Heat exchanger of pulse tube refrigerator

Abstract

This disclosure relates to the field of refrigeration technology, and in particular to a heat exchanger for a pulse tube refrigerator. The heat exchanger includes a gas-solid heat exchange section and a liquid-solid heat exchange section. The gas-solid heat exchange section has a cylindrical structure, and the liquid-solid heat exchange section surrounds the outer periphery of the gas-solid heat exchange section. The liquid-solid heat exchange section has multiple liquid cooling channels inside, each containing coolant. All liquid cooling channels are arranged at intervals along the circumference of the gas-solid heat exchange section, and at least some of the liquid cooling channels extend along the axial direction of the gas-solid heat exchange section. This ensures that all liquid cooling channels are at the same distance from the gas-solid heat exchange section, resulting in a more uniform heat exchange effect along the circumference of the gas-solid heat exchange section. This ensures the temperature uniformity of the gas-solid heat exchange section itself, thereby further guaranteeing the refrigeration performance of the refrigerator.

Description

Technical Field

[0001] This disclosure relates to the field of refrigeration technology, and in particular to a heat exchanger for a pulse tube refrigeration machine. Background Technology

[0002] With the development of superconducting technology, the application of high-capacity pulse tube refrigerators is becoming increasingly widespread. Pulse tube refrigerators are a common type of refrigeration equipment that achieves a cooling effect through gas pumping. The heat exchanger, as a crucial component of the pulse tube refrigerator, uses coolant to cool the high-pressure gas entering the refrigerator, thereby releasing heat into the environment.

[0003] However, due to limitations in manufacturing processes, traditional heat exchangers use straight channels with liquid cooling pipes arranged horizontally on the outside of the gas-solid heat exchange section. This results in uneven heat transfer from the liquid cooling pipes to the cylindrical gas-solid heat exchange section, leading to poor cooling performance of the refrigeration unit. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, this disclosure provides a heat exchanger for a pulse tube refrigerator.

[0005] This disclosure provides a heat exchanger for a pulse tube refrigerator, which includes a gas-solid heat exchange section and a liquid-solid heat exchange section. The gas-solid heat exchange section has a cylindrical structure, and the liquid-solid heat exchange section surrounds the outer periphery of the gas-solid heat exchange section.

[0006] The liquid-solid heat exchange section has multiple liquid cooling channels inside, each containing coolant. All the liquid cooling channels are arranged at intervals along the circumference of the gas-solid heat exchange section, and at least a portion of each liquid cooling channel extends along the axial direction of the gas-solid heat exchange section.

[0007] Optionally, the gas-solid heat exchange section includes a cylindrical main heat exchange section and a cylindrical secondary heat exchange section. All the liquid cooling channels are arranged at circumferential intervals along the secondary heat exchange section and the main heat exchange section, and the secondary heat exchange section and the main heat exchange section are coaxially arranged.

[0008] The main heat exchange section has a gas outlet, and a reflux channel is formed in the main heat exchange section. One end of the reflux channel is connected to the gas outlet, and the secondary heat exchange section is located at the other end of the reflux channel.

[0009] The diameter of the secondary heat exchange section is smaller than the diameter of the main heat exchange section.

[0010] Optionally, each of the liquid cooling channels includes an axial section and a radial section that are interconnected;

[0011] The axial segments of all the liquid cooling channels are arranged at intervals along the circumference of the main heat exchange section, and each axial segment extends along the axial direction of the main heat exchange section. The radial segments of all the liquid cooling channels are arranged at intervals along the circumference of the secondary heat exchange section, and each radial segment extends along the radial direction of the secondary heat exchange section.

[0012] Optionally, each of the radial segments includes a first radial segment and a second radial segment, wherein the first radial segment extends along the axis close to the secondary heat exchange section, and the second radial segment extends along the axis away from the secondary heat exchange section.

[0013] Each first radial segment is connected to a corresponding second radial segment via a connecting hole.

[0014] Optionally, the liquid-solid heat exchange section is provided with a liquid inlet and a liquid outlet, the liquid inlet and the liquid outlet are respectively located on both sides of the liquid-solid heat exchange section along the axial direction of the liquid-solid heat exchange section, and the two ends of the liquid cooling channel are respectively connected to the liquid inlet and the liquid outlet.

[0015] Optionally, the liquid-solid heat exchange section is further provided with a first confluence channel, which is arranged circumferentially within the liquid-solid heat exchange section. The liquid inlet is connected to the first confluence channel, and all the liquid cooling channels are connected to the first confluence channel.

[0016] Optionally, a second confluence channel is also provided in the liquid-solid heat exchange section. The second confluence channel is arranged circumferentially in the liquid-solid heat exchange section. The liquid outlet is connected to the second confluence channel, and all the liquid cooling channels are connected to the second confluence channel.

[0017] Optionally, the gas-solid heat exchange section includes a plurality of heat exchange fins, each of the heat exchange fins being arranged radially along the circumference of the gas-solid heat exchange section, and a gas channel being formed between two adjacent heat exchange fins.

[0018] Optionally, all the liquid cooling channels are evenly distributed along the circumference of the gas-solid heat exchange section.

[0019] Optionally, the gas-solid heat exchange section and the liquid-solid heat exchange section are integrally formed structures.

[0020] The technical solution provided in this disclosure has the following advantages compared with the prior art:

[0021] The heat exchanger of the pulse tube refrigerator disclosed herein provides multiple liquid cooling channels inside the liquid-solid heat exchange section, and all liquid cooling channels are arranged at intervals along the circumference of the gas-solid heat exchange section on the outer periphery of the gas-solid heat exchange section. This ensures that all liquid cooling channels are at the same distance from the gas-solid heat exchange section, resulting in a more uniform heat exchange effect in the circumference of the gas-solid heat exchange section and guaranteeing the temperature uniformity of the gas-solid heat exchange section itself, thereby further ensuring the refrigeration performance of the refrigerator. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0023] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the heat exchanger structure of the pulse tube refrigerator described in Embodiment 1 of this disclosure;

[0025] Figure 2 This is a schematic diagram of the heat exchanger of the pulse tube refrigerator described in Embodiment 1 of this disclosure from another perspective;

[0026] Figure 3 This is a cross-sectional schematic diagram of the heat exchanger of the pulse tube refrigerator described in Embodiment 1 of this disclosure;

[0027] Figure 4 for Figure 3 A partial structural diagram of part A in the middle;

[0028] Figure 5 for Figure 3 A schematic diagram of the cross-section along the BB direction;

[0029] Figure 6 for Figure 3 A schematic diagram of the cross-section along the CC direction;

[0030] Figure 7 This is a cross-sectional schematic diagram of the pulse tube refrigerator described in Embodiment 2 of this disclosure.

[0031] Among them, 1. Heat exchanger; 11. Gas-solid heat exchange section; 11a. Main heat exchange section; 11b. Secondary heat exchange section; 111. Reflux channel; 12. Liquid-solid heat exchange section; 121. Liquid inlet; 122. Liquid outlet; 123. First confluence channel; 124. Second confluence channel; 13. Liquid cooling channel; 131. Axial section; 132. Radial section; 132a. First radial segment; 132b. Second radial segment; 133. Connecting hole; 2. Cold accumulator; 3. Cold end heat exchange section; 4. Pulse tube; 5. Inertia tube. Detailed Implementation

[0032] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0033] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0034] Traditional pulse tube refrigerators, due to manufacturing limitations, use multiple layers of straight channels arranged horizontally outside the gas-solid heat exchange section for their liquid cooling pipes. These straight channels extend axially perpendicular to the gas-solid heat exchange section. However, the distance between these straight channels and the cylindrical gas-solid heat exchange section is unevenly distributed along the circumference of the section, leading to uneven circumferential heat conduction. Furthermore, the upstream and downstream relationships of the coolant within each layer of straight channels significantly increase the circumferential temperature inhomogeneity within the gas-solid heat exchange section, ultimately resulting in poor cooling performance.

[0035] To address the aforementioned deficiencies, this embodiment provides a heat exchanger for a pulse tube refrigerator. By improving the structure of the liquid-cooled pipes arranged circumferentially in the gas-solid heat exchange section, the uniformity of heat conduction in the circumferential direction of the gas-solid heat exchange section is ensured, thereby providing uniform and sufficient cooling to the gas-solid heat exchange section. This further guarantees the heat exchange effect of the heat exchange section and effectively improves the overall performance of the refrigerator. Specifically, the structural arrangement of the heat exchanger for this pulse tube refrigerator is described in the following embodiment.

[0036] Example 1

[0037] like Figure 1-6 As shown, this embodiment provides a heat exchanger 1 for a pulse tube refrigerator, which includes a gas-solid heat exchange section 11 and a liquid-solid heat exchange section 12. The gas-solid heat exchange section 11 has a cylindrical structure, and the liquid-solid heat exchange section 12 surrounds the outer periphery of the gas-solid heat exchange section 11.

[0038] The liquid-solid heat exchange section 12 surrounds the outer periphery of the gas-solid heat exchange section 11. For example, a receiving through hole can be formed at the middle position of the liquid-solid heat exchange section 12, and the gas-solid heat exchange section 11 can be disposed in the receiving through hole and tightly fitted with the hole wall. Alternatively, the liquid-solid heat exchange section 12 can be a cylindrical structure coaxial with the gas-solid heat exchange section 11, and the liquid-solid heat exchange section 12 can be sleeved on the outside of the gas-solid heat exchange section 11, while being tightly fitted with the gas-solid heat exchange section 11.

[0039] The gas-solid heat exchange section 11 has a gas channel inside its side wall for the gas working fluid to flow through. The gas channel extends along the axial direction of the gas-solid heat exchange section 11. The liquid-solid heat exchange section 12 can transfer cooling energy to the gas-solid heat exchange section 11, and the gas-solid heat exchange section 11 further transfers cooling energy to the gas working fluid in the gas channel.

[0040] The liquid-solid heat exchange section 12 is provided with a plurality of liquid cooling channels 13, each containing coolant. All liquid cooling channels 13 are arranged at intervals along the circumference of the gas-solid heat exchange section 11, and at least a portion of each liquid cooling channel 13 extends along the axial direction of the gas-solid heat exchange section 11.

[0041] The inlet and outlet of the liquid cooling channel 13 can be connected to the outside of the liquid-solid heat exchange section 12 to allow coolant to flow into the liquid cooling channel 13. In other feasible ways, the coolant can also achieve self-circulation within the liquid-solid heat exchange section 12. All liquid cooling channels 13 are arranged at intervals along the circumference of the gas-solid heat exchange section 11, thereby achieving annular cooling on the outside of the gas-solid heat exchange section 11, so that the gas-solid heat exchange section 11 can receive cooling at any position along the circumference. If at least a portion of the liquid cooling channels 13 are arranged to extend axially along the gas-solid heat exchange section 11, uniform axial cooling of the gas-solid heat exchange section 11 can be achieved.

[0042] The coolant can be cooling water or other liquids with higher heat capacity. The liquid cooling channel 13 can be configured as a channel with a circular or rectangular cross-section. In other embodiments, it can also be configured as other cross-sectional shapes, as long as it ensures that the coolant can flow uniformly and smoothly along the liquid cooling channel 13.

[0043] In practice, the coolant can enter the liquid cooling channel 13 from the inlet and flow simultaneously in all the liquid cooling channels 13. During the flow, heat exchange occurs between the liquid-solid heat exchange section 12 and the gas-solid heat exchange section 11, and the gaseous working medium in the gas-solid heat exchange section 11 receives the cooling energy from the coolant. Since all the liquid cooling channels 13 are arranged circumferentially along the gas-solid heat exchange section 11, heat exchange can occur simultaneously at all positions along the entire circumference of the gas-solid heat exchange section 11, ensuring uniform temperature throughout the circumference of the gas-solid heat exchange section 11. Finally, after flowing through the liquid cooling channel 13, the coolant is discharged through the outlet of the liquid cooling channel 13. The coolant is a low-temperature liquid, and the gaseous working medium is a high-temperature gas.

[0044] The heat exchanger 1 of the pulse tube refrigerator provided in this embodiment has multiple liquid-cooled channels 13 arranged inside the liquid-solid heat exchange section 12, and all the liquid-cooled channels 13 are arranged at intervals along the circumference of the gas-solid heat exchange section 11 on the outer periphery of the gas-solid heat exchange section 11. This ensures that all the liquid-cooled channels 13 are at the same distance from the gas-solid heat exchange section 11, resulting in a more uniform heat exchange effect in the circumference of the gas-solid heat exchange section 11. This ensures the temperature uniformity of the gas-solid heat exchange section 11 itself, thereby further guaranteeing the cooling performance of the refrigerator. At the same time, some of the liquid-cooled channels 13 are extended along the axial direction of the gas-solid heat exchange section 11, which also enables a more uniform heat exchange effect in the circumference of the gas-solid heat exchange section 11.

[0045] In some embodiments, all liquid cooling channels 13 can be evenly distributed along the circumference of the gas-solid heat exchange section 11, which can further ensure the temperature uniformity along the circumference of the gas-solid heat exchange section 11.

[0046] In one feasible approach, the gas-solid heat exchanger 11 and the liquid-solid heat exchanger 12 are designed as a single, integral piece. This reduces the number and complexity of product parts and avoids secondary connections and sealing issues between structures. For example, the entire heat exchanger can be integrally formed using 3D printing. Of course, in other embodiments, the gas-solid heat exchanger 11 and the liquid-solid heat exchanger 12 can also be separate components, and during assembly, they can be welded together using methods such as brazing or diffusion welding.

[0047] In this embodiment, the heat exchanger can be made of copper alloy. Of course, in other embodiments, the heat exchanger can also be made of other materials with high thermal conductivity.

[0048] In some embodiments, the liquid-solid heat exchange section 12 is further provided with a liquid inlet 121 and a liquid outlet 122. The liquid inlet 121 and the liquid outlet 122 are respectively disposed on both sides of the liquid-solid heat exchange section 12 along the axial direction of the liquid-solid heat exchange section 12, and the two ends of the liquid cooling channel 13 are respectively connected to the liquid inlet 121 and the liquid outlet 122.

[0049] Furthermore, the inlet 121 can be connected to the inlet of the liquid cooling channel 13, or the inlet 121 can directly form the inlet of the liquid cooling channel 13, so as to input coolant into the liquid cooling channel 13. The outlet 122 can be connected to the outlet of the liquid cooling channel 13, or the outlet 122 can directly form the outlet of the liquid cooling channel 13. A circulation pipeline connecting the inlet 121 and the outlet 122 can be provided outside the heat exchange section, and a coolant storage tank and a coolant cooler can be provided on the circulation pipeline to cool the coolant discharged from the outlet 122 and then input it back into the liquid cooling channel 13 through the inlet 121 to achieve circulating cooling.

[0050] The liquid inlet 121 and liquid outlet 122 are respectively located on both sides of the liquid-solid heat exchange section 12, which can further ensure the uniformity of the temperature conducted from the liquid-solid heat exchange section 12 to the gas-solid heat exchange section 11 in the circumferential direction. At the same time, based on the characteristic that the gas working medium in the gas-solid heat exchange section 11 flows axially along the gas-solid heat exchange section 11, the gas working medium can absorb more cooling capacity to the maximum extent. For example, the liquid outlet 122 can be located upstream of the gas working medium in the flow direction, and the liquid inlet 121 can be located downstream of the gas working medium in the flow direction, so that the gas working medium continuously absorbs more cooling capacity and achieves better heat exchange effect.

[0051] In one feasible embodiment, a first confluence channel 123 can be provided within the liquid-solid heat exchange section 12. The first confluence channel 123 is arranged circumferentially within the liquid-solid heat exchange section 12, with the liquid inlet 121 communicating with the first confluence channel 123, and all liquid cooling channels 13 communicating with the first confluence channel 123. By providing the first confluence channel 123, it is more convenient to simultaneously introduce coolant into all liquid cooling channels 13 through the liquid inlet 121, further improving the circumferential temperature uniformity of the gas-solid heat exchange section 11.

[0052] For example, since the liquid inlet 121 is located on one side of the liquid-solid heat exchange section 12, the first confluence channel 123 is correspondingly located on one side of the liquid-solid heat exchange section 12, and can be located on the outer periphery of the gas-solid heat exchange section 11, so that it can play a diversion role while also playing a cooling role for the gas-solid heat exchange section 11.

[0053] In other feasible embodiments, a second manifold 124 may be provided within the liquid-solid heat exchange section 12. The second manifold 124 is circumferentially arranged within the liquid-solid heat exchange section 12, with the liquid outlet 122 communicating with it. All liquid cooling channels 13 are also connected to the second manifold 124. By providing the second manifold 124, it is easier to discharge the coolant from all liquid cooling channels 13 through the liquid outlet 122, and it is also easier to configure the liquid outlet 122 and connect it to the liquid cooling channels 13.

[0054] For example, since the liquid outlet 122 is located on the other side of the liquid-solid heat exchange section 12, the second confluence channel 124 is correspondingly located on the other side of the liquid-solid heat exchange section 12, and can be located on the outer periphery of the gas-solid heat exchange section 11, so that it can play a confluence role while also playing a cooling role for the gas-solid heat exchange section 11.

[0055] In some embodiments, the gas-solid heat exchange section 11 includes a cylindrical main heat exchange section 11a and a cylindrical secondary heat exchange section 11b, with all liquid cooling channels 13 arranged circumferentially at intervals along the main heat exchange section 11a and the secondary heat exchange section 11b. A reflux channel 111 is formed within the main heat exchange section 11a, and the main heat exchange section 11a has a gas outlet. One end of the reflux channel 111 is connected to the gas outlet, and the secondary heat exchange section 11b is disposed at the other end of the reflux channel 111. The secondary heat exchange section 11b is coaxially arranged, and the diameter of the secondary heat exchange section 11b is smaller than the diameter of the main heat exchange section 11a.

[0056] In a pulse tube refrigerator, the gaseous working fluid in the gas-solid heat exchange section 11 needs to flow back and forth through an internal circulation path, thus passing through the gas-solid heat exchange section 11 twice. To facilitate different flow directions of the gaseous working fluid, the gas-solid heat exchange section 11 is divided into two parts: a main heat exchange section 11a and a secondary heat exchange section 11b. Furthermore, since the secondary heat exchange section 11b can transfer less cooling capacity, its diameter is set to be smaller than that of the main heat exchange section 11a.

[0057] In one feasible manner, each liquid cooling channel 13 may include interconnected axial segments 131 and radial segments 132. The axial segments 131 of all liquid cooling channels 13 are arranged circumferentially along the main heat exchange section 11a and extend axially along the main heat exchange section 11a. The radial segments 132 of all liquid cooling channels 13 are arranged circumferentially along the secondary heat exchange section 11b and extend radially along the secondary heat exchange section 11b.

[0058] This configuration allows for targeted cooling of the main heat exchange section 11a and the secondary heat exchange section 11b. While uniformly cooling the main heat exchange section 11a, it also brings the liquid cooling channel 13 closer to the secondary heat exchange section 11b, further enhancing its cooling effect. Simultaneously, the radially extending radial section 132 further cools the main heat exchange section 11a from its end.

[0059] In one possible implementation, each radial segment 132 includes a first radial segment 132a and a second radial segment 132b. The first radial segment 132a extends along an axis close to the secondary heat exchange section 11b, and the second radial segment 132b extends along an axis away from the secondary heat exchange section 11b. Each first radial segment 132a and its corresponding second radial segment 132b are connected via a connecting hole 133. This arrangement further increases the length of the liquid cooling channel 13 and facilitates communication between the radial segments 132 and the liquid outlet 122. For example, the connecting hole 133 may be located away from the main heat exchange section 11a to maximize the distance the coolant can flow within the radial segment 132.

[0060] In some embodiments, the gas-solid heat exchange section 11 includes a plurality of heat exchange fins arranged radially along the circumference of the gas-solid heat exchange section 11, and a gas channel is formed between two adjacent heat exchange fins. When the gas-solid heat exchange section 11 includes a main heat exchange section 11a and a secondary heat exchange section 11b, both the main heat exchange section 11a and the secondary heat exchange section 11b may adopt the above-described arrangement of heat exchange fins.

[0061] The heat exchange fins extend radially along the gas-solid heat exchange section 11, enabling the absorption of cooling energy from the liquid-solid heat exchange section 12 to be distributed over a large radial range along the gas-solid heat exchange section 11. All heat exchange fins are arranged at intervals along the circumference of the gas-solid heat exchange section 11, thereby cooperating with the circumferentially arranged liquid cooling pipes within the liquid-solid heat exchange section 12 to further ensure the circumferential uniformity of the temperature absorbed by the gas-solid heat exchange section 11.

[0062] In one feasible approach, all heat exchange fins can be evenly distributed along the circumference of the gas-solid heat exchange section 11. This facilitates the uniform flow of the gas working fluid, improves the heat exchange effect between the gas working fluid and the gas-solid heat exchange section 11, and allows the gas working fluid to receive uniform cooling along the circumference of the gas-solid heat exchange section 11.

[0063] Furthermore, this embodiment also provides a calculation method for the structural specifications of the liquid-cooled pipes. The number of liquid-cooled pipes within the liquid-solid heat exchange section 12 is closely related to the overall structural strength and manufacturing difficulty of the heat exchange section. Too many pipes increase the manufacturing cost, and once the number of pipes reaches a certain level, further increases do not significantly improve the heat exchange effect. Conversely, too few pipes result in excessively large spans between pipes, affecting both structural strength and the uniformity of cooling. Based on data obtained from multiple experiments, the number of liquid-cooled pipes can be set to 20-40; this embodiment uses 25 pipes.

[0064] For the design of liquid cooling pipe length, refer to the following calculation method:

[0065] The first step is to calculate the Reynolds number to determine the flow state of the coolant in the pipe:

[0066]

[0067] Where v is the coolant velocity, ρ is the coolant density, μ is the coolant dynamic viscosity coefficient, and d is the characteristic length. In the calculation, the total coolant flow rate needs to be divided by the number of liquid-cooled pipes to calculate the liquid flow pattern in each channel.

[0068] After calculating the Reynolds number, the flow regime of the coolant can be determined based on its magnitude. Specifically, Re < 2300 indicates laminar flow, while Re > 4000 indicates turbulent flow. Since the flow velocity of coolant in a conventional heat exchanger is generally greater than 10 m / s, its Reynolds number is much greater than 10000. Therefore, it can be directly assumed that the flow regime of coolant under normal conditions is turbulent.

[0069] The second step is to calculate the Prandtl number:

[0070]

[0071] Where v is the momentum diffusion coefficient of the fluid at the definite temperature, and a is the thermal diffusion coefficient of the fluid at the definite temperature.

[0072] The third step is to calculate the Nusselt number based on the Reynolds number and the Prandtl number:

[0073] For turbulent conditions, the Ditus-Belt correlation can be used for calculation:

[0074] Nu = 0.023 × Re 0.8 ×Pr n

[0075] in, Re is the Reynolds number, and Pr is the Prandtl number.

[0076] In the case of turbulence forming in the pipe:

[0077] For the straight pipe section, Re≥10 4 ,0.7≤Pr≤160.

[0078] When some parts of the pipe are bends, the bends change the direction of fluid flow, and the centrifugal force will generate secondary circulation in the fluid, increasing disturbance and enhancing convective heat transfer. Therefore, the following correction factor is required.

[0079] The first part, the correction factor for liquid in bent pipes, is:

[0080]

[0081] Where R is the pipe bending radius and d is the characteristic length.

[0082] The second part, the correction factor for the liquid in the short tube (considering the inlet effect), is:

[0083]

[0084] Combining the correction factors from Part 1 and Part 2, the Nusselt number for the case of a bent pipe can be obtained using the following formula:

[0085] Nu=c R c l ×0.023×Re 0.8 ×Pr n

[0086] By calculating the Nusselt number, the heat transfer system within the liquid-solid heat exchange section, including the pipes and the connection between the orifices and the structure, can be determined.

[0087] The third step, after obtaining the Nusselt number, is to calculate the heat transfer coefficient accordingly:

[0088]

[0089] Where Nu is the Nusselt number, λ is the thermal conductivity of the coolant at the characteristic temperature, and d is the total length of the pipes and holes located in the liquid-solid heat exchange section.

[0090] Then, the heat transfer can be calculated using Newton's law of cooling, or other values ​​can be calculated given that the heat transfer is known:

[0091] Q = h × A × ΔT

[0092] Where A is the sum of the surface areas of all pipes and holes located in the liquid-solid heat exchange section, h is the heat transfer coefficient, and ΔT is the average temperature difference between the fluid and the structural solid.

[0093] Using the above calculation method, given the heat exchange and the temperature difference between the structure and the coolant, the corresponding liquid cooling pipes can be designed. Furthermore, under the premise of uniform body temperature, the structure and dimensions of the liquid cooling pipes can be obtained, further increasing the accuracy and reliability of the structural design.

[0094] Example 2

[0095] like Figure 7 As shown, this embodiment provides a pulse tube refrigerator, which includes the heat exchanger 1 described in Embodiment 1.

[0096] The gas-solid heat exchange section 11 of the heat exchanger 1 further includes a main heat exchange section 11a and a secondary heat exchange section 11b, the main heat exchange section 11a and the secondary heat exchange section 11b are coaxially arranged, and the secondary heat exchange section 11b is located at one end of the main heat exchange section 11a.

[0097] The refrigerator includes a cold accumulator 2, a cold-end heat exchange section 3, a pulse tube 4, and an inertial tube 5. The cold accumulator 2 is located at the other end of the main heat exchange section 11a, and the end of the cold accumulator 2 furthest from the main heat exchange section 11a is connected to the cold-end heat exchange section 3, allowing the gaseous working fluid in the main heat exchange section 11a to exchange heat with its solid component, thus removing the heat transferred from the cold-end heat exchanger 3 via the cold accumulator 2. The pulse tube 4 is located within the main heat exchange section 11a, and its two ends are connected to the cold-end heat exchange section 3 and the secondary heat exchange section 11b, respectively, to impede heat transfer between the cold-end heat exchanger 3 and the secondary heat exchange section 11b, thereby reducing heat loss. The inertial tube 5 is connected to the pulse tube 4 through the secondary heat exchange section 11b, and serves to adjust the phase of the pressure wave and mass flow inside the refrigerator.

[0098] The heat exchanger 1 of the pulse tube refrigerator provided in this embodiment provides multiple liquid cooling channels 13 inside the liquid-solid heat exchange section 12, and arranges all the liquid cooling channels 13 at intervals along the circumference of the gas-solid heat exchange section 11 on the outer periphery of the gas-solid heat exchange section 11. This ensures that all the liquid cooling channels 13 are at the same distance from the gas-solid heat exchange section 11, so that the liquid can conduct the cooling amount to each position of the gas-solid heat exchange section 11 in the circumference evenly, thus ensuring the temperature uniformity of the gas-solid heat exchange section 11 itself, and further ensuring the cooling performance of the refrigerator.

[0099] The other technical features of the refrigeration unit in this embodiment are the same as those in the above embodiments, and can bring the same or similar technical effects, which will not be repeated here. For details, please refer to the description of the above embodiment one.

[0100] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0101] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A heat exchanger for a pulse tube refrigerator, characterized by, The gas-solid heat exchange part (11) is a cylindrical structure, and the liquid-solid heat exchange part (12) is arranged at the outer periphery of the gas-solid heat exchange part (11); The liquid-solid heat exchange part (12) is internally provided with a plurality of liquid cooling channels (13) containing cooling liquid, all the liquid cooling channels (13) are arranged in a circumferential direction of the gas-solid heat exchange part (11) and at least part of each liquid cooling channel (13) extends in an axial direction of the gas-solid heat exchange part (11); The gas-solid heat exchange part (11) comprises a cylindrical main heat exchange subpart (11a) and a cylindrical secondary heat exchange subpart (11b), the secondary heat exchange subpart (11b) is coaxially arranged with the main heat exchange subpart (11a), and the liquid cooling channels (13) are arranged in a circumferential direction of the secondary heat exchange subpart (11b) and the main heat exchange subpart (11a). The main heat exchange subpart (11a) is provided with a gas outlet, a reflux channel (111) is formed in the main heat exchange subpart (11a), one end of the reflux channel (111) is communicated with the gas outlet, and the secondary heat exchange subpart (11b) is arranged at the other end of the reflux channel (111). The diameter of the secondary heat exchange subpart (11b) is smaller than that of the main heat exchange subpart (11a).

2. A pulse tube refrigerator heat exchanger according to claim 1, characterized by, Each liquid cooling channel (13) comprises an axial segment (131) and a radial segment (132) which are communicated with each other. The axial segments (131) of all the liquid cooling channels (13) are arranged in a circumferential direction of the main heat exchange subpart (11a) and extend in an axial direction of the main heat exchange subpart (11a), and the radial segments (132) of all the liquid cooling channels (13) are arranged in a circumferential direction of the secondary heat exchange subpart (11b) and extend in a radial direction of the secondary heat exchange subpart (11b).

3. A pulse tube refrigerator heat exchanger according to claim 2, wherein The radial segment (132) comprises a first radial subsegment (132a) and a second radial subsegment (132b), the first radial subsegment (132a) and the second radial subsegment (132b) are communicated through a communication hole (133), cooling liquid flows into the first radial subsegment (132a) through the axial segment (131), the cooling liquid in the first radial subsegment (132a) flows towards the axis of the secondary heat exchange subpart (11b), and the cooling liquid in the second radial subsegment (132b) flows away from the axis of the secondary heat exchange subpart (11b).

4. A pulse tube refrigerator heat exchanger according to any one of claims 1 to 3, characterized in that, The liquid-solid heat exchange part (12) is provided with an inlet (121) and an outlet (122), the inlet (121) and the outlet (122) are arranged at two sides of the liquid-solid heat exchange part (12) in an axial direction of the liquid-solid heat exchange part (12), and two ends of the liquid cooling channel (13) are communicated with the inlet (121) and the outlet (122) respectively.

5. A pulse tube refrigerator heat exchanger according to claim 4, wherein The liquid-solid heat exchange part (12) is further provided with a first flow collecting channel (123), the first flow collecting channel (123) is annularly arranged in the liquid-solid heat exchange part (12) along the circumference of the liquid-solid heat exchange part (12), the liquid inlet (121) is communicated with the first flow collecting channel (123), and all the liquid cooling channels (13) are communicated with the first flow collecting channel (123).

6. The heat exchanger of a pulse tube refrigerator according to claim 4, wherein The liquid-solid heat exchange part (12) is further provided with a second flow collecting channel (124), the second flow collecting channel (124) is annularly arranged in the liquid-solid heat exchange part (12) along the circumference of the liquid-solid heat exchange part (12), the liquid outlet (122) is communicated with the second flow collecting channel (124), and all the liquid cooling channels (13) are communicated with the second flow collecting channel (124).

7. A pulse tube refrigerator heat exchanger according to any one of claims 1 to 3, wherein The gas-solid heat exchange part (11) comprises a plurality of heat exchange fins, all the heat exchange fins are radially arranged along the circumference of the gas-solid heat exchange part (11), and a gas channel is formed between two adjacent heat exchange fins.

8. A pulse tube refrigerator heat exchanger according to any one of claims 1 to 3, wherein All the liquid cooling channels (13) are uniformly distributed along the circumference of the gas-solid heat exchange part (11).

9. A pulse tube refrigerator heat exchanger according to any one of claims 1 to 3, wherein The gas-solid heat exchange part (11) and the liquid-solid heat exchange part (12) are integrally formed.

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