Cylindrical heat exchanger and micro gas turbine

Abstract

This invention provides a cylindrical heat exchanger and a micro gas turbine. The cylindrical heat exchanger includes a hollow inner cavity and a circumferential heat exchanger wall. The heat exchanger wall includes a first gas collecting pipe, a second gas collecting pipe, and a three-period minimally oriented curved surface (TPMS) structural unit. Multiple first and second gas collecting pipes are spaced apart circumferentially along the heat exchanger wall and are all arranged axially along the heat exchanger wall. A TPMS structural unit is provided between any two adjacent first and second gas collecting pipes. The TPMS structural unit includes a TPMS wall and TPMS holes. The first gas collecting pipe, the flow channel within the TPMS wall, and the second gas collecting pipe are sequentially connected to form a first flow channel, and the TPMS holes, which are separated by the TPMS wall, form a second flow channel. This invention, by using a TPMS wall surface in the cylindrical heat exchanger, achieves a lightweight structure with a large specific surface area, resulting in higher thermal efficiency, lightweight design, low resistance, and good noise reduction, while also reducing manufacturing costs.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, specifically to a cylindrical heat exchanger and a micro gas turbine. Background Technology

[0002] In current micro gas turbine systems, plate-fin heat exchangers, shell-and-tube heat exchangers, and printed circuit board heat exchangers (PCHEs) are commonly used to achieve efficient regenerative cycles. Although these traditional heat exchangers are mature in industrial applications, they often face problems such as high flow resistance, easy fouling and clogging, or difficulty in conformal manufacturing and high cost in scenarios like micro gas turbines where there are extremely high requirements for volume, weight, flow resistance, and heat exchange efficiency.

[0003] A Chinese patent with publication number CN117570763A discloses a cross-flow heat exchanger based on a TPMS structure, belonging to the field of heat exchanger technology. The cross-flow heat exchanger is suitable for cylindrical regions and is a modular additive manufacturing TPMS heat exchanger generated from a three-period minimal curved surface TPMS cell structure.

[0004] In existing technologies, it is difficult to control the flow resistance of TPMS structure heat exchangers. Under the high flow rate conditions of micro gas turbines, improper structural design may lead to excessive pressure drop, which in turn reduces the overall efficiency of the turbine.

[0005] Therefore, there is a need to provide a cylindrical heat exchanger and a micro gas turbine that have advantages such as higher thermal efficiency, lighter weight, lower resistance, and better noise reduction, thereby solving the problems existing in the prior art. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the purpose of this invention is to provide a cylindrical heat exchanger and a micro gas turbine.

[0007] According to the present invention, a cylindrical heat exchanger includes: a hollow inner cavity and a circumferential heat exchanger wall. The heat exchanger wall includes: a first gas collecting pipe, a second gas collecting pipe, and a three-period minimal curved surface TPMS structural unit. A plurality of first gas collecting pipes and a plurality of second gas collecting pipes are distributed circumferentially at intervals along the heat exchanger wall, and both the first gas collecting pipes and the second gas collecting pipes are arranged axially along the heat exchanger wall.

[0008] A TPMS structural unit is provided between any two adjacent first and second gas collection pipes. The TPMS structural unit includes a TPMS wall and TPMS holes. The first gas collection pipe, the flow channel inside the TPMS wall, and the second gas collection pipe are connected in sequence to form a first flow channel. The TPMS holes that are separated from each other by the TPMS wall form a second flow channel.

[0009] Preferably, the TPMS wall channel comprises multiple curved, spirally wound TPMS channels, which are smooth and spiral.

[0010] Preferably, the first flow channel and the second flow channel are intertwined but not connected to each other.

[0011] Preferably, both the first gas collecting pipe and the second gas collecting pipe extend into the interior of the TPMS wall.

[0012] Preferably, the cylindrical heat exchanger includes multiple heat exchange modules that are circumferentially fastened together to form a cylindrical shape. Each heat exchange module includes a first gas collecting pipe, a second gas collecting pipe, and a TPMS structural unit. The heat exchange module shares the first gas collecting pipe and the second gas collecting pipe with two adjacent heat exchange modules respectively.

[0013] Preferably, the cylindrical heat exchanger is integrally manufactured by additive manufacturing.

[0014] According to the present invention, a micro gas turbine includes a cylindrical heat exchanger as described in any one of the claims. The micro gas turbine further includes a compressor, a turbine, and a combustion chamber. The compressor, turbine, and cylindrical heat exchanger are arranged coaxially in sequence. The cylindrical heat exchanger is installed at the outlet of the turbine. The combustion chamber is disposed around the periphery of the turbine, and the exhaust port of the combustion chamber is connected to the turbine. The inlet of the combustion chamber is connected to the second gas collecting pipe of the cylindrical heat exchanger. The exhaust port of the compressor is connected to the first gas collecting pipe of the cylindrical heat exchanger.

[0015] Preferably, the high-temperature gas discharged from the turbine enters the inner cavity of the cylindrical heat exchanger, flows from the inner cavity to the second flow channel of the heat exchanger wall, and is discharged from the outer wall surface of the heat exchanger wall.

[0016] Preferably, the high-pressure gas flow discharged from the compressor flows into multiple first gas collecting pipes of the cylindrical heat exchanger. The high-pressure gas flow flows from the first gas collecting pipes to the first flow channel of the heat exchanger wall. The high-temperature gas in the second flow channel exchanges heat with the high-pressure gas flow in the first flow channel. The high-pressure gas flow flows from the first flow channel to the second gas collecting pipe of the heat exchanger wall. The high-pressure gas flow flows out from the high-pressure gas flow and enters the combustion chamber. The second high-temperature gas generated by the combustion chamber flows circumferentially into the turbine.

[0017] Preferably, a generator is installed on the side of the compressor away from the micro gas turbine, and the generator generates electricity by being driven by the compressor.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses a cylindrical heat exchanger with TPMS wall surface, which is lightweight and has a large specific surface area. It has advantages such as higher thermal efficiency, lightweight, low resistance and good noise reduction effect. It is integrally formed by additive manufacturing, which reduces processing cost and is especially suitable for aerospace flight propulsion.

[0019] 2. This invention employs a TPMS heat exchange structure, in which high-pressure airflow and high-temperature gas flow and exchange heat in the TPMS wall channels of the cylindrical heat exchanger, separated by a thin wall, resulting in high heat exchange efficiency. Furthermore, the porous structure provides a noise reduction effect, confining the high noise of the turbine's high-temperature gas within the inner cavity.

[0020] 3. The present invention has an air inlet and an exhaust outlet evenly distributed on the end circumference of the cylindrical heat exchanger, and the air inlet and exhaust outlet are arranged at intervals. The air inlet receives exhaust from the compressor, and the exhaust outlet is connected to the combustion chamber. The compressed air after absorbing heat enters the combustion chamber, with low flow resistance and higher energy efficiency.

[0021] 4. The cylindrical heat exchanger is installed as an independent component on the exhaust side of the micro gas turbine, which is convenient for installation and maintenance. The length of the cylindrical heat exchanger can be freely customized according to the heat exchange requirements to improve the heat exchange capacity. Furthermore, the increased omnidirectional exhaust flow area of ​​the turbine reduces the exhaust flow resistance, which can further improve the performance of the micro gas turbine power generation system. Attached Figure Description

[0022] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram illustrating the structure of a micro gas turbine, which is the main feature of this invention. Figure 2 This is a schematic diagram illustrating the structure of the cylindrical heat exchanger, which is the main feature of this invention. Figure 3 This is a side view of the cylindrical heat exchanger, which is the main feature of this invention.

[0023] Reference numerals: 1. Compressor; 2. Turbine; 4. Combustion cylinder; 6. Generator; 10. Cylindrical heat exchanger; 11. Intake air; 12. High-pressure airflow; 13. Circumferential airflow; 14. Heat-absorbing airflow; 15. Second high-temperature gas; 16. High-temperature gas; 18. Heat-absorbing gas; 20. Inner cavity; 22. First gas collecting pipe; 24. Second gas collecting pipe; 26. Second flow channel exhaust port; 30. End circumferential surface; 40. Heat exchanger wall; 50. Outer wall surface; 100. Micro gas turbine. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0025] Example 1 like Figures 1 to 3 As shown, a cylindrical heat exchanger 10 according to the present invention includes: a hollow inner cavity 20 and a circumferential heat exchanger wall 40. The heat exchanger wall 40 includes: a first gas collecting pipe 22, a second gas collecting pipe 24, and a three-period minimal surface TPMS structural unit. A plurality of first gas collecting pipes 22 and a plurality of second gas collecting pipes 24 are distributed circumferentially at intervals along the heat exchanger wall 40, and both the first gas collecting pipes 22 and the second gas collecting pipes 24 are arranged axially along the heat exchanger wall 40. A TPMS structural unit is provided between any two adjacent first gas collecting pipes 22 and second gas collecting pipes 24. The TPMS structural unit includes: a TPMS wall and TPMS holes. The first gas collecting pipe 22, the inner flow channel of the TPMS wall, and the second gas collecting pipe 24 are sequentially connected to form a first flow channel. A second flow channel is formed by the TPMS holes that are separated from each other through the TPMS wall. The second flow channel connects the inner cavity 20 and the external environment of the heat exchanger wall 40.

[0026] The cylindrical heat exchanger 10 is composed of a three-period minimal curved surface TPMS structure, including a hollow inner cavity 20 and a circumferential heat exchanger wall 40. Multiple heat exchange modules are formed within the heat exchanger wall 40. Each heat exchange module consists of a first gas collecting pipe 22, a second gas collecting pipe 24, and a three-period minimal curved surface TPMS structural unit sandwiched between them. Both the first and second gas collecting pipes 22 and 24 extend into the interior of the TPMS wall. The first and second flow channels exist within the TPMS wall of the cylindrical heat exchanger 10, intertwined but not interconnected, separated by the curved surface of the TPMS wall and exchanging heat through it. The spirally curved flow channels of the TPMS structure provide strong flow mixing, resulting in highly enhanced heat transfer performance.

[0027] The three-period minimal surface TPMS structure has a minimal surface lattice structure extending periodically along three coordinate directions, containing multiple curved and spirally wound TPMS flow channels, and the flow channels of different fluids are separated from each other by the walls of the TPMS lattice. It has the advantages of structural stability, self-support, lightweight, high strength-to-weight ratio, and high specific surface area. Since both cold and hot fluids flow and exchange heat within the entire TPMS wall of the cylindrical heat exchanger 10, the TPMS flow channels are smooth and spiral, resulting in less flow separation and dead zones. This provides a larger flow area, better flowability, and lower flow resistance compared to conventional heat exchangers where cold and hot fluids flow alternately in layers. TPMS includes various types; in this application, the Gyroid type and Diamond type are preferred.

[0028] The cylindrical heat exchanger 10 can be integrally manufactured by additive manufacturing, such as by laser powder bed fusion (LPBF). The cylindrical heat exchanger 10 can also be manufactured by casting; the materials can be stainless steel, nickel-based alloys, various metals and non-metals.

[0029] In other specific embodiments, the cylindrical heat exchanger 10 includes multiple heat exchange modules circumferentially fastened together to form a cylindrical shape. Each heat exchange module includes a first gas collecting pipe 22, a second gas collecting pipe 24, and a TPMS structural unit. Each heat exchange module shares the first gas collecting pipe 22 and the second gas collecting pipe 24 with two adjacent heat exchange modules. That is, multiple heat exchange modules share the first gas collecting pipe 22 and the second gas collecting pipe 24. By welding the first gas collecting pipe 22 and the second gas collecting pipe 24, multiple heat exchange modules can be combined into a single cylindrical heat exchanger 10. The first gas collecting pipe 22 serves as the inlet for the heat exchange fluid, and the second gas collecting pipe 24 serves as the outlet for the heat exchange fluid. Both the first gas collecting pipe 22 and the second gas collecting pipe 24 extend into the interior of the TPMS wall, providing uniform circumferential heat exchange fluid flow within the circumferential wall of the cylindrical heat exchanger 10.

[0030] The cylindrical heat exchanger 10 of this application has advantages such as higher thermal efficiency, lightweight, low resistance, and good noise reduction. It is integrally formed by additive manufacturing, resulting in low processing cost. The TPMS wall structure of the cylindrical heat exchanger 10 is lightweight and has a large specific surface area, making it a lightweight, efficient, and low-resistance high-temperature heat exchanger, especially suitable for aerospace propulsion.

[0031] Example 2 Based on Embodiment 1, a micro gas turbine 100 according to the present invention includes a cylindrical heat exchanger as described in any of claims 1-6. The micro gas turbine 100 further includes a compressor 1, a turbine 2, and a combustion chamber 4. The compressor 1, turbine 2, and cylindrical heat exchanger 10 are arranged coaxially in sequence. The cylindrical heat exchanger 10 is installed at the outlet of the turbine 2. The combustion chamber 4 is arranged around the turbine 2, and the exhaust port of the combustion chamber 4 is connected to the turbine 2. The inlet of the combustion chamber 4 is connected to the second gas collecting pipe 24 of the cylindrical heat exchanger 10. The exhaust port of the compressor 1 is connected to the first gas collecting pipe 22 of the cylindrical heat exchanger 10.

[0032] The cylindrical heat exchanger 10 is assembled with the micro gas turbine 100 on the end circumferential surface 30, and the two are tightly fitted without leakage. The cylindrical heat exchanger 10 has a first gas collecting pipe 22 and a second gas collecting pipe 24 evenly distributed along the circumference. The inlet of the first gas collecting pipe 22 serves as the air inlet on the end circumferential surface 30, and the outlet of the second gas collecting pipe 24 serves as the exhaust port on the end circumferential surface 30. The air inlet and exhaust port are arranged alternately. The air inlet receives the high-pressure airflow 12 discharged from the compressor 1, and the exhaust port is connected to the combustion chamber 4. The air that has absorbed heat enters the combustion chamber 4.

[0033] A cylindrical heat exchanger 10 is installed at the outlet of the turbine 2. The high-temperature exhaust gas 16 discharged from the turbine 2 enters the inner cavity 20 of the cylindrical heat exchanger 10 and flows outward through the heat exchanger wall 40 of the cylindrical heat exchanger 10. Since the cylindrical heat exchanger 10 is a porous heat exchange structure, its installation at the turbine 2 outlet not only efficiently recovers the waste heat from the turbine 2 exhaust of the micro gas turbine 100, but also reduces the noise of the turbine 2 exhaust. The axial end (tail) TPMS wall of the cylindrical heat exchanger 10 has a smaller porosity or a larger thickness, so that the high-temperature exhaust gas from the turbine 2 can flow out of the cylindrical heat exchanger 10 more evenly from all directions (omnidirectional), achieving lower flow resistance and efficient heat exchange.

[0034] Intake air 11 enters the compressor 1 of the micro gas turbine 100. The compressor 1 discharges high-pressure gas flow 12, which flows into multiple first gas collecting pipes 22 of the cylindrical heat exchanger 10. The multiple first gas collecting pipes 22 distribute the high-pressure gas flow 12 in the circumferential direction to multiple heat exchange modules of the cylindrical heat exchanger 10 for flow and heat exchange. After heat exchange with high-temperature gas 16, the high-pressure gas flow 12 converges into multiple second gas collecting pipes 24 in the circumferential direction of the cylindrical heat exchanger 10, and then flows out from the second gas collecting pipes 24 and enters the combustion chamber 4 to participate in combustion. That is, the high-pressure gas flow 12 flows from the first gas collecting pipe 22 to the first flow channel of the heat exchanger wall 40 to form a circumferential flow gas flow 13. The circumferential flow gas flow 13 flows and exchanges heat with the high-temperature gas 16 in the second flow channel to form a heat-absorbing gas flow 14. The heat-absorbing gas flow 14 flows out from the second gas collecting pipe 24 and enters the combustion chamber 4. The second high-temperature gas 15 generated by the combustion chamber 4 flows into the turbine 2 in the circumferential direction. At the same time, the high-temperature gas 16 flowing out from the inner cavity 20 to the second flow channel of the heat exchanger wall 40 exchanges heat with the circumferential flow airflow 13 to form heat-exchanged gas 18, which is then discharged from the exhaust hole 26 of the second flow channel on the outer wall surface 50.

[0035] The second high-temperature gas 15 generated by the combustion chamber 4 flows into the turbine 2 circumferentially and flows out from the turbine 2 in the axial direction to form high-temperature gas 16. The high-temperature gas 16 enters the inner cavity 20 and flows through the cylindrical heat exchanger 10, and is discharged from the outer wall surface 50 of the cylindrical heat exchanger 10.

[0036] A generator 6 is installed on the side of the compressor 1 away from the micro gas turbine 100. The generator 6 generates electricity by being driven by the compressor 1. To the left of the compressor 1 of the micro gas turbine 100, a high-speed generator 6 can be connected and driven to generate electricity, which has higher energy efficiency.

[0037] The cylindrical heat exchanger 10 of this application has a unique TPMS heat exchange structure, which has a large surface area and high heat exchange efficiency. At the same time, due to its porous structure, it has a noise reduction effect, which confines the high noise of the high-temperature gas 16 of the turbine 2 to the inner cavity 20.

[0038] In this application, the high-pressure gas flow 12 and the high-temperature gas 16 each flow and exchange heat in the TPMS wall channels of the cylindrical heat exchanger 10. The channels of the high-pressure gas flow 12 and the high-temperature gas 16 in the TPMS lattice are intertwined but separated by thin walls, thus the high-pressure gas flow 12 and the high-temperature gas 16 achieve high-efficiency heat exchange.

[0039] Furthermore, to improve the thermal efficiency of the cylindrical heat exchanger 10, the length of the cylindrical heat exchanger 10 can be easily increased. This increases the outflow area of ​​the gas 18 after heat exchange, reduces the exhaust pressure loss of the micro gas turbine 100, and helps to improve the overall efficiency of the micro gas turbine 100.

[0040] The cylindrical heat exchanger 10 of this application is suitable for use as a regenerator in a micro gas turbine 100, thereby improving the thermal efficiency of the micro gas turbine 100. The cylindrical heat exchanger 10 of this application has the advantages of large heat exchange area, large flow area, and low flow resistance, which results in low heat loss in the regenerating micro gas turbine device, and has the advantages of high thermal efficiency and compact structure.

[0041] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0042] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A cylindrical heat exchanger, characterized in that, The cylindrical heat exchanger (10) includes a hollow inner cavity (20) and a circumferential heat exchanger wall (40). The heat exchanger wall (40) includes a first gas collecting pipe (22), a second gas collecting pipe (24), and a three-period minimal curved surface TPMS structural unit. Multiple first gas collecting pipes (22) and multiple second gas collecting pipes (24) are distributed circumferentially along the heat exchanger wall (40), and both the first gas collecting pipes (22) and the second gas collecting pipes (24) are arranged axially along the heat exchanger wall (40). A TPMS structural unit is provided between any two adjacent first gas collection pipes (22) and second gas collection pipes (24). The TPMS structural unit includes a TPMS wall and TPMS holes. The first gas collection pipe (22), the flow channel inside the TPMS wall and the second gas collection pipe (24) are connected in sequence to form a first flow channel. The second flow channel is formed by the TPMS holes that are separated from each other by the TPMS wall.

2. The cylindrical heat exchanger as described in claim 1, characterized in that, The TPMS wall-mounted flow channel comprises multiple curved, spirally wound TPMS flow channels, which are smooth and spiral.

3. The cylindrical heat exchanger as described in claim 1, characterized in that, The first flow channel and the second flow channel are intertwined but not connected to each other.

4. The cylindrical heat exchanger as described in claim 1, characterized in that, The first gas collecting pipe (22) and the second gas collecting pipe (24) both extend into the interior of the TPMS wall.

5. The cylindrical heat exchanger as described in claim 1, characterized in that, The cylindrical heat exchanger (10) includes multiple heat exchange modules that are circumferentially fastened together to form a cylindrical shape. Each heat exchange module includes a first gas collection pipe (22), a second gas collection pipe (24), and a TPMS structural unit. The heat exchange module shares the first gas collection pipe (22) and the second gas collection pipe (24) with two adjacent heat exchange modules respectively.

6. The cylindrical heat exchanger as described in claim 1, characterized in that, The cylindrical heat exchanger (10) is manufactured in one piece by additive manufacturing.

7. A micro gas turbine, characterized in that, The micro gas turbine (100) includes a cylindrical heat exchanger as described in any one of claims 1-6. The micro gas turbine (100) further includes a compressor (1), a turbine (2), and a combustion chamber (4). The compressor (1), turbine (2), and cylindrical heat exchanger (10) are arranged coaxially in sequence. The cylindrical heat exchanger (10) is installed at the outlet of the turbine (2). The combustion chamber (4) is arranged on the periphery of the turbine (2), and the exhaust port of the combustion chamber (4) is connected to the turbine (2). The inlet of the combustion chamber (4) is connected to the second gas collecting pipe (24) of the cylindrical heat exchanger (10). The exhaust port of the compressor (1) is connected to the first gas collecting pipe (22) of the cylindrical heat exchanger (10).

8. The micro gas turbine as described in claim 7, characterized in that, The high-temperature gas (16) discharged from the turbine (2) enters the inner cavity (20) of the cylindrical heat exchanger (10), the high-temperature gas (16) flows from the inner cavity (20) to the second flow channel of the heat exchanger wall (40), and the high-temperature gas (16) is discharged from the outer wall surface (50) of the heat exchanger wall (40).

9. The micro gas turbine as described in claim 7, characterized in that, The high-pressure gas flow (12) discharged from the compressor (1) flows into a plurality of first gas collection pipes (22) of the cylindrical heat exchanger (10). The high-pressure gas flow (12) flows from the first gas collection pipe (22) to the first flow channel of the heat exchanger wall (40). The high-temperature gas (16) in the second flow channel flows and exchanges heat with the high-pressure gas flow (12) in the first flow channel. The high-pressure gas flow (12) flows from the first flow channel to the second gas collection pipe (24) of the heat exchanger wall (40). The high-pressure gas flow (12) flows out from the high-pressure gas flow (12) and enters the combustion chamber (4). The second high-temperature gas (15) generated by the combustion chamber (4) flows into the turbine (2) circumferentially.

10. The micro gas turbine as described in claim 7, characterized in that, A generator (6) is provided on the side of the compressor (1) away from the micro gas turbine (100), and the generator (6) generates electricity by being driven by the compressor (1).

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