin of the same volume, requires less structural mass, and the mechanical environment adaptability of the upward convex septum is qualitatively improved, making it more adaptable to the vibration and impact during the rocket launch phase.

Description

Technical Field

[0001] The present invention relates to the technical field of spacecraft power systems, and in particular to a surface tension tank with an upwardly convex diaphragm, which is suitable for propellant management of satellite or deep space probe propulsion systems. Background Art

[0002] With the development of aerospace technology, people's requirements for spacecraft are becoming increasingly higher. Existing spacecraft power systems such as satellites and deep space probes use a large number of surface tension tanks to store and supply airless propellant to the engines. These surface tension tanks are key components that determine spacecraft performance and safety. Lightweight, reliable, highly efficient, and capable of suppressing liquid sloshing are of great significance for reducing structural mass, improving spacecraft performance, ensuring launch safety, and ensuring long-term on-orbit life.

[0003] With the increasing demand for longer life, higher performance, and higher reliability in spacecraft, the volume of surface tension tanks used has continued to increase, and structural and discharge efficiency have also continued to improve. The fully managed propellant management system is no longer suitable for mission requirements. Large-volume surface tension tanks used in spacecraft propulsion systems are also gradually being partitioned to improve their performance. Currently, large-volume surface tension tanks generally use concave partitions to divide the tank into compartments, which has significant limitations in terms of structural efficiency and lower compartment volume. Furthermore, the concave partitions provide poor fluid management capabilities in the upper compartment, failing to suppress liquid sloshing during the final discharge phase of the upper compartment.

[0004] The existing publication number CN102991729B discloses a lightweight mesh surface tension tank, which uses a concave "middle bottom partition" to separate the upper and lower compartments, and adds an anti-sloshing cone in the upper compartment to suppress liquid sloshing and a special exhaust port structure.

[0005] The existing publication number CN114922744A discloses a load-bearing low-temperature common bottom tank for spacecraft, which uses a convex "common bottom" to separate the upper and lower compartments. However, the "common bottom" is a shell without openings or metal screens. After the division, the upper and lower compartments are completely independent and are used to load oxidizers and fuel respectively, which is completely different from the function of the partition described in this patent.

[0006] The existing technology has a low efficiency in the partitioned compartment structure, and the same lower compartment volume requires a larger structural size and mass, which is not suitable for the requirements of a high-performance, large-volume lower compartment. Moreover, after the compartments are divided, the microgravity liquid retention capacity in the upper compartment is insufficient, and an anti-sway device and a cantilever exhaust port are required. This leads to a complex structure of the propellant management device, reduced adaptability and reliability to the mechanical environment, and limited performance of the surface tension tank. There is room for improvement. Summary of the Invention

[0007] In view of the defects in the prior art, the object of the present invention is to provide a surface tension storage tank with an upwardly convex middle septum.

[0008] The surface tension tank with an upwardly convex septum provided by the present invention comprises a tank pressure shell, the tank pressure shell comprising an upper shell, a column segment, and a lower shell connected in sequence, an upwardly convex septum being provided inside the tank pressure shell, the septum dividing the tank into an upper compartment and a lower compartment, the upper compartment being used to accommodate propellant;

[0009] The top of the upper shell is provided with an air nozzle, the bottom of the lower shell is provided with a liquid nozzle, the top of the middle partition is provided with an air vent screen, the middle partition is provided with a middle partition screen, and the interior of the lower cabin is provided with a mesh channel;

[0010] The surface tension tank with the convex middle partition is used for a spacecraft. When the spacecraft is in the period of orbit change ignition, the pressurized gas enters the upper cabin through the gas nozzle, and the propellant inside the upper cabin enters the lower cabin through the middle partition screen. Liquid films are provided in the middle partition screen and the vent screen, and can prevent the pressurized gas from entering the lower cabin before the propellant is exhausted. The mesh channel can perform gas-liquid separation, and the gas inside the lower cabin is discharged to the upper cabin through the vent screen.

[0011] Preferably, the septum is arranged at the upper end of the lower shell and protrudes toward the column section to form a spherical or ellipsoidal thin shell structure.

[0012] Preferably, a wedge-shaped cavity is formed between the middle partition and the column section of the spherical or ellipsoidal thin shell structure, and during the orbit change ignition, the unused propellant in the upper cabin is retained in the wedge-shaped cavity.

[0013] Preferably, the septum is made of metal.

[0014] Preferably, a pair of connecting seats and a plurality of mesh channels are provided in the lower cabin, and the pair of connecting seats are respectively provided at the upper and lower ends of the lower cabin;

[0015] Both ends of the channel with net are respectively connected to the connecting seats arranged in pairs, and a plurality of channels with net are arranged along the circumference of the lower cabin.

[0016] Preferably, the mesh channel is a semi-ring structure with a U-shaped cross-section, and both ends of the semi-ring structure are respectively connected to the connecting seats arranged in pairs;

[0017] A metal screen is welded on the U-shaped opening of the mesh channel to form a liquid delivery channel.

[0018] Preferably, the bubble bursting points of the metal screen, the middle partition screen and the vent screen are not less than 3700Pa.

[0019] Preferably, the width of the U-shaped cross section is 35 mm to 45 mm, and the depth is 6 mm to 8 mm.

[0020] Preferably, the belt mesh channel is arranged between adjacent intermediate screen meshes.

[0021] Preferably, there are a plurality of the middle septum screens, and the plurality of middle septum screens are evenly arranged along the circumferential direction near the lower end of the middle septum.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention has a simple structure and is easy to operate. It adopts a convex septum structure to efficiently separate the tank. The septum required to separate the lower cabin of the same volume is smaller in size and the required structural mass is smaller. In addition, the first-order vibration frequency of the spherical or ellipsoidal septum is about 75Hz, which is shallower than the first-order frequency of the cone-plate septum and the butterfly septum of about 35Hz. The adaptability to the mechanical environment is qualitatively improved, and it can better adapt to the vibration and impact during the rocket launch phase.

[0024] 2. The present invention adopts the technical means of forming a wedge-shaped cavity with a septum and a column segment for retaining propellant in a microgravity environment. It also has the functions of anti-sloshing and compartmentalization, ensuring that the liquid can be accumulated in the wedge-shaped cavity under the action of surface tension in a microgravity environment. The structure is simple, suppresses liquid sloshing and has a significant retention effect, so that the septum screen at the bottom of the septum is always immersed in the propellant in the wedge-shaped cavity, which more stably ensures the efficient exhaustion of the propellant in the upper cabin.

[0025] 3. The present invention adopts the technical means of setting a vent screen on the top of the convex septum, replacing the solution of the prior art of installing an additional cantilever vent in the upper cabin of the concave septum. It has better structural stability, lighter weight and a smoother exhaust path. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0027] Figure 1 It is a structural schematic diagram of the present invention;

[0028] Figure 2 Schematic diagram of the distribution of propellant discharged from the upper cabin in a microgravity environment in the present invention;

[0029] The figure shows:

[0030] Air nozzle 1 Air vent screen 6

[0031] Upper shell 2 septum 7

[0032] Column section 3, middle screen 8

[0033] Lower shell 4 with net channel 9

[0034] Liquid nozzle 5 connecting seat 10 DETAILED DESCRIPTION

[0035] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0036] The present invention discloses a surface tension tank with an upward convex septum. The convex septum requires a smaller size to separate a lower cabin of the same volume, and the required structural mass is smaller. The first-order vibration frequency of the spherical or ellipsoidal septum is about 75Hz, which is lower than the first-order frequency of the shallow cone-plate septum and the butterfly septum of about 35Hz. The adaptability to the mechanical environment is qualitatively improved, and the tank can better adapt to the vibration and impact during the rocket launch phase.

[0037] According to the surface tension storage tank provided by the present invention, the convex septum is as follows: Figure 1-2As shown, the tank comprises a pressure-bearing shell, comprising an upper shell 2, a column section 3, and a lower shell 4 connected in sequence. An upwardly convex septum 7 is provided within the shell, dividing the tank into an upper compartment and a lower compartment. The upper compartment is used to hold propellant. The septum 7 is disposed at the upper end of the lower shell 4 and convex toward the column section 3, forming a spherical or ellipsoidal thin shell structure. The septum 7 and the lower shell 4 form a spherical lower compartment. Preferably, the septum 7 is made of metal. An air nozzle 1 is provided at the top of the upper shell 2, and a liquid nozzle 5 is provided at the bottom of the lower shell 4. A vent screen 6 is provided at the top of the septum 7, and a septum screen 8 is provided on the septum 7 to ensure fluid communication. A mesh channel 9 is provided within the lower compartment. Multiple septum screens 8 are provided, evenly spaced circumferentially near the lower end of the septum 7. Preferably, the septum 7 has no less than 4 holes on the upper side of the largest diameter, and a septum screen 8 is welded at the openings. The septum screen 8 is placed as much as possible at the wedge-shaped top corner of the wedge-shaped liquid storage chamber formed by the septum 7 and the column section 3. A hole with a diameter of no more than 30 mm is opened at the top of the septum 7, and a vent screen 6 is welded at the opening. The liquid or gas in the upper and lower compartments is connected through the screen, and the gas and liquid fluids in the two compartments can still flow through the pores of the screen, forming a separation without interruption effect, and ensuring that the pressurized gas will not enter the lower compartment before the liquid in the upper compartment is exhausted during on-orbit discharge. The vent screen 6 ensures that the propellant in the lower compartment can be completely filled during ground refueling, and there will be no air holding phenomenon. During on-orbit discharge, the liquid film on the vent screen 6 can effectively prevent the pressurized gas in the upper compartment from entering the lower compartment. Compared with the concave septum, it has the advantages of simple structure, good production and manufacturing process, and strong adaptability to mechanical environment.

[0038] The lower compartment is equipped with a pair of connecting seats 10 and multiple mesh channels 9. The paired connecting seats 10 are located at the upper and lower ends of the lower compartment. The mesh channels 9 are connected to the paired connecting seats 10 at both ends, and the multiple mesh channels 9 are arranged along the circumference of the lower compartment. The mesh channels 9 are semi-ring structures with a U-shaped cross-section, each end of which is connected to the paired connecting seats 10. A metal screen is welded to the U-shaped opening of the mesh channels 9, forming a liquid delivery channel. The mesh channels 9, the septum 7, the septum screen 8, and the vent screen 6 form a propellant management system. The mesh channels 9 separate gas and liquid, ensuring that the tank discharge is free of propellant. Preferably, at least four mesh channels 9 are evenly distributed circumferentially and welded to the upper and lower connecting seats 10. The two connecting seats 10 are further welded to the septum 7 and the lower shell 4, respectively, forming a gas-liquid separation device within the lower compartment, ensuring that pressurized gas does not escape the tank before the lower compartment liquid is depleted. The circumferential arrangement of the mesh channel 9 ensures that the mesh channel 9 is always submerged in the propellant during the attitude and orbit control phases of the spacecraft, thereby ensuring the supply of air-free propellant. Preferably, the metal screen, the intermediate screen 8, and the vent screen 6 all have a bubble burst point of no less than 3700 Pa.

[0039] A wedge-shaped cavity is formed between the spherical or ellipsoidal thin shell structure's septum 7 and the column section 3. During the orbit change ignition, the unused propellant in the upper cabin is retained in the wedge-shaped cavity. The septum 7 is an upward convex structure that forms a wedge-shaped angle with the tank column section 3. The wedge-shaped angle forms a liquid storage wedge cavity around the perimeter. The liquid storage cavity structure is a conical structure that has the function of exhausting and absorbing liquid in a microgravity environment. In the microgravity environment of space, the wedge-shaped cavity formed by the upward convex septum 7 and the column section 3 has a stronger liquid adsorption capacity than the column section 3 and the upper shell 2, ensuring that the liquid in the upper cabin can cover the septum screen 8 welded on the convex septum 7, thereby ensuring that the liquid propellant in the upper cabin is consumed first.

[0040] The surface tension tank with the convex middle partition is used for spacecraft. When the spacecraft is in the period of orbit change ignition, the pressurized gas enters the upper cabin through the gas nozzle 1, and the propellant inside the upper cabin enters the lower cabin through the middle partition screen 8. Liquid films are provided in the middle partition screen 8 and the vent screen 6, and can prevent the pressurized gas from entering the lower cabin before the propellant is exhausted. The mesh channel 9 can perform gas-liquid separation, and the gas inside the lower cabin is discharged to the upper cabin through the vent screen 6.

[0041] The assembly process of the present invention is as follows: Workers first weld the multiple mesh channels 9 and the connecting seat 10 together using argon arc welding. Simultaneously, the vent screen 6, the septum 7, and the septum screen 8 are welded together using vacuum electron beam welding to form the septum assembly. These two assemblies are then assembled and vacuum electron beam welded together with the lower shell 4 and the liquid nozzle 5 to form the tank lower compartment. Simultaneously, the gas nozzle 1, the upper shell 2, and the column section 3 are welded together using vacuum electron beam welding to form a single assembly. The assembly is then welded together with the lower shell 4 on the tank lower compartment to form the entire tank.

[0042] Example 1

[0043] The present embodiment discloses a surface tension storage tank with an upward convex septum, comprising an air nozzle 1, an upper shell 2, a column section 3, a lower shell 4, a liquid nozzle 5, an air vent screen 6, a septum 7, a septum screen 8, a mesh channel 9 and a connecting seat 10. The multiple mesh channels 9 and the connecting seat 10 are first welded into an assembly by argon arc welding; the air vent screen 6, the septum 7 and the septum screen 8 are welded into a septum assembly by vacuum electron beam welding, and then the two assemblies are assembled and vacuum electron beam welded together with the lower shell 4 and the liquid nozzle 5 to form a lower cabin. The air nozzle 1, the upper shell 2 and the column section 3 are welded into an assembly by vacuum electron beam welding and then welded together with the lower shell 4 to form an integral storage tank.

[0044] The thickness of the partition wall of the storage tank does not exceed 0.85mm, and the minimum distance between the partition screen and the weld between the partition and the shell does not exceed 35mm. The volume of the lower compartment of the storage tank can be adjusted by adjusting the diameter of the partition 7 and the welding position of the partition 7 to the storage tank shell. The upper convex partition 7 can be welded to the lower shell 4 or the column section 3 using high-energy beam welding with concentrated energy such as vacuum electron beam or laser welding. The number of partition edges welded on the partition 7 of the storage tank is 8. The opening area of ​​a single partition edge is not less than 950mm2. The number of the mesh channels 9 is 4, and the width of their U-shaped cross-section is 35mm to 45mm, and the depth is 6mm to 8mm. The mesh channels 9 are arranged in the middle position of adjacent partition screens 8 to ensure that the flow rate of liquid is relatively uniform everywhere when flowing from the partition screen 8 to the mesh channels 9.

[0045] The position of the weld between the middle septum 7 and the lower shell 4 is affected by the volume of the lower chamber and the size of the middle septum 7. If the weld between the middle septum 7 and the lower shell 4 is close to the weld between the column section 3 and the lower shell 4, vacuum electron beam welding is used, and it is necessary to ensure that the two welds are at least 10 mm apart.

[0046] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0047] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A surface tension storage tank with an upward convex septum, characterized in that: The invention comprises a tank pressure shell, wherein the tank pressure shell comprises an upper shell (2), a column section (3) and a lower shell (4) connected in sequence, and an upwardly convex partition (7) is provided inside the tank pressure shell, wherein the partition (7) divides the tank into an upper cabin and a lower cabin, and the upper cabin is used to accommodate propellant; The top of the upper shell (2) is provided with an air nozzle (1), the bottom of the lower shell (4) is provided with a liquid nozzle (5), the top of the middle partition (7) is provided with an air release screen (6), the middle partition screen (8) is provided on the middle partition (7), and a mesh channel (9) is provided inside the lower cabin; The surface tension tank with an upward convex middle partition is used for a spacecraft. When the spacecraft is in the period of orbit change ignition, pressurized gas enters the upper cabin through the gas nozzle (1), and the propellant inside the upper cabin enters the lower cabin through the middle partition screen (8). Liquid films are provided in the middle partition screen (8) and the air vent screen (6) and can prevent the pressurized gas from entering the lower cabin before the propellant is exhausted. The mesh channel (9) can perform gas-liquid separation, and the gas inside the lower cabin is discharged to the upper cabin through the air vent screen (6).

2. The surface tension tank with an upward convex septum according to claim 1, characterized in that: The septum (7) is arranged at the upper end of the lower shell (4) and protrudes toward the column section (3), forming a spherical or ellipsoidal thin shell structure.

3. The surface tension tank with an upward convex septum according to claim 2, characterized in that: A wedge-shaped cavity is formed between the spherical or ellipsoidal thin shell structure's septum (7) and the column section (3); during the orbit change ignition period, unused propellant in the upper cabin is stored in the wedge-shaped cavity.

4. The surface tension tank with an upward convex septum according to claim 1, characterized in that: The middle septum (7) is made of metal.

5. The surface tension tank with an upward convex septum according to claim 1, characterized in that: The lower cabin is provided with a pair of connecting seats (10) and a plurality of mesh channels (9), and the pair of connecting seats (10) are respectively provided at the upper and lower ends of the lower cabin; The two ends of the mesh channel (9) are respectively connected to the connecting seats (10) arranged in pairs, and a plurality of mesh channels (9) are arranged along the circumference of the lower cabin.

6. The surface tension tank with an upward convex septum according to claim 5, characterized in that: The mesh channel (9) is a semi-ring structure with a U-shaped cross-section, and both ends of the semi-ring structure are respectively connected to a pair of connecting seats (10); A metal screen is welded on the U-shaped opening of the mesh channel (9) to form a liquid delivery channel.

7. The surface tension tank with an upward convex septum according to claim 6, characterized in that: The bubble bursting points of the metal screen, the intermediate screen (8) and the vent screen (6) are all not less than 3700 Pa.

8. The surface tension tank with an upward convex septum according to claim 6, characterized in that: The width of the U-shaped cross section is 35 mm to 45 mm, and the depth is 6 mm to 8 mm.

9. The surface tension tank with an upward convex septum according to claim 5, characterized in that: The mesh channel (9) is arranged between adjacent intermediate screen meshes (8).

10. The surface tension tank with an upward convex septum according to claim 1, characterized in that: There are a plurality of middle septum screens (8), and the plurality of middle septum screens (8) are evenly arranged along the circumferential direction near the lower end of the middle septum (7).

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