CN103062951B - Low-temperature J-T (Joule-Thomson) throttling cooler precooled by Stirling/pulse tube composite type cooler - Google Patents

Abstract

The invention discloses a low-temperature JT throttling refrigerator for precooling of a Stirling/pulse tube composite refrigerator, which includes a precooling unit and a refrigeration unit, and the refrigeration unit includes a JT compressor and a first-stage regenerative heat exchanger , the second-stage regenerative heat exchanger, the pre-throttle heat exchanger, the throttle valve and the evaporator; JT throttling refrigeration cycle working medium helium is pre-cooled by multi-stage precooling refrigerant of Stirling/pulse tube composite refrigerator before entering the high-temperature side pipeline of the heat exchanger before throttling. The refrigerating performance of the JT throttling refrigeration cycle precooled by the Stirling/pulse tube composite refrigerator of the present invention is also higher than that of the existing JT throttling refrigeration cycle precooled by a single regenerative refrigerator, and the reliability is higher High, longer life, and has the advantages of compact structure.

Description

Low temperature J-T throttling refrigerator precooled by Stirling/pulse tube composite refrigerator

technical field

The invention relates to a refrigeration system, in particular to a low-temperature J-T throttling refrigerator precooled by a Stirling/pulse tube composite refrigerator.

Background technique

With the advancement of science and technology, cryogenic refrigeration technology has developed rapidly in the past half a century, and has extensive and irreplaceable applications in aerospace, national defense, superconductivity, medical treatment, energy, and cryogenic physics. At present, there are mainly liquid helium (or superfluid helium) Dewar technology and mechanical refrigeration technology for the refrigeration of space liquid helium temperature zone. Among them, the liquid helium Dewar refrigeration technology uses the evaporation and heat absorption of liquid helium or superfluid helium stored in a high-vacuum multi-layer adiabatic storage tank to achieve the cooling effect. This method can obtain a relatively stable temperature. In the field of early aerospace exploration It has a wide range of applications, and the technology is relatively mature, but it has the disadvantages of large size, heavy weight, complex insulation system, high launch cost, and limited service life by the amount of working fluid stored. With the progress and development of mechanical refrigeration technology, especially the application of leaf spring and gap seal technology, the long life problem that Dewar technology has never been able to overcome has been completely solved, making mechanical refrigeration technology such as Stirling refrigerator and pulse Tube refrigerators have developed rapidly in the aerospace field in the past 20 years and have occupied a considerable share. However, in the temperature range below 15K, helium seriously deviates from the ideal gas properties, and the volume specific heat capacity of the regenerative material drops sharply. As a result, Stirling refrigerators and Stirling-type pulse tube refrigerators that have been widely used in space are cooled in the liquid helium temperature range. less efficient. In actual space applications, it is often desired that the compressor unit be as close as possible to the heat dissipation unit for heat dissipation, and as far away from the cooled detector device as possible to reduce heat dissipation, mechanical vibration and electromagnetic interference caused by the compressor. However, the distance between the cold end and the hot end of the regenerative cryogenic refrigerator is relatively close, and it is difficult to realize the requirement of separating the compressor and the cold end, thus limiting its application in space missions.

Joule-Thomson cooler (Joule-Thomson Cooler, hereinafter referred to as J-T throttling refrigerator) uses the Joule-Thomson throttling effect caused by the significant non-ideal characteristics of helium when the temperature is lower than 15K to obtain refrigeration. Higher efficiency. Moreover, the J-T throttling refrigerator has a series of advantages brought about by the direct flow of the working fluid and the free design of the cold end according to the required cooling structure, making the J-T throttling refrigerator the mainstream of the space liquid helium temperature zone.

The mechanical refrigeration technology in the space liquid helium temperature zone is mainly concentrated in Japan Aerospace Exploration Agency (JAXA), NASA (National Aeronautics and Space Administration, NASA) and European Space Agency (European Space Agency, ESA). Table 1 shows the low-temperature space projects using mechanical refrigeration technology in the liquid helium temperature zone among the space probes that these institutions have launched or are about to launch in recent years.

Table 1 Low-temperature space missions using liquid helium temperature zone mechanical refrigeration technology

It can be seen from Table 1 that most of the mechanical refrigerators used in the liquid helium temperature zone of the above-mentioned research institutions in recent years are pre-cooling type J-T throttling refrigerators, and mainly adopt regenerative refrigeration For example, the J-T throttling refrigeration cycle in the liquid helium temperature zone in the SMILES, Asrto-H and SPICA projects uses a two-stage Stirling refrigerator for pre-cooling. In the bidding process of the ACTDP project, a four-stage refrigerator was used There are three different precooling methods of high-frequency pulse tube refrigerator, three-stage Stirling refrigerator and three-stage high-frequency pulse tube refrigerator.

Traditional refrigeration methods all have the technical problem of low cooling efficiency. At present, there is no report on the J-T throttling refrigeration system in the liquid helium temperature zone precooled by using a two-stage or above-stage Stirling/pulse tube composite refrigerator.

Contents of the invention

The invention provides a low-temperature J-T throttling refrigerator precooled by a Stirling/pulse tube composite refrigerator. The refrigeration system has high refrigeration performance and has the advantages of compact structure, long service life and high reliability.

A low-temperature J-T throttling refrigerator precooled by a Stirling/pulse tube composite refrigerator, comprising a precooling unit and a refrigeration unit, characterized in that the refrigeration unit includes a J-T compressor, a first-stage heat exchanger Heater, first-stage pre-cooling heat exchanger, second-stage regenerative heat exchanger, second-stage pre-cooling heat exchanger, pre-throttle heat exchanger, throttle valve and evaporator, according to the refrigerant flow direction, The outlet of the J-T compressor passes through the first-stage regenerative heat exchanger, the first-stage pre-cooling heat exchanger, the second-stage regenerative heat exchanger, the second-stage pre-cooling heat exchanger and the heat exchanger before throttling The high-temperature side pipeline of the evaporator and the throttle valve are connected with the evaporator inlet, and the evaporator outlet passes through the low-temperature side of the pre-throttle heat exchanger, the second-stage regenerative heat exchanger, and the first-stage regenerative heat exchanger in sequence. The pipeline is connected with the inlet of the J-T compressor; the precooling unit is a Stirling/pulse tube composite refrigerator mechanism of two or more stages, which are respectively used for the first stage precooling heat exchanger and the second stage precooling The refrigerant in the cold heat exchanger is pre-cooled.

The Stirling/Pulse Tube Composite Refrigerator uses the Stirling Refrigerator and the Pulse Tube Refrigerator because of the active control part-displacer in the Stirling unit, which can adjust the cold end pressure ratio of the refrigerator. The composite structure of the pulse tube refrigerator can realize the large pressure ratio and the small charging pressure required by the low temperature section of the pulse tube refrigerator. The refrigeration performance is higher than that of a single multi-stage Stirling refrigerator or a single multi-stage pulse tube refrigerator, and it is reliable Higher reliability, longer life, and both advantages of compact structure. Therefore, the refrigeration performance of the J-T throttling refrigeration cycle in the liquid helium temperature zone precooled by the Stirling/pulse tube composite refrigerator will also be better than that of the existing J-T throttling in the liquid helium temperature zone precooled by a single regenerative refrigerator Refrigeration cycles are better, but have other advantages as well.

Below is the further preferred technical scheme to above-mentioned technical scheme:

For the convenience of layout, as a preferred technical solution: the pre-cooling unit can choose a two-stage Stirling/pulse tube composite refrigerator mechanism, including a pre-cooler compressor, a hot end exchanger connected to the outlet of the pre-cooler compressor in sequence Heater, first stage Stirling cylinder, first stage cold end heat exchanger, second stage regenerator, second stage cold end heat exchanger, second stage pulse tube, second stage pulse tube hot end exchanger The heat exchanger and the second-stage phase adjustment component; the first-stage cold-end heat exchanger precools the refrigerant in the first-stage pre-cooling heat exchanger through the first-stage heat bridge; the second-stage cold-end The heat exchanger precools the refrigerant in the second-stage precooling heat exchanger through the second-stage heat bridge.

Various structures can be selected for the phase modulation component. In order to improve the overall refrigeration performance of the refrigeration system, as a preference, the second-stage phase modulation component is a second-stage inertial tube connected to the second-stage pulse tube hot-end heat exchanger. , and the second-level gas storage connected with the second-level inertia tube. As a further preference, the second-stage phase modulation component is connected to the first-stage thermal bridge at the same time. The phase adjustment of the pressure flow and mass flow in the second-stage regenerator can be realized through the phase adjustment component.

The pre-cooling unit can also choose a three-stage Stirling/pulse tube composite refrigerator mechanism. At this time, as a further optimization of the above-mentioned solution, the pre-cooling unit also includes the outlet of the second-stage cold end heat exchanger at the same time. The connected third-stage regenerator, and the third-stage cold-end heat exchanger, the third-stage pulse tube, the third-stage pulse tube hot-end heat exchanger and The third-stage phase adjustment component; the refrigeration unit also includes a third-stage counter-flow heat exchanger and a third-stage pre-cooling heat exchanger, and the outlet of the second-stage pre-cooling heat exchanger passes through the third-stage counter-flow heat exchanger in turn. The high-temperature side pipeline of the heat exchanger and the third-stage pre-cooling heat exchanger are connected with the high-temperature side pipeline inlet of the pre-throttling heat exchanger, and the low-temperature side pipeline outlet of the pre-throttling heat exchanger passes through the third-stage counter-flow exchanger. The low-temperature side pipeline of the heat exchanger communicates with the low-temperature side pipeline inlet of the second-stage regenerative heat exchanger; the third-stage cold-end heat exchanger connects the third-stage precooling heat exchanger The refrigerant inside is pre-cooled.

Both the second-stage phase-modulating component and the third-stage phase-modulating component are inertial tubes connected to the heat exchanger at the hot end of the corresponding pulse tube, and an air bank connected to the inertial tube. As a further preference, the second-stage phase modulation component is connected to the first-stage thermal bridge at the same time; the third-stage phase-modulation component is also connected to the second-stage thermal bridge.

When the pre-cooling unit uses a three-stage Stirling/pulse tube composite refrigerator mechanism, another preferred technical solution is: the pre-cooling unit is a three-stage Stirling/pulse tube composite refrigerator mechanism, including pre-cooling compressor, the hot end heat exchanger connected with the outlet of the pre-cooler compressor, the first-stage Stirling cylinder, the first-stage cold-end heat exchanger, the second-stage Stirling cylinder, and the second-stage cold end A heat exchanger, a third-stage regenerator, a third-stage cold-end heat exchanger, a third-stage pulse tube, a third-stage pulse tube hot-end heat exchanger, and a third-stage phase adjustment component; the refrigeration unit also includes The third-stage counter-flow heat exchanger and the third-stage pre-cooling heat exchanger, the outlet of the second-stage pre-cooling heat exchanger passes through the high-temperature side pipeline of the third-stage counter-flow heat exchanger and the third-stage pre-cooling heat exchanger The heat exchanger communicates with the inlet of the high-temperature side pipeline of the heat exchanger before throttling, and the outlet of the low-temperature side pipeline of the heat exchanger before throttling passes through the low-temperature side pipeline of the third-stage counterflow heat exchanger and the second-stage regenerative heat exchanger. The low-temperature side pipeline inlet of the heat exchanger is connected; the first-stage cold-end heat exchanger precools the refrigerant in the first-stage pre-cooling heat exchanger through the first-stage heat bridge; the second-stage cooling The end heat exchanger pre-cools the refrigerant in the second-stage pre-cooling heat exchanger through the second-stage heat bridge; the third-stage cold-end heat exchanger exchanges the third-stage pre-cooling The refrigerant in the heater is pre-cooled. .

The third-stage phase adjustment component is a third-stage inertial tube connected to the third-stage pulse tube hot-end heat exchanger, and a third-stage gas storage connected to the third-stage inertial tube. Likewise, preferably, the third-stage phase-modulating component is connected to the second-stage thermal bridge at the same time.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

The J-T throttling refrigeration system in the liquid helium temperature zone precooled by the Stirling/pulse tube composite refrigerator of the present invention can realize the large pressure ratio and small inflation pressure required by the low temperature section of the pulse tube refrigerator, and can increase the multi-stage The refrigeration performance and reliability of the regenerative refrigerator, the refrigeration performance of the J-T throttling refrigeration cycle pre-cooled by the Stirling/pulse tube composite refrigerator will also be better than that of the existing single regenerative refrigerator. The J-T throttling refrigeration cycle is high, and the reliability is high, the life is longer, and it has the advantages of compact structure and so on.

Description of drawings

Figure 1 is a schematic diagram of a low-temperature J-T throttling refrigerator precooled by a two-stage Stirling/pulse tube composite refrigerator.

Fig. 2 is a schematic diagram of a low-temperature J-T throttling refrigerator precooled by a one-stage Stirling two-stage pulse tube compound refrigerator.

Fig. 3 is a schematic diagram of a low-temperature J-T throttling refrigerator precooled by a two-stage Stirling one-stage pulse-tube composite refrigerator.

Among them: 1: precooler compressor, 2: ejector driving motor, 3: expansion unit, 4: single stage ejector, 5: hot end heat exchanger, 6: first stage Stirling cylinder, 7: second stage First-stage cold end heat exchanger, 8: first-stage thermal bridge, 9: second-stage regenerator, 10: second-stage cold-end heat exchanger, 11: second-stage thermal bridge, 12: second-stage pulse Tube, 13: second-stage pulse tube hot end heat exchanger, 14: second-stage inertia tube, 15: second-stage gas storage, 16: J-T compressor, 17: first-stage regenerative heat exchanger, 18 : First-stage pre-cooling heat exchanger, 19: Second-stage regenerative heat exchanger, 20: Second-stage pre-cooling heat exchanger, 21: Pre-throttle heat exchanger, 22: Throttle valve, 23: Evaporator, 24: third stage regenerator, 25: third stage cold end heat exchanger, 26: third stage heat bridge, 27: third stage pulse tube, 28: third stage pulse tube hot end heat exchange 29: The third-stage inertia tube, 30: The third-stage gas storage, 31: The third-stage counter-flow heat exchanger: 32: The third-stage pre-cooling heat exchanger, 33: The two-stage ejector, 34: The first Two-stage Stirling cylinder.

Detailed ways

Example 1

As shown in Figure 1, a low-temperature J-T throttling refrigerator precooled by a Stirling/pulse tube composite refrigerator includes a precooling unit and a refrigeration unit. The refrigeration unit includes a J-T compressor 16, a first-stage recuperative heat exchanger 17, a first-stage pre-cooling heat exchanger 18, a second-stage recuperative heat exchanger 19, and a second-stage pre-cooling heat exchanger 20 , Heat exchanger 21 before throttling, throttle valve 22 and evaporator 23. The pre-cooling unit is a two-stage Stirling/pulse tube composite refrigerator mechanism, including a pre-cooler compressor 1, a hot-end heat exchanger 5 sequentially connected to the outlet of the pre-cooler compressor 1, and a first-stage Stirling cylinder 6. The first-stage cold-end heat exchanger 7, the second-stage regenerator 9, the second-stage cold-end heat exchanger 10, the second-stage pulse tube 12, the second-stage pulse tube hot-end heat exchanger 13, the second-stage heat exchanger Second-stage inertia tube 14 and second-stage gas storage 15; the pre-cooling unit also includes a single-stage ejector 4 placed in the body of the Stirling refrigerator, an ejector drive motor 2 for driving the operation of the single-stage ejector 4, and an expansion unit 3.

The connection relationship of the above components is:

In the refrigeration unit: the outlet of the J-T compressor 16 is sequentially connected with the high-temperature side pipeline of the first-stage regenerative heat exchanger 17, the first-stage pre-cooling heat exchanger 18, and the second-stage regenerative heat exchanger through pipelines. The high-temperature side pipeline of 19, the high-temperature side pipeline of the second-stage pre-cooling heat exchanger 20 and the heat exchanger 21 before throttling, the throttle valve 22 and the inlet of the evaporator 23 are connected, and the outlet of the evaporator 23 is connected with the The low-temperature side pipeline of the pre-throttle heat exchanger 21, the low-temperature side pipeline of the second-stage regenerative heat exchanger 19, the low-temperature side pipeline of the first-stage regenerative heat exchanger 17, and the inlet of the J-T compressor 16 connected.

In the pre-cooling unit: the outlet of the pre-cooler compressor 1 is respectively connected to the expansion unit 3 and the hot-end heat exchanger through pipelines, the ejector drive motor 2 is arranged in the expansion unit 3 and connected to the single-stage ejector 4, and the heat The end heat exchanger 5 is sequentially connected with the first-stage Stirling cylinder 6, the first-stage cold-end heat exchanger 7, the second-stage regenerator 9, the second-stage cold-end heat exchanger 10, and the second-stage The pulse tube 12 , the heat exchanger 13 at the hot end of the second-stage pulse tube, the second-stage inertia tube 14 and the second-stage gas storage 15 are in communication. The single-stage ejector 4 passes through the heat exchanger 5 at the hot end, is arranged in the first-stage Stirling cylinder 6, and ensures a gap seal with the wall surface of the first-stage Stirling cylinder 6, and the first-stage regenerative filler is filled in Single ejector 4 in.

The first-stage cold-end heat exchanger 7 precools the refrigerant in the first-stage pre-cooling heat exchanger 18 through the first-stage heat bridge 8; the second-stage cold-end heat exchanger 10 passes through the second-stage heat bridge 11 The refrigerant in the second-stage precooling heat exchanger 20 is precooled.

The operation process of working fluid in the present embodiment is:

For the refrigeration unit, the operation process of the refrigerant is as follows: the refrigerant is compressed by the J-T compressor 16 to high pressure and discharged, and then flows through the high-temperature side pipeline of the first-stage regenerative heat exchanger 17, the first-stage pre-cooling heat exchange 18, the high-temperature side pipeline of the second-stage regenerative heat exchanger 19, the high-temperature side pipeline of the second-stage precooling heat exchanger 20 and the third-stage regenerative heat exchanger 21, enter the throttle valve 22 After reaching the low pressure and reaching the temperature of liquid helium, it enters the evaporator 23, and evaporates the low-pressure gas working fluid after exchanging heat with the outside world through the evaporator 23, and then flows through the low-temperature side of the third-stage regenerative heat exchanger 21 in turn The pipeline, the low-temperature side pipeline of the second-stage regenerative heat exchanger 19 and the low-temperature side pipeline of the first-stage recuperator heat exchanger 17 finally return to the J-T compressor 16 in the liquid helium temperature zone. There is only heat transfer between the composite refrigerator and the J-T throttling refrigeration cycle in the liquid helium temperature zone, and the first-stage cold-end heat exchanger 7 and the second-stage cold-end heat exchanger 10 respectively pass through the first-stage heat bridge 8 and the second The secondary thermal bridge 11 provides pre-cooling for the refrigerant in the first-stage pre-cooling heat exchanger 18 and the second-stage pre-cooling heat exchanger 19 .

For a two-stage Stirling/pulse tube composite refrigerator, its operation process is:

In the high-pressure stage, the high-temperature and high-pressure pre-cooling working fluid compressed by the pre-cooler compressor 1 is cooled to normal temperature and high pressure in the hot-end heat exchanger 5, and then enters the ejector 4 located in the first-stage Stirling cylinder 6 , by controlling the ejector driving motor 2 connected to the bottom of the ejector 4 in the expansion unit 3, the stroke control of the ejector 4 is realized, and at the same time, this part of the pre-cooling working fluid exchanges heat with the regenerated filler in the ejector 4, And part of it expands at the cold end of the cylinder 6 of the first-stage Stirling refrigerator, thereby generating a refrigeration effect, and the cooling capacity is used for precooling the first stage by the first-stage cold-end heat exchanger 7 through the first-stage thermal bridge 8 Precool the refrigerant in the heat exchanger 18.

The other part of the pre-cooling working fluid enters the second-stage regenerator 9 from the first-stage cold-end heat exchanger 7, and exchanges heat with the regenerative filler filled therein. Secondary cold-end heat exchanger 10, second-stage pulse pipe 12, second-stage pulse pipe hot-end heat exchanger 13, second-stage inertia tube 14 and second-stage gas storage 15, then the system pressure is reduced, and this part pre- The cold working fluid sequentially passes through the second-stage gas storage 15, the second-stage inertial tube 14, the second-stage pulse tube hot-end heat exchanger 13, the second-stage pulse tube 12, the second-stage cold-end heat exchanger 10, the second-stage The first-stage regenerator 9 and the first-stage cold-end hot-end heat exchanger 7 return to the first-stage Stirling cylinder 6. Due to the temperature difference between the pre-cooled working fluid entering and leaving the second-stage cold-end heat exchanger 10, the resulting Refrigeration effect, the cooling capacity is used by the second-stage cold-end heat exchanger 10 to pre-cool the refrigerant in the second-stage pre-cooling heat exchanger 20 through the second-stage heat bridge 11 .

In this embodiment, after the system is installed, vacuumize the interior of the refrigeration unit and the pre-cooling unit to about 10 ^-2 Pa, then fill in high-purity helium, keep it for about 5 minutes, and then vacuumize the interior of the system to 10 ^-2 Pa about. After repeated vacuuming and inflation for 3-4 times, the high-purity helium at the working pressure is finally charged to ensure the purity of the helium working medium in the system, and the same operation is performed on the composite refrigerator. Turn on the power supply of the compressor 1 of the pre-cooler and the power supply of the single-stage ejector 4, adjust the operating frequency of the two to the best pre-cooling performance and wait for them to stabilize, and ensure that the temperature of the second-stage cold-end heat exchanger 10 is lower than 15K , turn on the power of the JT compressor 16, adjust to the corresponding operating frequency, and continuously adjust the frequency of the pre-cooler compressor 1 and the single-stage ejector 4 during the temperature drop of the evaporator, so as to ensure the temperature stability of the secondary cold-end heat exchanger 10 Below 15K, until the temperature of the evaporator 23 stabilizes at the liquid helium temperature, then the refrigerating capacity of the liquid helium temperature can be obtained at the evaporator 23 .

The technical scheme of this embodiment 1 was simulated and optimized with the traditional two-stage Stirling or two-stage pulse tube refrigerator precooled J-T throttling refrigeration cycle, and the results were compared as follows:

Table 2 Simulation calculation results of J-T throttling refrigeration in liquid helium temperature zone with two-stage precooling

The hypothetical conditions of the J-T throttling refrigeration cycle are: the suction pressure of the J-T throttling refrigeration cycle compressor is 0.121MPa, the first stage pre-cooling temperature is 90K, the efficiency of the regenerative heat exchanger and the efficiency of the heat exchanger before throttling are both 0.97, The J-T high pressure interval in the table is the interval where the maximum COP is calculated.

For the overall performance of the J-T throttling refrigerator in the liquid helium temperature zone, the lower the pre-cooling temperature, the lower the high-temperature side pressure required to achieve the highest efficiency (and also the maximum cooling capacity), which affects the performance, life, and manufacturing cost of the entire machine. All aspects are beneficial. At present, the performance achieved by the two-stage Stirling refrigerator and the two-stage high-frequency pulse tube refrigerator is: the minimum refrigeration temperature is 11-13K (no refrigeration capacity at this time), and for the situation in the published literature, the two Grade Stirling generally precools the J-T cycle in the temperature range of 15K ~ 18K. The two-stage Stirling/pulse tube composite refrigerator can obtain 0.28W at 10K, and at the same time obtain 6.63W cooling capacity at 55K. Combined with the above table 2, it can be seen that the precooling of the composite refrigerator can greatly Improve the overall performance of the J-T throttling refrigerator.

In addition, the structure of the two-stage Stirling refrigerator is complicated. Although it has achieved a long life by overcoming related technical problems, it is still very short compared with the single-stage Stirling refrigerator. The Stirling/pulse-tube composite structure just overcomes this shortcoming, and then enables the J-T throttling refrigeration unit to simultaneously meet the space mission requirements of high efficiency and long life.

Example 2

A low-temperature J-T throttling refrigerator for precooling by a Stirling/pulse tube composite refrigerator. In this embodiment, the precooling unit adopts a three-stage Stirling/pulse tube composite refrigeration mechanism. The difference from Embodiment 1 is that : The pre-cooling unit also includes a third-stage regenerator 24 communicated with the outlet of the second-stage cold-end heat exchanger 10 at the same time, and a third-stage cold-end exchanger communicated with the outlet of the third-stage regenerator 24 sequentially through pipelines Heater 25 , third-stage pulse tube 27 , third-stage pulse tube hot-end heat exchanger 28 , third-stage inertia tube 29 and third-stage gas storage 30 . The refrigeration unit also includes a third-stage counter-flow heat exchanger 31 and a third-stage pre-cooling heat exchanger 32, and the outlet of the second-stage pre-cooling heat exchanger 20 passes through the high-temperature side pipeline of the third-stage counter-flow heat exchanger 31 in turn The third-stage precooling heat exchanger 32 communicates with the high-temperature side pipeline inlet of the pre-throttling heat exchanger 21, and the low-temperature side pipeline outlet of the pre-throttling heat exchanger 21 passes through the third-stage counterflow heat exchanger 31. The low-temperature side pipeline communicates with the low-temperature side pipeline inlet of the second-stage regenerative heat exchanger 19; The refrigerant is pre-cooled.

Example 3

A low-temperature J-T throttling refrigerator precooled by a Stirling/pulse tube composite refrigerator, the precooling unit is a three-stage Stirling/pulse tube composite refrigerator mechanism, including a precooler compressor 1, and an ejector drive Motor 2, expansion unit 3, two-stage ejector 33, and hot-end heat exchanger 5, first-stage Stirling cylinder 6, first-stage cold-end heat exchanger 7, The second-stage Stirling cylinder 34, the second-stage cold-end heat exchanger 10, the third-stage regenerator 24, the third-stage cold-end heat exchanger 25, the third-stage pulse tube 27, and the third-stage pulse tube heat exchanger End heat exchanger 28, third-stage inertia tube 29 and third-stage gas storage 30. The ejector driving motor 2 is arranged in the expansion unit 3 and is connected to the two-stage ejector 33. The two-stage ejector passes through the hot end heat exchanger 5 and the first stage cold end heat exchanger 7, and is arranged in the first stage Stirling Cylinder 6 and the second stage Stirling cylinder 34, and guarantee gap seal with both wall surfaces. The first-stage and second-stage regenerative fillers are filled in the two-stage ejector 33 .

The difference between the refrigeration unit and Embodiment 1 is that it also includes a third-stage counter-flow heat exchanger 31 and a third-stage pre-cooling heat exchanger 32, and the outlet of the second-stage pre-cooling heat exchanger 20 passes through the third-stage counter-flow heat exchanger in turn. The high-temperature side pipeline of 31 and the third-stage pre-cooling heat exchanger 32 communicate with the high-temperature side pipeline inlet of the pre-throttle heat exchanger 21, and the low-temperature side pipeline outlet of the pre-throttle heat exchanger 21 passes through the third-stage reverse flow The low-temperature side pipeline of the type heat exchanger 31 communicates with the low-temperature side pipeline inlet of the second-stage regenerative heat exchanger 19; The refrigerant in the cold heat exchanger 32 is pre-cooled.

Claims (1)

1. a kind of low temperature J-T throttling refrigerator of Stirling/pulse tube compound refrigerator precooling, comprise precooling unit and refrigeration unit, it is characterized in that, described refrigeration unit comprises J-T compressor (16), first Stage regenerative heat exchanger (17), first stage precooling heat exchanger (18), second stage regenerative heat exchanger (19), second stage precooling heat exchanger (20), throttling The front heat exchanger (21), the throttle valve (22) and the evaporator (23), according to the flow direction of the refrigerant, the outlet of the J-T compressor (16) passes through the first stage regenerative heat exchanger (17), the second stage The high-temperature side pipelines of the primary pre-cooling heat exchanger (18), the second-stage regenerative heat exchanger (19), the second-stage pre-cooling heat exchanger (20) and the pre-throttle heat exchanger (21) And the throttling valve (22) communicates with the inlet of the evaporator (23), and the outlet of the evaporator (23) passes through the pre-throttle heat exchanger (21), the second-stage regenerative heat exchanger (19) and the first-stage The low-temperature side pipeline of the regenerative heat exchanger (17) is communicated with the inlet of the J-T compressor (16); The pre-cooling unit is a two-stage Stirling/pulse tube composite refrigerator mechanism, including a pre-cooler compressor (1), and a hot-end heat exchanger (5) sequentially connected to the outlet of the pre-cooler compressor (1) , the first-stage Stirling cylinder (6), the first-stage cold-end heat exchanger (7), the second-stage regenerator (9), the second-stage cold-end heat exchanger (10), the second-stage pulse Tube (12), second-stage pulse tube hot-end heat exchanger (13) and second-stage phase modulation component; The first stage cold end heat exchanger (7) precools the refrigerant in the first stage precooling heat exchanger (18) through the first stage thermal bridge (8); The second-stage cold end heat exchanger (10) precools the refrigerant in the second-stage precooling heat exchanger (20) through the second-stage heat bridge (11); The pre-cooling unit also includes a third-stage regenerator (24) communicated with the outlet of the second-stage cold-end heat exchanger (10) at the same time, and communicated with the outlet of the third-stage regenerator (24) sequentially through pipelines The third stage cold end heat exchanger (25), the third stage pulse tube (27), the third stage pulse tube hot end heat exchanger (28) and the third stage phase adjustment component; The refrigeration unit also includes a third-stage counter-flow heat exchanger (31) and a third-stage pre-cooling heat exchanger (32), and the outlet of the second-stage pre-cooling heat exchanger (20) passes through the third-stage counter-flow The high-temperature side pipeline of the type heat exchanger (31) and the third-stage precooling heat exchanger (32) are connected with the high-temperature side pipeline inlet of the pre-throttle heat exchanger (21), and the pre-throttle heat exchanger (21 ) of the low temperature side pipeline outlet communicates with the low temperature side pipeline inlet of the second stage regenerative heat exchanger (19) through the low temperature side pipeline of the third stage counterflow heat exchanger (31); The third stage cold end heat exchanger (25) precools the refrigerant in the third stage precooling heat exchanger (32) through the third stage heat bridge (26); Both the second-stage phasing component and the third-stage phasing component are inertial tubes connected to the heat exchanger at the hot end of the corresponding pulse tube, and an air bank connected to the inertial tube; The second-stage phase-modulating component is connected to the first-stage thermal bridge (8) at the same time; the third-stage phase-modulating component is simultaneously connected to the second-stage thermal bridge (11).