Efficient outflow device of carrier rocket based on ideal non-collapsed surface

Abstract

This invention discloses a high-efficiency propellant discharge device for launch vehicles based on an ideal non-collapse profile. The device includes a tank with a non-collapse profile for the discharge, and the end of the non-collapse profile is connected to the delivery pipe through a rounded corner section, which can ensure that the liquid surface does not collapse during the discharge process. Furthermore, this invention adds anti-vortex blades inside the discharge profile, which can eliminate vortices and liquid surface collapse during the discharge process, thereby improving the propellant utilization rate of the tank.

Description

Technical Field

[0001] This invention relates to a high-efficiency outflow device for a launch vehicle propellant tank, belonging to the field of power technology. Background Technology

[0002] During the final stage of propellant outflow from the propellant tanks of liquid-fueled rockets, phenomena such as surface collapse and vortices may occur above the outflow outlet due to the influence of factors such as tank boundaries, outlets, and external disturbances on local flow characteristics. Vortex and collapse phenomena are unique to liquid-fueled rockets and occur at the end of a single-stage combustion phase. Without effective suppression measures, vortices and collapses can cause a large amount of gas to become trapped in the propellant, flowing through the delivery pipes to the engine turbopump, severely affecting the normal operation of the engine, and even causing cavitation and potentially leading to an engine explosion. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned defects and provide a high-efficiency outflow device for launch vehicles based on an ideal non-collapse profile. The device includes a tank with a non-collapse profile for the outflow, and the end of the non-collapse profile is connected to the delivery pipe through a rounded corner section, which can ensure that the liquid surface does not collapse during the outflow process. Furthermore, this invention designs anti-vortex blades inside the outflow profile, which can eliminate vortices and liquid surface collapse during the outflow process of the tank, thereby improving the propellant utilization rate of the tank.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] A high-efficiency outflow device for launch vehicles based on an ideal non-collapse surface, comprising a propellant tank;

[0006] The bottom of the storage tank is an outflow profile, which includes a non-collapse profile and a rounded corner section. The end of the non-collapse profile is connected to the conveying pipe through the rounded corner section.

[0007] The non-collapse profile satisfies the following non-collapse profile curve equation:

[0008]

[0009] Where a is the launch vehicle acceleration; r is the radius of any point on the non-collapse profile; h is the height of any point on the non-collapse profile; Q is the outflow volumetric flow rate; C is the loss coefficient; g c This is the acceleration due to gravity.

[0010] Furthermore, methods for determining the outflow profile include:

[0011] S1 assumes that the outflow profile is a non-collapse profile that satisfies the non-collapse profile curve equation. Select the starting point radius r0 of the non-collapse profile and determine the starting point slope of the non-collapse profile. Make the ending point radius r1 of the non-collapse profile equal to the radius of the conveying pipe.

[0012] S2 solves the non-collapse surface curve equation based on r0, r1 and the slope of the starting point of the non-collapse surface, and obtains the coordinates (r, h) of each point that satisfies the non-collapse surface curve equation within the range of r0≤r≤r1, and then obtains the non-collapse surface to be transitioned corresponding to the starting point radius r0.

[0013] S3 Repeat steps S1 and S2 to obtain multiple non-collapsed transition surfaces corresponding to different starting point radii;

[0014] S4 performs outflow simulation on multiple transition-free non-collapse profiles to obtain the remaining propellant amount corresponding to multiple transition-free non-collapse profiles, and selects the transition-free non-collapse profile with the remaining amount that meets the remaining amount target.

[0015] S5 uses rounded corners to transition the part of the non-collapsed profile obtained in step S4 that connects to the conveying pipe, forming an outflow profile that includes a non-collapsed profile and a rounded corner section.

[0016] Furthermore, the surface outside the outflow profile in the storage tank is designated as the upper profile;

[0017] In step S1, the slope of the starting point of the non-collapsed surface is determined such that the non-collapsed surface and the upper surface are tangent at the starting point of the non-collapsed surface.

[0018] Furthermore, in step S2, based on r0, r1 and the slope of the starting point of the non-collapse profile, as well as the flight overload and outflow volumetric flow rate, the Runge-Kutta algorithm is used to solve the non-collapse profile curve equation to obtain the coordinates (r, h) of each point within the range of r0≤r≤r1 that satisfies the non-collapse profile curve equation.

[0019] Furthermore, in step S4, Flow3D is used to perform outflow simulation on multiple non-collapse profiles to be transitioned, and Isight is used to select non-collapse profiles to be transitioned that meet the remaining amount target.

[0020] Furthermore, the radius of the rounded corner section is 0.1 to 0.3 times the diameter of the conveying pipe, preferably 0.2 times the diameter of the conveying pipe.

[0021] Furthermore, it also includes multiple anti-vortex blades installed inside the storage tank;

[0022] The outer side of each anti-vortex blade is connected to the outflow profile, and the outer shape of each anti-vortex blade matches the shape of the outflow profile; the inner sides of each anti-vortex blade are connected to each other.

[0023] Each anti-vortex blade has drag-reducing holes.

[0024] Furthermore, the number of anti-vortex blades is 6 to 10, preferably 8.

[0025] The drag-reducing holes in the anti-vortex blades account for 20% to 40% of the total area of ​​the anti-vortex blades.

[0026] Furthermore, the height of the anti-vortex blade is equal to the overall height of the outflow profile.

[0027] Furthermore, the equation for the non-collapse surface curve is obtained as follows:

[0028] The one-dimensional Bernoulli equation for the outlet of the storage tank is established as follows:

[0029]

[0030] Where ρ is the fluid density in the tank, p is the fluid pressure, and E f The indentation loss due to wall friction; V s The fluid velocity along the non-collapse profile curve;

[0031] To avoid cavitation in the flow, we make dp equal to zero in equation (a), and transform equation (a) into the following equation (b):

[0032]

[0033] Differentiating equation (b) with respect to r yields equation (c):

[0034]

[0035] Based on the slope of the non-collapse profile at each location -dh / dr and the relationship between the length s of the non-collapse profile and r and h, ds 2 =dr 2 +dh 2 In the axial velocity component V h equal to the cross-sectional average velocity Under the conditions, V is obtained s :

[0036]

[0037] Based on the differentiation of equation (d) with respect to r, we obtain...

[0038]

[0039] For incompressible flow, the head loss E due to wall friction f Represented as:

[0040]

[0041] Where R = d / 4, d is the diameter of the conveying pipe (3);

[0042] Based on equation (f), by successively differentiating variables s and r, we obtain...

[0043]

[0044] V s , Substituting into equation (c), we obtain the equation for the non-collapsed surface curve.

[0045] Compared with the prior art, the present invention has the following advantages:

[0046] (1) This invention innovatively proposes an outflow profile that includes a non-collapse profile and a rounded corner transition. Compared with the traditional outflow scheme of inverted cone + cover plate and half cover plate, the ideal non-collapse profile can significantly simplify the outflow scheme, reduce flow resistance, and improve cavitation margin. At the same time, the rounded corner transition can effectively reduce the flow resistance of the delivery port and improve the outflow cavitation margin, thus realizing the efficient outflow of propellant.

[0047] (2) The present invention has designed anti-vortex blades inside the outflow profile, which can eliminate the vortex phenomenon caused by disturbance, and the liquid propellant in the tank can be basically used up, greatly improving the utilization rate of the propellant in the tank.

[0048] (3) This invention proposes a simulation optimization process to optimize the starting position of the outflow profile, which obtains the best outflow profile and further improves the utilization rate of propellant in the tank;

[0049] (4) This invention proposes a non-collapse profile curve equation, which can accurately guide the design of the flow profile. Attached Figure Description

[0050] Figure 1 This is a cross-sectional view of the high-efficiency outflow device for the launch vehicle of the present invention;

[0051] Figure 2 This is a schematic diagram of the flow at the outlet of the storage tank.

[0052] Figure 3 These are multiple non-collapse surface curves corresponding to different starting point radii in this invention;

[0053] Figure 4 This invention provides a process for optimizing the outflow profile.

[0054] In the figure, 1-storage tank, 2-non-collapse profile, 3-conveying pipe, 4-rounded corner section; 5-anti-vortex blade. Detailed Implementation

[0055] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0056] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0057] Designing appropriate outflow devices to prevent or delay vortex and collapse can effectively improve the utilization rate of propellant in the tank, which is an effective way to ensure the normal operation of the launch vehicle's propulsion system and improve the launch vehicle's carrying capacity. For example... Figure 1 The present invention is based on a high-efficiency outflow device for a launch vehicle with a non-collapse profile, which is a storage tank 1. The bottom profile of the storage tank 1 is an outflow profile, which includes a non-collapse profile 2 and a rounded corner section. The end of the non-collapse profile 2 is connected to the delivery pipe 3 through the rounded corner section.

[0058] The design process of the outflow profile of this invention is as follows:

[0059] 1) Assuming that the axial velocity component along the streamline is equal to the average velocity of the cross section from the tank wall to the outlet center, according to Bernoulli's equation, the equation for the non-collapse profile curve without liquid surface collapse can be obtained as follows:

[0060]

[0061] In the formula: a is the launch vehicle acceleration; r is the radius of any point in the non-collapse surface; h is the height of any point in the non-collapse surface, more specifically, h is the distance in the height direction between any point in the non-collapse surface and the starting point of the non-collapse surface; Q is the volumetric flow rate; C is the loss coefficient; g c This is the acceleration due to gravity.

[0062] The flow diagram at the outlet is as follows: Figure 2 As shown, the specific derivation process of the equation for the non-collapse surface curve is as follows:

[0063] Without considering the fillet transition of the outflow profile, the overall outflow profile satisfies the equation for a non-collapse profile curve:

[0064] The one-dimensional Bernoulli equation for the outlet of the storage tank is as follows:

[0065]

[0066] In the formula, ρ is the fluid density in the tank, p is the fluid pressure, and E f The indentation loss due to wall friction; V s The velocity is the flow velocity along the profile curve.

[0067] To avoid cavitation of the flow, dp should be equal to zero.

[0068]

[0069] Differentiating the radius r at any position on the outflow profile, then...

[0070]

[0071] For a circular cross-section, the slope at each location of the profile is -dh / dr, and the profile length is ds. 2 =dr 2 +dh 2 ,but

[0072]

[0073] Where s is the length of the non-collapsed surface, i.e., the curve length;

[0074] Further, we can obtain:

[0075]

[0076] The axial velocity components and the cross-sectional average flow velocity are as follows:

[0077]

[0078] Among them, V h V is the axial velocity component. avg The average flow velocity across the cross section;

[0079] Flow velocity V along the profile curve s It can be represented as:

[0080]

[0081] Taking the differential with respect to r, we get:

[0082]

[0083] For incompressible flow, the head loss E due to wall friction f It can be represented as

[0084]

[0085] In the formula: C is the loss coefficient, more specifically, C is the Chezy loss coefficient, which can be obtained through the Manning formula. Where n is the roughness coefficient, n = 0.009 to 0.014, R = d / 4, and d is the diameter of the conveying pipe.

[0086] Based on the differential of s according to equation (10), we have:

[0087]

[0088] Therefore Ef Differentiate with respect to r:

[0089]

[0090] V s , Substituting into formula (3), the differential equation for the non-collapsed surface can be obtained as follows:

[0091]

[0092] 2) Based on the launch vehicle propellant tank profile (i.e., the upper profile other than the outflow profile) and the non-collapse profile curve equation, determine the outflow profile curve of the propellant tank according to the following steps;

[0093] a) Without considering fillet radius, the outflow profile is a non-collapse profile that satisfies the non-collapse profile curve equation; select the radius r0 of the starting point of the non-collapse profile, and obtain the slope corresponding to the starting point based on the upper profile of the tank to ensure that the starting end of the outflow profile is tangent to the end of the upper profile of the tank.

[0094] b) Using the Runge-Kutta algorithm in Matlab, based on the flight overload and the outflow rate, the second-order differential equation of the non-collapse surface is solved, i.e., formula (13), to obtain the height h corresponding to the radius r of each point, until r is equal to the radius d / 2 of the delivery pipe.

[0095] c) Based on the coordinates (r, h) of each point on the curve, obtain non-collapse surface curves with different initial radii, such as... Figure 3 As shown.

[0096] 3) For the non-collapse profile curve and the 3D model of the tank, Flow3D was used to conduct outflow simulation. Based on the propellant remaining amount at the tank outlet when gas is trapped, obtained from the simulation, the starting point radius of the non-collapse profile was optimized using the simulation optimization software Isight to determine the optimal non-collapse profile curve, ensuring that the remaining propellant in the tank is minimized. The simulation optimization process is as follows: Figure 4 As shown.

[0097] 4) A fillet transition is made between the non-collapse profile and the delivery pipe. The fillet radius is 0.2 times the diameter of the delivery pipe. This effectively reduces the flow resistance at the delivery port and improves the cavitation margin of the outflow, resulting in an outflow profile that includes both the non-collapse profile and the fillet section. At this point, the part connecting the non-collapse profile and the delivery pipe is replaced by a fillet, meaning that the non-collapse profile curve in the final outflow profile is most of the non-collapse profile curve obtained in step c).

[0098] Preferably, the high-efficiency outflow device for the launch vehicle of the present invention further includes anti-vortex blades 5; the present invention provides eight anti-vortex blades 5 with drag-reducing holes inside the outflow profile to eliminate vortices during the outflow process; the area of ​​the drag-reducing holes accounts for about 20% to 40% of the area of ​​the anti-vortex blades, which ensures the anti-vortex performance while reducing the load on the blades and ensuring the structural strength of the blades; the height of the anti-vortex blades 5 is equal to the overall height of the outflow profile.

[0099] This invention relates to a high-efficiency propellant outflow device for launch vehicles based on a non-collapse profile. The non-collapse profile curve is derived based on the premise of equal axial velocity at the outflow cross-section. The profile is optimized using Flow3D outflow simulation analysis, theoretically ensuring that the propellant tank does not collapse during the outflow process. Eight anti-vortex blades with drag-reducing holes are installed inside the outflow profile to eliminate vortices during the outflow process. Using this patented high-efficiency propellant outflow device based on a non-collapse profile, propellant outflow from the tank can be achieved without collapse, and outflow vortices can be eliminated, ensuring that the propellant in the tank can be largely utilized. Simultaneously, it provides a good foundation for the utilization of propellant in the delivery pipe. Compared to traditional inverted cone + cover plate or semi-cover plate outflow schemes, this ideal non-collapse profile significantly simplifies the outflow scheme, reduces flow resistance, and improves cavitation margin. This invention relates to a propellant tank for a certain type of launch vehicle. The outflow profile of the tank was designed according to the above method. After testing, there was no obvious liquid surface collapse during the outflow process, and the propellant in the tank could be fully utilized.

[0100] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0101] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A high-efficiency outflow device for launch vehicles based on an ideal non-collapse surface, characterized in that, Including storage tank (1); The bottom of the storage tank (1) is an outflow profile, which includes a non-collapse profile (2) and a rounded corner section (4). The end of the non-collapse profile (2) is connected to the conveying pipe (3) through the rounded corner section (4). The non-collapse profile (2) satisfies the following non-collapse profile curve equation: Where a is the launch vehicle acceleration; r is the radius of any point on the non-collapse profile; h is the height of any point on the non-collapse profile; Q is the outflow volumetric flow rate; C is the loss coefficient; g c It is the acceleration due to gravity; Methods for determining the outflow profile include: S1 assumes that the outflow profile is a non-collapse profile that satisfies the non-collapse profile curve equation. Select the starting point radius r0 of the non-collapse profile and determine the starting point slope of the non-collapse profile. Make the ending point radius r1 of the non-collapse profile equal to the radius of the conveying pipe (3). S2 solves the non-collapse surface curve equation based on r0, r1 and the slope of the starting point of the non-collapse surface, and obtains the coordinates (r, h) of each point that satisfies the non-collapse surface curve equation within the range of r0≤r≤r1, and then obtains the non-collapse surface to be transitioned corresponding to the starting point radius r0. S3 Repeat steps S1 and S2 to obtain multiple non-collapsed transition surfaces corresponding to different starting point radii; S4 performs outflow simulation on multiple transition-free non-collapse profiles to obtain the remaining propellant amount corresponding to multiple transition-free non-collapse profiles, and selects the transition-free non-collapse profile with the remaining amount that meets the remaining amount target. S5 uses rounded corners to transition the part of the non-collapse profile obtained in step S4 that is connected to the conveying pipe (3), forming an outflow profile that includes the non-collapse profile (2) and the rounded corner section (4); The surface outside the outflow profile in the storage tank (1) is designated as the upper profile; In step S1, the slope of the starting point of the non-collapsed surface is determined such that the non-collapsed surface and the upper surface are tangent at the starting point of the non-collapsed surface.

2. The high-efficiency outflow device for a launch vehicle based on an ideal non-collapse surface as described in claim 1, characterized in that, In step S2, based on r0, r1 and the slope of the starting point of the non-collapse profile, as well as the flight overload and outflow volumetric flow rate, the Runge-Kutta algorithm is used to solve the non-collapse profile curve equation and obtain the coordinates (r, h) of each point within the range of r0≤r≤r1 that satisfies the non-collapse profile curve equation.

3. The high-efficiency outflow device for launch vehicles based on an ideal non-collapse surface as described in claim 1, characterized in that, In step S4, Flow3D is used to perform outflow simulation on multiple non-collapse profiles to be transitioned, and Isight is used to select non-collapse profiles to be transitioned that meet the remaining amount target.

4. The high-efficiency outflow device for a launch vehicle based on an ideal non-collapse surface as described in claim 1, characterized in that, The radius of the rounded corner section (4) is 0.1 to 0.3 times the diameter of the conveying pipe (3).

5. The high-efficiency outflow device for a launch vehicle based on an ideal non-collapse surface as described in claim 1, characterized in that, It also includes multiple anti-vortex blades (5) installed inside the storage tank (1); The outer side of each anti-vortex blade (5) is connected to the outflow profile, and the outer shape of each anti-vortex blade (5) matches the shape of the outflow profile; the inner sides of each anti-vortex blade (5) are connected to each other. Each anti-vortex blade (5) has a drag-reducing hole.

6. The high-efficiency outflow device for a launch vehicle based on an ideal non-collapse surface as described in claim 5, characterized in that, The number of anti-vortex blades (5) is 6 to 10; The drag-reducing holes in the anti-vortex blade (5) account for 20% to 40% of the total area of ​​the anti-vortex blade (5).

7. The high-efficiency outflow device for a launch vehicle based on an ideal non-collapse surface as described in claim 5, characterized in that, The height of the anti-vortex blade (5) is equal to the overall height of the outflow profile.

8. The high-efficiency outflow device for a launch vehicle based on an ideal non-collapse surface as described in claim 1, characterized in that, The equation for the non-collapse profile curve is obtained using the following method: The one-dimensional Bernoulli equation for the outlet of the storage tank is established as follows: Where ρ is the fluid density in the tank, p is the fluid pressure, and E f The indentation loss due to wall friction; V s The fluid velocity along the non-collapse profile curve; To avoid cavitation in the flow, we make dp equal to zero in equation (a), and transform equation (a) into the following equation (b): Differentiating equation (b) with respect to r yields equation (c): Based on the slope of the non-collapse profile at each location -dh / dr and the relationship between the length s of the non-collapse profile and r and h, ds 2 =dr 2 +dh 2 In the axial velocity component V h equal to the cross-sectional average velocity Under the conditions, V is obtained s : Based on the differentiation of equation (d) with respect to r, we obtain... For incompressible flow, the head loss E due to wall friction f Represented as: Where R = d / 4, d is the diameter of the conveying pipe (3); Based on equation (f), by successively differentiating variables s and r, we obtain... V s , Substituting into equation (c), we obtain the equation for the non-collapsed surface curve.

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