Design method of spherical inclined installation parallel type tension storage tank for spacecraft

Abstract

The invention provides a design method of a spherical obliquely-mounted parallel tension storage tank for a spacecraft, which comprises the following steps of: comprehensively analyzing and determining the basic structure composition of a storage tank shell and a propellant management device according to the index requirements of a spacecraft liquid propulsion system; according to the index requirements of the spacecraft liquid propulsion system, structural design optimization is conducted on the storage box shell and the propellant management device in sequence; and carrying out modeling simulation on the optimized storage tank shell and the optimized propellant management device to obtain optimal structure parameters. According to the spacecraft liquid propulsion system index requirements, the storage tank shell and the propellant management device are optimally designed, the problem that an existing traditional storage tank design method cannot be suitable for a spherical obliquely-installed parallel tension storage tank is solved, and the design efficiency of the obliquely-installed storage tank is improved; and meanwhile, the requirements of a spacecraft propulsion system on the structural space utilization rate, light weight, long service life cycle and high reliability are met.

Description

Design method for spherical inclined parallel tension tanks for spacecraft Technical Field

[0001] This invention relates to the field of propellant tank design technology, and more specifically, to a design method for a spherical inclined parallel tension tank for spacecraft. Background Technology

[0002] In propellant systems for spacecraft such as satellites and deep space explorers, to improve the structural space utilization of spacecraft with relatively small propellant loading volumes, extend the service life of the spacecraft, and consider the requirements for spacecraft center-of-mass balance, a structure of four spherical surface tension tanks connected in parallel in pairs is adopted. That is, two tanks of the same type of propellant are connected in parallel to supply the engine with non-entrained propellant. In the above typical structural form, each tension tank is mounted horizontally with flanges, and the gas, liquid inlets, and management devices are all located in the direction of the main engine (vertical direction), that is, at the lowest point of the tank's spherical shell. For example, a tank disclosed in patent document CN113565651B and an aluminum alloy surface tension tank device disclosed in patent document CN117418967B both have horizontally mounted flanges, and the gas, liquid inlets, and management devices are all arranged vertically. In this case, the tank, except for the connecting nozzle, has an axisymmetric structure, resulting in good stress bearing capacity. As spacecraft demand increasingly stringent requirements for structural space utilization, spherical horizontally mounted parallel tension tanks can no longer meet the requirements. Therefore, spherical inclinedly mounted parallel tension tanks have emerged.

[0003] This type of tank, due to the vertical installation of gas and liquid inlets and management devices at an angle to the flanges, results in the connection points between the gas and liquid inlets / management devices and the spherical shell not being located at the extreme points. This disrupts the perfectly axisymmetric structure of traditional tanks, affecting the stress-bearing capacity of the tank shell and management devices. Traditional tank design methods based on axisymmetric structures are not applicable. Therefore, there is an urgent need in this field to propose a design method for a parallel tension tank with a spherical tilted installation in spacecraft to ensure that it meets system performance requirements. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a design method for a spherical tilt-mounted parallel tension tank for spacecraft.

[0005] The design method for a spherical inclined parallel tension tank for spacecraft provided by the present invention includes the following steps: Step S1: Based on the performance requirements of the spacecraft liquid propulsion system, comprehensively analyze and determine the basic structural composition of the tank shell and propellant management device; Step S2: Based on the performance requirements of the spacecraft liquid propulsion system, optimize the structural design of the tank shell to obtain an optimized tank shell; Step S3: Based on the performance requirements of the spacecraft liquid propulsion system and the optimized tank shell structural parameters, optimize the structural design of the propellant management device to obtain an optimized propellant management device; Step S4: Perform modeling and simulation on the optimized tank shell and the optimized propellant management device to obtain the optimal structural parameters.

[0006] Preferably, in step S1, the performance requirements of the spacecraft liquid propulsion system include: storage medium, pressure resistance, dynamics, flow rate, and flow resistance. Emission efficiency E, total / real-time propellant usage throughout the mission, acceleration, tilt angle α, minimum connectivity volume V, envelope and interface, and weight m. tank The pressure-bearing index includes the working pressure p. c Verify pressure p T And blast pressure p b The kinetic parameters include lateral overload acceleration a. H Vertical overload acceleration a V The vibration frequency and magnitude, the flow rate index includes the airflow rate q. g Liquid flow rate q y and connectivity q l The tank shell includes a main shell and an interface. The main shell includes a spherical shell, a flange connecting ring, and a base. The interface includes a liquid port, a gas port, and a connecting port. The base is installed at the bottom of the spherical shell, and the liquid port is installed at the bottom of the base. The gas port, the connecting port, and the flange connecting ring are all installed outside the spherical shell. The propellant management device includes an accumulator and blades. The accumulator includes an inner cylinder and an outer cylinder. The blades are disposed outside the outer cylinder of the accumulator. The accumulator is installed on the base and located inside the spherical shell.

[0007] Preferably, step S2 includes the following sub-steps: Step S2.1: Determine the tank volume V according to the total / real-time propellant usage requirements for the entire mission. tank The volume V of the propellant management device PMD According to the storage medium, the pressure, and the weight m tankThe material of the storage tank is initially determined according to the index requirements; Step S2.2: Based on the inclined installation angle α, the envelope and interface index requirements, the specific connection positions of the base, the air port, and the communication port with the spherical shell are determined; Step S2.3: Based on the envelope index requirements and the storage tank volume V... tank Determine the inner diameter D of the main housing i According to the inner diameter D of the main housing i and the volume V of the propellant management device PMD Determine the diameter D of the corresponding openings in the base and the spherical shell. d According to the gas flow rate q q Determine the diameter D of the air inlet and the corresponding opening on the spherical shell. q According to the fluid flow rate q y Determine the diameter D of the corresponding opening of the liquid inlet and the base. y According to the connectivity flow q l Determine the diameter D of the connecting port and the corresponding opening of the spherical shell. l Step S2.4: Based on the pressure bearing requirements, the tank material, and the main shell diameter D... i Calculate the basic wall thickness t of the main shell. bm and welded area reinforcement wall thickness t wm According to the reinforcement wall thickness t of the main shell welding area wm Determine the wall thickness t of the flange connecting ring structure. c Step S2.5: Based on the storage medium and the vertical overload acceleration a V The inclined installation angle α, the weight m tank The interface specifications and the tank volume V tank Calculate the flange lug thickness t of the flange connecting ring. f And quantity n; Step S2.6: According to the basic wall thickness t of the main shell bm The main shell welding area reinforcement wall thickness t wm The structural wall thickness t of the flange connecting ring c The flange lug thickness t of the flange connecting ring f The structure of the basic area, connection transition area and welding area of ​​each part of the tank shell is designed according to the quantity n; Step S2.7: Based on the tank shell structure obtained in step S2.6, a three-dimensional model is performed to determine whether the tank envelope and weight meet the index requirements. If the requirements are met, step S2.8 is continued. If the requirements are not met, steps S2.1-S2.7 are repeated until the requirements are met; Step S2.8: Based on the tank shell structure that meets the index requirements, a finite element model is performed to simulate the pressure and overload, and optimization is performed based on the simulation results.

[0008] Preferably, step S3 includes the following sub-steps: Step S3.1: Based on the diameter D d With the propellant management device volume V PMD Determine the outer diameter D of the accumulator. FSV-E and height H FSV-E Step S3.2: Based on the emission efficiency index and the tank volume V tank Determine the internal volume V of the accumulator. FSV-I According to the internal cavity volume V FSV-I The outer cylinder diameter D FSV-E The height H of the outer cylinder FSV-E Determine the inner diameter D of the accumulator. FSV-I and height H FSV-I Step S3.3: Based on the fluid flow rate q y The flow resistance The terminal acceleration index requires the design of the propellant management device structure to obtain the propellant management device structure; Step S3.4: After performing finite element modeling based on the combination of the propellant management device structure and the base, perform overload simulation and optimize according to the simulation results.

[0009] Preferably, step S4 includes the following sub-steps: Step S4.1: After performing finite element modeling of the tank structure based on the optimized tank shell and the optimized propellant management device, vibration simulation is performed; Step S4.2: Based on the vibration simulation results, iterative optimization is performed until the optimal structural parameters are obtained.

[0010] Preferably, in step S2.1, the tank volume V tank The volume V of the propellant management device is determined after considering component tolerances and welding shrinkage, with a margin of 1-5%, based on the total propellant usage throughout the spacecraft mission. PMD After ensuring the propellant usage during each reverse overload period of the spacecraft, a margin of 5-10% is allowed. The tank material is determined to be highly compatible with the propellant medium. In step S2.2, the base and the air inlet are connected to the spherical shell at the upper and lower poles of the tank in its installed state, respectively. The location of the communication port is determined by being as far away from the base as possible while meeting the minimum communication volume V requirement. In step S2.3, the basic inner surfaces of all parts of the main tank shell are concentric spherical surfaces, and the corresponding opening diameter D of the base and the spherical shell is... d Not greater than the inner diameter D of the tank shell i The diameter D of the air inlet and the corresponding opening on the spherical shell is 0.3 times that of the spherical shell end face, while also satisfying that the minimum distance between the corresponding opening and the end face of the spherical shell is not less than 100 mm. q The diameter D of the corresponding opening of the liquid inlet and the basey The diameter D of the connecting port and the corresponding opening of the spherical shell l All are taken as 2 to 3 times the corresponding nominal diameter; in step S2.4, the basic wall thickness t of the main shell is... bm and the wall thickness t of the welding area reinforcement wm The calculation formula is as follows:

[0011]

[0012] Where [σ] is the allowable tensile strength of the material, t c Here, t' is the corrosion allowance, φ is the rounding allowance, and φ is the welding coefficient.

[0013] Where, σ y σ is the yield strength of the material. b The tensile strength of the material; the calculated basic wall thickness t of the main shell. bm and the wall thickness t of the welding area reinforcement wm Satisfy the following formula:

[0014]

[0015]

[0016]

[0017] In step S2.5, the flange lug thickness t of the flange connecting ring f The calculation formula is as follows:

[0018] Where F is the total pressure, e is the distance from the center of the lug mounting hole to the root of the lug, and b is the width of the lug root.

[0019] Where ρ is the propellant density; and the wall thickness t of the flange connecting ring structure is... c Take 1 to 1.2 times the reinforcement wall thickness t of the main shell welding area. wm In step S2.6, the connection transition area of ​​each component of the main shell of the storage tank is determined by the basic wall thickness t of the basic area. bm Transition to the welded area reinforcement wall thickness t wmThe width is 3 to 10 times the width of the welding area. The connecting transition area of ​​the opening on the spherical shell is arranged around the central axis of the opening, and the remaining connecting transition areas are arranged around the central axis of the part. The welding area is designed with a mating surface according to the welding method. The simulation results in step S2.8 should meet the following conditions. If they are not met, the simulation should be repeated until they are met: working pressure p c The maximum equivalent stress of the tank shell described below does not exceed the allowable tensile strength of the material [σ]; verify the pressure p. T The maximum equivalent stress of the tank shell described below shall not exceed 0.9 times the material yield strength σ. y Explosive pressure P b The maximum equivalent stress of the tank shell described below does not exceed the tensile strength σ of the material. b Under vertical overload conditions, the maximum vertical stress at the root of the flange connecting ring lug shall not exceed the allowable shear strength of the material [τ]; local stress concentration shall not occur in the tank shell.

[0020] Preferably, when the welding zone is welded using a high-energy beam, the inward design thickness is 0.5 to 1.5 times the welding reinforcement wall thickness t. wm The bottom of the lock; when the welding area is argon arc welded, the design thickness is 0.2~0.5 times the welding reinforcement wall thickness t. wm The slope.

[0021] Preferably, in step S3.1, the diameter D of the outer cylinder of the accumulator is... FSV-E Take 0.7 to 1 times the diameter D of the base. d The height H of the outer cylinder of the accumulator FSV-E Take the outer diameter D of the liquid accumulator FSV-E 0.5 to 1 times, while simultaneously satisfying:

[0022] In step S3.2, the diameter D of the inner cylinder of the accumulator is... FSV-I Take 0.2 to 0.6 times the outer diameter D of the accumulator. FSV-E The height H of the inner cylinder of the accumulator FSV-I Take the height H of the outer cylinder of the liquid accumulator FSV-E 1.1 to 1.3 times, while simultaneously satisfying:

[0023] In step S3.3, the wall thickness t of the inner and outer cylinders of the liquid accumulator FSV The surface of the tank has multiple through holes with a diameter of 4-8 mm, with a diameter of 1-3 mm. A dense metal mesh for gas-liquid separation is sealed between the inner and outer cylinders. The total area of ​​the through holes meets the flow resistance index of the tank under the flow rate q. The calculation formula is as follows:

[0024] in, To reduce the flow resistance of propellant through the densely textured metal mesh, For dynamic pressure difference, For static pressure difference, The flow resistance caused by the liquid passing through the liquid outlet; the final metal mesh satisfies:

[0025] in, The flow resistance of the propellant through the screen in the final stage is given by 'a', the final acceleration is given by 'h', the distance from the liquid surface to the highest point of the dense metal mesh is given by 'BP', and the bubble burst point of the dense metal mesh is given by 't'. The blade wall thickness is given by 't'. V Take 1~1.5mm pieces, in quantities of 4~16 pieces, and distribute them evenly along the circumference of the liquid accumulator.

[0026] Preferably, in step S3.4, the simulation results of lateral overload should meet the following condition. If the condition is not met, the simulation should be repeated until it is met: the maximum equivalent stress at the connection between the accumulator and the base under overload conditions does not exceed 0.9 times the material yield stress σ. y Under overload conditions, the maximum equivalent stress of the metal mesh screen does not exceed 0.9 times the material yield stress σ. ys The propellant management device must not experience localized stress concentration.

[0027] Preferably, the vibration simulation results in step S4 should meet the following condition; if not, the simulation should be repeated until it is met: the maximum equivalent stress of the tank under vibration conditions does not exceed 0.9 times the material yield stress σ. y The propellant management device must not experience localized stress concentration.

[0028] Compared with the prior art, the present invention has the following beneficial effects: The present invention optimizes the design of the tank shell and propellant management device according to the performance requirements of the spacecraft liquid propulsion system, solves the problem that the current traditional tank design method cannot be applied to the spherical inclined installation parallel tension tank, improves the design efficiency of the inclined installation tank, and at the same time meets the requirements of the spacecraft propulsion system for structural space utilization, lightweight, long service life and high reliability. Attached Figure Description

[0029] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 is a schematic diagram of the overall process of the present invention; Figure 2 is a schematic diagram of the structure of the spherical inclined parallel tension tank for spacecraft in the present invention.

[0030] The diagram shows: Detailed Implementation

[0031] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0032] This invention discloses a design method for a spherical inclined parallel tension tank for spacecraft. Based on the requirements of the spacecraft liquid propulsion system, the tank shell and propellant management device are optimized, solving the problem that the current traditional tank design method cannot be applied to spherical inclined parallel tension tanks. This improves the design efficiency of inclined tanks and meets the requirements of spacecraft propulsion systems for high space utilization, lightweight design, long service life, and high reliability.

[0033] The design method for a spherical inclined parallel tension tank for spacecraft provided by the present invention, as shown in Figure 1, includes the following steps: Step S1: Based on the performance requirements of the spacecraft liquid propulsion system, the basic structural composition of the tank shell and propellant management device is determined through comprehensive analysis; the performance requirements of the spacecraft liquid propulsion system in Step S1 include: storage medium, pressure resistance (working pressure p) c / Verify pressure p T / burst pressure p b ), dynamics (lateral overload acceleration a) H Vertical overload acceleration a V (Vibration frequency and magnitude), flow rate, flow resistance Emission efficiency E, total / real-time propellant usage and acceleration throughout the mission, tilted installation angle α, minimum connectivity volume V, envelope and interface, weight m tank wait.

[0034] As shown in Figure 2, the tank shell includes a main shell and an interface. The main shell includes a spherical shell 2, a flange connecting ring 3, and a base 4. The interface includes a liquid port 5, a gas port 1, and a connecting port 8. The base 4 is installed at the bottom of the spherical shell 2. The liquid port 5 is installed at the bottom of the base 4. The gas port 1, the connecting port 8, and the flange connecting ring 3 are all installed on the outside of the spherical shell 2. The propellant management device includes an accumulator 6 and a blade 7. The accumulator 6 includes an inner cylinder and an outer cylinder. The blade 7 is located outside the outer cylinder of the accumulator 6. The accumulator 6 is installed on the base 4 and is located inside the spherical shell 2.

[0035] Step S2: Based on the performance requirements of the spacecraft's liquid propulsion system, optimize the structural design of the tank shell to obtain the optimized tank shell. This specifically includes the following sub-steps: Step S2.1: Determine the tank volume V based on the total / real-time propellant usage requirements throughout the mission. tank Propellant management device volume V PMD Based on the storage medium, pressure, and weight (m) tank The preliminary requirements for determining the tank material include: tank volume V. tank The volume V of the propellant management device is determined after considering the total propellant usage throughout the spacecraft mission, taking into account component tolerances and welding shrinkage, and leaving a margin of 1-5%. PMD After ensuring the propellant usage during each reverse overload period of the spacecraft is met, with a 5-10% margin, the tank material is determined to be first-class compatible with the propellant medium; Step S2.2: Based on the tilted installation angle α, envelope, and interface index requirements, determine the specific connection positions of the base 4, air inlet 1, and connecting port 8 to the spherical shell 2; wherein, the base 4 and air inlet 1 are connected to the spherical shell 2 at the upper and lower poles of the tank installation state, respectively, and the principle for confirming the position of the connecting port 8 is: to be as far away from the base 4 as possible while meeting the minimum connecting volume V index requirement; Step S2.3: Based on the envelope index requirements and the tank volume V tank Determine the inner diameter D of the main housing i According to the inner diameter D of the main shell i and propellant management device volume V PMD Determine the corresponding opening diameter D of base 4 and spherical shell 2. d According to the gas flow rate q q Determine the corresponding opening diameter D of air inlet 1 and spherical shell 2. q According to the liquid flow rate q y Determine the diameter D of the corresponding opening for liquid outlet 5 and base 4. y According to the connected flow q l Determine the diameter D of the corresponding opening in the connecting port 8 and the spherical shell 2. l Among them, the basic inner surfaces of each part of the main shell of the storage tank are concentric spherical surfaces, and the corresponding opening diameters D of the base 4 and the spherical shell 2 are... d Not greater than the inner diameter D of the storage tank shell i 0.3 times, while simultaneously satisfying that the minimum distance between the corresponding opening and the end face of the spherical shell 2 is not less than 100mm, and the diameter D of the corresponding opening of the air inlet 1 and the spherical shell 2. q The corresponding opening diameter D of liquid outlet 5 and base 4 y The diameter D of the corresponding openings of the connecting port 8 and the spherical shell 2 l Take 2 to 3 times the corresponding nominal diameter; Step S2.4: Based on the pressure bearing requirements, tank material, and main shell diameter D i Calculate the basic wall thickness t of the main shell bm and welded area reinforcement wall thickness twm Based on the reinforcement wall thickness t of the main shell welding area wm Determine the wall thickness t of the flange connection ring 3 structure. c The basic wall thickness of the main shell is t. bm and welded area reinforcement wall thickness t wm The calculation formula is as follows:

[0036]

[0037] Where [σ] is the allowable tensile strength of the material, t c Here, t' is the corrosion allowance, φ is the rounding allowance, and φ is the welding coefficient.

[0038] Where, σ y σ is the yield strength of the material. b The tensile strength of the material; the calculated basic wall thickness of the main shell, t. bm and welded area reinforcement wall thickness t wm Satisfy the following formula:

[0039]

[0040]

[0041]

[0042] Step S2.5: Based on the storage medium and vertical overload acceleration a V α, tilted installation angle, weight m tank Interface specifications and tank volume V tank Calculate the flange lug thickness t of flange connecting ring 3. f And the quantity n; where, the flange lug thickness t of the flange connecting ring 3 f The calculation formula is as follows:

[0043] Where F is the total pressure, e is the distance from the center of the lug mounting hole to the root of the lug, and b is the width of the lug root.

[0044] Where ρ is the propellant density; and t is the wall thickness of the flange connecting ring 3 structure. c Take 1 to 1.2 times the reinforcement wall thickness t of the main shell welding area wmStep S2.6: Based on the basic wall thickness t of the main shell bm Main shell welded area reinforcement wall thickness t wm The structural wall thickness t of flange connecting ring 3 c The flange lug thickness t of flange connecting ring 3 f The structure of the basic area, connection transition area, and welding area of ​​each part of the tank shell is designed based on the quantity n; among them, the connection transition area of ​​each part of the main tank shell is composed of the basic wall thickness t of the basic area. bm Transition to the weld zone and reinforce the wall thickness t wm The width is 3 to 10 times the width of the welding area. The connection transition area with the opening on the spherical shell 2 is arranged around the central axis of the opening, and the remaining connection transition areas are all arranged around the central axis of the parts. The welding area is designed with the butt joint surface according to the welding method. Among them, when high-energy beam welding is used for welding area, the inward design thickness is 0.5 to 1.5 times the welding reinforcement wall thickness t. wm The bottom of the weld; when using argon arc welding in the welding area, the design thickness is 0.2~0.5 times the welding reinforcement wall thickness t. wm The slope.

[0045] Step S2.7: Based on the tank shell structure obtained in Step S2.6, perform a 3D model to determine whether the tank envelope and weight meet the requirements. If they meet the requirements, continue to Step S2.8; if they do not meet the requirements, repeat Steps S2.1-S2.7 until they meet the requirements. Step S2.8: Based on the tank shell structure that meets the requirements, perform finite element modeling, conduct pressure and overload simulations, and optimize based on the simulation results. The simulation results should meet the following conditions; if not, repeat the simulation until they are met: 1) Working pressure p c 1) The maximum equivalent stress of the lower tank shell does not exceed the allowable tensile strength of the material [σ]; 2) Verify the pressure p T The maximum equivalent stress of the lower tank shell does not exceed 0.9 times the material yield strength σ. y ;3) Bursting pressure P b The maximum equivalent stress of the lower tank shell does not exceed the tensile strength σ of the material. b ;4) Under vertical overload conditions, the maximum vertical stress at the root of the flange connecting lug does not exceed the allowable shear strength of the material [τ];5) Local stress concentrations should not occur in the tank shell.

[0046] Step S3: Based on the performance requirements of the spacecraft's liquid propulsion system and the optimized structural parameters of the tank shell, the propellant management device is structurally optimized to obtain the optimized propellant management device; specifically, step S3 includes the following sub-steps: Step S3.1: Based on the diameter D d With propellant management device volume V PMD Determine the diameter D of the outer cylinder of the accumulator 6. FSV-E and height HFSV-E Among them, the outer cylinder diameter D of the accumulator 6 FSV-E Take 0.7 to 1 times the base diameter D. d , the height of the outer cylinder of the reservoir 6 is H FSV-E Take the diameter D of the outer cylinder of the reservoir 6 FSV-E 0.5 to 1 times, while simultaneously satisfying:

[0047] Step S3.2: Based on the emission efficiency index and the tank volume V tank Determine the internal volume V of the accumulator 6 FSV-I According to the internal cavity volume V FSV-I , outer cylinder diameter D FSV-E , outer cylinder height H FSV-E Determine the diameter D of the inner cylinder of the accumulator 6. FSV-I and height H FSV-I Among them, the inner diameter D of the accumulator 6 FSV-I Take 0.2~0.6 times the outer cylinder diameter D FSV-E The height H of the inner cylinder of the accumulator 6 FSV-I Take the height H of the outer cylinder of liquid reservoir 6 FSV-E 1.1 to 1.3 times, while simultaneously satisfying:

[0048] Step S3.3: Based on the liquid outlet flow rate q y Flow resistance The propellant management device structure was designed to meet the requirements of the terminal acceleration parameters, resulting in the propellant management device structure; among which, the inner and outer cylinder wall thicknesses of the accumulator 6 are t. FSV The surface of the tube is 1-3 mm thick and has multiple through holes with a diameter of 4-8 mm. A dense metal mesh for gas-liquid separation is held between the inner and outer cylinders for sealing. The total area of ​​the through holes meets the liquid flow rate q. y Flow resistance index of the storage tank under the specified conditions The calculation formula is as follows:

[0049] in, To reduce the flow resistance of propellant through the densely textured metal mesh, For dynamic pressure difference, For static pressure difference, The flow resistance caused by the liquid passing through the orifice; the final metal mesh satisfies:

[0050] in, t represents the flow resistance of the propellant through the screen in the final stage, a represents the final acceleration, h represents the distance from the liquid surface to the highest point of the densely textured metal mesh, and BP represents the bubble burst point of the densely textured metal mesh; the blade wall thickness t is 7.V Take 4 to 16 pieces with a diameter of 1 to 1.5 mm and distribute them evenly along the 6 circumferences of the accumulator.

[0051] Step S3.4: After performing finite element modeling of the assembly consisting of the propellant management device structure and the base 4, perform overload simulation and optimize based on the simulation results. The lateral overload simulation results should meet the following conditions. If not, repeat the simulation until they are met: 1) Under overload conditions, the maximum equivalent stress at the connection between the accumulator 6 and the base 4 does not exceed 0.9 times the material yield stress σ. y ;2) Under overload conditions, the maximum equivalent stress of the metal mesh screen does not exceed 0.9 times the material yield stress σ. ys 3) Local stress concentration must not occur in the propellant management device.

[0052] Step S4: Model and simulate the optimized tank shell and the optimized propellant management device to obtain the optimal structural parameters; specifically, this includes the following sub-steps: Step S4.1: Perform finite element modeling of the tank structure based on the optimized tank shell and the optimized propellant management device, and then conduct vibration simulation; Step S4.2: Perform iterative optimization based on the vibration simulation results until the optimal structural parameters are obtained. The vibration simulation results should meet the following condition; if not, repeat the simulation until it is met: Under vibration conditions, the maximum equivalent stress of the tank does not exceed 0.9 times the material yield stress σ. y The propellant management system must not experience localized stress concentration.

[0053] Example 1: The following describes the design method of the spherical inclined parallel tension tank for spacecraft according to the present invention, taking a spherical inclined parallel tension tank for spacecraft as an example.

[0054] Step S1: Based on the comprehensive analysis of the spacecraft liquid propulsion system requirements, determine the basic structural composition of the tank shell and propellant management device.

[0055] The performance requirements for the spacecraft's liquid propulsion system are shown in Table 1.

[0056]

[0057] Table 1: Specifications and Requirements for Liquid Propulsion System The tank shell includes a main shell and interfaces. The main shell includes a spherical shell 2, a flange connecting ring 3, and a base 4. The interfaces include a liquid port 5, a gas port 1, and a connecting port 8. The propellant management device includes an accumulator 6 and blades 7. The accumulator 6 includes inner and outer cylinders. The propellant management device is connected to the main shell via the base 4, the liquid port 5 is connected to the base 4, and the gas port 1 and connecting port 8 are connected to the spherical shell 2. The tank is connected to the propulsion system assembly structure via the flange connecting ring 3.

[0058] Step S2: Optimization of tank shell structure design. This includes the following steps: Step S2.1: Based on a total propellant usage of 1240L throughout the mission, and considering component tolerances and welding shrinkage with a 5% margin, determine the tank volume V. tank =1300L; The propellant management device volume V is determined after leaving a 10% margin based on the 10L propellant usage for mission reverse acceleration. PMD =11L. Considering that the storage media in the tank are MMH and MON-1, the titanium alloy TC4, which is first-order compatible with them, was selected as the tank material.

[0059] Step S2.2: Based on the tilted installation angle α, envelope and interface index requirements, determine that the base 4 and air port 1 are connected to the spherical shell 2 at the upper and lower poles of the storage tank installation state, respectively; based on the minimum connected volume V=40L, determine that the connection port 8 is located at the pole of the spherical shell 2 to satisfy the requirement.

[0060] Step S2.3: Based on the envelope index requirement of no more than Φ1450mm×1505mm and the tank volume V determined in step S2.1 tank =1300L determines the inner diameter D of the main shell. i =1358mm, the basic inner surfaces of all parts of the main shell of the storage tank are concentric spherical surfaces; based on the inner diameter D of the main shell... i =1358mm and propellant management device volume V PMD =11L determines the corresponding opening diameter D of the base and the spherical shell. d =356mm, satisfying D d ≤0.3D i The requirements are as follows: the minimum distance between the corresponding opening and the end face of the spherical shell should not be 370mm and should not be less than 100mm; based on the gas flow rate q of the storage tank. q =600g / s, liquid flow rate q y =600g / s, Continuous flow rate q l =600g / s The diameters of the gas inlet, liquid inlet, and connecting inlet are all determined to be 20mm. The diameter D of the gas inlet and the corresponding opening in the spherical shell is taken. q Liquid inlet and corresponding base opening D y Diameter D of the connecting port and the corresponding opening on the spherical shell l All are 50mm, meeting the requirement of 2 to 3 times the nominal diameter.

[0061] Step S2.4: Based on the tank pressure rating (p) c =2MPa, p T =3MPa,p b ≥4MPa) requirement and the main shell diameter D determined in step S2.3 i =1358mm, calculate its basic wall thickness t. bm =1.7mm and weld zone reinforcement wall thickness twm =2mm;

[0062] The basic wall thickness of the main shell is t bm and welded area reinforcement wall thickness t wm The calculation formula is as follows:

[0063]

[0064]

[0065] Calculated basic wall thickness t of the main shell bm and welded area reinforcement wall thickness t wm The following formula should be satisfied:

[0066]

[0067]

[0068]

[0069] Flange connection ring structure wall thickness t c Take the reinforcement wall thickness t of the main shell welding area wm =2mm.

[0070] Step S2.5: Based on the storage medium and vertical overload acceleration a V =18g, tilted installation angle α=35°, weight m tank =55kg, interface specifications and tank volume V determined in step S2.1 tank =1300L, calculate the flange lug thickness t of the flange connecting ring. f =12mm and quantity n=48. The specific process is as follows:

[0071]

[0072] Step S2.6: Based on the relevant parameters obtained in steps S2.4 and S2.5, perform detailed design of the basic area, connection transition area, and welding area of ​​each component of the tank shell. Specifically, the connection transition area of ​​each component of the main tank shell is determined by the basic wall thickness t of the basic area. bm The transition from 1.7mm to the reinforced wall thickness t in the welded area wm=2mm, the width is 10 times the wall thickness of the welding area, i.e., 20mm; the connection transition area of ​​the opening on the spherical shell is set around the central axis of the opening, and the remaining connection transition areas are all set around the central axis of the part; the welding area is designed with a thickness of 1.5 times the welding reinforcement wall thickness t according to the high-energy beam welding method. wm =2 lock bottom, i.e. 3mm; Step S2.7: Based on the tank shell structure obtained in step S2.6, use CREO software to perform three-dimensional modeling, determine the tank envelope as Φ1447mm×1503mm, and the weight as 52.4kg, both of which meet the index requirements.

[0073] Step S2.8: Based on the tank shell structure obtained in Step S2.6, finite element modeling was performed using ABAQUS mechanical simulation software, followed by pressure and overload simulations. Optimization was then performed based on the simulation results. The simulation results are as follows: 1) Working pressure p c The maximum equivalent stress of the lower tank shell is 403.2 MPa, which does not exceed the allowable tensile strength of the material [σ] = 447.5 MPa; 2) Verify the pressure p T The maximum equivalent stress of the lower tank shell is 689 MPa, which is no more than 0.9 times the material yield strength of 0.9σ. y =742.5MPa; 3) Burst pressure P b The maximum equivalent stress of the lower tank shell is 813 MPa, which does not exceed the tensile strength σ of the material. b =895MPa; 4) Under vertical overload conditions, the maximum vertical stress at the root of the tank flange lug is 501MPa, which does not exceed the allowable shear strength of the material [τ]=582MPa; 5) No local stress concentration occurs in the tank shell.

[0074] Step S3: Propellant management device structural design and optimization. This includes the following steps: Step S3.1: Based on the base diameter D determined in step S2.3... d =356mm and the propellant management device volume V determined in step S2.1 PMD =11L determines the outer cylinder diameter D of the accumulator. FSV-E =305mm and height H FSV-E =180mm. Satisfies D FSV-E =0.7~1D d H FSV-E =0.5~1D FSV-E Simultaneously satisfying:

[0075] Step S3.2: Based on the emission efficiency target E=99.6% and the tank volume V determined in step S2.1 tank =1300L Determine the internal volume V of the accumulator FSV-I =5.2L, based on the volume V of the accumulator cavity.FSV-I =7L and the outer diameter D of the accumulator determined in step S3.1 FSV-E =305mm and height H FSV-E =180mm determines the inner diameter D of the accumulator. FSV-I =180mm and height H FSV-I =230mm. Satisfies D FSV-I =0.2~0.6D FSV-E H FSV-I =1.1~1.3H FSV-E Simultaneously satisfying:

[0076] Step S3.3: Based on the fluid flow rate q y =600g / s, flow resistance ≤20000Pa, terminal acceleration a H-L =0.01g, a V-L =0.41g, and the propellant management device structure design is required according to the specifications. The inner and outer cylinder wall thicknesses are t. FSV The diameter is 1.5mm; a certain number of through holes with a diameter of 6mm are evenly distributed on its surface; a dense metal mesh for gas-liquid separation is sealed between the inner and outer cylinders, and the total area of ​​the through holes should meet the following requirements:

[0077] The late-stage metallic mesh satisfies:

[0078] Blade wall thickness t V Take 8 pieces of 1mm thickness and distribute them evenly along the axial direction of the accumulator.

[0079] Step S3.4: Using mechanical simulation software, a finite element model is created for the assembly consisting of the propellant management device structure obtained in Step S3.3 and the base obtained in Step S2. Overload simulation is then performed, and optimization is based on the simulation results. Specifically, the lateral overload simulation results should meet the following conditions: 1) Under overload conditions, the maximum equivalent stress at the connection between the accumulator and the base is 372 MPa, not exceeding 0.9 times the material yield stress of 0.9σ. y =742.5MPa; 2) Under overload conditions, the maximum equivalent stress of the metal mesh screen is 126MPa, which does not exceed 0.9 times the material yield stress of 0.9σ. ys =153MPa; 3) No local stress concentration occurred in the propellant management device.

[0080] Step S4: Overall optimization of the tank. This includes the following steps: Step S4.1: Based on the optimized shell and propellant management device obtained in Steps S2 and S3, vibration simulation is performed on the tank structure using finite element modeling software.

[0081] Step S4.2: Perform iterative optimization based on simulation results until the optimal structural parameters are obtained.

[0082] In step S4, the vibration simulation results should meet the following conditions: 1) Under vibration conditions, the maximum equivalent stress of the tank is 483 MPa, and the stress does not exceed 0.9 times the material yield stress of 0.9σ. y =742.5MPa; 2) No local stress concentration was observed in the propellant management device.

[0083] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0084] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A design method for a spherical inclined parallel tension tank for spacecraft, characterized in that, The process includes the following steps: Step S1: Based on the performance requirements of the spacecraft's liquid propulsion system, a comprehensive analysis is conducted to determine the basic structural composition of the tank shell and propellant management device; Step S2: Based on the performance requirements of the spacecraft's liquid propulsion system, the structural design of the tank shell is optimized to obtain the optimized tank shell. Step S3: Based on the performance requirements of the spacecraft liquid propulsion system and the structural parameters of the optimized tank shell, the propellant management device is structurally optimized to obtain the optimized propellant management device; Step S4: Model and simulate the optimized tank shell and the optimized propellant management device to obtain the optimal structural parameters.

2. The design method for a spherical inclined parallel tension tank for spacecraft according to claim 1, characterized in that, In step S1, the performance requirements for the spacecraft liquid propulsion system include: storage medium, pressure resistance, dynamics, flow rate, and flow resistance. Emission efficiency E, total / real-time propellant usage throughout the mission, acceleration, tilt angle α, minimum connectivity volume V, envelope and interface, and weight m. tank The pressure-bearing index includes the working pressure p. c Verify pressure p T And blast pressure p b The kinetic parameters include lateral overload acceleration a. H Vertical overload acceleration a V The vibration frequency and magnitude, the flow rate index includes the airflow rate q. g Liquid flow rate q y and connectivity q l The tank housing includes a main housing and an interface. The main housing includes a spherical shell (2), a flange connecting ring (3), and a base (4). The interface includes a liquid port (5), a gas port (1), and a connecting port (8). The base (4) is installed at the bottom of the spherical shell (2). The liquid port (5) is installed at the bottom of the base (4). The gas port (1), the connecting port (8), and the flange connecting ring (3) are all installed outside the spherical shell (2). The propellant management device includes a accumulator (6) and a blade (7). The accumulator (6) includes an inner cylinder and an outer cylinder. The blade (7) is located outside the outer cylinder of the accumulator (6). The accumulator (6) is installed on the base (4) and located inside the spherical shell (2).

3. The design method for a spherical inclined parallel tension tank for spacecraft according to claim 2, characterized in that, Step S2 includes the following sub-steps: Step S2.1: Determine the tank volume V according to the total / real-time propellant usage requirements for the entire mission. tank The volume V of the propellant management device PMD According to the storage medium, the pressure, and the weight m tank The material of the storage tank was initially determined based on the required specifications; Step S2.2: Determine the specific connection positions of the base (4), the air inlet (1), and the connecting port (8) with the spherical shell (2) according to the tilted installation angle α, the envelope and interface index requirements; Step S2.3: According to the envelope index requirements and the tank volume V tank Determine the inner diameter D of the main housing i According to the inner diameter D of the main housing i and the volume V of the propellant management device PMD Determine the corresponding opening diameter D of the base (4) and the spherical shell (2). d According to the gas flow rate q q Determine the corresponding opening diameter D of the air inlet (1) and the spherical shell (2). q According to the fluid flow rate q y Determine the corresponding opening diameter D of the liquid outlet (5) and the base (4). y According to the connectivity flow q l Determine the diameter D of the corresponding opening of the connecting port (8) and the spherical shell (2). l ; Step S2.4: Based on the pressure bearing requirements, tank material, and main shell diameter D... i Calculate the basic wall thickness t of the main shell bm and welded area reinforcement wall thickness t wm Based on the reinforcement wall thickness t of the main shell welding area wm Determine the wall thickness t of the flange connecting ring (3) c Step S2.5: Based on the storage medium and the vertical overload acceleration a V The inclined installation angle α, the weight m tank The interface specifications and the tank volume V tank Calculate the flange lug thickness t of the flange connecting ring (3). f And the quantity n; Step S2.6: Based on the basic wall thickness t of the main shell bm The main shell welding area reinforcement wall thickness t wm The structural wall thickness t of the flange connecting ring (3) c The flange lug thickness t of the flange connecting ring (3) f The structure of the basic area, connection transition area and welding area of ​​each part of the tank shell is designed according to the quantity n; Step S2.7: Based on the tank shell structure obtained in step S2.6, perform a three-dimensional model to determine whether the tank envelope and weight meet the requirements. If they meet the requirements, continue to step S2.

8. If they do not meet the requirements, repeat steps S2.1-S2.7 until they meet the requirements. Step S2.8: Based on the tank shell structure that meets the requirements, perform finite element modeling, conduct pressure and overload simulations, and optimize according to the simulation results.

4. The design method for a spherical inclined parallel tension tank for spacecraft according to claim 3, characterized in that, Step S3 includes the following sub-steps: Step S3.1: Based on the diameter D d With the propellant management device volume V PMD Determine the outer diameter D of the accumulator (6). FSV-E and height H FSV-E Step S3.2: Based on the emission efficiency index and the tank volume V tank Determine the internal volume V of the accumulator (6). FSV-I According to the internal cavity volume V FSV-I The outer cylinder diameter D FSV-E The height H of the outer cylinder FSV-E Determine the inner diameter D of the accumulator (6). FSV-I and height H FSV-I Step S3.3: Based on the fluid flow rate q y The flow resistance The propellant management device structure is designed based on the terminal acceleration requirements, and the structure of the propellant management device is obtained. Step S3.4: After performing finite element modeling based on the combination of the propellant management device structure and the base (4), perform overload simulation and optimize according to the simulation results.

5. The design method for a spherical inclined parallel tension tank for spacecraft according to claim 1, characterized in that, Step S4 includes the following sub-steps: Step S4.1: After performing finite element modeling of the tank structure based on the optimized tank shell and the optimized propellant management device, vibration simulation is performed; Step S4.2: Perform iterative optimization based on the vibration simulation results until the optimal structural parameters are obtained.

6. The design method for a spherical inclined parallel tension tank for spacecraft according to claim 3, characterized in that, In step S2.1, the tank volume V tank The volume V of the propellant management device is determined after considering component tolerances and welding shrinkage, with a margin of 1-5%, based on the total propellant usage throughout the spacecraft mission. PMD After ensuring the propellant usage during each reverse overload period of the spacecraft is met, with a 5-10% margin, the tank material is determined to be first-class compatible with the propellant medium; in step S2.2, the base (4) and the air inlet (1) are connected to the spherical shell (2) at the upper and lower poles of the tank installation state, respectively, and the principle for determining the position of the connecting port (8) is: to be as far away from the base (4) as possible while meeting the minimum connecting volume V index requirement; in step S2.3, the basic inner surface of each part of the main shell of the tank is a concentric spherical surface, and the corresponding opening diameter D of the base (4) and the spherical shell (2) is determined. d Not greater than the inner diameter D of the tank shell i The diameter of the air inlet and the corresponding opening of the spherical shell (2) is 0.3 times that of the spherical shell (2), and the minimum distance between the corresponding opening and the end face of the spherical shell is not less than 100 mm. q The diameter D of the corresponding opening of the liquid inlet and the base y The diameter D of the connecting port and the corresponding opening of the spherical shell l All are taken as 2 to 3 times the corresponding nominal diameter; in step S2.4, the basic wall thickness t of the main shell is... bm and the wall thickness t of the welding area reinforcement wm The calculation formula is as follows: Where [σ] is the allowable tensile strength of the material, t c Here, t' is the corrosion allowance, φ is the rounding allowance, and φ is the welding coefficient. Where, σ y σ is the yield strength of the material. b The tensile strength of the material; the calculated basic wall thickness t of the main shell. bm and the wall thickness t of the welding area reinforcement wm Satisfy the following formula: In step S2.5, the flange lug thickness t of the flange connecting ring (3) f The calculation formula is as follows: Where F is the total pressure, e is the distance from the center of the lug mounting hole to the root of the lug, and b is the width of the lug root. Where ρ is the propellant density; the flange connecting ring (3) has a structural wall thickness t c Take 1 to 1.2 times the reinforcement wall thickness t of the main shell welding area wm In step S2.6, the connection transition area of ​​each component of the main shell of the storage tank is determined by the basic wall thickness t of the basic area. bm Transition to the welded area reinforcement wall thickness t wm The width is 3 to 10 times the width of the welding area. The connecting transition area with the opening on the spherical shell (2) is set around the central axis of the opening. The remaining connecting transition areas are set around the central axis of the parts. The welding area is designed with a butt joint surface according to the welding form. The simulation results in step S2.8 should meet the following conditions. If they are not met, the simulation should be repeated until they are met: working pressure p c The maximum equivalent stress of the tank shell described below does not exceed the allowable tensile strength of the material [σ]; verify the pressure p. T The maximum equivalent stress of the tank shell described below shall not exceed 0.9 times the material yield strength σ. y Explosive pressure P b The maximum equivalent stress of the tank shell described below does not exceed the tensile strength σ of the material. b Under vertical overload conditions, the maximum vertical stress at the root of the flange connecting ring lug shall not exceed the allowable shear strength of the material [τ]; local stress concentration shall not occur in the tank shell.

7. The design method for a spherical inclined parallel tension tank for spacecraft according to claim 3 or 6, characterized in that, When high-energy beam welding is used in the welding zone, the inward design thickness is 0.5 to 1.5 times the welding reinforcement wall thickness t. wm The bottom of the lock; when the welding area is argon arc welded, the design thickness is 0.2~0.5 times the welding reinforcement wall thickness t. wm The slope.

8. The design method for a spherical inclined parallel tension tank for spacecraft according to claim 4, characterized in that, In step S3.1, the outer cylinder diameter D of the liquid accumulator (6) FSV-E Take 0.7 to 1 times the base diameter D. d The height H of the outer cylinder of the accumulator (6) FSV-E Take the outer cylinder diameter D of the liquid accumulator (6) FSV-E 0.5 to 1 times, while simultaneously satisfying: In step S3.2, the inner diameter D of the liquid accumulator (6) FSV-I Take 0.2~0.6 times the outer cylinder diameter D FSV-E The height H of the inner cylinder of the accumulator (6) FSV-I Take the height H of the outer cylinder of the liquid accumulator (6) FSV-E 1.1 to 1.3 times, while simultaneously satisfying: In step S3.3, the wall thickness t of the inner and outer cylinders of the liquid accumulator (6) FSV The surface of the tank has multiple through holes with a diameter of 4-8 mm, with a diameter of 1-3 mm. A dense metal mesh for gas-liquid separation is sealed between the inner and outer cylinders. The total area of ​​the through holes meets the flow resistance index of the tank under the flow rate q. The calculation formula is as follows: in, To reduce the flow resistance of propellant through the densely textured metal mesh, For dynamic pressure difference, For static pressure difference, The flow resistance caused by the liquid passing through the liquid outlet; the final metal mesh satisfies: in, The flow resistance of the propellant through the screen in the final stage, a is the final acceleration, h is the distance from the liquid surface to the highest point of the metal mesh, and BP is the bubble burst point of the metal mesh; the wall thickness t of the blade (7) V Take 1~1.5mm pieces, in quantities of 4~16 pieces, and distribute them evenly along the circumference of the liquid accumulator (6).

9. The design method for a spherical inclined parallel tension tank for spacecraft according to claim 4 or 8, characterized in that, In step S3.4, the simulation results of transverse overload should meet the following conditions. If they are not met, the simulation should be repeated until they are met: Under overload conditions, the maximum equivalent stress at the connection between the accumulator (6) and the base (4) does not exceed 0.9 times the material yield stress σ. y Under overload conditions, the maximum equivalent stress of the metal mesh screen does not exceed 0.9 times the material yield stress σ. ys The propellant management device must not experience localized stress concentration.

10. The design method for a spherical inclined parallel tension tank for spacecraft according to claim 5, characterized in that, The vibration simulation results in step S4 should meet the following conditions. If they do not, the simulation should be repeated until they are met: the maximum equivalent stress of the tank under vibration conditions does not exceed 0.9 times the material yield stress σ. y The propellant management device must not experience localized stress concentration.

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