Wall-integrated 3D printing heat exchange cylinder with water-drop-shaped cross-section channel

Abstract

The present application relates to a heat exchanger of a liquid rocket engine, and particularly relates to a wall integrated 3D printing high-efficiency heat exchange simple body with a water-drop-shaped cross-section flow channel, which is used to solve the problems of the existing liquid rocket engine, such as the complex heat exchanger and pipeline outside the engine, which not only is difficult to meet the compactness requirement of the engine system, but also increases the flow resistance of the liquid medium, thereby affecting the heating efficiency of the heat exchanger and the overall performance of the engine system. The wall integrated 3D printing high-efficiency heat exchange simple body with a water-drop-shaped cross-section flow channel integrates the heat exchanger into the high-temperature gas pipeline wall, the pressurized medium in the storage tank is introduced into the second flow channel for heating, and then is introduced into the storage tank to complete pressurization. Compared with the independent external heat exchange scheme, the volume and mass occupied by the wall integrated 3D printing high-efficiency heat exchange simple body are greatly reduced, which is conducive to improving the thrust-to-mass ratio of the engine, and the saved weight can be used to increase the payload.

Description

Technical Field

[0001] This invention relates to heat exchangers for liquid rocket engines, and more specifically to a wall-integrated 3D-printed heat exchange cylinder with a teardrop-shaped cross-section flow channel. Background Technology

[0002] Liquid rocket engines are the primary propulsion power source for deep space exploration vehicles. To ensure their stable operation in the complex space environment, heat exchangers are typically installed within the engine to heat the pressurized medium in the propellant tank. However, traditional heat exchanger designs have significant limitations and urgently need improvement to meet the specific requirements of deep space exploration.

[0003] Currently, common heat exchangers employ an independent external design, connecting to the engine and storage tank via a series of auxiliary pipes. While this structure is relatively simple, it exhibits the following problems in deep space exploration missions:

[0004] (1) Space occupation and weight increase: The external heat exchanger and its piping occupy a large space, increasing the size and weight of the aircraft. This design restricts the compactness and lightweight requirements of the aircraft, which is not conducive to reducing launch costs and improving mission execution efficiency.

[0005] (2) Layout constraints and design complexity: Due to the overall structure of the aircraft, traditional heat exchangers are difficult to adapt to the compact layout requirements of complex engine systems. This limitation not only increases the design complexity, but may also reduce the thermal efficiency of the system.

[0006] (3) Flow resistance and performance impact: The length and complexity of the external heat exchanger pipes increase the flow resistance of the liquid medium, thereby reducing the heating efficiency of the heat exchanger and having an adverse effect on the overall performance of the engine system.

[0007] In view of the above problems, liquid rocket engines urgently need an improved heat exchanger design to achieve greater compactness and thermal efficiency, thereby optimizing the performance of deep space exploration vehicles. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing liquid rocket engines where independently external heat exchangers and their piping connections not only fail to meet the compact requirements of complex engine systems, but also increase the flow resistance of the liquid medium due to the length and complexity of the piping, further affecting the heating efficiency of the heat exchanger and the overall performance of the engine system. The invention provides a wall-integrated 3D-printed heat exchange cylinder with a teardrop-shaped cross-section flow channel.

[0009] To address the shortcomings of the existing technology, the present invention provides the following technical solution:

[0010] A wall-integrated 3D-printed heat exchange cylinder with a teardrop-shaped cross-section flow channel is characterized by including an inner cylinder and an outer cylinder that are coaxially fitted and integrally formed by 3D printing.

[0011] The inner cavity of the inner cylinder serves as a first flow channel for containing high-temperature fluid, with its two ends acting as the inlet and outlet of the first flow channel, respectively. At least one rib is provided between the inner and outer cylinders, with the root and top of each rib connecting the inner and outer cylinders, respectively. The inner cylinder, outer cylinder, and all ribs together form a second flow channel for containing low-temperature fluid, with both the inlet and outlet of the second flow channel located on the outer cylinder. The high-temperature fluid is the high-temperature combustion gas in the engine system, and the low-temperature fluid is the pressurizing medium in the storage tank.

[0012] The second flow channel is a unidirectional flow channel composed of at least one spiral flow channel, or a reciprocating flow channel composed of multiple spiral flow channels;

[0013] The axial cross-section of each of the spiral flow channels is teardrop-shaped, which is composed of two circular arc segments with different radii and two curved segments. The circular arc segment with a smaller radius corresponds to the inner wall of the second flow channel, and the circular arc segment with a larger radius corresponds to the outer wall of the second flow channel. The two curved segments correspond to two adjacent ribs respectively.

[0014] The arcs on both sides of each rib satisfy the following condition:

[0015]

[0016] in, This represents the heat flux density along the central axis of the rib. This is the radial distance from the top to the root of the rib on the outer cylinder. This is the distance from the top of the rib. The convective heat transfer coefficient within the second flow channel represents the heat transfer intensity between the ribs and the cryogenic fluid. The temperature at the root of the rib. The temperature of the cryogenic fluid. The angle between the tangent on the surface of the rib at a distance X from the top of the rib and the central axis of the rib; It is a proportionality factor related to the rib height, fluid temperature, and convective heat transfer coefficient, used to control the rate of change of the rib curvature.

[0017] The outer cylinder is connected to the outside by flanges or welding at both ends.

[0018] Furthermore, a protruding expansion structure is provided on the inner wall of the first flow channel at the inlet end of the first flow channel. The protruding expansion structure is a radial convex ring, and the two sides of the radial convex ring are right angles or chamfers.

[0019] Furthermore, the ratio of the maximum radial flow area of ​​the first flow channel to the minimum radial flow area of ​​the sudden expansion structure is greater than 4.

[0020] Furthermore, the outer cylinder is connected to the outside via inlet flange and outlet flange at both ends, respectively.

[0021] Furthermore, the inlet flange is provided with an inlet connector that connects to the inlet end of the second flow channel, and the outer wall of the outer cylinder is provided with an outlet connector that connects to the outlet end of the second flow channel.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) The present invention has a wall-integrated 3D printed heat exchange cylinder with a teardrop-shaped cross-section flow channel, including an inner cylinder and an outer cylinder that are coaxially fitted and integrally formed by 3D printing. The present invention integrates the heat exchanger into the wall of the high-temperature gas pipeline. The pressurizing medium in the storage tank is introduced into the second flow channel for heating and then introduced into the storage tank to complete the pressurization. Although the outer diameter is increased, the volume occupied by the relatively independent external heat exchange scheme has been greatly reduced. Moreover, the weight increase of the present invention is very small, which is beneficial to improving the thrust-to-weight ratio of the engine. The weight saved can be used to increase the effective load.

[0024] (2) The present invention is manufactured by 3D printing and uses flange connection, with a weight of only 998g (if the two ends are welded, it can be reduced to 606g). Compared with traditional heat exchangers, the structural weight is reduced by more than 70%~85%, the production and testing cycle is shortened from more than 15 days to 2 days, and the production cost is reduced by more than 65%.

[0025] (3) In this invention, the axial cross section of each spiral channel is teardrop-shaped. After optimizing the rib height and surface curvature according to the above heat transfer formula, the weight of the rib can be reduced and the heat transfer efficiency can be improved. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of an embodiment of the wall-integrated 3D-printed heat exchange cylinder with a teardrop-shaped cross-section flow channel of the present invention.

[0027] Figure 2 This is a three-dimensional structural diagram of an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the cross-sectional design of the ribs in an embodiment of the present invention.

[0029] The reference numerals in the attached drawings are explained as follows: 1-Outer cylinder; 2-Inner cylinder; 3-First flow channel; 4-Second flow channel; 5-Expansion structure; 6-Inlet nozzle; 7-Outlet nozzle; 8-Inlet flange; 9-Outlet flange; 10-Rib. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0031] Reference Figures 1-3 A wall-integrated 3D-printed heat exchange cylinder with a teardrop-shaped cross-section flow channel includes an inner cylinder 2 and an outer cylinder 1 coaxially fitted together, which are integrally formed by 3D printing.

[0032] The inner cavity of the inner cylinder 2 is a first flow channel 3 for setting high-temperature fluid. The two ends are the inlet and outlet ends of the first flow channel 3, respectively. Multiple ribs 10 are provided between the inner cylinder 2 and the outer cylinder 1. The inner side and outer side of each rib 10 are connected to the inner cylinder 2 and the outer cylinder 1, respectively. The inner cylinder 2, the outer cylinder 1 and the multiple ribs 10 form a second flow channel 4 for setting low-temperature fluid. The inlet and outlet ends of the second flow channel 4 are both provided on the outer cylinder 1. An outlet pipe nozzle 7 that connects to the outlet end of the second flow channel 4 is provided on the outer wall of the outer cylinder 1.

[0033] In this embodiment, the high-temperature fluid is the high-temperature combustion gas in the engine system, and the low-temperature fluid is the pressurization medium in the storage tank.

[0034] The outer cylinder 1 is provided with an inlet flange 8 and an outlet flange 9 at its two ends for connection to the outside. The inlet flange 8 is provided with an inlet nozzle 6 that connects to the inlet end of the second flow channel 4, and the outlet flange 9 is provided at the outlet end of the second flow channel 4.

[0035] In other embodiments, the two ends of the outer cylinder 1 are connected to the outside by flanges or welding.

[0036] A sudden expansion structure 5 is provided on the inner wall of the first flow channel 3 at the inlet end of the first flow channel 3. The sudden expansion structure 5 is a radial convex ring with right angles or chamfers on both sides. The ratio of the maximum radial flow area of ​​the first flow channel 3 to the minimum radial flow area of ​​the sudden expansion structure 5 is greater than 4. The sudden expansion structure 5 is used to mix the high-temperature fluid when it passes through, reduce the radial cross-sectional temperature difference, increase the turbulence, and facilitate the heat exchange with the inner wall.

[0037] The second flow channel 4 is a unidirectional spiral flow channel composed of at least one spiral flow channel, or a reciprocating spiral flow channel composed of multiple spiral flow channels.

[0038] In this embodiment, the second flow channel 4 is a reciprocating spiral flow channel composed of multiple spiral flow channels. The flow process of the cryogenic fluid in the reciprocating spiral flow channel is as follows: when the cryogenic fluid spirals around one end of the outer cylinder 1 to the other end in a spiral flow channel with a spiral angle of ≤90°, it enters the adjacent spiral flow channel and returns with the same spiral angle, and so on.

[0039] The axial cross-section of each spiral flow channel is teardrop-shaped, which consists of two circular arc segments with different radii and two curved segments. In terms of cross-sectional layout, the circular arc segment with the smaller radius corresponds to the inner wall of the second flow channel 4, and the circular arc segment with the larger radius corresponds to the outer wall of the second flow channel 4.

[0040] Reference Figure 3 The arcs on both sides of each rib 10 satisfy the following conditions:

[0041]

[0042] in, The heat flux density along the central axis of rib 10 is... The distance from the top to the root of rib 10 in the radial direction of the outer cylinder 1. This is the distance from the top of the rib 10. The convective heat transfer coefficient within the second flow channel 4 represents the heat transfer intensity between the rib 10 and the cryogenic fluid. The temperature at the root of the 10 ribs. The temperature of the cryogenic fluid. The distance from the top of the rib 10 The angle between the tangent on the surface of rib 10 and the central axis of rib 10; It is a proportional factor related to the height of the rib 10, the fluid temperature, and the convective heat transfer coefficient, used to control the rate of curvature change of the rib 10.

[0043] The working principle of this embodiment is as follows:

[0044] High-temperature gas enters the inlet end of the first flow channel 3 and flows along the first flow channel 3. Low-temperature fluid enters from the inlet nozzle 6 of the second flow channel 4 and flows through the second flow channel 4 (reciprocating spiral flow channel) to the outlet nozzle 7. When flowing through the teardrop-shaped cross-section flow channel, the low-temperature fluid comes into full contact with the ribs 10 and the flow channel wall. It absorbs the heat of the gas through convection heat transfer, and the temperature gradually increases. The heated low-temperature fluid flows out from the outlet nozzle 7 and enters the storage tank to complete the pressurization.

Claims

1. A wall-integrated 3D printing heat exchange cylinder with a water-drop-like cross-section channel, characterized in that: It includes an inner cylinder (2) and an outer cylinder (1) that are coaxially fitted and integrally formed by 3D printing; The inner cavity of the inner cylinder (2) is a first flow channel (3) for setting high-temperature fluid, with its two ends serving as the inlet and outlet ends of the first flow channel (3), respectively. At least one rib (10) is provided between the inner cylinder (2) and the outer cylinder (1). The root and top of each rib (10) are connected to the inner cylinder (2) and the outer cylinder (1), respectively. The inner cylinder (2), the outer cylinder (1), and all the ribs (10) together form a second flow channel (4) for setting low-temperature fluid. The inlet and outlet ends of the second flow channel (4) are both located on the outer cylinder (1). The high-temperature fluid is the high-temperature combustion gas in the engine system, and the low-temperature fluid is the pressurizing medium in the storage tank. A protruding expansion structure (5) is provided on the inner wall of the first flow channel (3) at the inlet end of the first flow channel (3). The protruding expansion structure (5) is a radial convex ring, and the two sides of the radial convex ring are right angles or chamfers. The second flow channel (4) is a unidirectional flow channel composed of at least one spiral flow channel, or a reciprocating flow channel composed of multiple spiral flow channels; The axial cross section of each of the spiral channels is teardrop-shaped. The teardrop shape is composed of two circular arc segments with different radii and two curved segments. The circular arc segment with a smaller radius corresponds to the inner wall of the second channel (4), and the circular arc segment with a larger radius corresponds to the outer wall of the second channel (4). The two curved segments correspond to two adjacent ribs (10). The arcs on both sides of each rib (10) satisfy the following conditions to reduce the weight of the rib and improve the heat exchange efficiency: ； in, The heat flux density along the central axis of the rib (10) is... The distance from the top to the root of the rib (10) in the radial direction of the outer cylinder (1) is the distance between the top and the root of the rib (10). The distance from the top of the rib (10) is the distance from the top of the rib. The convective heat transfer coefficient within the second flow channel (4) represents the heat transfer intensity between the rib (10) and the cryogenic fluid. The temperature at the root of the rib (10), The temperature of the cryogenic fluid. Let X be the angle between the tangent on the surface of the rib (10) at a distance X from the top of the rib (10) and the central axis of the rib (10); It is a proportional factor related to the rib height, fluid temperature and convective heat transfer coefficient, used to control the rate of curvature change of the rib (10). The outer cylinder (1) is connected to the outside by flanges or welding at both ends.

2. The wall-integrated 3D-printed heat exchange cylinder with a teardrop-shaped cross-section flow channel according to claim 1, characterized in that: The ratio of the maximum radial flow area of ​​the first flow channel (3) to the minimum radial flow area of ​​the sudden expansion structure (5) is greater than 4.

3. A wall-integrated 3D-printed heat exchange cylinder with a teardrop-shaped cross-section flow channel as described in claim 1 or 2, characterized in that: The outer cylinder (1) is connected to the outside at both ends by an inlet flange (8) and an outlet flange (9).

4. The wall-integrated 3D-printed heat exchange cylinder with a teardrop-shaped cross-section flow channel according to claim 3, characterized in that: The inlet flange (8) is provided with an inlet nozzle (6) that connects to the inlet end of the second flow channel (4), and the outer wall of the outer cylinder (1) is provided with an outlet nozzle (7) that connects to the outlet end of the second flow channel (4).

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