A regenerative cooling structure for a rocket engine with periodic microchannels

Abstract

A periodic microchannel recirculating regenerative cooling structure for a rocket engine includes an outer shell and an inner shell. The space between the outer and inner shells forms a receiving cavity, within which cooling channels are provided. These cooling channels are constructed from TPMS (Potentially Transformed Modules) cells arranged in a conformal mapping manner. Each cooling channel includes a first subdomain and a second subdomain. The first subdomain includes several interconnected first channels, and the second subdomain includes several interconnected second channels. The first and second channels are spaced apart from each other. The structure also includes a liquid inlet located on the outer shell, connected to the inlet end of each first channel. The inlet end of each first channel connects to the outlet end of each second channel, and the outlet end of each second channel connects to a liquid outlet. The conformal mapping cell arrangement allows for efficient utilization of the TPMS structure's characteristics. Furthermore, the recirculating cooling channels, which possess TPMS features, extend the coolant flow path and simplify the coolant collection and management system.

Description

Technical Field

[0001] This invention relates to the field of aerospace engine structure technology, and in particular to a periodic microchannel recirculation cooling structure for rocket engines. Background Art

[0002] In the design and operation of liquid rocket engines, thrust chamber cooling is a critical technical challenge. Regenerative cooling, as a preferred method, utilizes fuel or propellant as a cooling medium, flowing through cooling channels on the thrust chamber walls before entering the thrust chamber to reduce the thrust chamber wall temperature. Simultaneously, the fuel is preheated before being delivered into the thrust chamber via the nozzle in the head to improve combustion efficiency.

[0003] However, regenerative cooling faces numerous challenges, including uneven cooling efficiency, complex overall structure, and difficult maintenance. Especially under extreme high-temperature and high-pressure conditions, traditional cooling channel designs often limit their cooling efficiency and heat exchange uniformity due to their simple linear groove structure. Furthermore, multiple cooling channels traversing the thrust chamber wall may weaken structural integrity and strength, while also increasing the complexity and maintenance difficulty of the cooling medium management and distribution system.

[0004] The three-period minimal surface has high specific surface area and smooth surface, making it an ideal structure for efficient heat transfer. However, the application of this structure depends on the arrangement of the unit cells. The traditional rectangular stacking method is difficult to adapt to the nozzle shape of liquid rocket thrust chambers, making it difficult to give full play to the advantages of the TPMS structure. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a periodic microchannel recirculation cooling structure for rocket engines.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A periodic microchannel recirculating rocket engine regenerative cooling structure includes an outer shell and an inner shell. The space between the outer shell and the inner shell forms a receiving cavity. The receiving cavity is provided with cooling channels. The cooling channels are formed by TPMS unit cells arranged in a conformally mapped unit cell configuration. Each cooling channel includes a first subdomain and a second subdomain. The first subdomain includes a plurality of interconnected first channels, and the second subdomain includes a plurality of interconnected second channels. The first and second channels are spaced apart from each other. The structure also includes a liquid inlet located on the outer shell. The liquid inlet is connected to the inlet end of each of the first channels. The inlet end of the first channel is connected to the outlet end of the second channel, and the outlet end of each of the second channels is connected to a liquid outlet.

[0008] Furthermore, each of the first flow channels is provided with an outlet baffle at the position where it contacts the liquid outlet; the receiving cavity is also provided with an inlet collection cavity that communicates with the liquid inlet, and each of the second flow channels is provided with an inlet baffle at the position where it contacts the inlet collection cavity. The inlet baffle and the outlet baffle ensure that the coolant can only flow into the first sub-domain and cannot reach the liquid outlet in advance.

[0009] Furthermore, the inlet baffle and the outlet baffle can be respectively located at one of the following positions: the upper end of the outer shell, near the throat of the outer shell, near the bottom end of the outer shell, the upper end of the inner shell, near the throat of the inner shell, or near the bottom end of the inner shell, according to the setting requirements of the inlet collection chamber and the outlet.

[0010] Furthermore, the bottom of the receiving cavity is provided with a reflux collection cavity, the inlet end of the first flow channel is connected to the reflux collection cavity, and the reflux collection cavity flows through the outlet end of the second flow channel.

[0011] Furthermore, the TPMS cell arrangement of the cooling channel can be controlled by the number of radial cells, the number of circumferential cells, and the number of height periods.

[0012] Furthermore, the number of radial lattice divisions in the TPMS unit cell is 1 to 15.

[0013] Furthermore, the number of lattices in the circumferential direction of the TPMS unit cell is 4 to 40.

[0014] Furthermore, the number of lattices on the height period of the TPMS cell is 1 to 15.

[0015] Furthermore, the wall thickness of the cooling channel is 1–5 mm.

[0016] Furthermore, the contact points between the cooling channel and the inner and outer shells are provided with transition fillets.

[0017] The beneficial effects of the present invention are:

[0018] 1. This invention proposes a periodic microchannel recirculating regenerative cooling structure for a rocket engine, comprising an outer shell and an inner shell. The space between the outer and inner shells forms a receiving cavity, within which cooling channels are provided. These cooling channels are constructed from TPMS unit cells arranged in a conformally mapped cell configuration. Each cooling channel includes a first subdomain and a second subdomain. The first subdomain includes several interconnected first channels, and the second subdomain includes several interconnected second channels. The first and second channels are spaced apart from each other. The structure also includes a liquid inlet located on the outer shell, connected to the inlet end of each first channel. The inlet end of each first channel is connected to the outlet end of each second channel, and the outlet end of each second channel is connected to an outlet. The conformally mapped cell arrangement allows for efficient utilization of the TPMS structural features. Furthermore, the recirculating cooling channels, characteristic of TPMS, extend the coolant flow path, reducing the number of channels that need to traverse the thrust chamber wall, maintaining the structural integrity of the wall design, and simplifying the coolant collection and management system.

[0019] 2. The present invention proposes a periodic microchannel recirculating rocket engine regenerative cooling structure, which adopts a conformal mapping arrangement strategy of TPMS cell structure to generate cooling channels in the cavity. This strategy allows the TPMS structure to be topologically deformed according to the shape characteristics of the thrust chamber, resulting in lower flow resistance and better overall heat exchange performance compared to other regenerative cooling channels with TPMS characteristics.

[0020] 3. The periodic microchannel recirculating rocket engine regenerative cooling structure proposed in this invention, with the support of additive manufacturing technology, allows for free adjustment of the inlet baffle's position to adapt to the inlet liquid collection chamber's requirements, greatly increasing the design freedom of the cooling system; with the support of additive manufacturing technology, it also allows for free adjustment of the outlet baffle's position to adapt to the injection position of the recirculating fuel, greatly increasing the design freedom of the rocket engine fuel injector.

[0021] 4. The regenerative cooling structure for a periodic microchannel rocket engine proposed in this invention, with the support of additive manufacturing technology, allows for free adjustment of the shape of the inlet and outlet baffles to adjust the inlet and outlet pressures, thereby optimizing the pressure distribution at the inlet and outlet of the cooling medium. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1This is an internal schematic diagram of a periodic microchannel recirculation cooling structure for a rocket engine according to the present invention.

[0024] In the figure, 10 is the outer shell; 20 is the inner shell; 30 is the first subdomain; 40 is the second subdomain; 501 is the liquid inlet; 502 is the inlet collection chamber; 60 is the liquid outlet; 701 is the inlet baffle; 702 is the outlet baffle; and 80 is the reflux collection chamber. Detailed Implementation

[0025] The following is combined Figure 1 The present invention will be described in detail below.

[0026] A periodic microchannel recirculating rocket engine regenerative cooling structure includes an outer shell 10 and an inner shell 20. The space between the outer shell 10 and the inner shell 20 forms a receiving cavity. Cooling channels are provided in the receiving cavity. The cooling channels are formed by TPMS cells arranged in a conformally mapped cell configuration. The cooling channels include a first subdomain 30 and a second subdomain 40. The first subdomain 30 includes a plurality of interconnected first channels, and the second subdomain 40 includes a plurality of interconnected second channels. The first channels and second channels are distributed at intervals. The structure also includes a liquid inlet 501 located on the outer shell 10. The liquid inlet 501 is connected to the inlet end of each first channel. The inlet end of the first channel is connected to the outlet end of the second channel, and the outlet end of each second channel is connected to the liquid outlet 60.

[0027] Through innovative cooling channel design, the high heat exchange efficiency and structural stability advantages of the TPMS (Triple Period Minimal Surface) structure are combined with the structural characteristics of the recirculating channel design, which extends the flow path of the cooling medium and reduces system complexity. This unique combination provides an effective solution to problems such as uneven cooling, poor structural stability, and excessive system complexity in traditional regenerative cooling systems. By optimizing the flow path of fuel as a coolant, both the preheating efficiency and heat exchange efficiency of regenerative cooling are simultaneously improved, enhancing the structural integrity of the thrust chamber and reducing the overall complexity of the cooling system.

[0028] Triply Periodic Minimal Surfaces (TPMS) structures are a class of minimal surfaces that repeat periodically, extending in a specific manner in three-dimensional space. They also occur in nature; for example, examples of TPMS structures can be found in the microstructures of some sponges and corals. TPMS structures, through their high surface area to volume ratio, provide a larger heat exchange area, allowing the cooling medium to absorb and transfer heat more efficiently. This also results in a more uniform distribution of the cooling medium and guides it along a more optimized path, reducing pressure loss.

[0029] As a lattice structure, TPMS can fill the application space according to different lattice arrangements. Common lattice stacking methods include square stacking, cylindrical stacking and spherical stacking.

[0030] This invention employs a conformal mapping lattice arrangement to fill TPMS unit cells into the containment cavity of the rocket thrust chamber, i.e., the regenerative cooling region.

[0031] The specific filling effect of a TPMS structure depends on the lattice arrangement parameters and the implicit control function of the structure type. The implicit control function of the structure type conforms to the following expression:

[0032] f(x,y,z)=C

[0033] Where f(x,y,z) is the implicit function equation of the minimal surface. Depending on the application requirements and the flow space of the coolant in the liquid rocket thrust chamber, control functions with structures such as Schwarz, Gyroid, or Diamond are selected. Common types include:

[0034] Primitive:cos(2απx)+cos(2βπy)+cos(2γπz)=C

[0035] Diamond:cos(2απx)cos(2βπy)cos(2γπz)-sin(2απx)sin(2βπy)sin(2γπz)=C

[0036] Gyroid:sin(2απx)cos(2βπy)+sin(2βπy)cos(2απx)+sin(2γπz)cos(2απx)=C

[0037] IWP:2(cos(2απx)cos(2βπy)+cos(2βπy)cos(2γπz)+cos(2γπz)cos(2απx)-(cos2(2απx)+cos

[0038] 2(2βπy)+cos 2(2γπz))=C

[0039] In the expression, C is a constant that controls the minimum surface offset. This parameter is used to adjust the wall thickness of the cooling channel.

[0040] Specifically, in this embodiment, the coolant, i.e., the cooling medium, is a propellant medium; this example uses a Diamond-type TPMS unit cell, whose implicit function is:

[0041] cos(2απx)cos(2βπy)cos(2γπz)-sin(2απx)sin(2βπy)sin(2γπz)=C

[0042] Set the C value in the bias function to make the wall thickness of the TPMS channel 2mm.

[0043] In this embodiment, each of the first flow channels is provided with an outlet baffle 702 at the position where it contacts the liquid outlet 60; the receiving cavity is also provided with an inlet collection cavity 502 that connects to the liquid inlet 501, and each of the second flow channels is provided with an inlet baffle 701 at the position where it contacts the inlet collection cavity 502. The inlet baffle 701 and the outlet baffle 702 ensure that the coolant can only flow into the first sub-domain 30 and cannot reach the liquid outlet 60 in advance.

[0044] Furthermore, the inlet baffle 701 and the outlet baffle 702 can be convex, concave, or flat. Specifically, the inlet baffle 701 and the outlet baffle 702 are flat and have a thickness of 2 mm.

[0045] In this embodiment, the inlet baffle 701 and the outlet baffle 702 can be respectively located at one of the following positions: the upper end of the outer shell 10, near the throat of the outer shell 10, near the bottom of the outer shell 10, the upper end of the inner shell 20, near the throat of the inner shell 20, or near the bottom of the inner shell 20, depending on the requirements of the inlet collecting chamber 502 and the outlet port 60. The positions of the inlet baffle 701 and the outlet baffle 702 can be adjusted according to the installation method of the other cooling systems connected to the rocket engine.

[0046] In this embodiment, a reflux collection chamber 80 is provided at the bottom of the receiving cavity. The inlet end of the first flow channel is connected to the reflux collection chamber 80, and the reflux collection chamber 80 flows through the outlet end of the second flow channel.

[0047] like Figure 1As shown, the dashed line represents the first sub-domain 30, the solid line represents the second sub-domain 40, the diagonal line represents the inlet baffle 701, the position with several marked points represents the outlet baffle 702, and the arrow represents part of the coolant flow path. Specifically, the inlet 501 and the inlet collecting chamber 502 are located at the upper end of the receiving cavity, and the return collecting chamber 80 is located at the lower end of the receiving cavity, i.e., the bottom. When the coolant enters from the inlet 501, it reaches the inlet collecting chamber 502, and then enters the first sub-domain 30 (without the inlet baffle 701) from the inlet collecting chamber 502, i.e., the inlet end of each first flow channel. It flows from top to bottom along the first sub-domain 30 to the return collecting chamber 80 and continues to flow upward. The coolant then enters the second sub-domain 40, i.e., the inlet end of each second flow channel. Each second flow channel outlet is connected to the liquid outlet 60. The flexibility in setting the liquid outlet 60 allows the structure to adjust its position and shape according to the design needs of the overall system. In this embodiment, the liquid outlet 60 is set at the upper end of the receiving cavity. The first sub-domain 30 and the second sub-domain 40 are only connected at the bottom return collection cavity 80, and the other positions are separated by the flow channel wall and are not connected to each other. Due to the characteristics of the TPMS structure, the coolant flow path of the first sub-domain 30, that is, each first flow channel is interconnected. That is, adjacent first flow channels are connected through the connection between the two first flow channels (similar to a bridge hole, the connection appears to be blocked, but there are actually holes below the connection for coolant to flow). Similarly, the coolant flow path of the second sub-domain 40, that is, each second flow channel is interconnected.

[0048] In this embodiment, the TPMS cell arrangement in the cooling channel can be controlled by the number of radial cells, the number of circumferential cells, and the number of height periods. TPMS is a periodic surface that is infinitely non-self-intersecting in three spatial directions. Its smooth curvature and high specific surface area enable efficient heat exchange while exhibiting low flow resistance. However, as a lattice structure, the arrangement of TPMS cells needs to be designed to maximize the application of its structural characteristics in the regenerative cooling system of rocket engines.

[0049] The volume fraction of the cooling channels along the radial direction is controlled by changing the number of radial lattice divisions in the conformal mapping; the number of TPMS reflow cooling channels is increased or decreased by changing the number of circumferential lattice divisions in the conformal mapping; and the volume fraction of the cooling channels along the axial direction is controlled by changing the number of height periods in the conformal mapping. The TPMS structure located in the preset space of the channels is obtained through Boolean operations.

[0050] In this embodiment, the number of radial lattices in the TPMS unit cell is 1 to 15. Specifically, the number of radial lattices in the TPMS unit cell is 1.

[0051] In this embodiment, the number of circumferential cells in the TPMS unit cell is 4 to 40. Specifically, the number of circumferential cells in the TPMS unit cell is 10.

[0052] In this embodiment, the number of cells on the height period of the TPMS unit cell is 1 to 15. Specifically, the number of cells on the height period of the TPMS unit cell is 10.

[0053] In this embodiment, the wall thickness of the cooling channel is 1–5 mm. Specifically, the wall thickness of the cooling channel is 2 mm.

[0054] In this embodiment, a transition fillet is provided at the contact position between the cooling channel and the inner shell 20 and the outer shell 10. The transition fillet is provided to achieve a smooth structural transition, avoid stress concentration, and enhance structural strength.

[0055] In this embodiment, the radius of the transition fillet is 0.5–5 mm. Specifically, the radius of the transition fillet is 1 mm.

[0056] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand and implement the present invention. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A periodic microchannel recirculating rocket engine regenerative cooling structure, characterized in that, The device includes an outer shell and an inner shell, with the space between the outer shell and the inner shell forming a receiving cavity. The receiving cavity is provided with cooling channels, which are formed by TPMS unit cells arranged in a conformally mapped unit cell configuration. Each cooling channel includes a first subdomain and a second subdomain. The first subdomain includes a plurality of interconnected first channels, and the second subdomain includes a plurality of interconnected second channels. The first and second channels are spaced apart from each other. The device also includes a liquid inlet located on the outer shell. The liquid inlet is connected to the inlet end of each of the first channels. The inlet end of the first channel is connected to the outlet end of the second channel, and the outlet end of each of the second channels is connected to a liquid outlet.

2. The periodic microchannel recirculation-type rocket engine regenerative cooling structure as described in claim 1, characterized in that, Each of the first flow channels is provided with an outlet baffle at the position where it contacts the liquid outlet; the receiving cavity is also provided with an inlet collection cavity that communicates with the liquid inlet, and each of the second flow channels is provided with an inlet baffle at the position where it contacts the inlet collection cavity. The inlet baffle and the outlet baffle ensure that the coolant can only flow into the first sub-domain and cannot reach the liquid outlet in advance.

3. The periodic microchannel recirculation-type rocket engine regenerative cooling structure as described in claim 2, characterized in that, The inlet baffle and outlet baffle can be respectively set at one of the following locations: the upper end of the outer shell, near the throat of the outer shell, near the bottom end of the outer shell, the upper end of the inner shell, near the throat of the inner shell, or near the bottom end of the inner shell, according to the setting requirements of the inlet collection chamber and the outlet.

4. The periodic microchannel recirculation-type rocket engine regenerative cooling structure as described in claim 1, characterized in that, The bottom of the receiving cavity is provided with a reflux collection chamber, the inlet end of the first flow channel is connected to the reflux collection chamber, and the reflux collection chamber flows through the outlet end of the second flow channel.

5. The periodic microchannel recirculation-type rocket engine regenerative cooling structure as described in claim 1, characterized in that, The TPMS cell arrangement of the cooling channel can be controlled by the number of radial cells, the number of circumferential cells, and the number of height cycles.

6. The periodic microchannel recirculation-type rocket engine regenerative cooling structure as described in claim 5, characterized in that, The number of radial lattice divisions in the TPMS unit cell is 1 to 15.

7. The periodic microchannel recirculation-type rocket engine regenerative cooling structure as described in claim 5, characterized in that, The number of circumferential cells in the TPMS unit cell is 4 to 40.

8. The periodic microchannel recirculation-type rocket engine regenerative cooling structure as described in claim 5, characterized in that, The number of cells on the height period of the TPMS unit cell is 1 to 15.

9. The periodic microchannel recirculation-type rocket engine regenerative cooling structure as described in claim 1, characterized in that, The wall thickness of the cooling channel is 1 to 5 mm.

10. The periodic microchannel recirculation-type rocket engine regenerative cooling structure as described in claim 1, characterized in that, The cooling channel has a rounded corner at the contact point with the inner and outer shells.

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