Metal diaphragm tank centroid transverse movement control method

Abstract

The application relates to the technical field of aerospace pressure containers, in particular to a centroid transverse movement control method for a metal diaphragm tank, which optimizes the manufacturing method of the metal diaphragm tank from three aspects of material control, structure design and processing control, solves the problems of large centroid transverse movement and high control difficulty of the metal diaphragm tank in the working process, and makes the centroid transverse movement of the metal diaphragm tank in the working process not greater than 5% of the maximum diameter of the tank.

Description

Technical Field

[0001] This application relates to the field of aerospace pressure vessel technology, and more specifically, to a method for controlling the transverse displacement of the center of mass of a metal diaphragm tank. Background Technology

[0002] A metal diaphragm propellant tank is a pressure vessel in a spacecraft used to store and supply liquid propellant. It primarily consists of a spherical metal shell and a nearly hemispherical metal diaphragm. The diaphragm divides the entire tank's interior into a gas chamber and a liquid chamber. The working medium in the gas chamber is pressurized gas, while the liquid chamber stores liquid propellant. When the pressure difference between the gas and liquid chambers reaches a certain level, the metal diaphragm begins to deform, increasing the volume of the gas chamber and decreasing the volume of the liquid chamber. This drives the propellant to exit from the bottom port until the metal diaphragm completely flips over, at which point the propellant is essentially emptied.

[0003] To ensure the smooth flight of spacecraft and minimize the impact of metal diaphragm flipping, there are high requirements for the lateral displacement of the center of mass of the metal diaphragm tank during the flipping process. However, the metal diaphragm undergoes nonlinear plastic deformation during the flipping process, and the lateral displacement of the center of mass is greatly affected by the material state, structural design, and manufacturing process, resulting in a large lateral displacement of the center of mass and high control difficulty. Summary of the Invention

[0004] This application provides a method for controlling the transverse displacement of the center of mass of a metal diaphragm tank, which solves the problem of large transverse displacement of the center of mass and high control difficulty during the operation of the metal diaphragm tank.

[0005] To achieve the above objectives, this application provides a method for controlling the lateral displacement of the center of gravity of a metal diaphragm tank, comprising the following steps: Step 1: Controlling the material of the metal diaphragm, selecting a metal material that is corrosion-resistant, has high specific strength, and is easy to process and weld; Step 2: Designing the shape of the inner and outer cavities of the metal diaphragm, so that the inner and outer surfaces of each part of the metal diaphragm are smoothly connected, and the wall thickness change of the metal diaphragm from bottom to top follows a segmented parabolic trend; Step 3: Setting anti-sway support rings in areas where lateral swaying is likely to occur during the metal diaphragm's flipping process; Step 4: Processing and manufacturing the metal diaphragm, following the processing sequence of turning the inner cavity surface and precision turning the bottom surface of the outer cavity; Step 5: Welding and fixing the processed metal diaphragm inside the tank.

[0006] Furthermore, in step 2, the metal diaphragm is divided into an arc segment, a conical segment, and a bottom segment from top to bottom. The connection between the inner and outer surfaces of each segment is tangent, with the inner side being the inner cavity and the outer side being the outer cavity.

[0007] Furthermore, in step 3, the anti-sway support ring is set at the conical section and bottom of the metal diaphragm and is attached to the outer cavity surface of the metal diaphragm. It includes a fixed end, a support end, and a ring body. The fixed end is a hemispherical cross-section ring body, with one side connected to the ring body and the other side welded to the end of the bottom flange circle of the metal diaphragm. The support end is a quadrilateral cross-section ring body, with one side connected to the ring body and the other side attached to the inner wall of the tank. The ring body has a uniform wall thickness and is attached to the outer cavity surface of the metal diaphragm as a whole.

[0008] Furthermore, multiple through holes are provided on the fixed end, the supporting end, and the ring body.

[0009] Furthermore, in step 4, the turning of the inner surface of the metal diaphragm includes the sequential rough turning, semi-rough turning, and finish turning of the inner surface.

[0010] Furthermore, in step 4, when the bottom surface of the outer cavity of the metal diaphragm is precision machined, a special internal and external support fixture is required to fix the metal diaphragm.

[0011] Furthermore, the special internal and external support fixture includes an internal support mold, a top block, and an external support ring. The top of the internal support mold is hemispherical, and the bottom flange is connected to the machining lathe by bolts. The top block is set above the top of the internal support mold. The external support ring is sleeved on the outside of the internal support mold. When fixed, the arc segment of the metal diaphragm is pressed against the spherical surface of the internal support mold by the top block, and the bottom flange is fixed on the external support ring.

[0012] Furthermore, the bottom diameter of the metal diaphragm has a machining accuracy of ≤ ±0.1 mm, and the bottom and cone thickness of the metal diaphragm have a machining accuracy of ≤ ±0.03 mm.

[0013] The present invention provides a method for controlling the transverse displacement of the center of mass of a metal diaphragm tank, which has the following beneficial effects: This application optimizes the manufacturing method of metal diaphragm tanks from three aspects: material control, structural design, and processing control. It solves the problems of large lateral displacement of the center of gravity and high control difficulty during the operation of metal diaphragm tanks, and ensures that the lateral displacement of the center of gravity during the operation of metal diaphragm tanks is no more than 5% of the maximum diameter of the tank. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This is a schematic diagram of a metal diaphragm tank provided according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the metal diaphragm provided according to an embodiment of this application; Figure 3 This is a schematic diagram illustrating the variation of the metal diaphragm wall thickness according to an embodiment of this application; Figure 4 This is a structural schematic diagram of the anti-sway support ring provided according to an embodiment of this application; Figure 5 This is a schematic diagram of the dedicated internal and external support tooling provided according to the embodiments of this application; In the figure: 1-tank, 2-metal diaphragm, 3-circular arc segment, 4-conical segment, 5-bottom, 6-inner cavity, 7-outer cavity, 8-fixed end, 9-supporting end, 10-ring body, 11-inner support mold, 12-top block, 13-outer support ring. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0016] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0017] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0018] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0019] In addition, the term "multiple" should mean two or more.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figure 1 As shown, the metal diaphragm 2 of the metal diaphragm tank 1 undergoes nonlinear plastic deformation during the flipping process, resulting in a large lateral displacement of its center of mass, which is difficult to control. The lateral displacement control method of the center of mass of the metal diaphragm tank 1 provided in this application optimizes the manufacturing method of the metal diaphragm tank 1 from three aspects: material control, structural design, and processing control. This reduces the lateral displacement of the center of mass of the metal diaphragm tank 1 during operation, ensuring that the lateral displacement of the center of mass of the metal diaphragm tank 1 during operation does not exceed 5% of the maximum diameter of the tank 1. Specifically, it includes the following steps: Step 1: Control the material of the metal diaphragm 2, and select a metal material that is corrosion-resistant, has high specific strength, and is easy to process and weld, such as pure aluminum, pure titanium, or stainless steel; to ensure good consistency of local mechanical properties of the metal diaphragm 2, the material used for the metal diaphragm 2 needs to be free of obvious component segregation; and the selected material should not have obvious texture and large average grain size differences in local areas during the subsequent processing and manufacturing of the metal diaphragm 2, especially after thermoplastic forming (hot stamping, hot spinning, hot forging, etc.); after the heat treatment of the metal diaphragm 2, ensure that the metal diaphragm 2 has no obvious residual stress.

[0022] Step 2: Design the shape of the inner cavity 6 and outer cavity 7 of the metal diaphragm 2 to ensure smooth connection between the inner and outer surfaces of each part of the metal diaphragm 2, and to make the wall thickness change of the metal diaphragm 2 from the bottom 5 to the top follow a piecewise parabolic trend; such as Figure 2 As shown, the metal diaphragm 2 is divided into an arc segment 3, a conical segment 4, and a bottom 5 from top to bottom. The connection between the inner and outer surfaces of each segment is tangent. The inner side is the inner cavity 6, and the outer side is the outer cavity 7. The bottom 5 of the metal diaphragm 2 is preferably a hemispherical annular shell, the conical segment 4 is preferably a conical shell, and the arc segment 3 is preferably a spherical cap shell. Figure 3 As shown, the wall thickness of the metal diaphragm 2 from the bottom 5 to the top is preferably divided into two parts. The wall thickness of the bottom 5 and the conical segment 4 is the same and does not change with position. The wall thickness of the arc segment 3 increases with height, and the rate of increase follows a parabolic trend.

[0023] Step 3: Install anti-sway support rings in areas prone to lateral swaying during the flipping of the metal diaphragm 2; such as... Figure 4 As shown, the anti-sway support ring is set on the conical section 4 and bottom 5 of the metal diaphragm 2, and is attached to the surface of the outer cavity 7 of the metal diaphragm 2. It includes a fixed end 8, a support end 9, and a ring body 10. The fixed end 8 is a hemispherical cross-section ring body, one side of which is connected to the ring body 10, and the other side is welded to the end of the flange circle of the bottom 5 of the metal diaphragm 2. The support end 9 is a quadrilateral cross-section ring body, one side of which is connected to the ring body 10, and the other side is attached to the inner wall of the storage tank 1. The distance between the ring body 10 and the inner wall of the storage tank 1 is 0-0.1mm. The ring body 10 has a uniform wall thickness and is attached to the surface of the outer cavity 7 of the metal diaphragm 2. Multiple through holes are provided on the fixed end 8, the support end 9, and the ring body 10.

[0024] Specifically, the anti-sway support ring is generally set in the conical section 4 and bottom 5 areas of the metal diaphragm 2 where lateral swaying is prone to occur, serving to fix and support the metal diaphragm 2. The anti-sway support ring is completely wrapped around and fitted to the surface of the outer cavity 7 of the metal diaphragm 2, with a distance of 0-0.1mm between the ring and the surface of the outer cavity 7. In order to reduce the overall weight of the anti-sway support ring, multiple through holes are evenly arranged on the fixed end 8, the supporting end 9, and the ring body 10; the through holes on the fixed end 8 also allow pressurized gas to quickly enter the flanged area of ​​the metal diaphragm 2.

[0025] Step 4: Fabricate the metal diaphragm 2, following the machining sequence of turning the inner cavity 6 surface and finishing turning the bottom 5 surface of the outer cavity 7. Turning the inner cavity 6 surface includes rough turning, semi-rough turning, and finish turning. Finish turning the bottom 5 surface of the outer cavity 7 requires the use of specialized internal and external support fixtures to secure the metal diaphragm 2. Figure 5 As shown, the special internal and external support fixture includes an inner support mold 11, a top block 12, and an outer support ring 13. The top of the inner support mold 11 is hemispherical, and the bottom flange 5 is connected to the machining lathe by bolts. The top block 12 is set above the top of the inner support mold 11. The outer support ring 13 is sleeved on the outside of the inner support mold 11. When fixed, the arc segment 3 of the metal diaphragm 2 is pressed against the spherical surface of the inner support mold 11 by the top block 12, and the flange of the bottom 5 is fixed on the outer support ring 13.

[0026] Specifically, when processing the metal diaphragm 2, the surface of the inner cavity 6 of the metal diaphragm 2 is first processed by rough turning, semi-rough turning, and finish turning of the inner cavity 6 surface in sequence. At this point, a semi-finished metal diaphragm 2 is obtained. The semi-finished metal diaphragm 2 has a large wall thickness and high rigidity. Then, the bottom 5 surface of the outer cavity 7 of the metal diaphragm 2 is finished to reduce the vibration of the metal diaphragm 2 and improve the processing accuracy. In order to strictly control the processing accuracy of the bottom 5 of the metal diaphragm 2, the outer cavity 7 of the metal diaphragm 2 is finished. When precision machining the bottom 5 surface of cavity 7, a special internal and external support fixture is required to fix the metal diaphragm 2. The special internal and external support fixture includes an inner support mold 11, a top block 12, and an outer support ring 13. During machining and fixing, the arc segment 3 of the metal diaphragm 2 is pressed onto the spherical surface of the inner support mold 11 by the top block 12, and the flange circle of the bottom 5 is fixed on the outer support ring 13. During the machining process, the machining accuracy of the bottom 5 diameter of the metal diaphragm 2 is ≤ ±0.1mm, and the machining accuracy of the bottom 5 and the tapered segment 4 thickness of the metal diaphragm 2 is ≤ ±0.03mm.

[0027] Step 5: Weld and fix the finished metal diaphragm 2 inside the storage tank 1.

[0028] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for controlling the transverse displacement of the center of mass of a metal diaphragm tank, characterized in that, Includes the following steps: Step 1: Control the material of the metal diaphragm, and select a metal material that is corrosion resistant, has high specific strength, and is easy to process and weld; Step 2: Design the inner and outer cavities of the metal diaphragm to ensure smooth connection between the inner and outer surfaces of each part of the metal diaphragm, and make the wall thickness change of the metal diaphragm from bottom to top follow a piecewise parabolic trend. Step 3: Install anti-sway support rings in areas where lateral swaying is likely to occur during the metal diaphragm flipping process; The anti-sway support ring is located at the conical section and bottom of the metal diaphragm, and fits against the outer surface of the metal diaphragm cavity. It includes a fixed end, a support end, and a ring body, wherein: The fixed end is a hemispherical cross-section ring, one side of which is connected to the ring body, and the other side is welded to the end of the bottom flange circle of the metal diaphragm; The support end is a quadrilateral cross-section ring, with one side connected to the ring and the other side attached to the inner wall of the storage tank; The ring has a uniform wall thickness and is integrally attached to the outer cavity surface of the metal diaphragm. Multiple through holes are provided on the fixed end, the supporting end, and the ring body; Step 4: Process the metal diaphragm by turning the inner surface of the diaphragm and finishing the bottom surface of the outer cavity. Step 5: Weld and fix the finished metal diaphragm inside the storage tank.

2. The method for controlling the transverse displacement of the center of gravity of a metal diaphragm tank according to claim 1, characterized in that, In step 2, the metal diaphragm is divided into an arc segment, a cone segment, and a bottom segment from top to bottom. The connection between the inner and outer surfaces of each segment is tangent, with the inner side being the inner cavity and the outer side being the outer cavity.

3. The method for controlling the transverse displacement of the center of gravity of a metal diaphragm tank according to claim 2, characterized in that, In step 4, the turning of the inner surface of the metal diaphragm includes the sequential rough turning, semi-rough turning, and finish turning of the inner surface.

4. The method for controlling the transverse displacement of the center of gravity of a metal diaphragm tank according to claim 3, characterized in that, In step 4, when the bottom surface of the outer cavity of the metal diaphragm is precision machined, special internal and external support fixtures are required to fix the metal diaphragm.

5. The method for controlling the transverse displacement of the center of gravity of a metal diaphragm tank according to claim 4, characterized in that, The dedicated internal and external support fixture includes an inner support mold, a top block, and an outer support ring, wherein: The top of the inner support mold is hemispherical, and the bottom flange is connected to the machining lathe by bolts. The top block is positioned above the top of the inner support mold; The outer support ring is sleeved on the outside of the inner support mold; When fixed, the arc segment of the metal diaphragm is pressed against the spherical surface of the inner support mold by the top block, and the bottom flange is fixed on the outer support ring.

6. The method for controlling the transverse displacement of the center of mass of a metal diaphragm tank according to claim 5, characterized in that, The bottom diameter of the metal diaphragm has a machining accuracy of ≤ ±0.1 mm, and the bottom and cone thickness of the metal diaphragm have a machining accuracy of ≤ ±0.03 mm.

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