A common base tank propellant management device

Abstract

The application provides a common bottom tank propellant management device, and belongs to the field of spacecraft propellant storage and delivery. The device solves the problem of unstable propellant discharge of a small common bottom tank of a satellite. The device comprises a common bottom tank, which is internally separated into a first cabin and a second cabin by a cabin separation part. The cabin separation part is in a circular arc protruding shape in the first cabin to form an edge liquid collection area in the first cabin. A first cabin PMD is connected to the same end of all first liquid delivery parts and second liquid delivery parts. A second cabin PMD is arranged in the second cabin and is provided with a plurality of third liquid delivery parts which are uniformly arranged in a circle and are co-shaped with the inner wall of the second cabin. The first liquid delivery part, the second liquid delivery part and the third liquid delivery part are kept at a preset distance from the corresponding cabin wall to form a capillary flow space. A capillary porous plate is arranged in each window to connect the inside of the corresponding delivery part with the capillary flow space. The device is mainly used for common bottom tank propellant management.

Description

Technical Field

[0001] This invention belongs to the field of spacecraft propellant storage and transportation, and in particular relates to a common-bottom tank propellant management device. Background Technology

[0002] With the development of small satellites, mobile satellites, and long-life on-orbit spacecraft, propulsion systems are facing higher demands for tank compactness, propellant utilization, fluid supply reliability, and on-orbit attitude adaptability. Common-bottom tanks can store two types of propellants separately in the upper and lower compartments of the same tank shell. Compared to two independent tanks, they offer advantages such as compact structure, high space utilization, high piping integration, and lower mass, making them suitable for lightweight and integrated design of small satellite propulsion systems.

[0003] However, during long-term operation in orbit, spacecraft exist in microgravity or low gravity environments. The position of the propellant within the tank is no longer primarily determined by gravity, but rather by surface tension, wall wettability, internal geometry, maneuvering acceleration, and the effects of pressurized gases. Without an effective propellant management system, the propellant may accumulate on the tank walls, in localized areas within the compartment, or in locations far from the nozzle, leading to problems such as gas accumulation near the nozzle, propellant gas expulsion, propellant supply interruption, or increased residual propellant.

[0004] The Propellant Management Device (PMD) is a key component in surface tension tanks. Its basic function is to use capillary forces to position, collect, store, and transport propellant under microgravity conditions. This allows the propellant to preferentially enter the supply channel connected to the liquid inlet, while the bubble burst point pressure generated by the capillary porous elements prevents pressurized gas from entering the channel, thus achieving gas-free propellant supply. Existing PMD structures typically include blades, channels, screens, accumulators, and collectors. For small common-bottom tanks, due to the presence of upper and lower ellipsoidal hemispheres, cylindrical sections, and intermediate bottom compartments, the internal space is limited and the boundary curvature changes significantly. Traditional single-blade or single-screen PMDs cannot simultaneously meet the requirements of structural adaptability, connectivity, anti-gas-entrainment capability, and the all-welded manufacturing requirements of metal tanks.

[0005] Therefore, it is necessary to propose a propellant management device for small common-bottom tanks for satellites, which can be matched with the ellipsoids of the upper and lower compartments and the intermediate bottom boundary, and realize the collection, storage and stable discharge of propellant through capillary management components, thereby improving the propellant management capability of the common-bottom tank under microgravity and attitude change conditions. Summary of the Invention

[0006] In view of this, the present invention aims to provide a common-bottom tank propellant management device to solve the problem of unstable propellant discharge from small common-bottom tanks in satellites.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a common-bottom tank propellant management device, comprising:

[0008] The common-bottom tank is internally divided into a first compartment and a second compartment by a compartmentalized section, wherein the compartmentalized section protrudes in an arc shape in the first compartment to form an edge liquid collection area in the first compartment;

[0009] The first compartment PMD is located inside the first compartment and has several circumferentially distributed first liquid delivery parts that conform to the side wall of the first compartment and second liquid delivery parts located in the edge liquid collection area that conform to the inner wall of the first compartment. All the first liquid delivery parts are connected to the second liquid delivery parts at the same end.

[0010] The second compartment PMD is located inside the second compartment and has several third liquid transport parts that are evenly arranged in a circle and conform to the inner wall of the second compartment.

[0011] The first liquid conveying unit, the second liquid conveying unit, and the third liquid conveying unit all maintain a preset distance from the corresponding chamber wall to form a capillary flow space. Several windows are evenly arranged on the end face near the capillary flow space. Each window is provided with a capillary porous plate that connects the interior of the corresponding conveying unit with the capillary flow space. All conveying units are used to convey liquid to the liquid port of the corresponding chamber.

[0012] Furthermore, the common-bottom tank includes a first hemisphere, a cylindrical section, and a second hemisphere connected in sequence. The compartment section is located inside the cylindrical section. The first hemisphere has a first air inlet located away from the compartment section and a first liquid inlet located near the compartment section. The second hemisphere has a second air inlet located near the compartment section and a second liquid inlet located away from it. The first liquid inlet corresponds to the position of the edge liquid collection area.

[0013] Furthermore, both the first and second hemispheres are ellipsoidal.

[0014] Furthermore, the third liquid delivery unit is elliptical in shape.

[0015] Furthermore, the first PMD compartment is ellipsoidal in shape.

[0016] Furthermore, the second PMD compartment is ellipsoidal in shape.

[0017] Furthermore, the first liquid delivery unit, the second liquid delivery unit, and the third liquid delivery unit are all hollow structures, and are connected to the capillary flow space through capillary porous plates and windows.

[0018] Furthermore, the first liquid delivery unit, the second liquid delivery unit, and the third liquid delivery unit all include a pressing part, a capillary porous plate, a support part, and a U-shaped channel. The opening side of the U-shaped channel is connected to the support part, and the support part cooperates with the pressing part to press the capillary porous plate. The window is formed on the pressing part.

[0019] Furthermore, the clamping part is provided with ribs to reinforce the window.

[0020] Furthermore, the capillary porous plate is arranged with a plurality of openings in an array.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. This management device divides the common-bottom tank into two chambers, a first chamber and a second chamber, through a compartmentalization section. Within the first chamber, the compartmentalization section protrudes to form an edge liquid collection area. This allows the liquid to collect at the edge liquid collection area under the combined action of the first liquid delivery section, microgravity, and the compartmentalization section, and be captured by the capillary flow space formed between the second liquid delivery section and the inner wall, thereby improving the liquid capture capacity in the first chamber. The interior of the second chamber is a normal ellipsoid, and the liquid is captured by a third liquid delivery section that is conformal to the inner wall of the second chamber and is located within the second chamber's PMD. This results in a space-saving structure that ensures the capture capacity of both the first and second chambers.

[0023] 2. This management device adopts a plate-hole combined capillary channel structure, which combines the gas-liquid isolation capability of the capillary porous plate with the liquid transport capability of the liquid transport section with a hollow channel structure, so as to realize the collection, storage and gas-free discharge of propellant under microgravity, low gravity or normal gravity conditions.

[0024] 3. The capillary porous plate of this management device is located on the side close to the inner wall of the tank. It can make full use of the characteristics of propellant wetting and spreading along the tank wall under microgravity conditions, so that the liquid preferentially enters the PMD channel through the capillary porous plate, thereby improving the propellant capture capacity and the reliability of liquid supply.

[0025] 4. The clamping and supporting parts of this management device clamp the capillary porous plate through the window and rib structure, which enhances the structural support capacity of the capillary porous plate while ensuring a large effective liquid inlet area. This can reduce the deformation of the metal sheet under pressure difference and vibration conditions and maintain stable bubble burst point performance.

[0026] 5. The first compartment PMD of this management device adopts a semi-ellipsoidal structure formed by the combination of arc-shaped segments and circular segments. The second compartment PMD adopts a combination of intersecting elliptical ring channels, which are adapted to the upper and lower ellipsoidal hemispheres and the middle bottom compartment space of the common bottom tank, respectively. This can improve the utilization rate of the limited internal space and is suitable for the integrated layout of small common bottom tanks.

[0027] 6. The PMDs in the first and second compartments of this management device are interconnected and directly connected to their respective liquid inlets, providing multi-path liquid intake capability under different attitudes or propellant distribution conditions, reducing the risk of liquid supply interruption caused by local liquid detachment.

[0028] 7. This management device is suitable for all-welded metal common-bottom tank structures. The PMD components can be connected by metal processing, welding or brazing, and have high structural reliability, propellant compatibility and engineering application value. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 This is a schematic diagram of the overall layout of a common-bottom tank propellant management device according to the present invention;

[0031] Figure 2 This is a schematic diagram of the spatial structure arrangement of the first PMD and the second PMD according to the present invention.

[0032] Figure 3 This is a schematic diagram of the structure of the first PMD compartment described in this invention;

[0033] Figure 4 This is a schematic diagram of the structure of the second PMD compartment described in this invention;

[0034] Figure 5 This is a cross-sectional schematic diagram of the liquid conveying section of the present invention;

[0035] Figure 6 This is a schematic diagram of the structure of the capillary porous plate described in this invention.

[0036] 1. Common-bottom tank; 2. First hemisphere; 3. Cylindrical section; 4. Second hemisphere; 5. Compartment section; 6. First compartment PMD; 7. Second compartment PMD; 8. First compartment air inlet; 9. First compartment liquid inlet; 10. Second compartment air inlet; 11. Second compartment liquid inlet; 12. First liquid conveying section; 13. Second compartment first elliptical annular channel; 14. Second compartment second compartment second elliptical annular channel; 15. Window; 16. Rib; 17. Pressing part; 18. Capillary porous plate; 19. Support part; 20. U-shaped channel; 21. Opening; 22. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0038] It should be noted that the descriptions of "left," "right," "left side," "right side," "upper part," "lower part," "top," and "bottom" in this invention are defined based on the orientation or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the described structure must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] In the description of this invention, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] Refer to the accompanying drawings to illustrate this embodiment, such as... Figure 1 As shown, this embodiment provides a common-bottom tank propellant management device, specifically a small common-bottom tank propellant management device applied to a satellite. The common-bottom tank 1 is an all-welded metal structure, including a cylindrical section 3, a first hemisphere 2, a second hemisphere 4, and a compartment section 5. The cylindrical section 3 is located in the middle of the common-bottom tank 1, the first hemisphere 2 is connected to the upper end of the cylindrical section, the second hemisphere 4 is connected to the lower end of the cylindrical section 3, and the compartment section 5 is located in the middle of the tank and connected to the cylindrical section, thereby dividing the interior of the tank into a first compartment and a second compartment. Both the first hemisphere 2 and the second hemisphere 4 are semi-ellipsoidal.

[0041] The first and second compartments are arranged vertically, with the first compartment located above the second compartment. They are used to store different propellants, such as oxidizer and fuel. The upper compartment is equipped with a first compartment gas inlet 8 and a first compartment liquid inlet 9, while the second compartment is equipped with a second compartment gas inlet 10 and a second compartment liquid inlet 11. The first compartment gas inlet 8 and the second compartment gas inlet 10 are respectively connected to the gas phase space of the corresponding compartment section, used to introduce pressurized gas or to achieve gas management during propellant discharge; the first compartment liquid inlet 9 and the second compartment liquid inlet 11 are respectively connected to the internal channels of the corresponding PMD, used to output propellant liquid to the engine, thruster, or downstream pipelines.

[0042] Since both the first and second compartments of the common-bottom tank have ellipsoidal hemispherical boundaries and are constrained by the space of the compartment section 5, it would be difficult to fully cover the possible liquid distribution areas within the compartments using traditional straight blades or a single planar screen structure. This management device installs a first-compartment PMD6 within the first compartment and a second-compartment PMD within the second compartment. Furthermore, the PMDs in both the first and second compartments are designed with conformal surfaces adapted to the shape of the corresponding compartment's inner wall.

[0043] like Figure 5 As shown, both the first compartment PMD6 and the second compartment PMD7 are composed of multiple plate-hole combined hollow channel units. The plate-hole combined hollow channel unit includes a pressing part 18, a capillary porous plate 19, a support part 20, and a U-shaped channel 21. The pressing part 18 is specifically a pressure plate, and the support part 20 is specifically a support plate.

[0044] The U-shaped channel 21 has a hollow rectangular or near-rectangular cross-section structure, forming a propellant delivery channel inside. The side of the U-shaped channel 21 closest to the inner wall of the tank is designated as an open side, covered by a capillary porous plate 19. A clamping part 18 is provided on the outer side of the capillary porous plate 19, and a supporting part 20 is provided on the inner side. The clamping part 18 and the supporting part 20 clamp and fix the capillary porous plate 19, so that the capillary porous plate 19 and the U-shaped channel 21 together form a capillary channel structure that allows liquid to enter from the outside and be delivered from the inside. The cross-section of the U-shaped channel is not limited to rectangle; it can also be trapezoidal, rounded rectangular, or other hollow cross-section forms.

[0045] Both the clamping part 18 and the supporting part 20 are composed of ribs 17 and rectangular windows 16. Multiple rectangular windows 16 are arranged at intervals along the length of the channel. Propellant liquid can contact the capillary porous plate 19 through the rectangular windows 16 and, under capillary force, pass through the capillary porous plate 19 into the interior of the U-shaped channel 21. Ribs 17 are located between adjacent rectangular windows 16 to provide zoned support for the capillary porous plate 19, preventing local bulging or depression of the capillary porous plate 19 due to pressure differential. The shape of the window 16 is not limited to rectangles; it can also be a rounded rectangle, an oblong hole, a trapezoidal hole, or other opening forms that are easy to process and meet support requirements.

[0046] The capillary porous plate 19 is made of a thin metal sheet, preferably with a thickness of 0.1 mm. The capillary porous plate 19 has openings 22, specifically a micropore array, preferably with a pore diameter of 15 μm and a pore spacing of 30 μm. The micropore array can be fabricated using laser processing. The micropores can be circular or non-circular with an equivalent pore diameter that meets the bubble burst point requirement. The micropores can be arranged in a square, triangular, or hexagonal array.

[0047] When the propellant liquid contacts the outer side of the capillary porous plate 19, the liquid enters the micropores and forms a meniscus under the action of wetting and micro-capillary pressure, and then enters the internal channel of the PMD. Due to the small size of the micropores, a high bubble burst point pressure can be formed at the gas-liquid interface at the micropores. Under the action of pressurized gas, as long as the gas-pressure difference is less than the bubble burst point pressure of the capillary porous plate, the gas will be prevented from entering the internal channel of the PMD, thus ensuring that the liquid outlet output is gas-free liquid.

[0048] like Figure 2 and Figure 3 As shown, the first compartment PMD6 is located within the first compartment of the common-bottom tank 1, maintaining a certain gap with the inner wall of the first compartment to form a capillary flow space. The first compartment PMD6 includes four first liquid delivery sections 12 arranged along the inner wall of the first compartment hemispherical shape, one second liquid delivery section 13 arranged along a cylindrical section or the circumference of the first compartment, and a connecting section communicating with the liquid inlet 9 of the first compartment. The first liquid delivery section 12 is specifically an arc-shaped section, and the second liquid delivery section 13 is specifically an annular section. The number of arc-shaped sections in the first compartment PMD6 is not limited to four; it can be set to two, three, four, or more depending on the tank size, liquid inlet position, and liquid supply requirements, and can be increased or decreased according to actual needs. The gap between the PMD and the inner wall of the tank can be adjusted according to the propellant type, surface tension, contact angle, and tank size.

[0049] Four arc-shaped segments are arranged at circumferential intervals and interconnected in the top area or near the center of the first compartment, enabling them to cover multiple areas of the inner wall of the upper compartment. A circular segment is arranged circumferentially along the first compartment and intersects and connects with the four arc-shaped segments, forming a multi-path, circumferentially connected capillary channel network. The circular segment enhances the first compartment's PMD6's ability to collect circumferentially distributed liquid; the arc-shaped segments enhance the capture and diversion of liquid on the hemispherical wall of the first compartment. The inner wall of the first compartment, in conjunction with the sub-compartment 5, forms an edge liquid collection zone. Influenced by microgravity and gas pressure, the liquid flows along the compartment wall and sub-compartment 5 towards the edge liquid collection zone. The circular segment, combined with the liquid collection, achieves better collection results. Finally, the liquid is output from the first compartment's liquid outlet 9 via a connecting section.

[0050] Both the arc-shaped and annular sections of the first compartment PMD6 employ a plate-perforated hollow channel structure. Each section has a capillary porous plate on the side closest to the inner wall of the first compartment, with interconnected internal U-shaped channels. After contacting the capillary porous plate near the inner wall of the upper compartment, the liquid can enter the internal channels through any arc-shaped or annular section and converge along the connecting channels to the liquid inlet 9 of the first compartment.

[0051] Under microgravity conditions, the propellant liquid may be distributed along the inner wall of the first compartment, the inner wall of the cylindrical section, or near the top wall of compartment 5. Since the first compartment PMD6 has both arc-shaped and annular sections, and the sections are interconnected, when a part of the PMD area comes into contact with the liquid, the liquid can be introduced into the channel through the capillary porous plate, reducing the risk of air entrapment at the liquid outlet due to uneven local distribution of the liquid.

[0052] like Figure 2 and Figure 4 As shown, the second compartment PMD7 is located inside the second compartment of the common-bottom tank 1, and maintains a certain gap with the inner wall of the second compartment to form a capillary flow space. The second compartment PMD7 includes a first elliptical annular channel 14 and a second elliptical annular channel 15. The first elliptical annular channel 14 and the second elliptical annular channel 15 are arranged intersectingly and are interconnected in the intersection area.

[0053] The first elliptical annular channel 14 and the second elliptical annular channel 15 in the second compartment are both matched with the shape of the inner wall of the elliptical hemisphere of the second compartment, forming an overall spatially curved annular structure. After the two elliptical annular channels are arranged in an intersecting manner, multiple liquid capture paths can be formed in the lower compartment, improving the adaptability of the second compartment PMD7 to liquid distribution under different attitudes.

[0054] Each elliptical annular channel in the second compartment PMD7 adopts a hollow channel structure combining plate and perforation. A capillary porous plate 19 is installed on the side closest to the inner wall of the lower compartment, and the capillary porous plate 19 is clamped and fixed by a clamping part 18 and a supporting part 20. After the propellant liquid in the second compartment comes into contact with the capillary porous plate 19, it enters the internal channel under the action of capillary force and converges at the liquid inlet 11 of the second compartment through the connecting area of ​​the two elliptical annular channels.

[0055] Due to the combined influence of the second compartment's ellipsoidal curvature and compartment 5, the propellant may be distributed in different orientations on the ellipsoidal wall of the second compartment under microgravity conditions. The intersecting elliptical annular channel structure increases the probability of PMD contact with the liquid within a limited space and ensures that the liquid can be delivered to the liquid inlet from multiple inlet directions through internal connecting channels. Of course, the number of elliptical annular channels within the second compartment can be increased or decreased according to actual needs.

[0056] Both the first compartment PMD6 and the second compartment PMD7 maintain a certain gap with the corresponding inner wall of the compartment. This gap serves both to meet assembly and welding tolerance requirements and to create a flow space for the propellant between the compartment wall and the capillary porous plate.

[0057] When the common-bottom tank 1 is in a microgravity or low-gravity environment, the propellant tends to adhere to the wall area with better wettability due to surface tension. The gap between the PMD and the inner wall of the tank allows the propellant to maintain a continuous liquid film or local liquid bridge near the wall, thereby increasing the contact probability between the capillary porous plate and the liquid. If the gap is too large, the capillary porous plate 19 may detach from the liquid on the wall, reducing the capture capacity; if the gap is too small, it may increase the difficulty of manufacturing and assembly and affect the propellant flow. Therefore, the gap can be determined based on the propellant surface tension, contact angle, tank size, PMD structural dimensions, and machining and assembly tolerances.

[0058] After the tanks are filled, the first and second compartments contain liquid propellant and pressurizing gas, respectively. When the propulsion system is operating, pressurizing gas is introduced into the corresponding compartment through the gas inlet or the internal pressure is maintained, while liquid propellant is discharged through the liquid outlet.

[0059] Under normal gravity conditions, the propellant liquid is concentrated at a lower position inside the chamber due to gravity. After contacting some of the PMD capillary porous plates, the liquid enters the internal channels of the PMD and is transported to the liquid inlet. Under microgravity or low gravity conditions, the propellant liquid may spread, accumulate, or migrate on the inner wall of the chamber. The PMD captures the liquid through capillary porous plates arranged near the inner wall, allowing the liquid to enter the internal channels.

[0060] When the liquid comes into contact with the capillary porous plate 19, the capillary pressure in the micropores drives the liquid through the capillary porous plate 19 into the internal channels of the PMD. Since the internal channels of the PMD are all connected to the liquid inlet, the propellant liquid entering the channel can be collected along the flow path to the liquid inlet and discharged. At the same time, if the pressurized gas attempts to enter the internal channels of the PMD, it needs to overcome the bubble burst point pressure of the meniscus at the micropores of the capillary porous plate 19. When the normal operating pressure difference is lower than the bubble burst point pressure, the gas is blocked outside the PMD or in the gas phase space inside the chamber, thus ensuring that the liquid output from the liquid inlet is not entrained.

[0061] When the tank attitude changes or is subjected to maneuvering acceleration disturbances, the arc-shaped and circular sections of the first compartment PMD6 and the intersecting elliptical annular channels of the second compartment PMD7 can provide liquid inlet paths in multiple directions and at multiple locations. Even if part of the PMD area is detached from the liquid, other areas in contact with the liquid can continue to supply liquid to the inlet, thereby improving the attitude adaptability and liquid supply continuity of the propellant management device.

[0062] The micropore diameter is not limited to 15 μm and can be set from 5 μm to 100 μm depending on the required bubble burst pressure, propellant surface tension, and contact angle. The micropore spacing is not limited to 30 μm and can be adjusted according to the requirements of porosity, strength, and flow resistance, preferably 1.5 to 5 times the pore diameter.

[0063] PMD components can be made of titanium alloy, stainless steel or other metal materials compatible with propellants, and can be fixed by welding, mechanical clamping or combination connection.

[0064] This management device has a compact structure and can be adapted to the upper and lower hemispherical compartments of the common-bottom propellant tank, making it suitable for all-welded metal tanks. The device achieves the collection, retention, and gas-free discharge of propellant liquid through a combination of plate-hole capillary channels. This improves the reliability of propellant supply and propellant utilization in small satellite propulsion systems under microgravity, low gravity, normal gravity, and attitude change conditions, demonstrating promising engineering application prospects.

[0065] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A common-bottom tank propellant management device, characterized in that, include: The common bottom tank (1) is divided into a first compartment and a second compartment by a compartment section (5), wherein the compartment section (5) protrudes in an arc shape in the first compartment to form an edge liquid collection area in the first compartment; The first compartment PMD (6) is set inside the first compartment and is provided with several circumferentially distributed first liquid delivery parts (12) that are conform to the side wall of the first compartment and a second liquid delivery part (13) located in the edge liquid collection area that is conform to the inner wall of the first compartment. All the first liquid delivery parts (12) are connected to the second liquid delivery part (13) at the same end. The second compartment PMD (7) is located inside the second compartment and is equipped with several third liquid transport parts that are evenly arranged in a circle and conform to the inner wall of the second compartment. Among them, the first liquid conveying unit (12), the second liquid conveying unit (13) and the third liquid conveying unit maintain a preset distance from the corresponding cabin wall to form a capillary flow space, and a number of windows (16) are uniformly arranged on the end face near the capillary flow space. Each window (16) is provided with a capillary porous plate (19) that connects the interior of the corresponding conveying unit with the capillary flow space. All conveying units are used to convey liquid to the liquid port of the corresponding cabin.

2. The common-bottom tank propellant management device according to claim 1, characterized in that: The common-bottom tank (1) includes a first hemisphere (2), a cylindrical section (3), and a second hemisphere (4) connected in sequence. The compartment section (5) is located inside the cylindrical section (3). The first hemisphere (2) has a first air inlet (8) located away from the compartment section (5) and a first liquid inlet (9) located near the compartment section (5). The second hemisphere (4) has a second air inlet (10) located near the compartment section (5) and a second liquid inlet (11) located away from the compartment section (5). The first liquid inlet (9) corresponds to the position of the edge liquid collection area.

3. The common-bottom tank propellant management device according to claim 2, characterized in that: Both the first hemisphere (2) and the second hemisphere (4) are ellipsoidal.

4. The common-bottom tank propellant management device according to claim 3, characterized in that: The third liquid delivery unit is elliptical in shape.

5. The common-bottom tank propellant management device according to claim 3, characterized in that: The first compartment PMD (6) is ellipsoidal in shape.

6. The common-bottom tank propellant management device according to claim 5, characterized in that: The second compartment PMD (7) is ellipsoidal in shape.

7. A common-bottom tank propellant management device according to any one of claims 1-6, characterized in that: The first liquid delivery unit (12), the second liquid delivery unit (13) and the third liquid delivery unit are all hollow structures and are connected to the capillary flow space through a capillary porous plate (19) and a window (16).

8. The common-bottom tank propellant management device according to claim 7, characterized in that: The first liquid delivery unit (12), the second liquid delivery unit (13) and the third liquid delivery unit each include a pressing part (18), a capillary porous plate (19), a support part (20) and a U-shaped channel (21). The opening side of the U-shaped channel (21) is connected to the support part (20). The support part (20) cooperates with the pressing part (18) to press the capillary porous plate (19). The window (16) is formed on the pressing part (18).

9. A common-bottom tank propellant management device according to claim 8, characterized in that: The clamping part (18) is provided with ribs (17) to reinforce the window (16).

10. A common-bottom tank propellant management device according to claim 1, 2, 3, 4, 5, 6, 8 or 9, characterized in that: A plurality of openings (22) are arranged in an array on the capillary porous plate (19).

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