A multi-fluid aircraft pre-cooler modular design structure and reinforcement method

Abstract

This invention provides a modular design structure and reinforcement method for a multi-fluid aerospace precooler, specifically belonging to the field of aircraft propulsion system technology. Through the series arrangement of three structural layers and the progressively increasing inner diameter of components, the flow field is systematically optimized. The fluid undergoes multiple distributions and adjustments as it passes through various levels of branch pipes and helical tubes, ultimately achieving highly uniform flow and avoiding localized overheating. A catalyst is coated on the inner wall of the first-stage branch / manifold pipe, utilizing its large diameter and low flow velocity to form a functional separation structure where "the first-stage pipe is primarily for endothermic reaction, and the second-stage pipe and helical tube are primarily for convective heat transfer," thus improving overall thermal efficiency. This invention includes a precooler, which employs a three-layer structure arranged in a stacked configuration along the fluid flow direction. Each structural layer is selected based on heat transfer capacity and flow resistance requirements. Each structural layer contains a first-stage branch / manifold pipe, a second-stage branch / manifold pipe, and a helical tube arranged in series along the flow path, with the inner diameter of corresponding components in different structural layers increasing progressively along the fluid flow direction.

Description

Technical Field

[0001] This invention relates to a modular design structure and reinforcement method for a multi-fluid aerospace precooler, specifically belonging to the field of aircraft propulsion system technology. Background Technology

[0002] Aircraft place extremely high demands on the thrust-to-weight ratio and thermal efficiency of their propulsion systems. The precooler, as a key component of the thermal management system, is used to cool the high-temperature incoming airflow in a very short time; its performance directly affects the stable operation of the engine and the performance limits of the aircraft. Traditional compact heat exchangers (such as plate-fin and shell-and-tube types) face the following bottlenecks when dealing with extreme thermal loads, large flow rates, and high thermal stress:

[0003] 1. Uneven flow distribution leads to decreased heat exchange efficiency: In complex multi-channel structures, the flow distribution of the working fluid is difficult to be uniform, which can easily cause local overheating or insufficient heat exchange, thus restricting the overall heat exchange efficiency. 2. Thermal stress concentration and insufficient structural reliability: Under drastic temperature changes, traditional integrated structures are prone to stress concentration, weld cracking or fatigue failure due to differences in the thermal expansion coefficients of materials, which affects service life. 3. Poor coupling between thermochemical reaction and heat exchange process: If the fuel is not sufficiently pre-cooled or reacted before heat exchange, it will directly enter the main heat exchange zone, which will reduce the temperature difference and affect the heat exchange intensity. The existing structure is difficult to achieve synergistic optimization of reaction and heat exchange.

[0004] 4. Bulky structure and difficult to adapt to multi-level thermal management requirements: Traditional designs are difficult to achieve comprehensive optimization of flow resistance, heat transfer, reaction and structural strength in a limited space, and often sacrifice compactness or efficiency to meet strength requirements. Therefore, there is an urgent need to develop an advanced precooler solution that can ensure high thermal efficiency while also possessing excellent flow uniformity, high structural reliability, and the ability to coordinate thermal, chemical, and mechanical processes. Summary of the Invention

[0005] The purpose of this invention is to provide a modular design structure and reinforcement method for a multi-fluid aerospace precooler, which achieves a balance between uniform flow distribution, efficient heat exchange and high structural reliability through a modular three-level structure, functional separation design, multi-functional integrated components and targeted reinforcement methods.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: The invention includes a precooler, which adopts a three-layer structure layer stacked along the fluid flow direction, and each structural layer is selected according to the heat exchange capacity and flow resistance requirements; each structural layer includes a primary branch / manifold, a secondary branch / manifold, and a spiral tube arranged in series along the flow direction, and the inner diameter of the corresponding components of different structural layers increases layer by layer along the fluid flow direction; the primary branch pipe includes a first primary branch pipe, a second primary branch pipe, and a third primary branch pipe; the primary manifold includes a first primary manifold, a second primary manifold, and a third primary manifold; the secondary branch pipe includes a first secondary branch pipe, a second secondary branch pipe, and a third secondary branch pipe; the secondary manifold includes a first secondary manifold, a second secondary manifold, and a third secondary manifold; the spiral tube includes a first spiral tube, a second spiral tube, and a third spiral tube.

[0007] Furthermore, through a three-layer cascaded distribution structure, the fluid undergoes multiple redistributions between layers, systematically eliminating the problem of uneven flow distribution in traditional structures and maximizing overall heat exchange efficiency; the design of progressively increasing inner diameter optimizes overall flow resistance. Each structural layer can be flexibly selected and combined according to different heat load and flow resistance requirements, achieving excellent modularity and scalability.

[0008] The inner wall of the primary manifold / shunt is coated with a catalyst coating; Furthermore, by utilizing the large diameter and low flow velocity of the primary distributor / manifold, the reaction residence time is extended, allowing the endothermic chemical reaction to primarily occur in this region, significantly reducing the fluid temperature. The fuel is significantly cooled before entering the main heat exchange zone, increasing the temperature difference within the main heat exchange zone and thus substantially improving the convective heat transfer coefficient and overall thermal efficiency. This forms a tiered utilization model of "heat absorption and cooling in the primary tube, and efficient heat exchange in the secondary tube and helical tube." This functional separation structure can be understood by referring to the fluid path and component layout shown in the diagram below.

[0009] The fluid flow path is as follows: After being distributed by the first-stage diverter, the fluid flows through the first-second-stage diverter and the first spiral tube; then it enters the downstream area, undergoes secondary distribution through the second-stage diverter, flows through the second-second-stage diverter and the second spiral tube; finally, it enters the downstream area, undergoes further distribution through the third-stage diverter, flows through the third-second-stage diverter and the third spiral tube, making the flow distribution along the flow direction nearly uniform; Furthermore, the specific process of the three-level allocation is clarified, which provides a feasible and concrete structural support for the effect of "approaching uniform distribution along the flow direction", thereby enhancing the feasibility and reliability of the technical solution.

[0010] The primary distribution / manifold is a multifunctional integrated component that integrates the functions of fluid distribution, catalytic endothermic reaction, and serving as the main load-bearing frame, connecting with the secondary distribution / manifold to form a spatially reinforced skeleton. Furthermore, the primary branch / manifold, as a through-type main load-bearing frame, connects with the secondary branch / manifold to form a spatial truss-type reinforced skeleton, providing the entire precooler with extremely high overall rigidity and resistance to pressure and vibration. This integrated design perfectly achieves comprehensive optimization of flow resistance, heat exchange, reaction and structural strength within a limited space, avoiding the traditional dilemma of sacrificing compactness or efficiency to meet strength requirements.

[0011] The reinforcement methods include: welding a back plate to the secondary branch / manifold to enhance its structural support and heat dissipation efficiency; and using a support plate to fix the spiral tube, with the diameter of the irregular holes on the support plate being larger than the outer diameter of the spiral tube to allow for the release of thermal stress. The backplate is welded to the third and second-stage shunt pipes and the third and second-stage manifold pipes; The fitting clearance between the irregular hole and the spiral tube is used to allow the spiral tube to make slight movements during thermal expansion to release thermal stress, and to reduce vibration and prevent displacement; Furthermore, the backplate welding enhances the structural strength of the secondary manifold / distributor, especially in cases with a large number of tubes, and provides additional heat conduction paths to aid heat dissipation, achieving a balance between mechanical and thermal reinforcement. The reinforcing effect of the backplate can be seen in the rear structure shown in the diagram below; the design of the irregularly shaped hole support plate is a key innovation. The reserved fitting clearance allows for minute displacements of the helical tubes caused by thermal expansion, thereby actively releasing thermal stress and effectively preventing thermal fatigue cracking, tube deformation, and vibration wear, ensuring long-term structural integrity under extreme thermal cycling.

[0012] The beneficial effects of this invention are: 1. By arranging the three-level structural layers in series and gradually increasing the inner diameter of the components, the flow field is systematically optimized. The fluid is distributed and regulated multiple times through each level of the distribution pipe and the spiral pipe, ultimately achieving a highly uniform flow rate, avoiding local overheating, and maximizing heat exchange efficiency. The inner wall of the first-level distribution / manifold is coated with a catalyst, which, by utilizing its large diameter and low flow velocity, allows the endothermic chemical reaction to be mainly completed in this area, forming a functional separation structure of "first-level pipe for main endothermic reaction, and second-level pipe and spiral pipe for main convective heat exchange". This significantly reduces the temperature of the fluid before entering the main heat exchange zone, increases the heat exchange temperature difference, and thus improves the overall thermal efficiency.

[0013] 2. The primary branch / manifold is not only a flow channel, but also serves as the main load-bearing frame that runs through all layers. It connects with the secondary branch / manifold to form a spatially reinforced skeleton, providing extremely high overall rigidity and vibration resistance. For the secondary branch / manifold, back plates are welded onto the tertiary secondary branch and tertiary secondary manifold, which not only enhances the local structural strength and stability, but also improves heat dissipation efficiency by using the back plates as an additional heat conduction path. The spiral tube bundle is fixed by a support plate with a special-shaped hole slightly larger than the outer diameter of the spiral tube. This allows the spiral tube to undergo slight displacement during thermal expansion, thereby actively releasing thermal stress and effectively preventing thermal fatigue cracking, tube bundle deformation, and vibration wear, ensuring the long-term safe operation of the device under extreme thermal cycling. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall rear three-dimensional structure of the present invention; Figure 2 This is a schematic diagram of the overall front-side three-dimensional structure of the present invention; Figure 3 This is a schematic diagram of the backplate structure of the present invention; Figure 4 This is a schematic diagram of the support plate structure of the present invention; Figure 5 This is a schematic diagram of the irregular hole of the present invention.

[0015] 1. First-stage diverter pipe; 2. Second-stage diverter pipe; 3. Third-stage diverter pipe; 4. First and second-stage diverter pipes; 5. Second and second-stage diverter pipes; 6. Third and second-stage diverter pipes; 7. First spiral pipe; 8. Second spiral pipe; 9. Third spiral pipe; 10. First-stage manifold pipe; 11. Second-stage manifold pipe; 12. Third-stage manifold pipe; 13. First and second-stage manifold pipes; 14. Second and second-stage manifold pipes; 15. Third and second-stage manifold pipes; 16. Fuel inlet; 17. Fuel outlet; 18. Back plate; 19. Support plate; 20. Irregularly shaped hole. Detailed Implementation

[0016] The following will be combined with the appendix Figure 1-5 The technical solutions in the embodiments are described clearly and completely.

[0017] Specific implementation method one: as follows Figures 1-2 As shown, the precooler adopts a modular design, the core of which is at least three layers of structure stacked along the fluid flow direction. Fuel enters from the fuel inlet 16, flows through each layer in sequence, and finally flows out from the fuel outlet 17. Each structural layer contains a set of components with the same function, namely the primary branch / manifold, the secondary branch / manifold and the spiral tube. However, the inner diameter of the corresponding components in different structural layers increases layer by layer along the flow direction to optimize flow resistance and flow distribution. Fuel first enters the first-stage distribution pipe 1 for initial distribution, then flows into the downstream first-secondary distribution pipe 4 for secondary fine distribution, and finally enters multiple first spiral pipes 7 for initial heat exchange; the fluid continues to flow to the downstream second-stage distribution pipe 2 for secondary distribution and regulation, and then through the second-secondary distribution pipe 5 and second spiral pipe 8 to achieve intra-layer flow balance and continue heat exchange; the fluid finally enters the third-stage distribution pipe 3 for further distribution and regulation, and through the third-secondary distribution pipe 6 and third spiral pipe 9 to complete the final heat exchange and make the flow distribution highly uniform; the heat-exchanged fluid then gathers through each stage of manifold and finally flows out from the fuel outlet 17. The three-stage distribution system ensures uniform flow and lays the foundation for efficient heat exchange; To achieve synergy between thermal management and chemical reaction, the inner walls of the first-stage distributor 1, the second-stage distributor 2, the third-stage distributor 3, and the first-stage manifold 10, the second-stage manifold 11, and the third-stage manifold 12 on the return side are all coated with a catalyst coating. Due to the large inner diameter and low fluid velocity of the first-stage distributors / manifolds, the fuel has sufficient residence time to undergo catalytic endothermic reactions such as cracking, resulting in a significant temperature reduction before entering the compact second-stage distributors / manifolds and the main heat exchange zone of the spiral tube. This forms a functional separation structure of "primary tubes for main endothermic reaction, and secondary tubes and spiral tubes for main convective heat exchange," increasing the temperature difference in the main heat exchange zone and improving the overall heat exchange efficiency. The primary distribution / manifolds are the core multi-functional integrated components. They not only undertake the functions of fluid distribution and catalytic reaction, but also serve as the main load-bearing frame that runs through the entire precooler. They are connected to the secondary distribution / manifolds between adjacent layers, together forming a robust spatial truss-type reinforced skeleton, providing the entire device with extremely high overall rigidity and stability. Specific implementation method two: such as Figures 3-5 As shown, a backplate 18 is welded onto the third and second secondary shunt 6 and the third and second secondary manifold 15. The backplate has two main functions: first, to provide additional mechanical support, thereby increasing the structural strength and vibration resistance of the tube bundle; and second, to serve as an additional heat conduction path, helping heat to dissipate more quickly and achieving synergistic enhancement of mechanical and heat dissipation functions. The spiral tube is fixed by using a support plate 19. The support plate 19 has a pre-drilled hole 20 with a diameter slightly larger than the outer diameter of the spiral tube. This facilitates the installation of the spiral tube and allows the spiral tube to undergo slight displacement within the hole 20 during operation due to temperature and pressure changes. This actively releases thermal stress and effectively prevents fatigue cracking, tube deformation, and vibration wear caused by thermal expansion and contraction, ensuring long-term safe operation under extreme thermal cycling. The device achieves a balance between uniform flow distribution, efficient heat exchange, and high structural reliability through a modular three-stage structure, functional separation design, multifunctional integrated components, and targeted reinforcement methods.

[0018] Workflow: The overall flow path of the fuel is as follows: it enters from the fuel inlet 16, flows through the three structural layers in sequence, and finally flows out from the fuel outlet 17 through the manifolds at each level, so that the whole process realizes the coordinated work of "distribution-reaction-heat exchange". High-temperature fuel first enters the first-stage diversion pipe 1 from the fuel inlet 16. Due to the large diameter of the pipe, the fluid undergoes initial flow distribution here. When flowing through the first-stage diversion pipe 1, due to the low flow velocity, the fuel comes into full contact with the catalyst coating on the inner wall of the pipe, and an endothermic chemical reaction such as cracking occurs, and the fuel temperature is initially reduced. After the initial distribution and reaction, the fuel flows into the downstream first and second diversion pipes 4 for secondary fine distribution, and then enters multiple first spiral pipes 7 to conduct preliminary convective heat exchange with external cold sources such as air. After the fluid flows out, it enters the second-stage diversion pipe 2, which performs secondary distribution and regulation of the fluid from upstream. At the same time, the catalyst coating on its inner wall allows the endothermic reaction to continue, further reducing the fuel temperature. The fuel then passes through the second-stage diversion pipe 5 and the second spiral pipe 8 to achieve intralayer flow balance and deep heat exchange. The fluid continues to enter the third-stage diversion pipe 3 for final regulation, ensuring that the flow rate of each branch is highly uniform. The catalytic endothermic reaction ends at this stage. The fuel finally flows through the third secondary diversion pipe 6 and the third spiral pipe 9. Since the fuel temperature has been significantly reduced by the catalytic reaction in the previous stage, the temperature difference with the cold source is the largest at this time. Therefore, the convective heat transfer efficiency is the highest in this stage, completing the final cooling process. The cooling fuel that has completed all heat exchange begins to collect; it flows sequentially through the third secondary manifold 15 → the third primary manifold 12 → the second secondary manifold 14 → the second primary manifold 11 → the first secondary manifold 13 → the first primary manifold 10, and finally flows out of the system from the fuel outlet 17.

[0019] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A modular design structure for a multi-fluid aerospace precooler, characterized in that, The precooler is a three-layer structure stacked along the fluid flow direction. Each layer is selected according to the heat exchange capacity and flow resistance requirements. Each layer contains a primary branch / manifold, a secondary branch / manifold and a spiral tube arranged in series along the flow direction. The inner diameter of the corresponding components in different layers increases layer by layer along the fluid flow direction. The primary shunt includes a first primary shunt (1), a second primary shunt (2), and a third primary shunt (3); the primary manifold includes a first primary manifold (10), a second primary manifold (11), and a third primary manifold (12); the secondary shunt includes a first secondary shunt (4), a second secondary shunt (5), and a third secondary shunt (6); the secondary manifold includes a first secondary manifold (13), a second secondary manifold (14), and a third secondary manifold (15); the spiral pipe includes a first spiral pipe (7), a second spiral pipe (8), and a third spiral pipe (9).

2. The modular design structure of a multi-fluid aerospace precooler according to claim 1, characterized in that, The inner wall of the primary manifold / shunt is coated with a catalyst coating.

3. The modular design structure of a multi-fluid aerospace precooler according to claim 1, characterized in that, The fluid flow path is as follows: After being distributed by the first primary distribution pipe (1), the fluid flows through the first secondary distribution pipe (4) and the first spiral pipe (7); then it enters the downstream, undergoes secondary distribution through the second primary distribution pipe (2), flows through the second secondary distribution pipe (5) and the second spiral pipe (8); finally it enters the downstream, undergoes further distribution through the third primary distribution pipe (3), flows through the third secondary distribution pipe (6) and the third spiral pipe (9), so that the flow distribution along the flow direction tends to be uniform.

4. The modular design structure of a multi-fluid aerospace precooler according to claim 2, characterized in that, The primary manifold is a multifunctional integrated component that integrates the functions of progressive fluid distribution, catalytic endothermic reaction, and serving as the main load-bearing frame, connecting with the secondary manifold to form a spatially reinforced skeleton.

5. A method for reinforcing the modular design structure of a multi-fluid aerospace precooler as described in any one of claims 1-4, characterized in that, include: A backplate (18) is welded onto the secondary branch / manifold to enhance its structural support and heat dissipation efficiency; The spiral tube is fixed by a support plate (19), and the diameter of the irregular hole (20) on the support plate is larger than the outer diameter of the spiral tube to allow thermal stress release.

6. The reinforcement method for a modular design structure of a multi-fluid aerospace precooler according to claim 5, characterized in that, The back plate (18) is welded to the third secondary shunt (6) and the third secondary manifold (15).

7. The reinforcement method for a modular design structure of a multi-fluid aerospace precooler according to claim 5, characterized in that, The fit clearance between the shaped hole (20) and the spiral tube is used to allow the spiral tube to move slightly during thermal expansion to release thermal stress, and to reduce vibration and prevent displacement.

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