Storage tank flow stabilizing equipment of liquid rocket and parameter determining method

Abstract

The invention provides storage tank flow stabilization equipment of a liquid rocket and a parameter determination method. The storage tank flow stabilization equipment comprises a first flow stabilization device and a second flow stabilization device, the first flow stabilizing device comprises a filter screen, a filter screen framework, an anti-collapse plate and fins; the second flow stabilizing device comprises a circular ring and a cross-shaped partition plate, in the flying process of the rocket, the circular ring is used for restraining the large shaking of the liquid caused by the acceleration change, and the cross-shaped partition plate is used for dividing the flow field of the liquid at the bottom of the rocket; when the liquid level in the storage tank is reduced, the anti-collapse plate is used for preventing local collapse of the liquid level; the fins are used for scattering residual vortexes, reaching the outlet area, of the cross partition plate. Through reasonable layout of all the components, the problems of rotation, shaking, collapse and the like of the propellant in the storage tank of the liquid rocket are reduced, continuous and reliable supply of the propellant in the storage tank is guaranteed, the installation efficiency is improved, and the installation difficulty is reduced.

Description

Technical Field

[0001] This invention relates to the field of spacecraft design technology, and also to a liquid rocket tank flow stabilization device and parameter determination method. Background Technology

[0002] During rocket flight, the propellant exists in a free liquid state within the propellant tank. Under the influence of flight loads, the propellant may experience sloshing, swirling, or surface collapse, all of which are detrimental to normal engine operation. To ensure a continuous and reliable propellant supply and guarantee normal engine operation, a rational design of the tank bottom is necessary. Existing propellant tanks with ellipsoidal bottoms are mostly formed by welding together a top cover and a petal-shaped structure; however, this structure has relatively low volumetric efficiency and is not conducive to rocket weight reduction design. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a liquid rocket propellant tank flow stabilization device and parameter determination method to ensure a continuous and reliable supply of propellant in the tank.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A liquid rocket propellant tank flow stabilization device, comprising: A first flow stabilizing device is fixedly connected to the bottom of a storage tank, wherein the bottom of the storage tank is an ellipsoidal bottom; A second flow stabilizing device that is located at a target distance from the first flow stabilizing device and is fixedly connected to the inner surface of the tank; The first current stabilizing device includes: Filter screen; A filter frame is installed at the bottom of the storage tank and connected to the filter screen, the filter frame being used to provide rigid support for the filter screen; An anti-collapse plate connected to the filter mesh frame, the anti-collapse plate extending out of the filter mesh frame; The fins are fixedly connected to the anti-collapse plate; The second current stabilizing device includes: A ring connected to the inner surface of the storage tank; A cross-shaped partition connected to the ring; During rocket flight, the ring is used to suppress large liquid sloshing caused by changes in acceleration; the cross baffle is used to divide the flow field of the liquid at the bottom of the tank, breaking the swirling flow of the liquid and allowing the liquid to flow smoothly towards the central outlet; when the liquid level in the tank drops, the anti-collapse plate is used to prevent local collapse of the liquid surface; the fins are used to disperse the residual vortices that reach the outlet area from the cross baffle, achieving non-swirling outflow.

[0005] Optionally, the bottom of the storage tank further includes: A vent flange is installed on the side away from the first and second flow stabilizers. The vent flange is used to fill propellant before rocket launch and to vent propellant after mission abort or testing.

[0006] Optionally, the bottom of the storage tank further includes: The outlet flange 7 is fixedly connected to the filter screen frame and is used as a sealing interface to connect the storage tank and the engine delivery pipeline.

[0007] Optionally, the filter frame includes an integrally formed support column and a base; the support column is vertically disposed on the edge of the base, and the filter screen is fixedly connected between two adjacent support columns.

[0008] Optionally, the bottom of the storage tank further includes: A transition flange for the tunnel pipe that is fixedly connected to the bottom of the storage tank; A tunnel pipe assembly is fixedly connected to the top of the adapter flange, the tunnel pipe assembly being used to provide a sealed passage for the sensor cables and pressurization lines inside the box to pass through the bottom of the box.

[0009] Optionally, the ring includes multiple quarter rings of the same size, with adjacent quarter rings connected by corner plates, and the ring is fixedly connected to the cross-shaped partition plate through the corner plates.

[0010] Optionally, the cross-shaped partition includes multiple partitions that are perpendicular to each other and fixedly connected, each partition having multiple holes evenly distributed on it, and the front end of each partition being attached to the inner surface of the tank.

[0011] A method for determining parameters of a liquid rocket propellant tank flow stabilization device, applied to the aforementioned liquid rocket propellant tank flow stabilization device, comprising: Obtain the structural parameters and outflow performance constraints of the target tank. The structural parameters include the ellipsoidal geometry of the tank bottom, the outer diameter of the filter screen frame, and the outer diameter of the cross-shaped baffle. The outflow performance constraints include the minimum operating liquid level, the maximum allowable outflow entrainment ratio, and the allowable additional system pressure drop. Based on the structural parameters, a parameter processing model and optimization variables for the current stabilization device are determined, wherein the optimization variable is the axial distance between the center of the first current stabilization device and the center of the second current stabilization device; Based on the lowest working liquid level in the outflow performance constraint data, the optimization variable is extracted within its preset value range to obtain multiple candidate distance values.

[0012] The multiple candidate distance values ​​are input into the parameter processing model of the flow stabilization device to perform transient two-phase flow simulation processing and obtain the flow field dataset. The flow field dataset is extracted and processed to obtain the system performance evaluation index corresponding to each candidate distance value. The system performance evaluation index includes the air entrainment risk index, the liquid surface stability index, and the vortex suppression index of the cross-shaped baffle region. Based on the system performance evaluation index and the outflow performance constraint data, a total objective function is determined, and the optimization objective is to minimize the value of the total objective function. The optimal target distance between the first and second current stabilizing devices is then determined from the multiple candidate distance values.

[0013] Optionally, the formula for calculating the air entrapment risk index is: ; in, Indicates the risk index of gas entrapment. Indicates the start time of the simulation. Indicates the simulation termination time. This represents the gas volume fraction at the outlet at time t. This represents a series of candidate values ​​for the optimization variable L within a preset range [L_min, L_max]. The formula for calculating the liquid level stability index is: ; in, Indicates the stability index of the liquid level. This represents the lowest liquid level height along the tank axis at time t; The formula for calculating the vortex suppression index is: ; in, Indicates the vortex suppression index. Represents the spatial point at time t vorticity at a given location. This indicates the fluid space region near the pre-set cross-shaped partition.

[0014] Optionally, the expression for the overall objective function is: ; in, Let be the overall objective function. , , Indicates the weighting coefficient. This represents the total volume of gas entering the pipe during the entire outflow process at a distance of L_i. This represents the normalized reference benchmark for the gas trap risk index. This represents the height of the lowest point of the liquid surface during the entire outflow process at a distance of L_i. The normalized reference standard representing the liquid level height index This represents the rotational intensity measure of the most intense vortex appearing in the cross-shaped diaphragm region at a distance of L_i. This represents the normalized reference standard for vortex intensity indices.

[0015] The above-described solution of the present invention has at least the following beneficial effects: The above-mentioned solution of the present invention, through the rational layout of components such as ellipsoidal base, filter screen, filter screen skeleton, anti-collapse plate, fins, ring, and cross partition, minimizes problems such as propellant swirl, shaking, and collapse in the liquid rocket's propellant tank, ensures a continuous and reliable supply of propellant in the tank, improves installation efficiency, and reduces installation difficulty. Attached Figure Description

[0016] Figure 1 This is an overall structural diagram of the liquid rocket's tank flow stabilization device according to the present invention; Figure 2 This is a side sectional view of the liquid rocket's tank flow stabilization device of the present invention; Figure 3 This is a schematic diagram of the connection points of various components in the liquid rocket's tank flow stabilization device of the present invention; Figure 4 This is a schematic diagram of the first current stabilizing device of the present invention; Figure 5 This is a flowchart illustrating the method for determining the parameters of the liquid rocket's propellant tank flow stabilization device according to the present invention.

[0017] Explanation of reference numerals in the attached figures: 1: Ellipsoidal base; 2: Circular ring; 3: Cross-shaped partition; 4: Tunnel pipe assembly; 5: Tunnel pipe transition flange; 6: Anti-collapse plate; 7: Outlet flange; 8: Add / relieve flange; 9: Fin; 10: Filter screen frame; 11: Welding joint between outlet flange and tank bottom; 12: Welding joint between add / relieve flange and tank bottom; 13: Welding joint between tunnel pipe transition flange and tank bottom; 14: Threaded connection between circular ring and cross-shaped partition; 15: Threaded connection between circular ring and tank bottom; 16: Threaded connection between cross-shaped partitions; 17: Threaded connection between cross-shaped partition and tank bottom; 18: Connection between tunnel pipe assembly and tunnel pipe transition flange; 19: Threaded connection between filter screen frame and outlet flange; 20: Threaded connection between anti-collapse plate and filter screen frame; 21: Threaded connection between fin and anti-collapse plate; 22: Threaded connection between fin and ellipsoidal base. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0019] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a liquid rocket propellant tank flow stabilization device, comprising: A first flow stabilizing device is fixedly connected to the bottom of the storage tank, wherein the bottom of the storage tank is an ellipsoidal bottom 1; A second flow stabilizing device that is located at a target distance from the first flow stabilizing device and is fixedly connected to the inner surface of the tank; The first current stabilizing device includes: Filter screen; The filter frame 10 is disposed at the bottom of the storage tank and connected to the filter screen, and the filter frame 10 is used to provide rigid support for the filter screen; An anti-collapse plate 6 is connected to the filter frame 10, and the anti-collapse plate 6 extends out of the filter frame 10; The fins 9 are fixedly connected to the anti-collapse plate 6; The second current stabilizing device includes: The ring 2 is connected to the inner surface of the storage tank; The cross-shaped partition 3 is connected to the ring 2; During rocket flight, the ring 2 is used to suppress large liquid sloshing caused by changes in acceleration; the cross baffle 3 is used to divide the flow field of the liquid at the bottom of the tank, break the swirling flow of the liquid, and make the liquid flow smoothly towards the central outlet; when the liquid level in the tank drops, the anti-collapse plate 6 is used to prevent local collapse of the liquid surface; the fins 9 are used to disperse the residual vortices that reach the outlet area from the cross baffle 3, so as to achieve non-swirling outflow.

[0020] In this embodiment, the liquid rocket tank flow stabilization device includes a first flow stabilization device and a second flow stabilization device, both integrated inside the ellipsoidal base 1. The first flow stabilization device includes a filter screen, a filter screen frame 10, an anti-collapse plate 6, and fins 9. The filter screen frame 10 is fixedly installed at the center of the bottom of the ellipsoidal base 1, providing rigid support for the filter screen. The anti-collapse plate 6 is connected to the filter screen frame 10 and extends outward to prevent liquid surface collapse. The fins 9 are fixed to the anti-collapse plate 6 to disperse vortices. The second flow stabilization device consists of a circular ring 2 and a cross-shaped partition 3. The circular ring 2 is fixedly connected to the inner wall of the ellipsoidal base 1 to suppress large liquid sloshing. The cross-shaped partition 3 is connected to the circular ring 2 to divide the flow field at the bottom of the tank, breaking the swirling flow of the liquid. All components are connected by standard parts such as bolts to ensure structural stability and convenient installation.

[0021] During installation and use, in rocket flight, the circular ring 2 first suppresses large-angle sloshing of the liquid caused by changes in acceleration; the cross-shaped baffle 3 further divides the flow field, allowing the liquid to flow smoothly towards the central outlet; when the liquid level in the tank decreases, the anti-collapse plate 6 effectively prevents local collapse of the liquid surface, while the fins 9 disperse residual vortices that the cross-shaped baffle 3 could not completely eliminate, achieving vortex-free outflow; the filter screen continuously filters out excess material. The entire system, through the synergistic effect between its components, ensures a stable supply of propellant and reliable engine operation in complex flight environments.

[0022] The optimal target distance between the first current stabilizing device and the second current stabilizing device is determined through the following process: (1) Obtain the structural parameters and outflow performance constraint data of the target tank, wherein the structural parameters include the ellipsoidal geometry of the tank bottom, the outer diameter of the filter screen frame 10 and the outer diameter of the cross partition 3; the outflow performance constraint data includes the minimum working liquid level, the maximum allowable outflow entrainment ratio and the allowable additional system pressure drop; (2) Based on the structural parameters, determine the parameter processing model and optimization variables of the current stabilization device, wherein the optimization variable is the axial distance between the center of the first current stabilization device and the center of the second current stabilization device; (3) Based on the lowest working liquid level in the outflow performance constraint data, the optimization variable is extracted within its preset value range to obtain multiple candidate distance values; (4) Input the multiple candidate distance values ​​into the parameter processing model of the flow stabilization device, perform transient two-phase flow simulation processing, and obtain the flow field dataset; (5) Extract and process the flow field dataset to obtain the system performance evaluation index corresponding to each candidate distance value. The system performance evaluation index includes the air entrainment risk index, the liquid surface stability index, and the vortex suppression index of the cross baffle 3 region. (6) Based on the system performance evaluation index and the outflow performance constraint data, determine the overall objective function, and optimize the optimal target distance between the first flow stabilizing device and the second flow stabilizing device from the multiple candidate distance values, with minimizing the value of the overall objective function as the optimization objective.

[0023] In some alternative implementations, the formula for calculating the air entrapment risk index is: ; in, Indicates the risk index of gas entrapment. Indicates the start time of the simulation. Indicates the simulation termination time. This represents the gas volume fraction at the outlet at time t. This represents a series of candidate values ​​for the optimization variable L within a preset range [L_min, L_max]. The formula for calculating the liquid level stability index is: ; in, Indicates the stability index of the liquid level. This represents the lowest liquid level height along the tank axis at time t; The formula for calculating the vortex suppression index is: ; in, Indicates the vortex suppression index. Represents the spatial point at time t vorticity at a given location. This indicates the fluid space region near the preset cross-shaped partition 3.

[0024] In some alternative implementations, the expression for the overall objective function is: ; in, Let be the overall objective function. , , Indicates the weighting coefficient. This represents the total volume of gas entering the pipe during the entire outflow process at a distance of L_i. This represents the normalized reference benchmark for the gas trap risk index. This represents the height of the lowest point of the liquid surface during the entire outflow process at a distance of L_i. The normalized reference standard representing the liquid level height index This represents the rotational intensity measure of the most intense vortex appearing in region 3 of the cross-shaped diaphragm at a distance of L_i. This represents the normalized reference standard for vortex intensity indices.

[0025] In some alternative implementations, according to Determine the spacing of the fins 9 that are fixedly connected around the perimeter of the anti-collapse plate 6, wherein, This represents the minimum value of the objective function for the spacing of fin 9. express, Indicates the weighting coefficient. This represents the standard deviation of the velocity distribution at a spacing of s. This represents the additional pressure drop generated when the spacing is s. This indicates the spacing between fins 9.

[0026] according to Determine the height of fin 9, where, The objective function representing the minimum value of the height of fin 9 is... Indicates the stable height of the target liquid level. This represents the actual minimum liquid level height measured in the simulation when the height of fin 9 is h. , This represents a weighting coefficient used to balance the importance of two objectives. This represents the average gas volume fraction monitored at the outlet when the height of fin 9 is h, where h represents the current height of fin 9.

[0027] according to Determine the diameter of each hole in the cross-shaped partition, where, This indicates the diameter of each hole in the partition. Indicates the effective vertical height in the liquid. This represents the empirical coefficient.

[0028] according to Determine the total area of ​​all holes in the cross-shaped diaphragm, where, This represents the total flow area of ​​all the openings. Indicates the total number of holes. Indicates the diameter of a single hole. Indicates the safety factor for current flow. This indicates the cross-sectional area of ​​the downstream pipeline.

[0029] according to Determine the solid wall thickness between the holes in the cross-shaped diaphragm, where, This indicates the minimum solid wall thickness between the holes in the cross-shaped diaphragm. Indicates the center distance of the holes. Indicates the diameter of a single hole. Indicates the strength reduction coefficient. This indicates the original thickness of the partition material.

[0030] At the structural design level, this invention employs a two-stage distributed flow stabilization system: the first flow stabilization device at the bottom (including a filter screen frame 10, anti-collapse plate 6, and fins 9) and the second flow stabilization device at the top (including a circular ring and a cross baffle) form a complementary and synergistic flow stabilization system. This achieves full-process flow control from macroscopic sloshing suppression to microscopic vortex elimination. Specifically, the circular ring effectively suppresses large-scale liquid sloshing, the cross baffle divides and breaks up the rotating flow field, the anti-collapse plate prevents local liquid surface collapse at low liquid levels, and the fins further disperse residual small-scale vortices. All components are connected using standard parts, ensuring structural reliability while facilitating assembly and maintenance.

[0031] Furthermore, this invention transforms the complex multi-component coupled flow problem of the first and second flow stabilization devices into a quantifiable and computable optimization problem: by establishing a parameterized digital model, the axial distance between the two stages is used as the core optimization variable; feasible design space is intelligently screened based on engineering constraints such as the minimum working liquid level; high-fidelity transient two-phase flow simulation is used to accurately predict flow characteristics at different distances; and finally, the optimal distance is scientifically determined through a multi-objective decision function. This process realizes the transformation from experience-based design to model-driven design, significantly improving design efficiency and accuracy.

[0032] In some alternative implementations, the tank bottom further includes: A vent flange 8 is provided on the side away from the first and second flow stabilizing devices. The vent flange 8 is used to add propellant before rocket launch and to vent propellant after mission abort or testing.

[0033] In this embodiment, the filling / removing flange 8 is located at the bottom of the tank, away from the first flow stabilizing device composed of the filter screen frame 10, the anti-collapse plate 6, and the fins 9, and the second flow stabilizing device composed of the anti-sway ring 2 and the cross partition 3. This layout ensures that the main pipeline for filling / removing operations does not interfere with the flow stabilizing and anti-swaying structures inside the tank bottom, facilitating pipeline installation and maintenance, while avoiding potential impacts of high-speed fluid on the flow stabilizing device during filling / removing.

[0034] In terms of specific connection, the vent flange 8 is connected by welding, as shown in the reference. Figure 3 The filling and draining flange 12 is welded to the bottom of the storage tank, and the filling and draining flange 8 is directly welded to the shell of the ellipsoidal base 1, forming a sealed, pressure-bearing, and reliable interface. Quick couplings or valves for external filling or draining pipelines can be connected to the storage tank through this flange.

[0035] During rocket launch preparation, the ground refueling system injects liquid propellant into the propellant tank through this refueling / draining flange 8. If the rocket launch mission is aborted, or after ground testing is completed, the remaining propellant in the propellant tank needs to be safely recovered into the ground storage tank through this refueling / draining flange 8. This function is crucial for ensuring test safety, reducing mission costs, and performing propellant recovery and disposal.

[0036] In some alternative implementations, the tank bottom further includes: The outlet flange 7 is fixedly connected to the filter screen frame 10. The outlet flange 7 is used to connect the sealed interface between the storage tank and the engine delivery pipeline.

[0037] In this embodiment, the outlet flange 7 is a key sealing and pressure-bearing interface connecting the inside of the storage tank to the engine propellant delivery pipeline. This outlet flange 7 is directly and sealingly connected to the ellipsoidal base 1 of the tank via welding (see reference). Figure 4(Connection 11), forming part of the pressure-bearing structure, establishes the final outlet location for propellant outflow.

[0038] In some alternative implementations, the filter frame 10 includes an integrally formed support column and a base; the support column is vertically disposed on the edge of the base, and the filter screen is fixedly connected between two adjacent support columns.

[0039] In this embodiment, the filter frame 10 is not only a supporting structure for the filter, but also a connection to the anti-collapse plate 6 (see reference). Figure 4 The key components of the anti-collapse plate 6 and the filter screen frame 10 (20) and the outlet flange 7 (see reference) Figure 4 The filter screen frame 10 is bolted to the outlet flange 7 at point 19. The filter screen frame 10 is manufactured using a one-piece molding process, and its main structure consists of a base and a support column. Specifically: The base is a disc-shaped or annular structure with a central through hole and peripheral connecting holes. The central through hole of the base is aligned with the inner diameter of the outlet flange 7, forming the main flow path of the propellant. Bolt holes 19 are provided on the base for bolting the filter screen skeleton to the outlet flange.

[0040] The support pillars consist of multiple pillars extending vertically upwards along the circumferential edge of the base (the anti-collapse plate 6 is screwed to the pillars, thus achieving the screwing connection between the anti-collapse plate 6 and the filter screen frame 10, see reference). Figure 4 (The threaded connection is 20). The number, cross-sectional shape, and height of the supports are designed and optimized according to the size of the filter screen and the required rigidity. A "window" is formed between two adjacent supports. The filter screen (usually a high-mesh metal wire mesh) is cut to a size that matches the shape of the "window" and fixedly connected between the two adjacent supports by welding, brazing, or special mechanical clamping. In this way, all the supports and the base together form a sturdy cage-like or cylindrical frame, and the filter screen covers the lateral flow area of ​​the frame.

[0041] Connected to the anti-collapse plate 6 are fins 9, which are typically long, strip-shaped plates. At their root (the end closest to the anti-collapse plate 6), there are one or more through holes (21 where the fin is screwed to the anti-collapse plate, and 22 where the fin is screwed to the ellipsoidal base). Each fin 9 is screwed to the anti-collapse plate through holes and bolts. Each fin 9 is also screwed to the ellipsoidal base via corner plates.

[0042] In some alternative implementations, the tank bottom further includes: The adapter flange 5 of the tunnel pipe is fixedly connected to the bottom of the storage tank; The tunnel pipe assembly 4 is fixedly connected to the top of the tunnel pipe adapter flange 5. The tunnel pipe assembly 4 is used to provide a sealed channel for the sensor cables and pressurization pipelines inside the box to pass through the bottom of the box.

[0043] In this embodiment, the transition flange 5 is welded (corresponding to the attached...). Figure 3 The 13 welds in the flange are directly fixed to the box body of the ellipsoidal base 1, forming a pressure-bearing and sealed base. The flange is usually located in the non-central area of ​​the bottom of the box, and is kept at a certain distance from the outlet, filling and drain ports, etc., to avoid interfering with the main fluid flow.

[0044] In terms of specific connection, the tunnel pipe assembly 4 is connected via its bottom flange (corresponding to the attached flange). Figure 3 The 18 points in the tunnel pipe assembly are bolted to the tunnel pipe adapter flange 5 welded to the bottom of the box. This flange-to-flange connection method ensures the sealing and disassembly of the connection, facilitating the installation, maintenance, or replacement of the tunnel pipe assembly itself.

[0045] In some alternative implementations, the ring 2 comprises a plurality of quarter rings of the same size, with adjacent quarter rings connected by corner bolts, and the ring 2 is fixedly connected to the cross partition 3 by the corner bolts.

[0046] In this embodiment, the composition and connection method of the ring 2, i.e., the anti-sloshing ring, are provided as a specific implementation scheme. In the liquid rocket tank flow stabilization device of the present invention, the anti-sloshing ring is used to form the main structure of the second flow stabilization device for suppressing liquid sloshing.

[0047] The ring 2 is composed of four quarter-circular segments (i.e., quarter rings) with identical structural dimensions. The modular design is primarily based on the following engineering considerations: First, it reduces the manufacturing difficulty and tooling costs of individual parts, especially for large-diameter tanks where the forming, transportation, and installation of an integral ring structure are quite difficult; second, the modular design facilitates internal assembly and subsequent maintenance through the relatively small manhole on the tank. The ring 2 has through holes, through which the ring 2 is screwed to the bottom of the tank (i.e., the screw connection point 15 between the ring and the bottom of the tank).

[0048] Regarding the assembly and connection of Ring 2 itself: Connecting corner pieces are pre-installed or installed at the ends of the two quarter rings that need to be spliced. During installation, align the ends of the two quarter rings so that the through holes on their shared connecting corner pieces are aligned with the mounting holes at the ends of the quarter rings. Then, use bolts, nuts, and supplemented with washers and fuses to tighten and prevent loosening. In this way, the four quarter rings are connected in pairs, ultimately forming a complete rigid circular ring structure within the cross-section of the tank.

[0049] Regarding the fixed connection between the circular ring 2 and the cross-shaped partition 3: the connecting corner pieces are not only used to connect adjacent 1 / 4 rings, but some corner pieces at specific locations (corresponding to point 14 in the connection description) are also designed with additional connection interfaces. Corresponding mounting holes are also provided at the ends or specific parts of the cross-shaped partition 3. During assembly, the corresponding part of the cross-shaped partition 3 is placed tightly against the inner side of the circular ring 2 or at the designated position, and then bolts are used to pass through the holes on the cross-shaped partition 3 and the additional through holes on the connecting corner pieces of the circular ring 2 to secure the two together. This connection method ensures that the cross-shaped partition 3 is firmly supported and positioned on the circular ring 2, and the two together form a cooperative flow-stabilizing assembly.

[0050] In some alternative implementations, the cross-shaped partition 3 includes multiple partitions that are perpendicular to each other and fixedly connected, each partition having multiple holes evenly distributed on it, and the front end of each partition being attached to the inner surface of the tank.

[0051] In this embodiment, the cross-shaped partition 3 is composed of four flat plate structures. In a typical implementation, four identical partitions are used. These four partitions are arranged at equal 90-degree intervals on the horizontal plane with the vertical centerline of the tank as the axis, thus forming a "cross" structure in the top view. They are connected to each other by a through hole (corresponding to point 16 in the connection description) in the central area where the four partitions intersect. During assembly, the centers of the four partitions are aligned, and a special connector (such as a central connecting block with bolts) is used, or the through holes of adjacent partitions are aligned and bolts are passed through and tightened to achieve rigid interconnection of the four partitions at the center point, forming an integral structure.

[0052] The cross-shaped partition 3 is also screwed to the bottom of the storage tank (corresponding to point 17 in the connection description).

[0053] The surface of the cross-shaped baffle 3 has multiple evenly distributed holes. These holes are typically circular, square, or other regular shapes. These holes allow limited fluid communication between different sectors separated by the baffle, helping to balance the pressure in each area and prevent excessive pressure differentials caused by complete isolation. Local resistance is generated when the fluid flows through the holes, which helps to further dissipate the fluid's rotational kinetic energy and enhances the vortex suppression effect. While ensuring structural strength, the perforated design effectively reduces the mass of the baffle itself.

[0054] This invention reduces problems such as propellant swirl, shaking, and collapse in liquid rocket tanks through the rational layout of components such as ellipsoidal base, filter screen, filter screen skeleton, anti-collapse plate, fins, ring, and cross partition. It ensures a continuous and reliable supply of propellant in the tank, improves installation efficiency, and reduces installation difficulty.

[0055] In one application scenario, the rocket has successfully launched, and the first-stage engine continues to operate. At this point, the flight control system issues a command for the rocket to perform a roll maneuver of approximately 30 degrees to adjust its flight attitude. This rapid turn subjectes the liquid propellant in the propellant tank to a strong lateral inertial force, causing the previously calm liquid surface to begin moving violently. At this moment, a ring fixed to the inner wall of the tank immediately comes into play. As the liquid surges in, it directly impacts the ring, dissipating and dispersing the kinetic energy of the liquid surge into numerous chaotic small eddies. This suppresses the liquid surge into manageable small-scale flow disturbances, ensuring the attitude stability of the rocket body during the maneuver.

[0056] Then, the small eddies are physically blocked by the cross-shaped baffles. The small holes in the baffles allow a small amount of liquid to pass through, balancing the pressures and preventing the generation of new instabilities.

[0057] As the engine continues to consume propellant, the propellant level steadily decreases. When the level drops to just above the bottom outlet of the tank, the surface is highly susceptible to localized depressions due to the complex flow field and the suction effect at the outlet. At this point, the anti-collapse plate provides physical support, preventing catastrophic localized collapses of the propellant level at critical locations and ensuring that the propellant always covers the outlet.

[0058] After being combed by the cross-shaped baffle, the liquid flowing from four directions to the central outlet area may still carry some residual rotational energy (residual vortices) that has not been completely eliminated. Several fins, vertically mounted on the anti-collapse plate, extend into this final confluence area, cutting into the liquid flow and completely breaking up and cutting these last, small rotating flows into even smaller turbulence, so that their rotational energy is completely dissipated.

[0059] Finally, any tiny particles that might fall out of the tank are intercepted by the filter, allowing the propellant to flow out cleanly and smoothly through the outlet flange.

[0060] All of these components are interconnected, gradually mitigating the complex and harmful fluid movements caused by the rocket's violent maneuvers and the final stages of exhaustion. This ensures that no matter how external conditions change, the propellant flowing out of the tank outlet is always the stable, pure, and continuous flow required by the engine.

[0061] like Figure 5 As shown, an embodiment of the present invention proposes a method for determining the parameters of a liquid rocket propellant tank flow stabilization device, applicable to the liquid rocket propellant tank flow stabilization device described in any of the above claims, comprising: Step 11: Obtain the structural parameters and outflow performance constraint data of the target tank. The structural parameters include the ellipsoidal geometry of the tank bottom, the outer diameter of the filter screen frame 10, and the outer diameter of the cross-shaped baffle 3. The outflow performance constraint data includes the minimum working liquid level, the maximum allowable outflow entrainment ratio, and the allowable additional system pressure drop. Step 12: Based on the structural parameters, determine the parameter processing model and optimization variables for the current stabilization device, wherein the optimization variable is the axial distance between the center of the first current stabilization device and the center of the second current stabilization device; Step 13: Based on the lowest working liquid level in the outflow performance constraint data, extract the optimization variable within its preset value range to obtain multiple candidate distance values.

[0062] Step 14: Input the multiple candidate distance values ​​into the parameter processing model of the flow stabilization device, perform transient two-phase flow simulation processing, and obtain the flow field dataset; Step 15: Extract and process the flow field dataset to obtain the system performance evaluation index corresponding to each candidate distance value. The system performance evaluation index includes the air entrainment risk index, the liquid surface stability index, and the vortex suppression index of the cross baffle 3 region. Step 16: Based on the system performance evaluation index and the outflow performance constraint data, determine the overall objective function, and optimize the optimal target distance between the first current stabilizing device and the second current stabilizing device from the multiple candidate distance values, with minimizing the value of the overall objective function as the optimization objective.

[0063] In step 11 of this embodiment, the structural parameters and outflow performance constraints of the target tank are obtained. The structural parameters include the major and minor axes of the generatrix of the tank's ellipsoidal base, the outer diameter of the filter mesh frame 10, and the outer diameter of the cross-shaped partition 3. The outflow performance constraints include the minimum operating liquid level required by engineering, the maximum propellant entrainment ratio allowed by the engine, and the maximum additional pressure loss allowed by the installation of this equipment in the hydraulic system.

[0064] In step 12, based on the obtained structural parameters, a parametric digital model of the flow stabilizing device is established in 3D modeling software, including an ellipsoidal base 1, a filter screen frame 10, an anti-collapse plate 6, fins 9, a ring 2, and a cross-shaped partition 3. This model is the parameter processing model of the flow stabilizing device. The tank flow stabilizing device includes: a first flow stabilizing device fixedly connected to the bottom of the tank, the bottom of the tank being an ellipsoidal base 1; a second flow stabilizing device located at a target distance from the first flow stabilizing device and fixedly connected to the inner surface of the tank; the first flow stabilizing device includes: a filter screen; a filter screen frame 10 disposed on the bottom of the tank and connected to the filter screen, the filter screen frame 10 providing rigid support for the filter screen; an anti-collapse plate 6 connected to the filter screen frame 10, the anti-collapse plate 6 extending beyond the filter screen frame 10; and a second flow stabilizing device fixedly connected to the inner surface of the tank. The anti-collapse plate 6 is fixedly connected to the fins 9; wherein, the second flow stabilizing device includes: a ring 2 connected to the inner surface of the tank; a cross-shaped baffle 3 connected to the ring 2; during rocket flight, the ring 2 is used to suppress large liquid sloshing caused by acceleration changes; the cross-shaped baffle 3 is used to divide the flow field of the liquid at the bottom of the tank, break the swirling flow of the liquid, and make the liquid flow smoothly towards the central outlet; when the liquid level in the tank decreases, the anti-collapse plate 6 is used to prevent local collapse of the liquid surface; the fins 9 are used to disperse the residual vortices reaching the outlet area through the cross-shaped baffle 3, achieving non-swirling outflow.

[0065] Meanwhile, the distance between the center of the first flow stabilizing device, i.e. the center of the filter screen frame 10, and the center of the second flow stabilizing device, i.e. the geometric center of the ring 2, in the direction of the tank axis is defined as the optimization variable.

[0066] In step 13, based on the constraint of the minimum working liquid level, to prevent the second flow stabilizing device from malfunctioning when the liquid level is too low, the preset value range of the optimization variables is limited to the range from the bottom vertex of the ellipsoid to the minimum working liquid level height. Within this range, multiple candidate distance values ​​are extracted using equal spacing or non-uniform methods.

[0067] In step 14, each candidate distance value is assigned to a parameterized digital model and imported into computational fluid dynamics software. Boundary and motion conditions consistent with the actual flight attitude and outflow process of the rocket are set to perform transient two-phase flow simulation calculations on the propellant discharge process inside the tank. The simulation records the velocity, pressure, and gas phase distribution data of the flow field inside the tank at each moment, forming a flow field dataset.

[0068] In step 15, the flow field dataset is post-processed and analyzed. For each simulation result, three system performance evaluation indicators are extracted: first, the air entrainment risk indicator, characterized by the duration for which the gas phase volume fraction at the outlet exceeds the threshold; second, the liquid surface stability indicator, characterized by the amplitude of liquid surface undulations near ring 2; and third, the vortex suppression indicator, characterized by the vortex intensity of the fluid in the downstream region of cross baffle 3.

[0069] In step 16, weights are assigned to each evaluation index based on the outflow performance constraint data, and a total objective function F is constructed. The optimization objective is to minimize the total objective function F. By comparing the F values ​​corresponding to each candidate distance value, the candidate distance value that minimizes the F value is determined as the optimal target distance between the first and second current stabilizing devices.

[0070] This method constructs a complete, closed-loop, and quantifiable design process, from design input, parametric modeling, simulation analysis to multi-objective decision-making. It effectively overcomes the shortcomings of traditional flow stabilization equipment design, which relies on empirical formulas, incurs high trial-and-error costs, and struggles to balance multiple performance indicators. By transforming a complex physical device (including a flow stabilization system with multiple components working collaboratively, such as filter frames, anti-collapse plates, fins, rings, and cross-shaped baffles) into a parametrically driven digital model, and using the core geometric parameter—the axial distance between the two-stage flow stabilization devices—as an optimization variable, it achieves precise description and efficient exploration of the design space.

[0071] In addition, this method places key engineering constraints such as "minimum working liquid level" in advance and directly transforms them into the value boundaries of optimization variables, ensuring the functional reliability of all candidate design schemes under extreme working conditions from the source.

[0072] Subsequently, with the help of high-fidelity transient two-phase flow simulation technology, it is possible to accurately predict the details and effects of a series of complex flow phenomena under different distance schemes, such as anti-collapse plate to prevent collapse, ring to suppress swaying, cross baffle to break vortex, and fin to eliminate residual vortex. It can also extract system performance indicators that can be directly quantified and compared, such as air trapping risk, liquid surface stability and vortex suppression degree.

[0073] Ultimately, by constructing a scientific multi-objective decision function, a systematic trade-off and global optimization of multiple coupled and even contradictory performance indicators was achieved while meeting the engine's rigid performance constraints (such as maximum entrainment ratio and maximum additional pressure drop). This not only reduced the development cycle and cost but also enabled the tailoring of optimal flow stabilization device parameters for specific mission models, effectively ensuring high reliability, stability, and efficiency of propellant supply for liquid rockets in complex flight environments, thereby improving the rocket's overall mission adaptability and reliability.

[0074] In some alternative implementations, the formula for calculating the air entrapment risk index is: ; in, Indicates the risk index of gas entrapment. Indicates the start time of the simulation. Indicates the simulation termination time. This represents the gas volume fraction at the outlet at time t. This represents a series of candidate values ​​for the optimization variable L within a preset range [L_min, L_max]. In this embodiment, the start time of the simulation and the current optimization variables are first determined. The value (input value) is the gas volume fraction at the outlet monitored at each moment during the simulation. Based on the gas volume fraction at the outlet monitored at all moments, the corresponding optimization variable is determined. The risk index of air entrainment is obtained. Finally, the risk index of air entrainment corresponding to each candidate value in [L_min, L_max] is obtained.

[0075] The formula for calculating the liquid level stability index is: ; in, Indicates the stability index of the liquid level. This represents the lowest liquid level height along the tank axis at time t; In this embodiment, the start time of the simulation and the current optimization variables are first determined. The value (input value) is the lowest liquid level height on the tank axis at each moment monitored during the simulation. Based on the lowest liquid level height on the tank axis at all monitored moments, the corresponding optimization variable is determined. The liquid level stability index is obtained. Finally, the liquid level stability index corresponding to each candidate value in [L_min, L_max] is obtained.

[0076] The formula for calculating the vortex suppression index is: ; in, Indicates the vortex suppression index. Represents the spatial point at time t vorticity at a given location. This indicates the fluid space region near the preset cross-shaped partition 3.

[0077] In this embodiment, the start time of the simulation and the current optimization variables are first determined. The value (input value) will be the eddy current of the monitored area at each moment during the simulation. Based on the eddy current at all monitored moments, the corresponding optimization variables will be determined. The vortex suppression index is obtained. Finally, the vortex suppression index corresponding to each candidate value in [L_min, L_max] is obtained.

[0078] In some alternative implementations, the expression for the overall objective function is: ; in, Let be the overall objective function. , , Indicates the weighting coefficient. This represents the total volume of gas entering the pipe during the entire outflow process at a distance of L_i. This represents the normalized reference benchmark for the gas trap risk index. This represents the height of the lowest point of the liquid surface during the entire outflow process at a distance of L_i. The normalized reference standard representing the liquid level height index This represents the rotational intensity measure of the most intense vortex appearing in region 3 of the cross-shaped diaphragm at a distance of L_i. This represents the normalized reference standard for vortex intensity indices.

[0079] In some alternative implementations, according to Determine the spacing of the fins 9 that are fixedly connected around the perimeter of the anti-collapse plate 6, wherein, This represents the minimum value of the objective function for the spacing of fin 9. express, Indicates the weighting coefficient. This represents the standard deviation of the velocity distribution at a spacing of s. This represents the additional pressure drop generated when the spacing is s. This indicates the spacing between fins 9.

[0080] according to The height of fixed fin 9, of which, The objective function representing the minimum value of the height of fin 9 is... Indicates the stable height of the target liquid level. This represents the actual minimum liquid level height measured in the simulation when the height of fin 9 is h. , This represents a weighting coefficient used to balance the importance of two objectives. This represents the average gas volume fraction monitored at the outlet when the height of fin 9 is h, where h represents the current height of fin 9.

[0081] according to Determine the diameter of each hole in the cross-shaped partition, where, This indicates the diameter of each hole in the partition. Indicates the effective vertical height in the liquid. This represents the empirical coefficient.

[0082] according to Determine the total area of ​​all holes in the cross-shaped diaphragm, where, This represents the total flow area of ​​all the openings. Indicates the total number of holes. Indicates the diameter of a single hole. Indicates the safety factor for current flow. This indicates the cross-sectional area of ​​the downstream pipeline.

[0083] according to Determine the solid wall thickness between the holes in the cross-shaped diaphragm, where, This indicates the minimum solid wall thickness between the holes in the cross-shaped diaphragm. Indicates the center distance of the holes. Indicates the diameter of a single hole. Indicates the strength reduction coefficient. This indicates the original thickness of the partition material.

[0084] In this embodiment, the air trapping risk index, liquid surface stability index, and vortex suppression index corresponding to each candidate value in [L_min, L_max] are input into the overall objective function. In, get each The total objective function value, corresponding to the minimum total objective function value. These were determined as the final optimization variables. Then, the spacing of the fins 9 fixedly connected around the anti-collapse plate 6, the minimum objective function value of the fin height 9, the diameter of each hole on the cross partition plate, the total area of ​​all holes on the cross partition plate, and the minimum solid wall thickness between the holes on the cross partition plate were determined in sequence.

[0085] In one application scenario of the method for determining the parameters of a liquid rocket's propellant tank flow stabilization device proposed in an embodiment of the present invention: 1. First, obtain the structural parameters of the target tank, including the ellipsoidal geometry of the tank bottom, the outer diameter of the filter screen frame 10, and the outer diameter of the cross-shaped baffle 3; determine the outflow performance constraint data, including the minimum working liquid level, the maximum allowable outflow entrainment ratio, and the allowable additional system pressure drop; 2. Within a reasonable range for the project (e.g., from L_min=0.5m to L_max=1.5m), select a series of candidate distance values ​​L_i at equal intervals; 3. For each L_i, simulate the flow field during the final stage of rocket engine operation and extract the air entrainment risk index. Liquid level stability index vortex suppression index ; 4. Based on the overall objective function The degree of "suboptimal" for each distance scheme was quantified, and the following was selected. The minimum value corresponding to L_i is taken as the optimal installation distance between the two flow stabilization devices. This distance allows the anti-sloshing ring and cross baffle to effectively suppress initial sloshing while creating optimal flow field conditions for downstream anti-collapse and vortex elimination.

[0086] 5. After determining the installation examples of the first and second flow stabilizers, the specific structures of the first and second flow stabilizers can be further refined. For example, for the cross-shaped baffle, the aperture, total area of ​​the aperture, and distance between each aperture can be further determined; for the fins, the installation distance and fin height of the fins fixed around the anti-collapse plate 6 can be further determined.

[0087] As an example, based on the above steps, the installation scheme can be obtained as follows: Layout parameters: The optimal center distance between the first and second current stabilizing devices is 0.92m.

[0088] Cross-shaped partition: It adopts a uniform hole scheme with a hole diameter of 16mm and a hole center distance of 32mm.

[0089] Fin assembly: adopts a circumferentially distributed scheme with a height of 150mm and a spacing of 80mm.

[0090] This invention, based on the structure of a liquid rocket propellant tank flow stabilization device, further defines the design dimensions and installation distances of each component. This not only gives the propellant tank flow stabilization device structural advantages but also refines the specific structural details, enabling each component to better cooperate and achieve a continuous and reliable propellant supply within the tank.

[0091] For details on the parameters of the liquid rocket's propellant tank flow stabilization device, please refer to the relevant content on the liquid rocket's propellant tank flow stabilization device.

[0092] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A liquid rocket propellant tank flow stabilization device, characterized in that, include: A first flow stabilizing device is fixedly connected to the bottom of the storage tank, wherein the bottom of the storage tank is an ellipsoidal bottom (1). A second flow stabilizing device that is located at a target distance from the first flow stabilizing device and is fixedly connected to the inner surface of the tank; The first current stabilizing device includes: Filter screen; A filter frame (10) is disposed at the bottom of the storage tank and connected to the filter screen. The filter frame (10) is used to provide rigid support for the filter screen. An anti-collapse plate (6) is connected to the filter frame (10), and the anti-collapse plate (6) extends out of the filter frame (10). The fins (9) are fixedly connected to the anti-collapse plate (6); The second current stabilizing device includes: A circular ring (2) connected to the inner surface of the tank; A cross-shaped partition (3) connected to the ring (2); During rocket flight, the ring (2) is used to suppress large-scale liquid sloshing caused by acceleration changes; the cross baffle (3) is used to divide the flow field of the liquid at the bottom of the tank, break the rotational flow of the liquid, and make the liquid flow smoothly to the center outlet; when the liquid level in the tank drops, the anti-collapse plate (6) is used to prevent local collapse of the liquid surface; the fins (9) are used to disperse the residual vortex of the cross baffle (3) reaching the outlet area, so as to achieve non-rotational outflow.

2. The liquid rocket tank flow stabilization device according to claim 1, characterized in that, The bottom of the storage tank also includes: A vent flange (8) is provided on the side away from the first and second flow stabilizers. The vent flange (8) is used to fill the propellant before rocket launch and to vent the propellant after mission abort or testing.

3. The liquid rocket propellant tank flow stabilization device according to claim 1, characterized in that, The bottom of the storage tank also includes: The outlet flange (7) is fixedly connected to the filter screen frame. The outlet flange (7) is used to connect the storage tank and the engine delivery pipeline to a sealed interface.

4. The liquid rocket propellant tank flow stabilization device according to claim 1, characterized in that, The filter frame (10) includes an integrally formed support column and a base; the support column is vertically arranged on the edge of the base, and the filter screen is fixedly connected between two adjacent support columns.

5. The liquid rocket propellant tank flow stabilization device according to claim 1, characterized in that, The bottom of the storage tank also includes: The adapter flange (5) of the tunnel pipe is fixedly connected to the bottom of the storage tank. A tunnel pipe assembly (4) is fixedly connected to the top of the adapter flange (5), the tunnel pipe assembly (4) being used to provide a sealed passage for the sensor cables and pressurization lines inside the box to pass through the bottom of the box.

6. The liquid rocket propellant tank flow stabilization device according to claim 1, characterized in that, The circular ring (2) includes multiple quarter rings of the same size, and adjacent quarter rings are screwed together by corner plates. The circular ring (2) is fixedly connected to the cross partition (3) by the corner plates.

7. The liquid rocket propellant tank flow stabilization device according to claim 1, characterized in that, The cross-shaped partition (3) includes multiple partitions that are perpendicular to each other and fixedly connected. Each partition has multiple holes evenly distributed on it, and the front end of the partition is attached to the inner surface of the storage tank.

8. A method for determining the parameters of a liquid rocket's propellant tank flow stabilization device, characterized in that, The method is applied to the tank flow stabilization device of the liquid rocket according to any one of claims 1 to 7, comprising: Obtain the structural parameters and outflow performance constraint data of the target tank, wherein the structural parameters include the ellipsoidal geometry of the tank bottom, the outer diameter of the filter screen frame (10) and the outer diameter of the cross baffle (3); the outflow performance constraint data includes the minimum working liquid level, the maximum allowable outflow entrainment ratio and the allowable additional system pressure drop; Based on the structural parameters, a parameter processing model and optimization variables for the current stabilization device are determined, wherein the optimization variable is the axial distance between the center of the first current stabilization device and the center of the second current stabilization device; Based on the lowest working liquid level in the outflow performance constraint data, the optimization variable is extracted within its preset value range to obtain multiple candidate distance values. The multiple candidate distance values ​​are input into the parameter processing model of the flow stabilization device to perform transient two-phase flow simulation processing and obtain the flow field dataset. The flow field dataset is extracted and processed to obtain the system performance evaluation index corresponding to each candidate distance value. The system performance evaluation index includes the air entrainment risk index, the liquid surface stability index, and the vortex suppression index of the cross baffle (3) region. Based on the system performance evaluation index and the outflow performance constraint data, a total objective function is determined, and the optimization objective is to minimize the value of the total objective function. The optimal target distance between the first and second current stabilizing devices is then determined from the multiple candidate distance values.

9. The method for determining the parameters of the liquid rocket's propellant tank flow stabilization device according to claim 8, characterized in that, The formula for calculating the air entrapment risk index is: ； in, Indicates the risk index of gas entrapment. Indicates the start time of the simulation. Indicates the simulation termination time. This represents the gas volume fraction at the outlet at time t. This represents a series of candidate values ​​for the optimization variable L within a preset range [L_min, L_max]. The formula for calculating the liquid level stability index is: ； in, Indicates the stability index of the liquid level. This represents the lowest liquid level height along the tank axis at time t; The formula for calculating the vortex suppression index is: ； in, Indicates the vortex suppression index. Represents the spatial point at time t vorticity at a given location. This indicates the fluid space region near the preset cross-shaped partition (3).

10. The method for determining the parameters of the liquid rocket's propellant tank flow stabilization device according to claim 8, characterized in that, The expression for the overall objective function is: ； in, Let be the overall objective function. , , Indicates the weighting coefficient. This represents the total volume of gas entering the pipe during the entire outflow process at a distance of L_i. This represents the normalized reference benchmark for the gas trap risk index. This represents the height of the lowest point of the liquid surface during the entire outflow process at a distance of L_i. The normalized reference standard representing the liquid level height index This represents the rotational intensity measure of the most intense vortex appearing in the region of the cross-shaped diaphragm (3) at a distance of L_i. This represents the normalized reference standard for vortex intensity indices.

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