Wall surface integrated type 3D printing efficient heat exchange barrel with water-drop-like section flow channel

Abstract

The invention relates to a heat exchanger of a liquid rocket engine, in particular to a wall surface integrated type 3D printing efficient heat exchange barrel with a water-drop-like section flow channel, and aims to solve the problems that an independent external heat exchanger and a pipeline thereof in an existing liquid rocket engine are complex, so that the requirement for compactness of an engine system is difficult to meet; and the complex pipeline increases the flow resistance of the liquid medium and affects the heating efficiency of the heat exchanger and the overall performance of the engine system. According to the wall surface integrated type 3D printing efficient heat exchange barrel with the water-drop-shaped section flow channel, a heat exchanger is integrated into the wall surface of a high-temperature gas pipeline, a pressurizing medium in a storage box is introduced into a second flow channel for heating, and then the pressurizing medium is introduced into the storage box to complete pressurizing; and compared with an independent external heat exchange scheme, the occupied volume and mass are greatly reduced, the thrust-mass ratio of the engine is increased, and the saved weight can be used for increasing the effective load.

Description

Technical Field

[0001] The invention relates to a heat exchanger for a liquid rocket engine, and in particular to a wall-integrated 3D-printed high-efficiency heat exchange cylinder having a water drop-shaped cross-section flow channel. Background Art

[0002] Liquid rocket engines are the main propulsion power source for deep space exploration vehicles. To ensure their stable operation in the complex space environment, a heat exchanger is usually installed in the engine to heat the pressurized medium in the tank. However, the traditional heat exchanger design has obvious limitations and needs to be improved to meet the special needs of deep space exploration.

[0003] The common heat exchanger currently adopts an independent external design, which is connected to the engine and tank through a series of auxiliary pipes. Although this structure is relatively simple, it has the following problems in deep space exploration missions:

[0004] (1) Occupied space and increased weight: The external heat exchanger and its pipelines occupy a large space, increasing the volume 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) Limited layout and complex design: Due to the overall structural limitations 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 pipeline leads to an increase in the flow resistance of the liquid medium, thereby reducing the heating efficiency of the heat exchanger and adversely affecting 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 higher compactness and thermal efficiency, thereby optimizing the performance of deep space exploration vehicles. Summary of the invention

[0008] The purpose of the present invention is to solve the problem that the independent external heat exchanger and its pipeline connection in the existing liquid rocket engine are not only difficult to meet the compact requirements of the complex engine system, but the length and complexity of the pipeline also increase the flow resistance of the liquid medium, further affecting the heating efficiency of the heat exchanger and the overall performance of the engine system. A wall-integrated 3D printed high-efficiency heat exchange cylinder with a teardrop-shaped cross-section flow channel is provided.

[0009] In order to solve the deficiencies of the above-mentioned prior art, the present invention provides the following technical solutions:

[0010] A wall-integrated 3D-printed high-efficiency heat exchange cylinder with a water drop-shaped cross-section flow channel, which is special in that it includes an inner cylinder and an outer cylinder coaxially sleeved and integrally formed by 3D printing;

[0011] The inner cavity of the inner cylinder is a first flow channel for arranging a high-temperature fluid, and the two ends serve as an inlet end and an outlet end of the first flow channel respectively. At least one rib is arranged between the inner cylinder and the outer cylinder, and the root and the top of each rib are respectively connected to the inner cylinder and the outer cylinder. The inner cylinder, the outer cylinder and all the ribs constitute a second flow channel for arranging a low-temperature fluid, and the inlet end and the outlet end of the second flow channel are both arranged on the outer cylinder; the high-temperature fluid is the high-temperature fuel gas in the engine system, and the low-temperature fluid is the pressurized medium in the 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 spiral flow channel is teardrop-shaped, and the teardrop-shaped shape is composed of two arc segments with different radii and two curved segments, the arc segment with a smaller radius corresponds to the inner wall of the second flow channel, the arc segment with a larger radius corresponds to the outer wall of the second flow channel, and the two curved segments correspond to two adjacent ribs respectively;

[0014] The arcs on both sides of each rib meet the following conditions:

[0015]

[0016] Where q is the heat flux density in the direction of the central axis of the rib, L is the distance from the top of the rib to the root in the radial direction of the outer cylinder, X is the distance from the top of the rib, h is the convection heat transfer coefficient in the second flow channel, which indicates the heat transfer intensity between the rib and the cryogenic fluid, T o is the temperature at the root of the rib, T f is the temperature of the cryogenic fluid, α is the angle between the rib surface tangent at a distance X from the top of the rib and the central axis of the rib; r is a proportional factor related to the rib height, fluid temperature and convection heat transfer coefficient, which is used to control the rate of change of the rib curvature;

[0017] The two ends of the outer cylinder are connected to the outside by flanges or welding.

[0018] Furthermore, a sudden expansion structure is provided on the inner wall of the first flow channel at the inlet end of the first flow channel, and the sudden expansion structure is a radial convex ring, and 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, both ends of the outer cylinder are connected to the outside by an inlet flange and an outlet flange respectively.

[0021] Furthermore, an inlet nozzle communicating with the inlet end of the second flow channel is arranged on the inlet flange, and an outlet nozzle communicating with the outlet end of the second flow channel is arranged on the outer wall of the outer cylinder.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

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

[0024] (2) The present invention is manufactured through 3D printing and flange connection, with a mass of only 998g (if welding is used at both ends, it can be reduced to 606g). Compared with traditional heat exchangers, the structural mass is reduced by more than 70% to 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 the present invention, the axial cross-section of each spiral flow channel is teardrop-shaped. After the rib height and surface curvature are optimized according to the above heat transfer formula, the rib weight can be reduced and the heat transfer efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of an embodiment of a wall-integrated 3D-printed high-efficiency heat exchange cylinder having a water drop-shaped cross-section flow channel according to the present invention;

[0027] Figure 2 A schematic diagram of a three-dimensional structure of an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the cross-sectional design of the ribs in the embodiment of the present invention.

[0029] The reference numerals are as follows: 1 - outer cylinder; 2 - inner cylinder; 3 - first flow channel; 4 - second flow channel; 5 - sudden expansion structure; 6 - inlet nozzle; 7 - outlet nozzle; 8 - inlet flange; 9 - outlet flange; 10 - rib. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and exemplary embodiments.

[0031] Reference Figures 1 to 3A wall-integrated 3D-printed high-efficiency heat exchange cylinder with a water drop-shaped cross-section flow channel includes a coaxially sleeved inner cylinder 2 and an outer cylinder 1, and the inner cylinder 2 and the outer cylinder 1 are integrally formed by 3D printing.

[0032] The inner cavity of the inner cylinder 2 is used to set the first flow channel 3 for high-temperature fluid, and the two ends serve as the inlet end and the outlet end of the first flow channel 3 respectively. A plurality of ribs 10 are arranged between the inner cylinder 2 and the outer cylinder 1. The inner side and the outer side of each rib 10 are respectively connected to the inner cylinder 2 and the outer cylinder 1. The inner cylinder 2, the outer cylinder 1 and the plurality of ribs 10 constitute a second flow channel 4 for setting the low-temperature fluid. The inlet end and the outlet end of the second flow channel 4 are both arranged on the outer cylinder 1, and an outlet pipe nozzle 7 connected to the outlet end of the second flow channel 4 is arranged 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 pressurized medium in the tank.

[0034] The two ends of the outer tube 1 are respectively provided with an inlet flange 8 and an outlet flange 9 for connecting to the outside. The inlet flange 8 is provided with an inlet nozzle 6 connected to the inlet end of the second flow channel 4. The outlet flange 9 is provided at the outlet end of the second flow channel 4.

[0035] In other embodiments, both 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, and the two sides of the radial convex ring are right angles or chamfers. 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 temperature difference of its radial cross-section, increase the turbulence, and is conducive to strengthening 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, and the flow process of the low-temperature fluid in the reciprocating spiral flow channel is as follows: when the low-temperature fluid spirally surrounds from one end of the outer tube 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 repeats this process.

[0039] The axial cross-section of each spiral flow channel is teardrop-shaped, which is composed of two arc segments with different radii and two curved segments. In the cross-sectional layout, the arc segment with a smaller radius corresponds to the inner wall of the second flow channel 4, and the arc segment with a 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 meet the following conditions:

[0041]

[0042] Wherein, q is the heat flux density in the central axis direction of the rib 10, L is the distance from the top to the root of the rib 10 in the radial direction of the outer cylinder 1, X is the distance from the top of the rib 10, h is the convection heat transfer coefficient in the second flow channel 4, indicating the heat transfer intensity between the rib 10 and the cryogenic fluid, T o is the temperature at the root of rib 10, T f is the temperature of the low-temperature fluid, α is the angle between the tangent line 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; r is a proportional factor related to the height of the rib 10, the fluid temperature and the convection heat transfer coefficient, which is used to control the curvature change rate of the rib 10.

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

[0044] The high-temperature gas enters the inlet end of the first flow channel 3 and flows along the first flow channel 3. The low-temperature fluid enters from the inlet nozzle 6 of the second flow channel 4 and flows to the outlet nozzle 7 through the second flow channel 4 (reciprocating spiral flow channel). When flowing through the teardrop-shaped cross-section flow channel, the low-temperature fluid fully contacts the ribs 10 and the flow channel wall, absorbs the heat of the gas through convection heat exchange, 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 printed high-efficiency heat exchange cylinder with a water drop-shaped cross-section flow channel, characterized in that: It comprises an inner cylinder (2) and an outer cylinder (1) which are coaxially sleeved and integrally formed by 3D printing; The inner cavity of the inner cylinder (2) is a first flow channel (3) for arranging a high-temperature fluid, and the two ends serve as an inlet end and an outlet end of the first flow channel (3) respectively. At least one rib (10) is arranged between the inner cylinder (2) and the outer cylinder (1), and the root and the top of each rib (10) are respectively connected to the inner cylinder (2) and the outer cylinder (1). The inner cylinder (2), the outer cylinder (1) and all the ribs (10) form a second flow channel (4) for arranging a low-temperature fluid, and the inlet end and the outlet end of the second flow channel (4) are both arranged on the outer cylinder (1); the high-temperature fluid is the high-temperature fuel gas in the engine system, and the low-temperature fluid is the pressurized medium in the tank; 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 spiral flow channel is drop-shaped, and the drop-shaped shape is composed of two arc segments with different radii and two curved segments, the arc segment with a smaller radius corresponds to the inner wall of the second flow channel (4), the arc segment with a larger radius corresponds to the outer wall of the second flow channel (4), and the two curved segments correspond to two adjacent ribs (10) respectively; The arcs on both sides of each rib (10) meet the following conditions: Wherein, q is the heat flux density in the direction of the central axis of the rib (10), L is the distance from the top to the root of the rib (10) in the radial direction of the outer cylinder (1), X is the distance from the top of the rib (10), h is the convection heat transfer coefficient in the second flow channel (4), indicating the heat transfer intensity between the rib (10) and the cryogenic fluid, T o is the temperature at the root of the rib (10), T f is the temperature of the cryogenic fluid, α is the angle between the tangent line 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); r is a proportional factor related to the rib height, the fluid temperature and the convection heat transfer coefficient, and is used to control the curvature change rate of the rib (10); Both ends of the outer cylinder (1) are connected to the outside by flanges or welding.

2. According to claim 1, a wall-integrated 3D printed high-efficiency heat exchange cylinder with a water droplet-shaped cross-section flow channel, characterized in that: 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, and two sides of the radial convex ring are right angles or chamfered.

3. The wall-integrated 3D printed high-efficiency heat exchange cylinder with a water droplet-shaped cross-section flow channel according to claim 2, 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.

4. A wall-integrated 3D printed high-efficiency heat exchange cylinder with a water drop-shaped cross-section flow channel according to any one of claims 1 to 3, characterized in that: The two ends of the outer cylinder (1) are connected to the outside by means of an inlet flange (8) and an outlet flange (9) respectively.

5. The wall-integrated 3D printed high-efficiency heat exchange cylinder with a water drop-shaped cross-section flow channel according to claim 4, characterized in that: The inlet flange (8) is provided with an inlet nozzle (6) connected 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) connected to the outlet end of the second flow channel (4).

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