High efficiency fuel oil heat exchanger system for small turbojet engines

Abstract

The application discloses a high-efficiency fuel-oil heat exchange system for a small turbojet engine and belongs to the field of aeroengines. The high-efficiency fuel-oil heat exchange system comprises an air-cooled radiator and a fuel-oil heat exchanger; the air-cooled radiator utilizes high-speed cooling air flow in an engine air inlet to radiate and cool lubricating oil passing through the air-cooled radiator and simultaneously heat the engine air inlet; and the fuel-oil heat exchanger is used for exchanging heat between the lubricating oil radiated and cooled by the air-cooled radiator and low-temperature fuel oil, thereby reducing the temperature of the lubricating oil and increasing the temperature of the fuel oil. The high-speed cooling air flow generated during the operation of the turbojet engine and the characteristics of the low-temperature fuel oil are utilized to cool and reduce the temperature of the lubricating oil by relying on the structure of the turbojet engine; the high-temperature characteristics of the lubricating oil during the operation of the engine are utilized to achieve the purpose of deicing of the engine air inlet system; and the fuel-oil heat exchanger is used for further cooling of the lubricating oil and simultaneously heating of the fuel oil to improve the atomization quality and the combustion efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to a fuel-oil heat exchange system, in particular to a high-efficiency fuel-oil heat exchange system for small turbojet engines, and belongs to the field of aero-engines. BACKGROUND

[0002] At present, most of the small turbojet engines on the market adopt independent closed lubrication mode, and the circulation supply of lubricating oil in the whole machine system is realized through a separate oil tank and an oil pump. However, due to the fact that the conventional cooling method (i.e. the cooling is realized by natural convection heat exchange between the lubricating oil flowing through the pipeline and the external air) is extremely limited in heat dissipation of the lubricating oil, the lubricating oil supplied to the bearing cannot be fully cooled in time, which makes the working condition of the shaft system relatively poor, accelerates the wear and aging of the related parts, and affects the service life and high reliability of the engine. SUMMARY

[0003] The technical problem to be solved by the present application is to overcome the defects of the prior art, and to provide a high-efficiency fuel-oil heat exchange system for small turbojet engines, which can fully cool the lubricating oil, realize ice removal in the intake area of the turbojet engine, and improve the fuel combustion efficiency.

[0004] In order to solve the above technical problems, the high-efficiency fuel-oil heat exchange system for small turbojet engines provided by the present application comprises an air-cooled radiator and a fuel / oil heat exchanger.

[0005] The air-cooled radiator utilizes the high-speed cooling air flow in the engine intake duct to dissipate heat and cool the lubricating oil passing through the air-cooled radiator, and simultaneously heats the engine intake duct.

[0006] The fuel / oil heat exchanger is used to exchange heat between the lubricating oil cooled by the air-cooled radiator and the low-temperature fuel, so as to reduce the temperature of the lubricating oil and increase the temperature of the fuel.

[0007] In the present application, the air-cooled radiator comprises a reciprocating fin channel group, the reciprocating fin channel group is arranged along the circumference of the engine intake duct, and an oil passage sealing sleeve is installed on the outer side of the reciprocating fin channel group.

[0008] The oil passage sealing sleeve is provided with a lubricating oil inlet and a lubricating oil outlet.

[0009] The lubricating oil flows out of the lubricating oil outlet after reciprocating and turning back at least twice in the reciprocating fin channel group.

[0010] In the present application, the reciprocating fin channel group comprises at least three flow channels, and each flow channel is composed of two spaced thin-wall partitions.

[0011] The thin-wall partition layer in the flow channel at the lubricating oil inlet and the lubricating oil outlet is in a continuous state, and the rest of the thin-wall partition layers are in a disconnected state;

[0012] The thin-wall partition layer in the continuous state divides the lubricating oil inlet and the lubricating oil outlet into two independent regions of different sizes, respectively.

[0013] The thin-wall partition layer in the continuous state at the lubricating oil inlet and the thin-wall partition layer in the continuous state at the lubricating oil outlet are staggered with each other.

[0014] In the present application, the fuel / lubricating oil heat exchanger comprises a heat exchanger shell, and two interconnected cavities are arranged in the heat exchanger shell.

[0015] The heat dissipation core is arranged in each cavity, and the heat dissipation core comprises an inner flow channel and an outer flow channel.

[0016] The inner flow channel of the heat dissipation core in any one cavity is communicated with the outer flow channel of the heat dissipation core in the other cavity, and the outer flow channel of the heat dissipation core in any one cavity is communicated with the inner flow channel of the heat dissipation core in the other cavity.

[0017] The heat exchanger shell is respectively provided with a fuel inlet and a fuel outlet, and a lubricating oil inlet and a lubricating oil outlet.

[0018] The fuel inlet is communicated with the outer flow channel of the heat dissipation core in any one cavity, and the fuel outlet is communicated with the inner flow channel of the heat dissipation core in the other cavity.

[0019] The lubricating oil inlet is communicated with the inner flow channel of the heat dissipation core in any one cavity, and the lubricating oil outlet is communicated with the outer flow channel of the heat dissipation core in the other cavity.

[0020] In the present application, the outer part of the heat dissipation core is a circumferential uniform flow channel in a spiral upward shape, and the inner part adopts a radial fin structure.

[0021] In the present application, the outer flow channel of the heat dissipation core is a three-head spiral groove guide structure.

[0022] In the present application, the gap at the center of each fin in the radial fin structure in the heat dissipation core is not less than 0.2 mm.

[0023] In the present application, the two cavities are arranged in a head-to-tail reverse arrangement.

[0024] The high-efficiency fuel / lubricating oil heat exchange system for small turbojet engines of the present application further comprises a pressure opening valve, the inlet of the pressure opening valve is connected with the lubricating oil supply unit, and the outlet is connected with the engine.

[0025] The present application has the following advantages: (1) The high-speed cooling air flow and low-temperature fuel generated during the operation of the turbojet engine are fully utilized to cool and lower the temperature of the lubricating oil, and the structure is compact and the cooling effect is remarkable. Meanwhile, the high-temperature characteristics of the lubricating oil during engine operation are also utilized to exchange heat with the inlet duct of the turbojet engine, achieving the purpose of deicing the inlet system of the turbojet engine. At the same time, the fuel / oil heat exchanger further cools the lubricating oil while heating the fuel to improve the atomization quality and combustion efficiency, and has the advantage of high functional density. The fully cooled lubricating oil enters the turbojet engine, which will provide better protection for the engine shafting and help to achieve long service life and high reliability of the turbojet engine. (2) The positions of the continuous thin-wall partitions at the lubricating oil inlet and the continuous thin-wall partitions at the lubricating oil outlet are staggered, which can increase the number of reciprocating turns of the lubricating oil in the complex finned channel group, prolong the heating time and area with the engine inlet duct, and further improve the heat exchange efficiency. (3) The lubricating oil flows through the two heat dissipation cores of the heat exchanger in turn, so as to fully exchange heat with the low-temperature fuel, thereby achieving the purposes of reducing the temperature of the lubricating oil, improving the temperature of the fuel and improving the atomization quality. (4) The three-head spiral rising structure is adopted for the heat dissipation core and the outside, which provides three circumferentially distributed flow channels for the lubricating oil and fuel, which can reduce the pipeline flow resistance while ensuring sufficient heat dissipation area. (5) The gap at the center of each fin in the radial fin inside the heat dissipation core is not less than 0.2mm, which is convenient for one-time processing and forming by wire cutting, which not only maximizes the contact area between the fluid and the wall, but also ensures the processability and realizability. (6) The two chambers are arranged in reverse at the head and tail, which can not only effectively reduce the size of the structure and make the heat dissipation system compact, but also rely on the two heat dissipation cores respectively located in the chambers to exchange heat with each other, further reducing the temperature of the lubricating oil. (7) The pressure opening valve is used as a parallel bypass, which will trigger the valve core to open when the environmental temperature is low and the viscosity of the lubricating oil is too large, and the high-viscosity lubricating oil will directly enter the engine shafting through the pressure opening valve, thereby adapting to different temperature working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art of the present application, the drawings needed in the following specific embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0027] Figure 1 The structural principle diagram of the high-efficiency fuel-oil heat exchange system for small turbojet engines;

[0028] Figure 2For air-cooled intake passage structure, (a) shows the axonometric view of the oil area, (b) shows the axonometric view of the oil intake area;

[0029] Figure 3 For air-cooled intake passage structure schematic Figure 2 , (a) plan view, (b) sectional view;

[0030] Figure 4 For air-cooled radiator structure and assembly diagram;

[0031] Figure 5 For lubricating oil circulation in reciprocating finned channel schematic diagram;

[0032] Figure 6 For fuel / oil heat exchanger housing structure schematic, (a) internal structure diagram, (b) axonometric view;

[0033] Figure 7 For radiator core structure schematic, (a) external structure diagram, (b) side view, (C) internal structure diagram, (d) A-A sectional view in figure (a), (e) fin arrangement schematic;

[0034] Figure 8 For fuel / oil heat exchanger assembly structure Figure 1 , (a) external structure diagram, (b) internal structure Figure 1 , (C) internal structure Figure 2 ;

[0035] Figure 9 For fuel / oil heat exchanger assembly structure Figure 2 , (a) bottom view, (b) left view, (C) rear view, (d) A-A sectional view in figure (a), (e) B-B sectional view in figure (a);

[0036] Figure 10 For lubricating oil and fuel flow path schematic diagram.

[0037] In the figure, 1-air-cooled intake passage, 2-oil passage sealing sleeve, 3-O-shaped sealing ring, 4-oil intake plug, 5-oil outlet plug, 6-screw, 7-nut, 8-heat exchanger housing, 9-first radiator core, 10-second radiator core, 11-lubricating oil intake end cover, 12-lubricating oil outlet nozzle, 13-fuel oil intake nozzle, 14-fuel oil outlet end cover, 15-fuel oil process plug, 16-lubricating oil process plug. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0040] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0041] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0042] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0043] In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0045] like Figure 1 As shown, the high-efficiency fuel-oil heat exchange system for a small turbojet engine in this embodiment includes an oil tank, an oil pump, an air-cooled radiator, a fuel / oil heat exchanger, a pressure-opening valve, and related connecting pipelines. The outlet of the oil tank is connected to the inlet of the oil pump. The outlet of the oil pump is connected via pipeline to the inlet of the air-cooled radiator. The outlet of the air-cooled radiator is connected via pipeline to the oil inlet of the fuel / oil heat exchanger. The oil outlet of the fuel / oil heat exchanger is connected via pipeline to the engine for lubrication. The engine is then connected to the inlet of the oil tank via pipeline to achieve oil circulation. The fuel inlet and outlet of the fuel / oil heat exchanger are connected to the fuel supply system. In addition, the outlet of the oil pump is connected via pipeline to the inlet of the pressure-opening valve, and the outlet of the pressure-opening valve is connected via pipeline to the engine, allowing direct supply of oil to the engine.

[0046] The specific working process of the high-efficiency fuel-oil heat exchange system for a small turbojet engine in this embodiment is as follows: Lubricating oil is drawn from the oil tank using a lubricating oil pump and enters the air-cooled radiator through the lubricating oil inlet via a connecting pipe. The lubricating oil fully contacts and flows back and forth within the reciprocating channels of the air-cooled radiator, exchanging heat thoroughly with the forced convection heat exchange in the air-cooled intake duct. This lowers the lubricating oil temperature and raises the air-cooled intake duct temperature, achieving the dual purpose of cooling the lubricating oil and de-icing the intake duct. The lubricating oil, after heat exchange, flows out from the lubricating oil outlet and enters the fuel / oil heat exchanger via the connecting pipe. Within the fuel / oil heat exchanger, the lubricating oil flows sequentially through the first and second radiating cores, allowing for thorough heat exchange with the low-temperature fuel, thereby achieving the goals of lowering the lubricating oil temperature, raising the fuel temperature, and improving atomization quality. Meanwhile, this embodiment takes into full account the significant temperature-dependent effect of lubricating oil viscosity. Specifically, under the low-temperature conditions of initial start-up of a turbojet engine, the lubricating oil viscosity is high, and it cannot be supplied normally when flowing through the internal channels of the air-cooled radiator and the fuel / oil heat exchanger due to excessive flow resistance. Therefore, this embodiment adds a pressure-opening valve to the pipeline, forming a parallel connection with the air-cooled radiator and the fuel / oil heat exchanger. When the oil pressure in the lubricating oil circuit exceeds the opening pressure of the pressure-opening valve, the valve core will be triggered to open, and the high-viscosity lubricating oil will directly enter the engine shaft system through the pressure-opening valve. After the lubricating oil is heated in the engine shaft system, its viscosity drops significantly, and it can then be cooled and circulated through the air-cooled radiator and the fuel / oil heat exchanger. This design enables the system to adapt to different temperature conditions.

[0047] like Figures 2 to 5As shown, the air cooling radiator includes an air cooling air inlet 1, an oil passage sealing sleeve 2, an O-shaped sealing ring 3, an oil inlet plug 4 and an oil outlet plug 5. The outer surface of the air cooling air inlet 1 is provided with a complex fin groove in the circumferential direction. The complex fin groove is separated from each other by a plurality of thin wall partitions, and the thin wall partitions increase the contact area of the lubricating oil to achieve high efficiency heat exchange. Two O-shaped sealing rings 3 are assembled on both sides of the complex fin groove, and the complex fin groove is sealed by being compressed in contact with the inner surface of the oil passage sealing sleeve 2. The flange surface on one side of the oil passage sealing sleeve 2 is connected to the flange surface of the air cooling air inlet 1 by a screw 6 and a nut 7 to form a whole, and the flange surface on the other side of the oil passage sealing sleeve 2 can be connected to the front end of the turbojet engine as the air inlet system of the turbojet engine.

[0048] The oil passage sealing sleeve 2 is provided with a lubricating oil inlet and a lubricating oil outlet which are arranged in axial symmetry. The lubricating oil inlet and the lubricating oil outlet are in the form of vertical intersecting holes for introducing and discharging lubricating oil into the fin groove, and the vertical intersecting holes are realized by process holes.

[0049] The oil inlet plug 4 and the oil outlet plug 5 are used to block the process holes at the oil inlet and the oil outlet respectively.

[0050] In this embodiment, the complex fin groove is provided with 9 flow channels which are formed by thin wall partitions arranged in parallel and are independent of each other. The thin wall partitions forming the flow channels at the position corresponding to the lubricating oil inlet are disconnected, and the thin wall partition between the 3rd flow channel and the 4th flow channel arranged from outside to inside is retained, so as to divide the disconnected area into two independent areas of different sizes, and the top of the area with larger size is sealed during assembly. The thin wall partitions forming the flow channels at the position corresponding to the lubricating oil outlet are disconnected, and the thin wall partition between the 3rd flow channel and the 4th flow channel arranged from inside to outside is retained, so as to divide the disconnected area into two independent areas of different sizes, and the top of the area with larger size is sealed during assembly. In this way, the thin wall partitions in continuous state at the lubricating oil inlet and the thin wall partitions in continuous state at the lubricating oil outlet are staggered in position.

[0051] As shown in Figure 2 and 4 , the lubricating oil flows along the 1st to 3rd flow channels after entering the oil inlet, and flows along the 1st to 6th flow channels after passing through the disconnected area of the oil outlet. After circulating to the disconnected area of the oil inlet, the lubricating oil flows along the 4th to 9th flow channels. After circulating to the disconnected area of the oil outlet, part of the lubricating oil flows out of the oil outlet from the 6th to 9th flow channels.

[0052] The working principle of the air-cooled radiator in the embodiment is as follows: the lubricating oil enters the air-cooled inlet channel 1 along the lubricating oil inlet, and is sealed by the two O-shaped sealing rings 3 and the oil passage sealing sleeve 2, so that the lubricating oil can only flow back and forth in the reciprocating fin groove. After being folded back twice in the reciprocating fin groove, the lubricating oil flows out along the lubricating oil outlet. When the turbojet engine is working, a large amount of high-speed cooling airflow will flow through the inner wall surface of the air-cooled inlet channel 1, and the forced convection heat exchange between the cooling airflow and the inner wall surface of the air-cooled inlet channel 1 can rapidly reduce the wall surface temperature of the air-cooled inlet channel 1. After the lubricating oil fully contacts the surface area of the groove thin wall partition in the flowing process, the temperature of the lubricating oil is reduced to a certain extent, and at the same time, the temperature of the air-cooled inlet channel 1 and the entire inlet area is increased to a certain range. This process not only reduces the temperature of the lubricating oil, but also has the effect of deicing the inlet area of the air-cooled inlet channel 1.

[0053] As shown in Figures 6 to 9 The fuel / lubricating oil heat exchanger in the embodiment includes a heat exchanger shell 8, a first heat dissipation core 9, a second heat dissipation core 10, a lubricating oil inlet end cover 11, a lubricating oil outlet nozzle 12, a fuel oil inlet nozzle 13, a fuel oil outlet end cover 14, a fuel oil process plug 15, and a lubricating oil process plug 16. The heat exchanger shell 8 is divided into two chambers arranged side by side, the two chambers are communicated, and the two chambers are arranged in head-tail reverse. With such a design, not only can the size of the heat exchanger shell 8 be effectively reduced to make the heat dissipation system compact, but also the two heat dissipation cores can perform mutual heat transfer by the chambers where they are arranged, further reducing the temperature of the lubricating oil.

[0054] In the embodiment, the first heat dissipation core 9 and the second heat dissipation core 10 are similar in structure and are each divided into an inner channel and an outer channel. The outer channel adopts a three-head spiral rising structure to provide three circumferentially distributed flow channels for lubricating oil and fuel flow, and the three spiral rising flow channels reduce the flow resistance of the pipeline while ensuring sufficient contact heat exchange area and allowing the lubricating oil and the fuel to be spaced apart from each other in the chamber but to be fully heat exchanged. The inner channel adopts a radial fin structure, and the gap at the center of each fin is not less than 0.2 mm, which facilitates one-time processing and forming by wire cutting, maximizes the contact area between the fluid and the wall surface, and ensures the processability and realizability of processing. In assembly, the first heat dissipation core 9 is installed with O-shaped sealing rings 3 at the two ends, and then is pressed into one of the chambers to realize sealing between the first heat dissipation core 9 and the chamber through the O-shaped sealing rings 3. The second heat dissipation core 10 is pressed into the other chamber in the same way, and then the lubricating oil inlet end cover 11 and the fuel outlet end cover 14 with the O-shaped sealing rings 3 are connected to the corresponding first heat dissipation core 9, second heat dissipation core 10 and heat exchanger shell 8 by screws 6. The lubricating oil outlet nozzle 12 and the fuel inlet nozzle 13 are installed in place at the corresponding positions of the heat exchanger shell 8 by screws 6, and the end faces are sealed by O-shaped sealing rings 3. The heat exchanger shell 8 is internally processed with two interpenetrating holes for communication, and the fuel process plug 15 and the lubricating oil process plug 16 are used to seal the process holes.

[0055] As shown in Figure 10 the embodiment, the working principle of the fuel / lubricating oil heat exchanger is as follows: the lubricating oil enters from the lubricating oil inlet, flows to the inner channel of the first heat dissipation core 9, and the first heat dissipation core 9 adopts a radial fin structure to increase the heat dissipation area of the lubricating oil, while the outer channel has fuel flowing from the fuel inlet, and the outer channel adopts a three-head spiral groove guide structure to allow the lubricating oil and the fuel to be spaced apart from each other in the chamber but to be fully heat exchanged; then, the lubricating oil flows along the bottom of the first heat dissipation core 9 to the outer channel of the second heat dissipation core 10 in the other chamber through the interpenetrating hole, and the fuel flows to the bottom of the second heat dissipation core 10 through the internal interpenetrating hole and flows into the inner channel of the second heat dissipation core 10, and since the second heat dissipation core 10 is similar in structure to the first heat dissipation core 9, in the other chamber, the lubricating oil flows along the three-head spiral groove of the outer channel, and the fuel flows along the radial fin structure of the inner channel, and after the lubricating oil and the fuel are fully heat exchanged, the cooled lubricating oil flows out from the lubricating oil outlet and enters the turbine engine shaft system for lubrication, and the heated fuel flows out from the fuel outlet and enters the turbine engine combustion chamber for combustion.

[0056] During use, since the fuel flow is relatively large compared to the lubricating oil flow, in order to reduce the pipeline loss during oil supply, the pitch of the three-head spiral channel is appropriately enlarged when the first heat dissipation core 9 is designed, so as to ensure the heat exchange effect and improve the flow. After this process, the lubricating oil temperature can be greatly reduced, and the fuel also completes the warming process to a certain extent while taking away the heat of the lubricating oil, which is more conducive to the subsequent fuel atomization and organization combustion.

[0057] In the embodiment, in addition to achieving the lubricating oil cooling purpose through two heat dissipation cores, the two heat dissipation cores are reversely arranged at the head and tail of the chamber, which not only can effectively reduce the size of the structure and make the heat dissipation system compact, but also can rely on the heat transfer between the two chambers where the two heat dissipation cores are respectively located, so as to further reduce the lubricating oil temperature.

[0058] In the embodiment, the temperature of the lubricating oil can be greatly reduced after the lubricating oil passes through the air-cooled radiator and the fuel / lubricating oil heat exchanger. The lubricating oil after sufficient cooling enters the turbojet engine, which can better protect the engine shafting and help to realize the long-life and high-reliability work of the turbojet engine. At the same time, the lubricating oil cooling process also realizes the ice removal of the air-cooled intake duct 1 and the warming of the fuel.

[0059] The application provides a high-efficiency fuel / lubricating oil heat exchange system for a small turbojet engine, and there are many methods and ways to realize the technical scheme, and the above description is only the preferred embodiment of the application. It should be pointed out that for ordinary skilled persons in the art, without departing from the principle of the application, some improvements and refinements can be made, which should be regarded as the protection scope of the application. The components not explicitly described in the embodiment can be realized by the existing technology.

Claims

1. A high efficiency fuel oil heat exchanger system for small turbojet engines, characterized by: The air cooling radiator and the fuel / oil heat exchanger are included. The air cooling radiator utilizes high-speed cooling air flow in the engine intake passage to cool and heat the lubricating oil passing through the air cooling radiator. The fuel / oil heat exchanger is used to exchange heat between the lubricating oil cooled by the air cooling radiator and the low-temperature fuel oil, so as to reduce the temperature of the lubricating oil and increase the temperature of the fuel oil. The air cooling radiator includes a reciprocating fin channel group arranged along the circumference of the engine intake passage, and an oil passage sealing sleeve is arranged on the outer side of the reciprocating fin channel group. The oil passage sealing sleeve is provided with a lubricating oil inlet and a lubricating oil outlet. The lubricating oil flows out of the lubricating oil outlet after at least two reciprocating turns in the reciprocating fin channel group. The reciprocating fin channel group includes at least three flow channels composed of two spaced thin wall partitions. The thin wall partition in the flow channel at the lubricating oil inlet and the lubricating oil outlet is in a continuous state, and the remaining thin wall partitions are in a disconnected state. The continuous thin wall partition divides the lubricating oil inlet and the lubricating oil outlet into two independent areas of different sizes, respectively. The positions of the continuous thin wall partition at the lubricating oil inlet and the continuous thin wall partition at the lubricating oil outlet are staggered. The fuel / oil heat exchanger includes a heat exchanger shell, and two interconnected chambers are arranged in the heat exchanger shell. The chambers are respectively provided with heat dissipation cores, and the heat dissipation cores include inner flow channels and outer flow channels. The inner flow channel of the heat dissipation core in any chamber is connected with the outer flow channel of the heat dissipation core in the other chamber, and the outer flow channel is connected with the inner flow channel of the heat dissipation core in the other chamber. The heat exchanger shell is respectively provided with a fuel inlet and a fuel outlet, and a lubricating oil inlet and a lubricating oil outlet. The fuel inlet is connected with the outer flow channel / inner flow channel of the heat dissipation core in any chamber, and the fuel outlet is connected with the inner flow channel / outer flow channel of the heat dissipation core in the other chamber. The lubricating oil inlet is connected with the inner flow channel / outer flow channel of the heat dissipation core in any chamber, and the lubricating oil outlet is connected with the outer flow channel / inner flow channel of the heat dissipation core in the other chamber.

2. The high efficient fuel oil heat exchanger system for small turbojet engine according to claim 1, wherein: The outer flow channel of the heat dissipation core is a three-head spiral groove guide structure.

3. The high efficient fuel oil heat exchanger system for small turbojet engine according to claim 1, wherein: The gap between the centers of the fins in the inner radial fin structure of the heat dissipation core is not less than 0.2 mm.

4. The high efficient fuel oil heat exchanger system for small turbojet engine according to claim 1, wherein: The two chambers are arranged in a head-to-tail reversed manner.

5. The high efficient fuel oil heat exchanger system for small turbojet engine according to claim 1, wherein: A pressure opening valve is further included, the inlet of the pressure opening valve is connected with a lubricating oil supply unit, and the outlet is connected with an engine.

6. The high efficient fuel oil heat exchanger system for small turbojet engines, according to claim 1, wherein: ​

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