A novel pulse tube device for high-capacity high-frequency pulse tube refrigerators

Abstract

This invention relates to a novel pulse tube device for a high-capacity, high-frequency pulse tube refrigerator, comprising a pulse tube outer shell and an inner pulse tube. The inner pulse tube is concentrically arranged on the central axis inside the pulse tube and is the same length as the pulse tube. An annular airflow channel is formed between the inner pulse tube and the inner wall of the outer shell. The inner pulse tube is made of thin-walled stainless steel with low thermal conductivity, forming a circular channel. The annular airflow channel and the inner circular channel of the inner pulse tube are connected in parallel to form the pulse tube flow channel. The inner wall surfaces of the outer shell and the inner and outer walls of the inner pulse tube meet low roughness requirements. Compared with the prior art, this invention can effectively suppress laminar instability and improve the flow state under high-capacity, high-frequency operation conditions; significantly reduce heat and cold mixing losses, and improve refrigeration efficiency.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment technology, and in particular to a novel pulse tube device for a high-capacity high-frequency pulse tube refrigerator. Background Technology

[0002] As an important branch of cryogenic technology, pulse tube refrigerators have significant advantages in cryogenic fields such as aerospace, deep space exploration, and infrared detection due to their lack of moving parts at the cold end, simple structure, low cold head vibration, and extremely high reliability. With the gradual expansion of cryogenic applications, pulse tube refrigerators are currently developing towards higher operating frequencies (greater than 70Hz) and larger cooling capacities (hundred-watt level).

[0003] The pulse tube, as a core component, primarily functions to achieve phase control of pressure and flow rate through alternating gas flow within the tube, transmitting acoustic power without mechanical motion, and isolating the hot and cold ends to reduce cold-end vibration. However, the losses within the pulse tube are mainly divided into heat transfer losses and flow losses. Under high-frequency operating conditions, the gas inside the pulse tube will generate non-ideal flows, such as secondary flows and turbulence, leading to uneven temperature distribution in the middle of the pulse tube and resulting in severe heat-cold mixing losses. Especially for high-capacity high-frequency pulse tube refrigerators, the larger diameter means a longer characteristic length, and to achieve high cooling capacity, the gas is driven by high frequency, generating a larger pressure ratio, increasing the axial velocity gradient, and further increasing the Reynolds number. These losses significantly weaken the overall cooling performance of the unit.

[0004] CN201710043451.7 discloses a hollow-structure pulse tube refrigerator, including a compressor, a cold head, and a phase adjuster unit. The cold head includes a hot-end heat exchanger, a regenerator, a cold-capacity heat exchanger, and a pulse tube. The pulse tube and the regenerator are coaxially arranged inside and outside the cold head. A hollow structure is provided inside the pulse tube, forming an annular channel for gas flow between the hollow structure and the outer wall of the pulse tube. The annular channel is separated from and does not communicate with the hollow structure. However, its versatility is limited. For high-frequency operating conditions, when applied to low-frequency pulse tube refrigerators, efficiency may be reduced due to unnecessary increases in flow resistance. Furthermore, this solution is limited to a single configuration where the pulse tube and the regenerator are coaxially arranged. Compared with the above-mentioned prior art, this invention innovatively improves the internal structure of the pulse tube and the overall layout of the machine. The pulse tube also has an airflow channel inside, breaking through the bottleneck of limited versatility of the original equipment. This invention can not only effectively avoid the efficiency degradation caused by additional flow resistance under low-frequency operating conditions, but also achieve high-efficiency operation over a wider frequency band. Meanwhile, this invention breaks the constraints of existing technologies that are limited to coaxial configurations. In specific implementations, it provides two different overall structure schemes: linear and coaxial, which can more flexibly adapt to various complex and diverse spatial layouts and engineering application needs.

[0005] Currently, conventional optimization methods to improve airflow distribution within pulse tubes mainly focus on placing several layers of wire mesh or porous media at both ends of the pulse tube (i.e., the junction of the cold and hot ends) as end rectifiers. However, end rectifiers can only improve the initial distribution of airflow when it first enters the pulse tube, but they are difficult to effectively control the large-scale secondary flow generated by the gas during long-distance alternating flow in the middle section of the pulse tube. In addition, increasing the number of wire mesh layers or reducing the porosity to pursue better rectification will significantly increase the flow resistance of the system, resulting in additional pressure drop losses. Therefore, there is an urgent need for a novel structure that can directly optimize the flow field distribution in the middle section of the pulse tube without significantly increasing flow resistance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art by providing a novel pulse tube device for high-capacity high-frequency pulse tube refrigerators, which effectively suppresses laminar instability and improves flow conditions; significantly reduces heat and cold mixing losses and improves refrigeration efficiency; minimizes additional heat conduction losses; and has a simple structure that is easy to integrate.

[0007] The objective of this invention can be achieved through the following technical solutions: This invention provides a novel pulse tube device for a high-capacity, high-frequency pulse tube refrigerator, comprising a pulse tube outer shell and a pulse tube inner tube. The pulse tube inner tube is concentrically arranged on the central axis inside the pulse tube outer shell and is the same length as the pulse tube outer shell. An annular airflow channel is formed between the pulse tube inner tube and the inner wall of the pulse tube outer shell. The pulse tube inner tube is made of stainless steel with low thermal conductivity.

[0008] Furthermore, when the inner diameter of the pulse tube shell is greater than 30mm, the inner tube of the pulse tube is a hollow, thin-walled circular tube structure, forming two parallel airflow channels inside the pulse tube: an inner circular channel and an outer annular channel. Large-diameter tubes are prone to generating asymmetric, large-scale secondary flow. The inner tube of the pulse tube divides the flow channel into two parallel airflow channels: an inner circular channel and an outer annular channel. This design reduces the equivalent diameter, constraining the airflow with wall viscous resistance, and greatly limiting the radial velocity gradient and large-scale gas mixing. The wall thickness of the inner tube of the pulse tube... .

[0009] Furthermore, the outer diameter of the pulse tube's internal tube... d With the inner diameter of the pulse tube D diameter ratio α Satisfy the formula α = d / D Furthermore, the range of the diameter ratio parameter is limited to 0.3 ≤ α ≤ 0.5. This ensures sufficient flow area to reduce flow resistance while minimizing the mixing of hot and cold gases in the center.

[0010] Furthermore, the two ends of the pulse tube are respectively embedded and fixed in the positioning structures reserved in the cold end heat exchanger and the hot end heat exchanger.

[0011] Furthermore, the positioning structure is a concentric positioning groove or an end face protrusion.

[0012] Furthermore, the stainless steel has a low thermal conductivity.

[0013] Furthermore, the pulse tube is a hollow stainless steel round tube.

[0014] Furthermore, the two ends of the pulse tube's internal tube are machined with chamfers or narrow edges.

[0015] Furthermore, the roughness range of the inner wall surface of the pulse tube housing and the inner wall surface of the pulse tube housing with the outer wall surface is defined as follows: To reduce viscous dissipation, wall laminar fluidization instability is implemented to mitigate shuttle heat loss and reduce distortion of the airflow phase distribution.

[0016] Compared with the prior art, the present invention has the following advantages: (1) Effectively suppressing laminar instability and improving flow state: By adding an internal tube inside the pulse tube shell, the flow channel structure of the traditional single hollow circular tube is changed, and the equivalent diameter of the airflow channel is reduced. This makes the airflow subject to stronger wall viscous resistance in high-frequency alternating flow, thereby significantly limiting the generation of radial velocity gradient and large-scale secondary flow, making the gas flow state inside the pulse tube more uniform, and effectively suppressing the laminar instability phenomenon that is prone to occur under high cooling capacity and high frequency conditions. At the same time, the ratio of the outer diameter (d) of the internal tube to the inner diameter (D) of the pulse tube (α= d / D) is optimized in the range of 0.3≤α≤0.5. This design ensures sufficient flow area to reduce flow resistance while maximally suppressing the mixing of hot and cold gases in the central region, achieving a good balance between flow resistance and rectification effect.

[0017] (2) Significantly reduce cold and hot mixing losses and improve refrigeration efficiency: The improved flow state directly reduces the mixing losses between cold and hot air masses caused by airflow mixing and turbulence. More uniform and stable laminar flow improves the lossless transmission efficiency of acoustic power (the synergistic effect of pressure wave and mass flow) in the pulse tube, thereby improving the performance of the entire refrigeration unit.

[0018] (3) Minimize additional heat conduction loss: The inner tube of the pulse tube is made of stainless steel with low thermal conductivity. This key material selection ensures that while optimizing the internal flow field, no significant additional axial heat conduction leakage is introduced between the cold and hot ends of the pulse tube due to the addition of internal components, thereby preserving the core insulation performance of the refrigerator.

[0019] (4) Minimize viscous dissipation: The roughness range of the inner wall surface of the pulse tube housing 6 and the inner wall surface and outer wall surface of the pulse tube housing 7 is limited to the following: The inner wall of the pulse tube shell and the inner and outer walls of the pulse tube's internal tube are smooth, meeting the low roughness requirements. This reduces viscous dissipation, prevents rough peaks from inducing micro-eddies, weakens shuttle heat loss, reduces distortion of the airflow phase distribution, and effectively solves the problem of laminarization instability.

[0020] (5) Simple structure and easy integration: The pulse tube is a concentric structure installed inside the pulse tube shell. Its two ends can be fixed by embedding the positioning grooves or end face protrusions reserved in the hot end heat exchanger and cold end heat exchanger. This installation method does not require complex modification of the main structure of the refrigeration unit and is easy to implement and integrate. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the novel pulse tube device used in a high-capacity, high-frequency linear pulse tube refrigerator, as shown in Example 1. Figure 2 This is a schematic diagram of the novel pulse tube device structure for a high-capacity, high-frequency coaxial pulse tube refrigerator, as shown in Example 2. Figure 3 This is a cross-sectional view of the pulse tube's outer casing and internal tubes. Reference numerals in the attached figures: 1-Linear compressor; 2-Connecting pipe; 3-Stage aftercooler; 4-Circular regenerator; 5-Cold end heat exchanger; 6-Pulse tube outer shell; 7-Pulse tube inner tube; 8-Hot end heat exchanger; 9-Inertial tube; 10-Gas storage; 11-Annular regenerator; 12-New type of pulse tube device. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0023] Example 1 This embodiment provides a novel pulse tube device for a high-capacity, high-frequency linear pulse tube refrigerator, such as... Figure 1 As shown, it includes a pulse tube outer shell 6 and a pulse tube inner tube 7. The pulse tube inner tube 7 is concentrically arranged on the central axis inside the pulse tube outer shell 6 and is the same length as the pulse tube outer shell 6. An annular airflow channel is formed between the pulse tube inner tube 7 and the inner wall of the pulse tube outer shell 6. The pulse tube inner tube 7 is made of stainless steel with low thermal conductivity.

[0024] like Figure 3As shown, the pulse tube housing 6 and the pulse tube internal tube 7 together constitute the novel pulse tube device 12.

[0025] In this embodiment, the high-capacity high-frequency pulse tube refrigerator is a linear pulse tube refrigerator, including: a linear compressor 1, a connecting pipe 2, a stage aftercooler 3, a circular regenerator 4, a cold end heat exchanger 5, a pulse tube outer shell 6, a pulse tube inner tube 7, a hot end heat exchanger 8, an inertial tube, and an air reservoir 10.

[0026] In a specific embodiment, when the inner diameter of the pulse tube outer shell 6 is greater than 30 mm, the pulse tube inner tube 7 is a hollow thin-walled circular tube structure, forming two parallel airflow channels—an inner circular channel and an outer annular channel—within the novel pulse tube device 12. Large-diameter tubes easily generate asymmetric, large-scale secondary flows. The hollow circular tube divides the flow channel into two parallel airflow channels: an inner circular channel and an outer annular channel. This design reduces the equivalent diameter, constraining the airflow with wall viscous resistance, and greatly limiting the radial velocity gradient and large-scale gas mixing. The wall thickness of the pulse tube inner tube 7... The dual-channel design increases the peripheral length of fluid wetting, according to the formula... This effectively reduces the equivalent diameter of the fluid, thereby improving the stability of the flow and eliminating heat dissipation caused by gravity convection.

[0027] In a specific embodiment, the outer diameter of the pulse tube built into the tube 7 d With the inner diameter of the pulse tube housing 6 D diameter ratio α Satisfy the formula α = d / D Furthermore, the range of the diameter ratio parameter is limited to 0.3 ≤ α ≤ 0.5. This ensures sufficient flow area to reduce flow resistance while minimizing the mixing of hot and cold gases in the center.

[0028] In a specific embodiment, the two ends of the pulse tube built-in tube 7 are respectively embedded and fixed in the positioning structure reserved in the cold end heat exchanger 5 and the hot end heat exchanger 8.

[0029] In a specific implementation, the positioning structure is a concentric positioning groove or an end face protrusion.

[0030] In a specific embodiment, the stainless steel has a low thermal conductivity.

[0031] In a specific embodiment, the pulse tube housing 6 is a hollow stainless steel round tube.

[0032] In a specific embodiment, the two ends of the pulse tube 7 are chamfered or have narrow edges.

[0033] In a specific embodiment, the roughness range of the inner wall surface of the pulse tube housing 6 and the inner wall surface and outer wall surface of the pulse tube housing 7 is defined as follows: To reduce viscous dissipation, wall laminar instability, and shuttle heat loss, thereby minimizing distortion of the airflow phase distribution, the inner and outer walls of the pulse tube and its inner tube must be smooth to meet low roughness requirements. This reduces viscous dissipation, prevents rough peaks from inducing micro-vortices, weakens shuttle heat loss, minimizes distortion of the airflow phase distribution, and effectively solves the laminar instability problem.

[0034] Adding an axial laminar fluidization device can suppress laminar fluidization instability in large-capacity, high-frequency, and large-size pulse tubes by changing the flow channel shape, thereby improving the efficiency of large-capacity high-frequency pulse tubes and thus improving the overall efficiency. The appropriate internal tube for the pulse tube can be selected according to the diameter of the pulse tube.

[0035] The linear compressor 1 generates alternating pressure waves, driving the refrigerant through the connecting pipe 2 into the aftercooler 3. As the refrigerant flows through the aftercooler 3, it releases its heat of compression, lowering its temperature to ambient temperature. The cooled refrigerant then enters the circular regenerator 4. Flowing from left to right through the regenerator 4, the refrigerant exchanges heat with the cold storage packing material, absorbing the heat and gradually decreasing its temperature along the axial gradient to a low-temperature state. The low-temperature refrigerant then enters the cold-end heat exchanger 5, where it expands and absorbs heat from the external heat load, thus outputting cooling capacity. Subsequently, the low-temperature gas exiting the cold-end heat exchanger 5 enters the novel pulse tube device 12. The refrigerant entering the novel pulse tube device 12 is guided and flows towards the hot end through the circular airflow channel of the internal pulse tube 7 and the annular airflow channel formed by the pulse tube outer shell 6 and the internal pulse tube 7, finally entering the hot-end heat exchanger 8. The outer shell 6 of the pulse tube is not completely insulated. The internal tube 7 of the pulse tube suppresses laminar fluidization instability of the gas inside the tube and improves the efficiency of sound power transfer to the hot end. The working fluid is transferred to the hot-end heat exchanger 8 through the outer shell 6 of the pulse tube and the internal tube 7 to discharge waste heat, and then enters the phase adjustment mechanism composed of the inertial tube 9 and the gas storage 10. Through the resistance and inertial effect adjustment of the inertial tube 9, the pressure wave and mass flow phase at the cold-end heat exchanger 5 are optimally matched, improving the refrigeration efficiency. During the negative half-cycle of the pressure wave, the working fluid flows back from the gas storage 10 in reverse, passing through the inertial tube 9, the outer shell 6 of the pulse tube, and the internal tube 7 of the pulse tube (new pulse tube device 12), the cold-end heat exchanger 5, and finally passing through the circular regenerator 4 in reverse to absorb heat and return to the linear compressor 1, completing a complete thermodynamic cycle.

[0036] Example 2 This embodiment provides a novel pulse tube device for a high-capacity, high-frequency coaxial pulse tube refrigerator, such as... Figure 2As shown, it includes a pulse tube outer shell 6 and a pulse tube inner tube 7. The pulse tube inner tube 7 is concentrically arranged on the central axis inside the pulse tube outer shell 6 and is the same length as the pulse tube outer shell 6. An annular airflow channel is formed between the pulse tube inner tube 7 and the inner wall of the pulse tube outer shell 6. The pulse tube inner tube 7 is made of thin-walled stainless steel with low thermal conductivity.

[0037] like Figure 3 As shown, the pulse tube housing 6 and the pulse tube internal tube 7 together constitute the novel pulse tube device 12.

[0038] In this embodiment, the high-capacity high-frequency pulse tube refrigerator is a coaxial pulse tube refrigerator, including: a linear compressor 1, a connecting pipe 2, a stage aftercooler 3, a cold end heat exchanger 5, a pulse tube outer shell 6, a pulse tube inner tube 7, a hot end heat exchanger 8, an inertial tube 9, a gas storage 10, and an annular regenerator 11.

[0039] In a specific embodiment, when the inner diameter of the pulse tube outer shell 6 is greater than 30 mm, the pulse tube inner tube 7 is a hollow thin-walled circular tube structure, forming two parallel airflow channels—an inner circular channel and an outer annular channel—within the novel pulse tube device 12. Large-diameter tubes easily generate asymmetric, large-scale secondary flows. The hollow circular tube divides the flow channel into two parallel airflow channels: an inner circular channel and an outer annular channel. This design reduces the equivalent diameter, constraining the airflow with wall viscous resistance, and greatly limiting the radial velocity gradient and large-scale gas mixing. The wall thickness of the pulse tube inner tube 7... The dual-channel design increases the peripheral length of fluid wetting, according to the formula... This effectively reduces the equivalent diameter of the fluid, thereby improving the stability of the flow and eliminating heat dissipation caused by gravity convection.

[0040] In a specific embodiment, the outer diameter of the pulse tube built into the tube 7 d With the inner diameter of the pulse tube housing 6 D diameter ratio α Satisfy the formula α = d / D Furthermore, the range of the diameter ratio parameter is limited to 0.3 ≤ α ≤ 0.5. This ensures sufficient flow area to reduce flow resistance while minimizing the mixing of hot and cold gases in the center.

[0041] In a specific embodiment, the two ends of the pulse tube built-in tube 7 are respectively embedded and fixed in the positioning structure reserved in the aftercooler 3 and the cold end heat exchanger 5.

[0042] In a specific implementation, the positioning structure is a concentric positioning groove or an end face protrusion.

[0043] In a specific embodiment, the stainless steel has a low thermal conductivity.

[0044] In a specific embodiment, the pulse tube housing 6 is a hollow stainless steel round tube.

[0045] In a specific embodiment, the two ends of the pulse tube 7 are chamfered or have narrow edges.

[0046] In a specific embodiment, the roughness range of the inner wall of the pulse tube housing 6 and the inner wall surface of the pulse tube housing 7, and the outer wall surface, is defined as follows: To reduce viscous dissipation, wall laminar instability, and shuttle heat loss, thereby minimizing distortion of the airflow phase distribution, the inner and outer walls of the pulse tube and its inner tube must be smooth to meet low roughness requirements. This reduces viscous dissipation, prevents rough peaks from inducing micro-vortices, weakens shuttle heat loss, minimizes distortion of the airflow phase distribution, and effectively solves the laminar instability problem.

[0047] Adding an axial laminar fluidization device can suppress laminar fluidization instability in large-capacity, high-frequency, and large-size pulse tubes by changing the flow channel shape, thereby improving the efficiency of large-capacity high-frequency pulse tubes and thus improving the overall efficiency. The appropriate internal tube for the pulse tube can be selected according to the diameter of the pulse tube.

[0048] The linear compressor 1 generates alternating pressure waves, driving the refrigerant through the connecting pipe 2 into the aftercooler 3. As the refrigerant flows through the aftercooler 3, it releases its heat of compression, lowering its temperature to ambient temperature. The cooled refrigerant then enters the annular regenerator 11. Flowing from left to right through the annular regenerator 11, the refrigerant exchanges heat with the cold storage packing material, absorbing the heat and gradually decreasing its temperature along the axial gradient to a low-temperature state. The low-temperature refrigerant then enters the cold-end heat exchanger 5, where it expands and absorbs heat from the external heat load, thus outputting cooling capacity. Subsequently, the low-temperature gas exiting the cold-end heat exchanger 5 undergoes a 180° deflection and enters the pulse tube 12. The refrigerant entering the pulse tube 12 flows towards the hot end through the circular airflow channel of the internal pulse tube 7 and the annular airflow channel formed by the pulse tube outer shell 6 and the internal pulse tube 7, finally entering the aftercooler 3. The pulse tube outer shell 6 is not completely insulated. The internal pulse tube 7 suppresses laminar fluidization instability of the gas inside the tube, improving the efficiency of sound power transfer to the hot end. The working fluid is transferred to the aftercooler 3 via the pulse tube outer shell 6 and the internal pulse tube 7 to discharge waste heat, and then enters the phase adjustment mechanism composed of the inertial tube 9 and the gas storage 10. Through the resistance and inertial effect adjustment of the inertial tube 9, the pressure wave and mass flow phase at the cold end heat exchanger 5 are optimally matched, improving refrigeration efficiency. During the negative half-cycle of the pressure wave, the working fluid flows back in reverse from the gas storage 10, passing sequentially through the inertial tube 9, the pulse tube outer shell 6, and the internal pulse tube 7 (new pulse tube device 12), and the cold end heat exchanger 5. Finally, it flows back 180° in reverse through the annular regenerator 11 to absorb heat and return to the linear compressor 1, completing a complete thermodynamic cycle.

[0049] This invention is an improvement on a conventional pulse tube refrigeration device. The main difference between this invention and the conventional pulse tube system is the addition of a pulse tube internal tube 7. The low-temperature gas from the cold end heat exchanger 5 enters the pulse tube 12 through a 180° deflection, and enters the aftercooler 3 through the circular airflow channel of the internal pulse tube 7 and the annular airflow channel formed by the pulse tube shell 6 and the internal pulse tube 7. During operation, the pulse tube shell 6 is a hollow stainless steel circular tube and is not completely insulated.

[0050] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0051] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A novel pulse tube device for a high-capacity, high-frequency pulse tube refrigerator, characterized in that, The device includes a pulse tube housing (6) and a pulse tube inner tube (7). The pulse tube inner tube (7) is concentrically arranged on the central axis inside the pulse tube housing (6) and is the same length as the pulse tube housing (6). An annular airflow channel is formed between the pulse tube inner tube (7) and the inner wall of the pulse tube housing (6). The pulse tube inner tube (7) is a circular channel made of thin-walled stainless steel with low thermal conductivity. The inner wall surface of the pulse tube housing (6) and the inner and outer wall surfaces of the pulse tube inner tube (7) meet the low roughness requirements.

2. A novel pulse tube device for a high-capacity high-frequency pulse tube refrigerator according to claim 1, characterized in that, When the inner diameter of the pulse tube shell (6) is greater than 30 mm, the pulse tube inner tube (7) is a hollow thin-walled circular tube structure, so that two parallel airflow channels, an inner circle and an outer ring, are formed inside the pulse tube shell (6).

3. A novel pulse tube device for a high-capacity, high-frequency pulse tube refrigerator according to claim 1, characterized in that, The outer diameter of the pulse tube built-in tube (7) d With the inner diameter of the pulse tube housing (6) D diameter ratio α Satisfy the formula α = d / D Furthermore, the range of the diameter ratio parameter is limited to 0.3 ≤ α ≤ 0.

5.

4. A novel pulse tube device for a high-capacity high-frequency pulse tube refrigerator according to claim 1, characterized in that, The two ends of the pulse tube (7) are respectively embedded and fixed in the positioning structure reserved in the cold end heat exchanger (5) and the hot end heat exchanger (8).

5. A novel pulse tube device for a high-capacity high-frequency pulse tube refrigerator according to claim 5, characterized in that, The positioning structure is a concentric positioning groove or an end face protrusion.

6. A novel pulse tube device for a high-capacity high-frequency pulse tube refrigerator according to claim 1, characterized in that, The stainless steel with low thermal conductivity.

7. A novel pulse tube device for a high-capacity high-frequency pulse tube refrigerator according to claim 1, characterized in that, The outer shell (6) of the pulse tube is a hollow stainless steel round tube.

8. A novel pulse tube device for a high-capacity high-frequency pulse tube refrigerator according to claim 1, characterized in that, The two ends of the pulse tube (7) are chamfered or have narrow edges.

9. A novel pulse tube device for a high-capacity high-frequency pulse tube refrigerator according to claim 1, characterized in that, The roughness range of the inner wall surface of the pulse tube housing (6) and the inner and outer wall surfaces of the pulse tube housing (7) is defined as follows: .

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