Heat transfer device and stirling engine

Abstract

The present application relates to heat exchange device technical field, provide a kind of heat transfer device and stirling engine, wherein, heat transfer device is used to transfer heat to the heat end heat exchanger of stirling engine, heat transfer device includes the shell for containing condensing medium;Shell includes evaporation part, condensing part and transition part, condensing part is used to be covered in the outside of heat end heat exchanger, evaporation part is located below condensing part and evaporation part is communicated with the lower end of condensing part, so that the liquid condensing medium of condensing part flows to evaporation part under the action of gravity, the first end of transition part is communicated with condensing part, second end is communicated with evaporation part, the cross-sectional area of the first end of transition part is greater than the cross-sectional area of the second end of transition part.Such setting, directly make the condensing part of heat transfer device cover on heat end heat exchanger, can guarantee the heat exchange efficiency between heat transfer device and heat end heat exchanger;Avoid the setting of red copper block, it is favorable to reduce quality, and then can solve the problem of heavy of high-power stirling engine.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, and more particularly to a heat transfer device and a Stirling engine. Background Technology

[0002] A free-piston Stirling engine consists of a cold-end heat exchanger, a regenerator, a hot-end heat exchanger, and a piston. The hot-end heat exchanger is mainly used to transfer heat from a heat source to the working medium to heat it. In many practical applications, the heat source cannot directly exchange heat with the hot-end heat exchanger, and heat transfer devices such as heat pipes are often installed between the heat source and the hot-end heat exchanger.

[0003] For the connection between the heat pipe and the hot-end heat exchanger, a copper block is typically placed on the outside of the hot-end heat exchanger, and the condenser section of the heat pipe is inserted into the copper block. The copper block then transfers the heat from the condenser section of the heat pipe to the hot-end heat exchanger. However, this structure is only suitable for lower-power Stirling engines. If this structure is applied to a higher-power Stirling engine, the size of the copper block will increase accordingly, resulting in a larger thermal conductivity temperature difference and greater mass, making the Stirling engine very bulky and significantly reducing its efficiency. Summary of the Invention

[0004] The present invention provides a heat transfer device and a Stirling engine to solve the above-mentioned problems.

[0005] The present invention provides a heat transfer device for transferring heat to the hot end heat exchanger of a Stirling engine, the heat transfer device including a shell for containing a condensate medium;

[0006] The shell includes an evaporator, a condenser, and a transition section. The condenser is used to cover the outside of the hot-end heat exchanger. The evaporator is located below the condenser and is connected to the lower end of the condenser so that the liquid condensing medium in the condenser flows to the evaporator under the action of gravity. The transition section is disposed between the condenser and the evaporator. The first end of the transition section is connected to the condenser, and the second end is connected to the evaporator. The cross-sectional area of ​​the first end of the transition section is larger than the cross-sectional area of ​​the second end of the transition section.

[0007] According to a heat transfer device provided by the present invention, the surface of the condensing section that is in contact with the hot end heat exchanger is a condensing surface, and the condensing surface is inclined downward.

[0008] The evaporation section is provided with a liquid-absorbing core, which extends along the axial direction of the evaporation section.

[0009] According to the heat transfer device provided by the application, the side wall of the transition part is arranged downwardly inclined, and the liquid absorbing core extends into the transition part near one end of the condensing part.

[0010] According to the heat transfer device provided by the application, the axis of the evaporating part is a straight line.

[0011] The axis of the evaporating part coincides with the vertical direction, or the axis of the evaporating part has an included angle with the vertical direction.

[0012] According to the heat transfer device provided by the application, the condensing part is in the shape of a circular ring, and the condensing part is arranged to be capable of being sleeved outside the heat end heat exchanger and being in contact with the outer surface of the heat end heat exchanger.

[0013] According to the heat transfer device provided by the application, the heat end heat exchanger has a plurality of heat exchange pipes through which the working medium of the Stirling engine flows, and the condensing part is provided with penetrating channels through which the heat exchange pipes penetrate.

[0014] According to the heat transfer device provided by the application, the condensing surface is located on one side of the evaporating part.

[0015] And / or, the inside of the condensing part is provided with a flow guide plate, the flow guide plate is located on the side of the condensing surface close to the evaporating part, and the flow guide plate is arranged to prevent the gaseous condensing medium of the evaporating part from directly acting on the condensing surface when entering the condensing part.

[0016] According to the heat transfer device provided by the application, the shell is provided with a plurality of shells, the plurality of shells are independent of each other, and the condensing parts of the plurality of shells are arranged to be distributed along the circumferential direction of the heat end heat exchanger.

[0017] The application further provides a Stirling engine comprising the heat transfer device.

[0018] According to the Stirling engine provided by the application, the heat transfer device is provided with a plurality of heat transfer devices, the plurality of heat transfer devices are independent of each other, and the plurality of heat transfer devices are distributed along the axis direction of the Stirling engine.

[0019] The heat transfer device provided by the application is characterized in that the condensing part is wrapped outside the heat end heat exchanger, and the evaporating part extends to the heat source. The evaporating part is heated, and the condensing medium in the evaporating part is heated to evaporate into gaseous condensing medium. The gaseous condensing medium flows to the condensing part through the transition part, and is condensed into liquid condensing medium in the condensing part, while releasing heat. The heat is transferred to the heat end heat exchanger through the shell. The liquid condensing medium flows downward along the side wall of the condensing part under the action of gravity and enters the evaporating part through the transition part. The liquid condensing medium entering the evaporating part is heated to evaporate again, and the cycle is repeated. In this way, the condensing part is directly wrapped on the heat end heat exchanger, which can ensure the heat exchange efficiency between the heat transfer device and the heat end heat exchanger, improve the efficiency of the Stirling engine, avoid the setting of the red copper block, and facilitate the reduction of mass, thereby solving the problem of the heavy Stirling engine with high power.

[0020] Further, in the Stirling engine provided by the application, since the heat transfer device is provided, the Stirling engine also has the advantages of the heat transfer device. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0022] Figure 1 is a structure schematic diagram of the heat transfer device provided by the application when the heat transfer device is arranged on the Stirling engine Figure 1 ;

[0023] Figure 2 is a structure schematic diagram of the heat transfer device provided by the application Figure 1 ;

[0024] Figure 3 is a structure schematic diagram of the heat transfer device provided by the application Figure 2 ;

[0025] Figure 4 is a structure schematic diagram of the heat transfer device provided by the application when the heat transfer device has two shells

[0026] Figure 5 is a structure schematic diagram of the heat transfer device provided by the application when the heat transfer device has three shells

[0027] Figure 6 is a structure schematic diagram of the heat transfer device provided by the application when the heat transfer device is arranged on the Stirling engine Figure 2 ;

[0028] Figure 7 is a structure schematic diagram of the heat transfer device provided by the applicationFigure 3 .

[0029] Reference signs:

[0030] 1: hot end heat exchanger; 2: shell; 3: evaporation part; 4: condensation part; 5: wick; 6: heat exchange pipe; 7: through channel; 8: transition part; 9: condensation surface; 10: flow guide plate. DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0032] The heat transfer device of the present application will be described below. Figures 1 to 7

[0033] As shown in Figures 1 to 7 , the heat transfer device provided by the embodiment of the present application is arranged between a heat source and a hot end heat exchanger 1 of a Stirling engine, so as to transfer heat of the heat source to the hot end heat exchanger 1 of the Stirling engine and provide heat for the hot end heat exchanger 1.

[0034] The heat transfer device in the embodiment of the present application comprises a shell 2, and the shell 2 contains a condensation medium in the inside. The condensation medium can be sodium, potassium, lithium or the like. The shell 2 comprises an evaporation part 3, a condensation part 4 and a transition part 8. Specifically, the condensation part 4 is arranged to cover the outside of the hot end heat exchanger 1. The evaporation part 3 is arranged below the condensation part 4 and is communicated with the lower end of the condensation part 4, so that the liquid condensation medium in the condensation part 4 flows to the evaporation part 3 under the action of gravity.

[0035] The transition part 8 is arranged between the condensation part 4 and the evaporation part 3, and the transition part 8 is a cylindrical structure with both ends open. The first end of the transition part 8 is communicated with the condensation part 4, and the second end is communicated with the evaporation part 3. The cross-sectional area of the first end of the transition part 8 is greater than that of the second end, and the flow rate of the gaseous condensation medium in the evaporation part 3 is reduced when the gaseous condensation medium flows to the condensation part 4 through the transition part 8. The flow direction of the gaseous condensation medium in the condensation part 4 is opposite to or forms an obtuse angle with the flow direction of the liquid condensation medium on the condensation surface 9. The gaseous condensation medium directly blows on the condensation surface 9, which hinders the flow of the liquid condensation medium. After reducing the flow rate of the gaseous condensation medium, the hindering effect of the gaseous condensation medium on the flow of the liquid condensation medium due to the excessively high flow rate of the gaseous condensation medium can be reduced, and the entrainment limit in the transition part 8 and the condensation part 4 can be avoided.

[0036] ​In the process of transferring heat from the heat transfer device to the hot-end heat exchanger 1, the condensing part 4 is wrapped outside the hot-end heat exchanger 1, and the evaporating part 3 extends to the heat source.

[0037] The evaporating part 3 absorbs heat from the heat source, and the condensing medium in the evaporating part 3 is heated and evaporated into gaseous condensing medium, which flows to the condensing part 4. The gaseous condensing medium is condensed into liquid condensing medium in the condensing part 4, and at the same time releases heat, which can be transferred to the hot-end heat exchanger 1 through the shell 2.

[0038] The liquid condensing medium flows downward along the side wall of the condensing part 4 under the action of its own gravity and enters the evaporating part 3, and the liquid condensing medium entering the evaporating part 3 is heated and evaporated again, and the cycle continues.

[0039] In this way, when the heat transfer device is used to transfer heat to the hot-end heat exchanger 1, the condensing part 4 is directly wrapped on the hot-end heat exchanger 1, which is compact in structure and can ensure the heat transfer efficiency between the heat transfer device and the hot-end heat exchanger 1, thereby improving the efficiency of the Stirling engine. Moreover, the setting of the red copper block is avoided, which is conducive to reducing the mass, and the heat transfer device in the embodiment is not only suitable for Stirling engines with small power, but also suitable for Stirling engines with large power, and can solve the problem of the Stirling engine being heavy.

[0040] The surface of the condensing part 4 for contacting the hot-end heat exchanger 1 is a condensing surface, and in the embodiment, the condensing surface is inclined downward, so that the liquid condensing medium on the condensing surface can flow downward under the action of its own gravity.

[0041] A wick 5 is arranged in the evaporating part, and the wick 5 extends along the axis direction of the evaporating part 3. The wick 5 is made of capillary porous material, and can transport the liquid condensing medium to the evaporating part 3 through capillary action.

[0042] It should be noted that the condensing part 4 capable of being wrapped outside the hot-end heat exchanger 1 is generally of a special shape, and in the embodiment, only the wick 5 is arranged in the evaporating part 3, and no wick 5 is arranged in the condensing part 4, which can reduce the processing difficulty of the condensing part 4, reduce the production cost, and avoid the influence of the heat transfer performance of the heat transfer device in the process of processing the special-shaped structure.

[0043] The flow direction of the gaseous condensing medium in the evaporating part 3 is opposite to that of the liquid condensing medium, and the gaseous condensing medium hinders the flow of the liquid condensing medium, which is prone to the problem of carrying limit. The arrangement of the wick 5 can effectively prevent the premature occurrence of the carrying limit in the evaporating part 3, and ensure the stability of the flow process and the evaporation process in the evaporating part 3.

[0044] Furthermore, the aforementioned liquid-absorbing core 5 can also assist the flow of liquid condensing medium within the evaporation section 3, reducing restrictions on the structural shape and setting angle of the evaporation section 3. The evaporation section 3 can be set in any curved shape or in a straight line. The axis of the evaporation section 3 can be set vertically or at an angle to the vertical direction. That is, the axis of the evaporation section 3 can be set vertically, inclined, or even horizontally, depending on the actual space conditions.

[0045] In existing technologies, the wick 5 is generally machined inside a straight tube, and the technology for machining the wick 5 inside a straight tube is relatively mature. For machining the wick 5 inside curved or other irregularly shaped tubes, the common practice is to first sinter the wick 5 inside the straight tube, and then bend the straight tube. Bending is more difficult, and during the bending process, the internal structure of the wick 5 and other components inevitably gets affected, thus impacting the heat transfer performance of the heat transfer device.

[0046] Therefore, in this embodiment, the axis of the evaporation section 3 is set to a straight line, that is, the evaporation section 3 is straight and straight tube-shaped, which can reduce the processing difficulty of the liquid absorption core 5 in the evaporation section 3 and help ensure the heat transfer performance of the heat transfer device.

[0047] In this embodiment, the sidewall of the transition section 8 is inclined downward to ensure that the liquid condensing medium dripping from the condensing surface to the transition section 8 can flow downward under its own gravity. The end of the liquid suction core 5 near the condensing section 4 extends into the transition section 8 to prevent the liquid condensing medium from being blown away by contact with the high-speed gaseous condensing medium in the evaporation section 3 and the transition section 8.

[0048] The hot-end heat exchanger 1 of a Stirling engine is typically a ring-shaped finned heat exchanger. In this embodiment of the invention, the aforementioned condenser 4 is configured as a ring shape, as shown in the reference. Figure 2 The condenser 4 is fitted onto the outside of the hot-end heat exchanger 1 and comes into close contact with its outer surface. It should be noted that the condenser 4 can be fitted onto the outside of the hot-end heat exchanger, or onto the outside of the Stirling engine casing at a position corresponding to the hot-end heat exchanger 1.

[0049] The Stirling engine's axis is horizontally oriented, and correspondingly, the condenser 4's axis is also horizontally oriented, with the evaporator 3 positioned below the condenser 4. The surface of the condenser 4 that contacts the hot-end heat exchanger 1 is the condensing surface 9, which is a cylindrical surface with its axis horizontally oriented. The gaseous condensing medium condenses on the condensing surface 9 to form a liquid condensing medium, which flows downward along the cylindrical surface and drips onto the evaporator 3.

[0050] If the hot end heat exchanger 1 of the Stirling engine is a tube bundle heat exchanger, that is, the hot end heat exchanger 1 has a plurality of heat exchange tubes 6 for the working medium of the Stirling engine to flow through, as shown in Figure 6 At this time, a corresponding through channel 7 needs to be arranged on the condensing portion 4 for the heat exchange tubes 6 to pass through, as shown in Figure 6 and Figure 7 .

[0051] Specifically, for a free piston Stirling engine, the hot end heat exchanger 1 is generally arranged in a circular ring structure, and the plurality of heat exchange tubes 6 constituting the hot end heat exchanger 1 are arranged in parallel and side by side, and are distributed in a circular ring shape. Correspondingly, the condensing portion 4 is also arranged in a circular ring structure, and a plurality of through holes are formed on the side wall of the condensing portion 4, the number of the through holes is consistent with the number of the heat exchange tubes 6, and the through holes are distributed in a circular ring shape. When the heat exchange device is assembled with the tube bundle heat exchanger, the heat exchange tubes 6 pass through the condensing portion 4 through the through holes, and the side wall of each through hole is sealingly connected with the side wall of the heat exchange tube 6, so as to ensure that the inside of the shell 2 is a closed chamber.

[0052] The wall surface of the heat exchange tube 6 serves as the condensing surface 9, and the heat released by the gaseous condensing medium when condensed is exchanged with the working medium in the hot end heat exchanger 1 through the heat exchange tube 6, which can reduce the temperature difference of heat transmission and make the temperature distribution of the hot end heat exchanger 1 uniform.

[0053] The liquid condensing medium on each condensing surface 9 flows downward under the action of gravity and flows to the inner ring wall surface of the condensing portion 4 and then flows to the evaporation portion 3.

[0054] In this embodiment, the evaporation portion 3 and the condensing portion 4 are staggered, and the condensing surface 9 of the condensing portion 4 is located on one side of the evaporation portion 3, as shown in Figure 3 , so as to avoid the gaseous condensing medium in the evaporation portion 3 from directly blowing on the condensing surface 9, which can further reduce the hindering effect of the gaseous condensing medium on the flow of the liquid condensing medium.

[0055] In this embodiment, a flow guide plate 10 can be arranged inside the condensing portion 4, and the flow guide plate 10 is arranged on the side of the condensing surface 9 close to the evaporation portion 3, and the flow guide plate 10 has a spacing with the condensing surface 9, as shown in Figure 3 and Figure 4The gaseous condensing medium in the evaporation part 3 flows from bottom to top on the side of the flow guide plate 10 away from the condensing surface 9, which is opposite to the flowing direction of the liquid condensing medium on the condensing surface. The flow guide plate can prevent the gaseous condensing medium in the evaporation part 3 from directly acting on the condensing surface when entering the condensing part 4. After the gaseous condensing medium is guided to the upper end of the condensing part 4 by the flow guide plate 10, the gaseous condensing medium flows downward along the condensing surface 9 from top to bottom. After the gaseous condensing medium is condensed on the condensing surface 9, the gaseous condensing medium flows downward along the condensing surface 9, that is, the flowing direction of the gaseous condensing medium near the condensing surface 9 is the same as or forms an acute angle with the flowing direction of the liquid condensing medium on the condensing surface 9, which can avoid the hindering effect of the gaseous condensing medium on the flowing of the liquid condensing medium.

[0056] To ensure the heat transfer capacity of the heat transfer device, the heat transfer device in the embodiment includes a plurality of shells 2, each of which includes at least an evaporation part 3 and a condensing part 4, and each of the shells 2 is independent of each other. The condensing part 4 of each of the shells 2 is in contact with the heat end heat exchanger 1, and the condensing parts 4 of the plurality of shells 2 are distributed along the circumferential direction of the heat end heat exchanger 1, as shown in Figure 4 and Figure 5 so that the condensing parts 4 of the plurality of shells 2 cooperatively surround the entire circumference of the heat end heat exchanger 1. The evaporation part 3 of each of the shells 2 extends to the heat source, which increases the heat carried by the condensing medium to the condensing part 4 and ensures that the heat demand of the heat end heat exchanger 1 can be met.

[0057] Considering that the liquid condensing medium can flow downward to the evaporation part 3 under the action of gravity, the number of the shells 2 of the heat transfer device in the embodiment is preferably 2 and at most 6.

[0058] It should be noted that a plurality of evaporation parts 3 can be arranged in one shell 2, and the plurality of evaporation parts 3 are in communication with the same condensing part 4. The condensing medium in each of the evaporation parts 3 absorbs heat to form gaseous condensing medium, which is collected in the same condensing part 4 for condensation and heat release. This can increase the heat carried by the condensing medium to the condensing part 4, thereby improving the heat transfer capacity of the heat transfer device.

[0059] On the other hand, the embodiment of the present application also provides a Stirling engine including the heat transfer device provided by any of the above embodiments. The heat transfer device provided by any of the above embodiments can ensure the heat exchange efficiency between the heat transfer device and the heat end heat exchanger 1, avoids the use of red copper block, is beneficial to reducing the mass, and can solve the problem of the heavy Stirling engine with large power. Therefore, the performance of the Stirling engine provided by the embodiment of the present application is improved, the problems of large mass and heaviness when the power requirement is large are solved, and the Stirling engine has the advantages of compact structure, light weight and high efficiency. The derivation process of the beneficial effects of the Stirling engine in the embodiment of the present application is similar to that of the heat transfer device, and therefore will not be described here.

[0060] In the embodiment, the heat transfer devices are arranged on the Stirling engine, and the heat transfer devices are distributed along the axial direction of the Stirling engine, so as to ensure the heat exchange area of the heat transfer devices and the heat supply to the heat end heat exchanger 1. The heat transfer devices are independent of each other and do not affect each other, so that the Stirling engine can operate normally even if one or part of the heat transfer devices fails.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A heat transfer device, characterized by, The application relates to a heat transfer device for transferring heat to a hot end heat exchanger of a Stirling engine, the heat transfer device comprising a housing for containing a condensing medium; The housing comprises an evaporation part, a condensation part and a transition part, the condensation part is used for covering the outside of the hot end heat exchanger, the evaporation part is located below the condensation part and communicates with the lower end of the condensation part, so that the liquid condensing medium of the condensation part flows to the evaporation part under the action of gravity, the transition part is arranged between the condensation part and the evaporation part, the first end of the transition part communicates with the condensation part, the second end communicates with the evaporation part, and the cross-sectional area of the first end of the transition part is greater than that of the second end of the transition part; The surface of the condensation part used for contacting the hot end heat exchanger is a condensation surface, and the condensation surface is arranged to be inclined downward; The evaporation part is provided with a wick, and the wick extends along the axis direction of the evaporation part; The side wall of the transition part is arranged to be inclined downward, and one end of the wick close to the condensation part extends into the transition part; The condensation surface is located on one side of the evaporation part; The inside of the condensation part is provided with a flow guide plate, the flow guide plate is located on the side of the condensation surface close to the evaporation part, and the flow guide plate is arranged to prevent the gaseous condensing medium of the evaporation part from directly acting on the condensation surface when entering the condensation part.

2. The heat transfer device of claim 1, wherein The axis of the evaporation part is a straight line; The axis of the evaporation part coincides with the vertical direction, or the axis of the evaporation part has an included angle with the vertical direction.

3. The heat transfer device of claim 1, wherein The condensation part is in the shape of a circular ring, and the condensation part is arranged to be capable of being sleeved on the outside of the hot end heat exchanger and in close contact with the outer surface of the hot end heat exchanger.

4. The heat transfer device of claim 1, wherein The hot end heat exchanger has a plurality of heat exchange pipes for the working medium of the Stirling engine to flow through, and the condensation part is provided with penetrating channels for the heat exchange pipes to penetrate.

5. The heat transfer device of claim 1, wherein The housing is provided in plurality, the plurality of housings are independent of each other, and the condensation parts of the plurality of housings are arranged to be distributed along the circumferential direction of the hot end heat exchanger.

6. A Stirling engine characterised by The heat transfer device comprises the heat transfer device according to any one of claims 1 to 5.

7. A Stirling engine according to claim 6, characterised in that The heat transfer device is provided in plurality, the plurality of heat transfer devices are independent of each other, and the plurality of heat transfer devices are distributed along the axis direction of the Stirling engine.

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