Engine air inlet precooling heat exchanger
By using engine intake pre-cooling heat exchangers with cracked thermal fuel, the problems of high thermal stress, frost and poor safety in the liquid hydrogen and liquid helium pre-cooling solutions are solved, efficient and safe engine cooling is achieved, and the economic benefits of the engine are improved.
Patent Information
- Application Number
- CN202510516123.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-23
- Publication Date
- 2025-07-04
AI Technical Summary
The existing liquid hydrogen pre-cooling and liquid helium pre-cooling closed circulation heat exchange solutions have problems such as high thermal stress, frost, hydrogen embrittlement risks and low economic benefits. In particular, the low-temperature storage and complex circulation systems of liquid hydrogen and liquid helium lead to increased engine weight and poor safety.
The cracking and heat absorption type fuel is used as the cooling medium, and the high-temperature intake air inlet of the engine is cooled by the fuel inlet assembly, fuel outlet assembly and return heat exchange assembly through the fuel inlet assembly, the fuel outlet assembly and the reflux heat exchange assembly. The catalyst is coated on the wall of the reaction section heat exchange pipe, the porous medium is filled in the fuel outlet assembly, and the fuel exchanges heat in the countercurrent and downstream directions.
It reduces the high-temperature intake temperature difference between the cooling medium and the engine, avoids thermal stress and frost problems, improves the safety and economic benefits of the engine, and reduces the engine weight.
Smart Images
Figure CN120251392A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the technical field of gas turbines / aero-engines, and particularly relates to an engine inlet pre-cooling heat exchanger. Background Art
[0002] In recent years, aircraft have evolved towards higher and faster flight goals, which poses a severe test for the design and manufacture of aero-engines. With the increase in flight speed, the total temperature of the inlet air flow of the engine increases, which makes the engine components have to bear an increasing thermal load. On the one hand, when working under high-temperature conditions for a long time, the structural strength and service life of the engine components will decrease; on the other hand, with the increase in the total temperature of the inlet air flow of the engine, due to the limitation of the physical rotational speed, the operating point of the engine compression components moves down along the operating envelope, resulting in a decrease in engine thrust. To solve a series of problems brought by the high total temperature of the inlet air flow of the engine, pre-cooling the high-temperature inlet air of the engine has become a necessary technical means.
[0003] Currently, the pre-cooling of high-temperature inlet air of engines generally adopts a liquid hydrogen direct pre-cooling heat exchange scheme or a liquid helium pre-cooling closed-cycle heat exchange scheme.
[0004] For the liquid hydrogen direct pre-cooling heat exchange scheme, the liquid hydrogen pre-cooling heat exchanger is installed at the engine inlet, and the high-temperature inlet air of the engine inlet duct is directly cooled by liquid hydrogen. After the liquid hydrogen fully absorbs heat, it enters the compressor, then expands and does work in the turbine, and finally enters the combustion chamber and the afterburner for combustion.
[0005] As Figure 1 shown, for the liquid helium pre-cooling closed-cycle heat exchange scheme,
[0006] the liquid helium pre-cooling heat exchanger is installed at the engine inlet, and the high-temperature inlet air of the engine inlet duct is cooled by liquid helium. The helium flowing out of the liquid helium pre-cooling heat exchanger is then cooled by liquid hydrogen, and the cold helium then flows to the circulation pump, and then to the liquid nitrogen pre-cooling heat exchanger to start the next cycle.
[0007] However, both the liquid hydrogen pre-cooling heat exchange scheme and the liquid helium pre-cooling closed-cycle heat exchange scheme have relatively large technical problems, including:
[0008] 1) High technical difficulty
[0009] The liquid hydrogen pre-cooling heat exchange scheme and the liquid helium pre-cooling closed-cycle heat exchange scheme need to use liquid hydrogen and liquid helium. The liquefaction temperatures of hydrogen and helium are low, usually lower than -200°C, resulting in a large temperature difference between the cooling medium and the high-temperature inlet air of the engine. The large temperature difference will cause problems such as large thermal stress and frosting in the pre-cooling heat exchanger;
[0010] 2) Poor safety
[0011] Both the liquid hydrogen precooling heat exchange scheme and the liquid helium precooling closed-cycle heat exchange scheme use liquid hydrogen as the final cooling medium. Heat exchangers involving liquid hydrogen are prone to hydrogen embrittlement. Once hydrogen fuel leaks into the main flow channel, it is likely to trigger an explosion.
[0012] 3) Low economic efficiency
[0013] The liquid helium precooling closed-cycle heat exchange scheme requires adding a set of complex circulation systems, which increases the weight of the engine. At the same time, due to the small density and large flow rate of helium, the volume of the circulation system is relatively large, increasing the flight resistance of the engine and reducing the economic efficiency of the engine. Summary of the Invention
[0014] The purpose of this application is to provide an engine intake air precooling heat exchanger to solve or alleviate at least one problem in the background art.
[0015] The technical solution of this application is: an engine intake air precooling heat exchanger, including: a fuel inlet assembly, a fuel outlet assembly, and a confluence heat exchange assembly, where:
[0016] The fuel inlet assembly includes a fuel inlet shunt ring and fuel inlet shunt pipes. A fuel inlet is provided inside the fuel inlet shunt ring. The fuel inlet shunt pipes are straight tube structures and there are multiple of them. The fuel inlet shunt pipes are circumferentially and evenly arranged on the fuel inlet shunt ring and are connected to the fuel inlet shunt ring.
[0017] The fuel outlet assembly includes a fuel outlet confluence ring and fuel outlet confluence pipes. The fuel outlet confluence ring is arranged outside the fuel inlet shunt ring. A fuel outlet is provided on the fuel outlet confluence ring. The fuel outlet confluence pipes are arranged outside the fuel inlet shunt pipes and are circumferentially and evenly arranged on the fuel outlet shunt ring and are connected to the fuel outlet shunt ring.
[0018] The reflux heat exchange assembly includes a fuel confluence pipe, a gasification section heat exchange pipe, and a reaction section heat exchange pipe. The fuel confluence pipes are circumferentially and evenly arranged. The gasification section heat exchange pipe connects the fuel inlet shunt pipe and the side wall surface of the fuel confluence pipe. The reaction section heat exchange pipe connects the fuel outlet shunt pipe and the side wall surface of the fuel confluence pipe.
[0019] After the cracking endothermic fuel passes through the fuel inlet assembly, it absorbs heat and cracks with the hot air flowing in from the engine intake duct in the confluence heat exchange assembly, and then flows out through the fuel outlet assembly and is discharged into the combustion chamber to participate in combustion.
[0020] Preferably, the gasification section heat exchange pipe and the reaction section heat exchange pipe are of non-linear structures, and the connecting line of the two end points of the gasification section heat exchange pipe and the reaction section heat exchange pipe has a predetermined angle with the annular radius.
[0021] Preferably, the gasification section heat exchange pipe is a spiral microchannel heat exchange pipe.
[0022] Preferably, the wall surface of the heat exchange tubes in the reaction section is coated with a catalyst required for fuel cracking.
[0023] Preferably, the inner diameter of the heat exchange tubes in the reaction section is larger than that of the heat exchange tubes in the gasification section.
[0024] Preferably, the fuel outlet manifold is longer and / or wider than the fuel inlet manifold.
[0025] Preferably, the fuel outlet manifold is filled with a porous medium, and the catalyst is coated on the surface of the porous medium.
[0026] Preferably, the cracking endothermic fuel includes ethanol and liquid ammonia.
[0027] Preferably, when the fuel is heated to 600 °C, the fuel cracking rate is not less than 95%.
[0028] Preferably, the flow direction of the fuel in the heat exchange tubes of the reaction section is countercurrent to the hot air, and the flow direction of the fuel in the heat exchange tubes of the gasification section is concurrent with the hot air.
[0029] The engine intake pre-cooling heat exchanger provided by this application has the following advantages:
[0030] 1) Using the cracking endothermic fuel as the cooling medium, the cooling medium does not need to be stored at a low temperature (below -200 °C), is liquid at room temperature, does not use liquid hydrogen or liquid helium as the cooling medium, the temperature difference between the cooling medium and the high-temperature intake air of the engine is small, the thermal stress of the pre-cooling heat exchanger is small, and there is no frosting problem;
[0031] 2) There is no risk of hydrogen embrittlement, and the safety and reliability of the engine are improved;
[0032] 3) Do not use a liquid helium circulation system, the engine does not carry a dead weight, and the efficiency of the engine is improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] In order to more clearly illustrate the technical solutions provided by this application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.
[0034] Figure 1 Schematic diagram of a liquid helium pre-cooled closed-cycle heat exchange solution for the prior art.
[0035] Figure 2 Schematic diagram of the structure of the engine intake pre-cooling heat exchanger of this application.
[0036] Figure 3 Front view of the engine intake pre-cooling heat exchanger of this application.
[0037] Figure 4Side view of the engine intake pre-cooling heat exchanger of the present application.
[0038] Figure 5 Isometric view of the engine intake pre-cooling heat exchanger of the present application.
[0039] Figure 6 Schematic diagram of the usage position of the engine intake pre-cooling heat exchanger of the present application. Detailed implementation manners
[0040] To make the purpose, technical solutions and advantages of the implementation of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application.
[0041] The present application provides an engine intake pre-cooling heat exchanger based on fuel cracking endotherm. By using low-temperature cracked fuel to cool the high-temperature intake air of the engine intake duct, catalysts are arranged in the cracking section, and a porous medium structure is filled in the manifold pipe to meet the catalyst arrangement requirements and promote fuel cracking endotherm.
[0042] As Figures 2 to 5 shown, the engine intake pre-cooling heat exchanger 10 provided by the present application includes a fuel inlet assembly 11, a fuel outlet assembly 12, and a manifold heat exchange assembly 13.
[0043] Among them, the fuel inlet assembly 11 includes a fuel inlet diverter ring 112 and a fuel inlet diverter pipe 113. The fuel inlet diverter ring 112 is a ring structure, and a fuel inlet 111 is provided on its inner ring. The fuel inlet diverter pipes 113 are straight pipe structures and there are multiple of them. The fuel inlet diverter pipes 113 are circumferentially and evenly arranged on the fuel inlet diverter ring 112 and communicate with the fuel inlet diverter ring 112.
[0044] The fuel outlet assembly 12 includes a fuel outlet manifold ring 122 and a fuel outlet manifold pipe 123. The fuel outlet manifold ring 122 is a ring structure, which is arranged outside the fuel inlet diverter ring 112, and a fuel outlet 121 is provided on the fuel outlet manifold ring 122. The fuel outlet manifold pipes 123 are straight pipe structures and have the same number as the fuel inlet diverter pipes 113. The fuel outlet manifold pipes 123 are arranged outside the fuel inlet diverter pipes 113 and are circumferentially and evenly arranged on the fuel outlet diverter ring 122, so as to communicate with the fuel outlet diverter ring 122.
[0045] In some embodiments of the present application, the fuel inlet 111 on the fuel inlet diverter ring 112 is arranged towards the inner side of the ring, and the fuel outlet 121 on the fuel outlet manifold ring 122 is arranged towards the outer side of the ring, thus facilitating the input and output of fuel. Further, the fuel inlet diverter ring 112 and the fuel outlet manifold ring 122 can be formed into an integral structure by welding a plate, and the integral structure is separated by a partition 14, so that the inner side of the integral structure is the fuel inlet manifold ring 112 and the outer side is the fuel outlet manifold ring 122.
[0046] In a preferred embodiment of the present application, the fuel outlet manifold pipe 123 is longer and / or wider than the fuel inlet diverter pipe 113. In some embodiments, the fuel outlet manifold pipe 123 and the fuel inlet diverter pipe 113 can use the same metal pipe, and a partition 14 is arranged inside the metal pipe to separate the fuel outlet manifold pipe 123 and the fuel inlet diverter pipe 113.
[0047] The reflux heat exchange assembly 13 includes a fuel manifold pipe 131, a gasification section heat exchange pipe 132 and a reaction section heat exchange pipe 133. The number of fuel manifold pipes 131 is multiple, which is the same as the number of the fuel inlet diverter pipes 113 or the fuel outlet manifold pipes 123. The multiple fuel manifold pipes 131 are circumferentially arranged evenly, and can be fixed on the flange ring 134 to achieve the circumferential arrangement of the multiple fuel manifold pipes 131. The gasification section heat exchange pipe 132 is connected to the side wall surface of the fuel inlet diverter pipe 113 and the fuel manifold pipe 131, and the reaction section heat exchange pipe 133 is connected to the side wall surface of the fuel outlet diverter pipe 123 and the fuel manifold pipe 131, thus forming a reflux heat exchange unit. Each reflux heat exchange unit includes multiple gasification section heat exchange pipes 132 and reaction section heat exchange pipes 133. The gasification section heat exchange pipes 132 and the reaction section heat exchange pipes 133 are arranged side by side, thus almost occupying the entire side wall surfaces of the fuel inlet diverter pipe 113, the fuel outlet diverter pipe 123 and the fuel manifold pipe 131.
[0048] In the present application, the gasification section heat exchange pipe 132 connecting the fuel inlet diverter pipe 113 and the fuel manifold pipe 131 and the reaction section heat exchange pipe 133 connecting the fuel outlet diverter pipe 123 and the fuel manifold pipe 131 are in a non-linear structure. As shown in Figure 3 shown, the gasification section heat exchange pipe 132 and the reaction section heat exchange pipe 133 are curved, and the connecting line of the two end points of the gasification section heat exchange pipe 132 and the reaction section heat exchange pipe 133 has a certain angle with the annular radius. Further, the gasification section heat exchange pipe 132 is usually a spiral microchannel heat exchange pipe.
[0049] In a preferred embodiment of the present application, to promote the endothermic cracking of the fuel, the wall surface of the reaction section heat exchange tube 133 is coated with a catalyst required for fuel cracking. The reaction section heat exchange tube 133 can be subjected to pretreatment processes such as pickling, alkali washing, and high-temperature roasting, which facilitate the attachment of the catalyst to the inner wall surface of the reaction section heat exchange tube 133, and then the catalyst is coated by coating methods such as hydrothermal synthesis method and Washcoating method.
[0050] Furthermore, generally, the diameter of the reaction section heat exchange tube 133 is larger than the inner diameter of the gasification section heat exchange tube 132, so as to reduce the fuel flow rate, increase the contact time between the fuel and the catalyst, and increase the endothermic heat of cracking.
[0051] In the present application, to promote the endothermic cracking of the fuel, a porous medium is filled in the fuel outlet manifold 123, and the catalyst is coated on the surface of the porous medium. The porous medium can be of any shape - for example, hexagonal, triangular, etc., which is convenient for attaching the catalyst.
[0052] Combined Figure 6 As shown, the engine intake pre-cooling heat exchanger 10 of the present application is installed in the engine intake passage 20 through the mounting bracket 30 and is located in front of the fan 40. The installation method usually adopts bolt connection, which can ensure the reliability of the connection between the two on the one hand and is convenient for disassembly on the other hand. The engine intake pre-cooling heat exchanger 10 is used to cool the high-temperature intake air of the engine, and the cooling medium is the fuel required for engine combustion.
[0053] In some embodiments of the present application, the fuel is usually a cracking endothermic fuel, such as ethanol, liquid ammonia, etc. Preferably, the fuel usually has the characteristic that the fuel cracking rate is not less than 95% when heated to 600 °C, so as to provide a strong chemical endothermic capacity.
[0054] Fuel usually enters the engine inlet pre-cooling heat exchanger 10 in a liquid state and is then distributed to the gasification section heat exchange tubes 132 through the fuel inlet flow splitting ring 112. Inside the gasification section heat exchange tubes 132, the engine inlet air (hot air) transfers heat to the fuel, causing the fuel to change from a liquid state to a gaseous state, absorbing heat during gasification. The gasified fuel converges in the fuel manifold 131 and is then distributed to the reaction section heat exchange tubes 133. The catalyst required for fuel cracking is coated on the wall surface of the reaction section heat exchange tubes 133 to promote the release of chemical heat sinks by the fuel. Since the density of the fuel at this time is lower than that before gasification, to ensure that the fuel flow rate does not change suddenly, the flow area of the reaction section heat exchange tubes is usually larger than that of the micro-channel heat exchange tubes. That is, under the condition of the same number of tubes, the inner diameter of the reaction section heat exchange tubes is larger than that of the gasification section heat exchange tubes. The flow direction of the fuel in the reaction section heat exchange tubes 133 is countercurrent to the hot air (i.e., the two flow in opposite directions), and the flow direction of the fuel in the gasification section heat exchange tubes 132 is concurrent with the hot air (i.e., the two flow in the same direction). After passing through the reaction section heat exchange tubes 133, the fuel converges in the fuel outlet manifold 123, and the temperature of the fuel is relatively high at this time. The fuel outlet manifold 123 is filled with a porous medium, and the catalyst adheres to the porous medium, facilitating full contact with the fuel to further catalyze fuel cracking. After sufficient cracking, the fuel decomposes into small molecular products that can burn, converges in the fuel outlet flow splitting ring 122, and then flows out through the fuel outlet 121, and finally enters the combustion chamber of the engine for combustion.
[0055] The engine inlet pre-cooling heat exchanger provided by this application makes full use of the physical and chemical heat sinks of the cracking endothermic fuel to cool the high-temperature inlet air of the engine. Compared with the liquid hydrogen pre-cooling heat exchanger scheme and the liquid helium pre-cooled closed-cycle heat exchanger scheme, the engine inlet pre-cooling heat exchanger of this application has the following advantages:
[0056] 1) Using the cracking endothermic fuel as the cooling medium, the cooling medium does not need to be stored at a low temperature (below -200°C), is in a liquid state at room temperature, does not use liquid hydrogen or liquid helium as the cooling medium, the temperature difference between the cooling medium and the high-temperature inlet air of the engine is small, the thermal stress of the pre-cooling heat exchanger is small, and there is no frosting problem;
[0057] 2) The pre-cooling heat exchanger has no risk of hydrogen embrittlement, improving the safety and reliability of the engine;
[0058] 3) Without using a liquid helium circulation system, the engine does not carry a dead weight, improving the efficiency of the engine.
[0059] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.
Claims
1. An engine intake pre-cooling heat exchanger, characterized in that, Comprising: A fuel inlet assembly (11), a fuel outlet assembly (12), and a confluence heat exchange assembly (13), wherein: The fuel inlet assembly (11) includes a fuel inlet diverter ring (112) and fuel inlet diverter pipes (113). Inside the fuel inlet diverter ring (112) is provided a fuel inlet (111). The fuel inlet diverter pipes (113) are of a straight pipe structure and there are multiple of them. The fuel inlet diverter pipes (113) are circumferentially and evenly arranged on the fuel inlet diverter ring (112) and are in communication with the fuel inlet diverter ring (112); The fuel outlet assembly (12) includes a fuel outlet confluence ring (122) and fuel outlet confluence pipes (123). The fuel outlet confluence ring (122) is arranged outside the fuel inlet diverter ring (112). On the fuel outlet confluence ring (122) is provided a fuel outlet (121). The fuel outlet confluence pipes (123) are arranged outside the fuel inlet diverter pipes (113) and are circumferentially and evenly arranged on the fuel outlet diverter ring (122) and are in communication with the fuel outlet diverter ring (122); The reflux heat exchange assembly (13) includes a fuel confluence pipe (131), a gasification section heat exchange pipe (132), and a reaction section heat exchange pipe (133). The fuel confluence pipe (131) is circumferentially and evenly arranged. The gasification section heat exchange pipe (132) connects the fuel inlet diverter pipe (113) to the side wall surface of the fuel confluence pipe (131). The reaction section heat exchange pipe (133) connects the fuel outlet diverter pipe (123) to the side wall surface of the fuel confluence pipe (131); After the cracking endothermic fuel passes through the fuel inlet assembly (11), it absorbs heat and cracks in the confluence heat exchange assembly (13) with the hot air flowing in from the engine intake duct, and then flows out through the fuel outlet assembly (12) and is discharged into the combustion chamber to participate in combustion.
2. The engine intake pre-cooling heat exchanger according to claim 1, wherein The gasification section heat exchange pipe (132) and the reaction section heat exchange pipe (133) are of a non-linear structure, and the line connecting the two end points of the gasification section heat exchange pipe (132) and the reaction section heat exchange pipe (133) has a predetermined angle with the annular radius.
3. The engine intake pre-cooling heat exchanger according to claim 2, wherein The gasification section heat exchange pipe (132) is a spiral microchannel heat exchange pipe.
4. The engine intake pre-cooling heat exchanger according to claim 2, wherein, The wall surface of the reaction section heat exchange pipe (133) is coated with a catalyst required for fuel cracking.
5. The engine intake pre-cooling heat exchanger according to claim 3 or 4, characterized in that, The inner diameter of the reaction section heat exchange pipe (133) is larger than the inner diameter of the gasification section heat exchange pipe (132).
6. The engine intake air pre-cooling heat exchanger according to claim 5, characterized in that, The fuel outlet confluence pipe (123) is longer and / or wider than the fuel inlet diverter pipe (113).
7. The engine intake pre-cooling heat exchanger according to claim 6, characterized in that The fuel outlet confluence pipe (123) is filled with a porous medium, and the catalyst is coated on the surface of the porous medium.
8. The engine intake pre-cooling heat exchanger according to claim 1, characterized in that, The cracking endothermic fuel includes ethanol and liquid ammonia.
9. The engine intake pre-cooling heat exchanger according to claim 8, characterized in that, When the fuel is heated to 600 °C, the fuel cracking rate is not less than 95%.
10. The engine intake pre-cooling heat exchanger according to claim 8 or 9, characterized in that, The flow direction of the fuel in the reaction section heat exchange pipe (133) is countercurrent to the hot air, and the flow direction of the fuel in the gasification section heat exchange pipe (132) is concurrent with the hot air.