Cam-driven compression-type elastic card refrigeration prototype and refrigeration method thereof

Abstract

The present disclosure relates to a cam-driven compression type solid-state elastic card refrigeration prototype and its refrigeration method, which comprises a cam subsystem, wherein a rotary motor drives a cam to rotate through a rotating shaft, and then drives a linear guide to move linearly; a solid-state elastic card refrigerant structure configured as a shape memory alloy pipe with fins for reverse phase change to generate refrigeration capacity when unloaded; a chuck subsystem for loading solid-state elastic card refrigerants; and a fluid subsystem operating two flow processes. The solid-state elastic card refrigeration prototype developed by the present disclosure utilizes the heat absorption effect of the shape memory alloy pipe with fins to achieve refrigeration during the unloading process, and outputs refrigeration capacity through the fluid system, which has the characteristics of green and high efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of elastic card refrigeration, and can be used for a solid-state refrigeration device with a NiTi shape memory alloy pipe as a refrigerant, and particularly relates to design of an elastic card refrigeration prototype cam loading system, a NiTi pipe loading method based on a buckling-restrained structure, and a refrigeration method based on a heat exchange fluid system. BACKGROUND

[0002] Refrigeration systems consume 20% of the world's energy supply every year. As of now, gas compressors are the most mature technology and are widely used in refrigeration equipment such as air conditioners and refrigerators. However, this technology must use refrigerants such as hydrofluorocarbons in principle, which can cause serious greenhouse effects and exacerbate the destruction of the ozone layer. The exacerbation of the greenhouse effect further increases the demand of humans for refrigeration equipment, forming a vicious cycle and leading to increasingly serious global environmental problems, so it is particularly necessary to develop new environmentally friendly and pollution-free refrigeration technologies.

[0003] Among the many new refrigeration technologies (such as magnetic card refrigeration, electric card refrigeration, and elastic card refrigeration), the magnetic card refrigeration technology has been relatively mature after decades of development, but its fatal flaw is that it requires the use of expensive rare earth element gadolinium as a component of the refrigerant in principle. Since the first refrigeration prototype machine was developed by the University of Maryland in the United States in 2015, the elastic card refrigeration technology based on the elastic heating effect of NiTi shape memory alloy has been developed initially, which has excellent refrigeration efficiency, is environmentally friendly, has low refrigerant prices, and is renewable, and has attracted the attention of scholars. Therefore, in 2014, the elastic card refrigeration was rated by the U.S. Department of Energy as the most promising new solid-state refrigeration technology.

[0004] The driving system and the refrigerant structure design matched therewith are core technologies in solid-state elastic card refrigeration, which determine the refrigeration performance and fatigue life of the elastic card refrigeration prototype. As of now, related scholars at home and abroad have developed several elastic card refrigeration prototype systems based on tensile and compression driving modes. The tensile elastic card refrigeration prototype shows a large refrigeration capacity, but its fatal flaw is that the fatigue life of the NiTi refrigerant under the tensile driving mode is extremely low (less than 10,000 cycles of loading). Fortunately, related scholars from the Hong Kong University of Science and Technology have shown that the NiTi shape memory alloy has a super-high fatigue life under the compression driving mode, which theoretically indicates that the compression solid-state refrigeration method has great development potential.

[0005] The existing compression type solid-state refrigeration prototype system mainly has the following two problems. One is to ignore the design of the driving system, and to load by means of a large hydraulic driving device commonly used for material characterization. The second is to use commercial NiTi shape memory alloy pipe directly as refrigerant, which has small specific heat exchange area and poor heat exchange capacity, resulting in limited refrigeration output of the system.

[0006] For example, Qian et al. of Xi'an Jiaotong University developed a compression commercial NiTi pipe refrigerant based on the elastic card refrigeration prototype. In its supporting solid-state refrigerant, since it uses several NiTi pipe fittings with small heat exchange area as refrigerant, the refrigeration prototype has not made relevant optimization to the refrigerant structure, and the maximum specific refrigeration power of the refrigeration prototype is only 480 WKg -1 Chinese patent CN201810660524.1 (publication number CN108954901A, publication date 2018.12.07) discloses a refrigeration method using a linear electric push rod to compress shape memory alloy pipe, the basic feature of which is to control the linear cycle of the electric push rod to compress the NiTi shape memory alloy pipe refrigerant, so that the refrigerant undergoes forward and reverse phase change. This method illustrates the configuration that the compression elastic card refrigeration prototype should have in principle, but since the force required to drive a single shape memory alloy pipe is large (about 10kN), the electric push rod driving equipment can only load at low frequency (0.3Hz), and the electric push rod thrust is limited, which can only maintain the compression of a single pipe in principle, and has no potential to further compress multiple pipes. On the other hand, the NiTi pipe used in this method still has the problem of small specific heat exchange area, and it does not show the actual refrigeration capacity of the device. SUMMARY

[0007] In order to solve at least one of the above problems, a compression type elastic card refrigeration prototype based on cam driving is provided, and an improved shape memory alloy pipe refrigerant structure with fins inside and a corresponding fluid system are used, which can realize fast and stable loading and unloading of the shape memory alloy pipe, thereby obtaining large refrigeration capacity.

[0008] According to one aspect of the present disclosure, a cam-driven compression-type spring refrigeration prototype is provided, which comprises: a cam subsystem comprising a rotary motor, a rotary shaft, a cam, and a linear guide, the rotary motor being capable of driving the cam to rotate through the rotary shaft, thereby pushing the linear guide to move linearly; a solid spring refrigerant structure configured as a shape memory alloy pipe with fins inside, capable of absorbing heat during reverse phase change when unloaded; a chuck subsystem comprising an upper chuck and a lower chuck, the two chucks being used to load the solid spring refrigerant structure, wherein the upper chuck moves with the linear guide to load and unload the shape memory alloy pipe with fins; and a fluid subsystem driven by a fluid pump to perform a first flow process and a second flow process, wherein in the first flow process, the latent heat released by the shape memory alloy pipe with fins after being loaded is carried away by the heat exchange fluid flowing therethrough, and in the second flow process, the shape memory alloy pipe with fins absorbs the heat of the heat exchange fluid flowing therethrough after being unloaded, thereby discharging the cooled heat exchange fluid for refrigeration.

[0009] Optionally, the cam-driven compression-type spring refrigeration prototype uses a shape memory alloy pipe with fins made of NiTi alloy, wherein the fins are used to increase the heat exchange area and improve the refrigeration capacity.

[0010] Optionally, the cam is made of hard alloy steel, and the difference between the maximum radius and the minimum radius of the outer side of the cam is greater than or equal to 4% of the length of the shape memory alloy pipe with fins. In this way, it can release all the latent heat during complete phase change.

[0011] Optionally, the inner side of the cam is provided with a first key groove, the outer side of the rotary shaft is provided with a key groove identical to the first key groove of the cam, the rotary shaft and the cam are connected by placing a key, and the inner side of the rotary shaft is provided with a second key groove identical in size to the key position on the rotary shaft of the rotary motor, the rotary motor and the cam are connected by placing a key.

[0012] Optionally, the rotary shaft is connected to two bearing seats symmetrically distributed at the two ends of the cam in addition to being connected to the cam, and the bearing seats are used to bear the tension of the rotary shaft during driving.

[0013] Optionally, the compression-type spring refrigeration prototype further comprises a support structure comprising an upper top plate and a lower bottom plate connected by a screw rod, which is used to fix the components of the cam subsystem.

[0014] Optionally, the linear guide is a linear bearing, which converts the rotary motion of the cam into linear motion to drive the shape memory alloy pipe with fins.

[0015] Optionally, the end portion of the linear guide rail in contact with the cam is connected by a layer of brass, mainly to reduce friction.

[0016] Optionally, the rotary motor, the cam, the rotating shaft, the bearing seat and the linear guide rail are all fixed on the upper top plate.

[0017] Optionally, four through holes are formed on the four corners of the upper top plate, and four screw rods are loaded in the through holes by nuts, and then connected with the lower bottom plate.

[0018] Optionally, the position of the upper top plate on the four screw rods can be adjusted along the length direction of the screw rod, so as to adapt to the loading of the finned shape memory alloy pipe with different lengths.

[0019] Optionally, the chuck sub-system further comprises an end fixer fixed on the lower bottom plate, which supports the lower chuck in the compression direction of the finned shape memory alloy pipe. The purpose is to prevent the deviation of the center axis of the end fixed position and the upper chuck in the force direction.

[0020] Optionally, a force sensor for outputting a force signal is arranged between the linear guide rail and the upper chuck, which is used for feedback control of the start and stop of the rotary motor and the switching of the fluid.

[0021] Optionally, a groove is arranged on the end surface of the upper chuck and the lower chuck, which is used for loading a gasket directly contacting the finned shape memory alloy pipe. The gasket is made of hard alloy steel or ceramic.

[0022] Optionally, a flow channel is arranged inside the upper chuck and the lower chuck, which is used for the inflow and outflow of heat exchange fluid.

[0023] Optionally, a plurality of cylindrical guide rails are arranged between the upper chuck and the lower chuck, wherein the guide rails are not subjected to axial force, which is used for controlling the strict centering of the upper chuck and the lower chuck during movement without deviation.

[0024] Optionally, the finned shape memory alloy pipe is filled with a plastic inner plug, which is used to increase the proportion of heat exchange fluid participating in heat exchange in the pipe.

[0025] Optionally, the finned shape memory alloy pipe is wrapped by a plastic pipe outside, which is used to prevent the loss of refrigeration capacity from the outside of the pipe.

[0026] Optionally, an anti-buckling component is provided outside the plastic tube to wrap the finned shape memory alloy tube, which is made of metal material to prevent the buckling of the finned shape memory alloy tube during compression.

[0027] Optionally, in the first flow process, the heat exchange fluid enters one end of the finned shape memory alloy tube in the compressed state from the lower chuck and takes away heat; in the second flow process, the heat exchange fluid enters the other end of the finned shape memory alloy tube in the relaxed state from the upper chuck and takes away cold.

[0028] According to another aspect of the present disclosure, a cam-driven compression-type snap-on refrigeration prototype refrigeration method is provided, which comprises the following steps: rotating the rotating shaft by driving the rotating motor, moving the cam by the rotating shaft, moving the linear guide in a straight line by the rotating movement of the cam, and then the linear guide pushes the upper chuck to uniformly load and unload the finned shape memory alloy tube, wherein, when the finned shape memory alloy tube is loaded, the loading state is maintained for a predetermined time, during which the first flow process works to take away the heat of the finned shape memory alloy tube; and when the finned shape memory alloy tube is unloaded, the unloading state is maintained for a predetermined time, during which the second flow process works, and the finned shape memory alloy tube absorbs the heat of the heat exchange fluid, thereby discharging the cooled heat exchange fluid to achieve refrigeration.

[0029] Compared with the prior art, the present disclosure drives the finned shape memory alloy tube by a cam, utilizes the heat release / heat absorption effect of the finned shape memory alloy tube during loading / unloading, and takes away heat and cold by a fluid system to achieve refrigeration, which is green and efficient. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is the overall structure schematic diagram of the cam-driven compression-type snap-on refrigeration prototype of the present disclosure;

[0031] Figure 2 is the displacement of the linear guide with time when the rotating motor of the cam-driven compression-type snap-on refrigeration prototype of the present disclosure is continuously running at 1 second, wherein the maximum designed displacement is 2.5 mm.

[0032] Figure 3 is the fluid subsystem structure schematic diagram of the cam-driven compression-type snap-on refrigeration prototype of the present disclosure, which shows that the operation of the fluid subsystem includes two processes in the present disclosure in each cycle;

[0033] Figure 4 is the running result schematic diagram of the cam-driven compression-type elastic card refrigeration prototype according to the first exemplary embodiment of the present disclosure, showing the stress state of the refrigerant during the execution process, the temperature of the refrigeration area and the heat discharge area, and the temperature change of the outlet fluid in the corresponding different flow stages;

[0034] Figure 5 is the running result schematic diagram of the cam-driven compression-type elastic card refrigeration prototype according to the second exemplary embodiment of the present disclosure, showing the stress state of the refrigerant during the execution process, the temperature of the refrigeration area and the heat discharge area, and the temperature change of the outlet fluid in the corresponding different flow stages (different from the first embodiment).

[0035] Figure 6 is the refrigerant subsystem structure schematic diagram of the third exemplary embodiment of the cam-driven compression-type elastic card refrigeration prototype according to the present disclosure, in order to more clearly show its internal structure, part of the components are shown in the form of partial enlargement and transparency.

[0036] Explanation of reference signs:

[0037] 01 rotary motor 02 bearing seat 03 cam

[0038] 04 screw 05 rotating shaft 0501 key 1

[0039] 0502 key 2 06 linear guide rail 07 upper top plate

[0040] 08 force sensor 09 nut 10 chuck subsystem

[0041] 1001 upper chuck 1002 lower chuck 1003 end fixer

[0042] 1004 cylindrical guide rail 1005 gasket 1006 flow channel

[0043] 1007 shape memory alloy pipe with fins 1008 anti-buckling structure 1009 plastic pipe

[0044] 1010 plastic inner plug 11 lower bottom plate S1 first flow process

[0045] S2 second flow process A1 heat discharge area A2 refrigeration area

[0046] H1 heat exchanger 1 H2 heat exchanger 2 P1 fluid pump 1

[0047] P2 fluid pump 2 V1-6 valve O1 port 1

[0048] O2 port 2 1005-2 gasket 2 1008-2 multi-pipe anti-buckling structure

[0049] 1009-2 Multi-pipe Plastic Fittings 1011 Metal Outer Sleeve Detailed Implementation

[0050] To enable those skilled in the art to better understand the technical solutions of this disclosure, the following detailed description of the cam-driven compression cartridge refrigeration prototype and its refrigeration method provided in this disclosure is given in conjunction with the accompanying drawings.

[0051] First exemplary embodiment

[0052] Figure 1 The structure of a cam-driven compression-type cartridge refrigeration prototype according to a first exemplary embodiment of this disclosure is shown. The refrigeration prototype of this disclosure functions to continuously input cooling energy into the area to be refrigerated to maintain its temperature or further reduce its temperature. Figure 1As shown, it is the overall structure schematic diagram of the cam-driven compression-type elastic card refrigeration prototype based on the present disclosure, in order to more clearly show the internal structure of the prototype, part of the components are shown in the form of partial enlargement and transparency. The cam-driven compression-type elastic card refrigeration prototype based on the present disclosure includes: a cam subsystem, which includes a rotary motor 01, a bearing seat 02, a cam 03, a rotating shaft 05, key positions 1 and 2 connecting the rotating shaft 05 and the motor, and a linear guide rail 06, the rotation of the rotary motor 01 can drive the cam 03 to rotate through the rotating shaft 05, and then the rotary motion of the cam 03 can drive the linear guide rail 06 to move linearly; a chuck subsystem, which mainly includes an upper chuck 1001, a lower chuck 1002 and an end fixer 1003, wherein the end fixer 1003 is fixed on the bottom plate 11, the lower chuck 1002 is constrained by the end fixer 1003 in the compression direction, and the linear motion of the linear guide rail 06 drives the upper chuck 1001 to move linearly; a refrigerant subsystem (solid elastic card refrigerant structure), which mainly includes a shape memory alloy pipe 1007 with fins inside and an external anti-buckling structure 1008 for maintaining the stability of the shape memory alloy pipe 1007 with fins when it is compressed, wherein the upper chuck 1001 is in close contact with the shape memory alloy pipe 1007 with fins in the initial state, and the upper chuck 1001 will first move linearly downward to compress the shape memory alloy pipe 1007 with fins, causing it to undergo positive phase change and generate heat, and then the upper chuck 1001 moves linearly upward to unload the pressure on the shape memory alloy pipe 1007 with fins, causing it to undergo reverse phase change and generate cold; a fluid subsystem, which includes two flow processes S1 and S2 controlled by pumps P1-P2 and valves V1-V6 in each cycle, in the first flow process S1, heat exchange fluid from the area to be cooled A2 flows into the port O1 of the shape memory alloy pipe 1007 with fins in the compressed state, and flows out from the other port O2 to the heat exchanger H1, and the fluid carrying heat further dissipates heat to the heat discharge area A1 through the heat exchanger H1; in the second flow process S2, heat exchange fluid from the heat discharge area A1 flows into the port O2 of the shape memory alloy pipe 1007 with fins in the relaxed state, and flows out from the other port O1 to the heat exchanger H2, and the fluid carrying cold further transfers cold to the area to be cooled A2 through the heat exchanger H2. The cam-driven compression-type elastic card refrigeration prototype based on the present disclosure has complete device structure and function, simple driving components, and does not require large servo hydraulic driving equipment, providing a feasible solution for integrated and efficient green refrigeration based on shape memory alloy.

[0053] In this embodiment, the temperature of the region to be refrigerated A2 and the heat discharge region A1 are both 303 K, and the refrigeration target of this example is to continuously input cold energy into the region to be refrigerated A2, with the purpose of embodying the maximum refrigeration power that the refrigeration prototype can output at the start of an actual refrigeration cycle, and the specific details are described as follows.

[0054] The cam 03 is in contact with the shape memory alloy tube 1007 with fins at the position of the smallest radius before the compression type elastic card refrigeration prototype provided by the present disclosure is started, and the pre-stress acting on the shape memory alloy tube 1007 with fins is 50 MPa. After the prototype is started, the rotating motor 01 is controlled by the program to rotate 0.5 turns at the fastest speed (about 0.4 s / cycle) and then stop, during which the linear guide 06 synchronously drives the upper clamp 1001 to move downward, completing the compression loading process of the shape memory alloy tube 1007 with fins. Simultaneously, the force sensor 08 obtains the force signal, and after signal processing, it can be known that the stress of the shape memory alloy tube 1007 with fins is about 800 MPa. At this time, the shape memory alloy tube 1007 with fins releases latent heat, and the average temperature increases significantly. Then, the compression state is maintained for 1.8 s. After the control system detects that the stress signal is greater than the threshold value required for the first flow process S1 of the starting fluid, the first flow process S1 is started, the valves V1, V3 and V5 are opened, the fluid pump P1 drives the fluid in the heat discharge area A1 with a temperature of 303 K to perform self-circulation, and the fluid pump P2 drives the heat exchange fluid in the area A2 to be refrigerated with a temperature of 303 K to flow into the port O1 of the shape memory alloy tube 1007 with fins in the compression state and flow out from the other port O2 to the heat exchanger H1. After the heat exchange fluid contacts the shape memory alloy tube 1007 with fins, the temperature of the heat exchange fluid increases, the heat exchange fluid carrying heat further dissipates heat to the heat discharge area A1 with a temperature of 303 K through the heat exchanger H1, and simultaneously, due to the heat being carried out, the average temperature of the shape memory alloy tube 1007 with fins decreases and returns to the initial state.After the compression state is maintained, the rotary motor 01 is controlled by the program to continue rotating at the fastest speed (about 0.4 s / cycle) for 0.5 cycles and then stop, during which the linear guide 06 synchronously drives the upper clamp 1001 to move upward, completing the unloading process of the compressed shape memory alloy pipe 1007 with fins, and synchronously, the force sensor 08 obtains the force signal, after signal processing, the stress borne by the shape memory alloy pipe 1007 with fins is known to be restored to 50 MPa, at this time, the shape memory alloy pipe 1007 with fins absorbs latent heat to reverse phase change, the average temperature is greatly reduced, and then this unloading state is maintained for 1.8 s, after the control system detects that the stress signal is less than the threshold value required for the second fluid flow process S2 to start, the second fluid flow process S2 starts, the valves V2, V4 and V6 are opened, and the fluid pump P2 drives the fluid in the to-be-cooled area A2 at a temperature of 303 K to self-cycle, and the fluid pump P1 drives the heat exchange fluid in the heat discharge area A1 at a temperature of 303 K to flow into the port O2 of the shape memory alloy pipe 1007 with fins in the unloading state, after the heat exchange fluid contacts the shape memory alloy pipe 1007 with fins, the temperature decreases, and the heat exchange fluid flows out from the other port O1 to the heat exchanger H2, the heat exchange fluid carrying cold energy further absorbs heat from the to-be-cooled area A2 at a temperature of 303 K through the heat exchanger H2, and the description of this process is equivalent to that the fluid carrying cold energy delivers cold energy to the to-be-cooled area A2 at a temperature of 303 K, and at the same time, due to the cold energy being carried out, the average temperature of the shape memory alloy pipe 1007 with fins increases and restores to close to the initial state. The above-described process continues to operate in a cycle, and the fluid can continuously input cold energy to the to-be-cooled area A2 at a temperature of 303 K through the shape memory alloy pipe 1007 with fins, and continuously discharge the heat carried out to the heat discharge area A1 at a temperature of 303 K.

[0055] As described above, the refrigeration target of the present example is achieved, the stress borne by the shape memory alloy pipe 1007 with fins, the temperature of the to-be-cooled area, the temperature of the heat discharge area, and the temperature change of the fluid carrying heat or cold energy are as shown in the following table: Figure 4 In the present example, the actual refrigeration power calculated by the difference between the temperature of the fluid carrying cold energy and the temperature of the to-be-cooled area is 1300 W Kg -1 .

[0056] Second exemplary embodiment

[0057] Next, a second exemplary embodiment of the cam-driven compression-type pop-on refrigeration prototype according to the present disclosure will be described. It should be noted that in the following, the same parts as those described in the first exemplary embodiment described above will not be described again, and the description is limited only to the differences between the two exemplary embodiments.

[0058] In this embodiment, the temperature of the region to be refrigerated A2 is 300K, the temperature of the heat discharge region A1 is 303K, and the refrigeration target of this example is to continuously extract heat from the region to be refrigerated A2 (or described as continuously inputting cold into the region to be refrigerated A2) to maintain the temperature thereof, and to transport the extracted heat to the heat discharge region A1 to discharge it, the details of which are described below.

[0059] The cam 03 is in the same state as the first embodiment before the start of the compression-type snap-action refrigeration prototype based on cam driving provided by the present disclosure. After the prototype is started, the shape memory alloy pipe fitting 1007 with fins is loaded in the same way as the first embodiment to release latent heat, the average temperature is greatly increased, and then the same as the first embodiment, the compression state is maintained for 1.8s, the control system starts the first flow process S1, the fluid operation mode driven by the valve and pump is the same as the first embodiment, the difference is that the temperature of the heat exchange fluid in the region to be refrigerated A2 is 300K. After the compression state is maintained, the shape memory alloy pipe fitting 1007 with fins is unloaded in the same way as the first embodiment to absorb latent heat for reverse phase change, the average temperature is greatly reduced, and then the same as the first embodiment, the unloading state is maintained for 1.8s, the control system starts the second flow process S2, the fluid operation mode driven by the valve and pump is the same as the first embodiment, the difference is that the fluid flows out from the port O1 to the heat exchanger H2, and the fluid carrying cold further absorbs heat from the region to be refrigerated A2 with a temperature of 300K through the heat exchanger H2. The above-described process is continuously operated in a cycle, the fluid can continuously input cold into the region to be refrigerated A2 with a temperature of 300K through the shape memory alloy pipe fitting 1007 with fins, and continuously discharge the extracted heat to the heat discharge region A1 with a temperature of 303K.

[0060] As described above, the refrigeration target of this example is achieved, the stress on the shape memory alloy pipe fitting 1007 with fins described above, the temperature of the region to be refrigerated, the temperature of the heat discharge region, and the temperature change of the fluid carrying heat or cold are as shown in Figure 5 The actual refrigeration power calculated by the difference between the temperature of the fluid carrying cold and the temperature of the region to be refrigerated in this example is 650W Kg -1 .

[0061] Third exemplary embodiment

[0062] Next, a third exemplary embodiment of the compression-type snap-action refrigeration prototype based on cam driving according to the present disclosure will be described. It should be noted that in the following, the same parts as those described in the first and second exemplary embodiments described previously will not be described again, and the description is limited to the differences between the two exemplary embodiments.

[0063] Figure 6 A schematic diagram of the solid cartridge refrigerant structure and the gasket structure on the clamp of a third example of a cam-driven compression cartridge refrigeration prototype according to this disclosure is shown; the other parts are the same as those in the first and second exemplary embodiments described above. Figure 6 As shown, this exemplary embodiment further extends the foregoing embodiments to accommodate multiple finned shape memory alloy tubes 1007. The buckling-resistance structure 1008 in the foregoing example is further improved into a multi-tube buckling-resistance structure 1008-2. Optionally, the multi-tube buckling-resistance structure 1008-2 is made of a material with good thermal conductivity, such as a metallic material, and has internal pores to accommodate three finned shape memory alloy tubes 1007. During the fluid communication phase, fluid can pass through both the interior of the finned shape memory alloy tubes 1007 and the exterior of the multi-tube buckling-resistance structure 1008-2. The fluid flowing inside can directly exchange heat with the inner surface of the finned shape memory alloy tubes 1007, while the fluid passing through the exterior of the multi-tube buckling-resistance structure 1008-2 can indirectly exchange heat with the outer surface of the finned shape memory alloy tubes 1007 through the thermally conductive multi-tube buckling-resistance structure 1008-2. Compared with the previous embodiments, this embodiment expands the number of loadable refrigerant pipes. In addition, besides the inner surface of the finned shape memory alloy pipe 1007 participating in heat exchange, the outer surface of the finned shape memory alloy pipe 1007 in this embodiment also participates in the heat exchange process, further increasing the heat exchange area and improving the refrigeration efficiency.

[0064] Compared with existing technologies, this disclosure develops an integrated and miniaturized refrigeration prototype by using a cam-driven compression of a finned shape memory alloy tube to achieve refrigeration through its exothermic and endothermic effects during loading and unloading. This provides a feasible solution for the further commercialization of cartridge-type solid-state refrigeration prototypes.

[0065] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A cam-driven compression-type poppet refrigeration prototype, characterized in that, The application relates to a compression-type elastic snap refrigeration device. The cam subsystem comprises a rotary motor, a rotary shaft, a cam and a linear guide rail, the rotary motor can drive the cam to rotate through the rotary shaft, and the linear guide rail is driven to move linearly. The solid elastic snap refrigerant structure is a shape memory alloy pipe with fins inside, which can absorb heat during reverse phase change when unloaded and release latent heat during forward phase change when loaded. The chuck subsystem comprises an upper chuck and a lower chuck, and the solid elastic snap refrigerant structure is loaded between the two chucks, wherein the upper chuck moves along with the linear guide rail to load and unload the shape memory alloy pipe with fins. The fluid subsystem is driven by a fluid pump to carry out a first flow process and a second flow process, wherein in the first flow process, the latent heat released by the shape memory alloy pipe with fins after being loaded is taken away by the heat exchange fluid flowing through the pipe, and in the second flow process, the shape memory alloy pipe with fins absorbs the heat of the heat exchange fluid flowing through the pipe after being unloaded, so that the cooled heat exchange fluid is discharged for refrigeration. The shape memory alloy pipe with fins is filled with a plastic inner plug. The shape memory alloy pipe with fins is wrapped by a plastic pipe. An anti-buckling component is arranged outside the plastic pipe wrapping the shape memory alloy pipe with fins, and the anti-buckling component is made of a metal material. Grooves are arranged on the end faces of the upper chuck and the lower chuck for loading gaskets directly contacting the shape memory alloy pipe with fins, and the gaskets are made of hard alloy steel or ceramic. The shape memory alloy pipe with fins can withstand a stress of 800Mpa.

2. The cam-driven compression poppet refrigeration prototype of claim 1, wherein, The cam is made of hard alloy steel, and the difference between the maximum radius and the minimum radius of the outer side of the cam is greater than or equal to 4% of the length of the shape memory alloy pipe with fins.

3. The cam-driven compression poppet refrigeration prototype of claim 2, wherein, A first key groove is arranged on the inner side of the cam, a key groove with the same size as the first key groove of the cam is arranged on the outer side of the rotary shaft, the rotary shaft and the cam are connected through the key, and a second key groove with the same size as the key position on the rotary shaft of the rotary motor is arranged on the inner side of the rotary shaft, the rotary motor and the cam are connected through the key.

4. The cam-driven compression poppet refrigeration prototype of claim 3, wherein, The rotary shaft is connected with two bearing seats symmetrically arranged at the two ends of the cam in addition to being connected with the cam, and the bearing seats are used for bearing the tension of the rotary shaft during driving.

5. The cam-driven compression poppet refrigeration prototype of claim 4, wherein, The compression-type elastic snap refrigeration device further comprises a support structure, the support structure comprises an upper top plate and a lower bottom plate connected through a screw rod, and is used for fixing various components of the cam subsystem.

6. The cam-driven compression poppet refrigeration prototype of claim 5, wherein, The linear guide rail is a linear bearing, which converts the rotary motion of the cam into linear motion to drive the shape memory alloy pipe with fins.

7. The cam-driven compression poppet refrigeration prototype of claim 6, wherein, The end part of the linear guide rail in contact with the cam is connected with a layer of brass.

8. The cam-driven compression poppet refrigeration prototype of claim 5, wherein, The rotary motor, the cam, the rotary shaft, the bearing seat and the linear guide rail are fixed on the upper top plate.

9. The cam-driven compression poppet refrigeration prototype of claim 8, wherein, Four holes are formed in the four corners of the upper top plate, four screw rods are loaded in the holes through nuts, and the upper top plate is connected with the lower bottom plate.

10. The cam-driven compression poppet refrigeration prototype of claim 9, wherein, The position of the upper top plate on the four screw rods can be adjusted along the length direction of the screw rods.

11. The cam-driven compression poppet refrigeration prototype of claim 6, wherein, The collet sub-system further comprises an end fixer fixed on the lower bottom plate, which supports the lower collet in the compression direction of the finned shape memory alloy pipe.

12. The cam-driven compression poppet refrigerator prototype of claim 11, wherein, A force sensor is arranged between the linear guide rail and the upper collet to output a force signal for feedback control of the start and stop of the rotary motor and switching of the fluid.

13. The cam drive based compression poppet refrigeration prototype of claim 1, wherein, A channel is arranged in the upper collet and the lower collet for inflow and outflow of the heat exchange fluid.

14. The cam-driven compression poppet refrigerator prototype of claim 13, wherein, A plurality of cylindrical guide rails are arranged between the upper collet and the lower collet, which are not subjected to axial force and are used to control the strict centering of the upper collet and the lower collet during movement.

15. The cam-driven compression poppet refrigerator prototype of claim 13, wherein, In the first flow process, the heat exchange fluid enters one end of the finned shape memory alloy pipe in the compressed state from the lower collet and takes away heat; in the second flow process, the heat exchange fluid enters the other end of the finned shape memory alloy pipe in the relaxed state from the upper collet and takes away cold.

16. A method for refrigeration of a cam-driven compression-type poppet refrigeration prototype according to any one of claims 1 to 15, characterized in that, The refrigeration method comprises the following steps: The rotary shaft is driven to rotate by the rotary motor, the cam is driven to move by the rotary shaft, the linear guide rail is driven to move linearly by the rotary motion of the cam, and the upper collet is driven to uniformly load and unload the finned shape memory alloy pipe by the linear guide rail, wherein When the finned shape memory alloy pipe is loaded, the loading state is maintained for a predetermined time, during which the first flow process works to take away the heat of the finned shape memory alloy pipe; And When the finned shape memory alloy pipe is unloaded, the unloading state is maintained for a predetermined time, during which the second flow process works, the finned shape memory alloy pipe absorbs the heat of the heat exchange fluid, and the cooled heat exchange fluid is discharged to achieve refrigeration.

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