CN104197591B - Use helium as the deep hypothermia regenerator of backheat medium and vascular refrigerator thereof - Google Patents

Abstract

The invention discloses a deep low temperature regenerator adopting helium as the heat recovery medium, which comprises a tube shell and a heat recovery filler placed in the tube shell, and the heat recovery filler is a sealed seal filled with helium heat exchange structure. The invention also discloses a pulse tube refrigerator adopting the above-mentioned deep-low temperature regenerator. The invention utilizes the characteristic of high volume specific heat capacity of helium gas at low temperature, and seals it in a certain space as a heat recovery medium to exchange heat with helium gas as a refrigerant; it can be selected according to the working pressure of the pulse tube refrigerator. Fill the closed space with helium gas of appropriate pressure to realize that the volumetric specific heat capacity of helium gas as the heat recovery medium in the deep low temperature zone is higher than that of helium gas as the refrigerant working medium, realize efficient heat recovery, and finally improve the efficiency of liquid helium. Performance of temperature-zone pulse tube refrigerators. At the same time, compared with the magnetic regenerating material, the cryogenic regenerator using helium as the regenerating medium of the present invention has the advantages of low price, easy availability, and no influence of magnetic field.

Description

Deep low temperature regenerator using helium as heat recovery medium and its pulse tube refrigerator

technical field

The invention relates to a regenerative low-temperature refrigerator, in particular to a deep-low temperature regenerator using helium gas as a regenerating medium and a pulse tube refrigerator thereof.

Background technique

The liquid helium temperature zone plays an indispensable and important role in the fields of national defense, military, energy, medical, aerospace, low temperature physics and so on. Since the Dutch physicist Kamerlingh.Onnes first realized the liquefaction of helium in 1908, the liquid helium temperature zone (4K) has been the focus and difficulty of the research in the field of cryogenic engineering. At the same time, especially since the 1980s, human beings have higher technical and performance requirements for cryogenic refrigeration technology, and more and more stringent requirements have been put forward for the efficiency, reliability, volume, weight, and vibration of cryogenic refrigerators. Require.

The pulse tube refrigerator was proposed by Gifford and Longsworth in 1964. It has no moving parts at the cold end and has the potential advantages of high reliability and long life. After nearly half a century of development, the pulse tube refrigerator has been widely used in Aerospace, low-temperature superconductivity and other fields. According to different driving sources, pulse tube refrigerators are mainly divided into G-M pulse tube refrigerators (also called low-frequency pulse tube refrigerators) and Stirling pulse tube refrigerators (also called high-frequency pulse tube refrigerators); G-M pulse tube refrigerators are composed of The G-M refrigerator is driven by the compressor, and its operating frequency is generally 1 to 2 Hz. The Stirling pulse tube refrigerator is driven by a linear compressor, and its operating frequency is generally 30 Hz.

At present, the lowest temperature that can be obtained by G-M pulse tube refrigerator is 1.3K, and the commercial application of liquid helium and above temperature zone has been realized, but its efficiency in the liquid helium temperature zone is very low (1W cooling capacity at 4.2K needs input 6-10kW electric power); compared with the G-M pulse tube refrigerator, the Stirling pulse tube refrigerator has a series of advantages such as compact structure, high efficiency, and light weight, and its technology in the temperature range of 35K and above is relatively mature. At present, it has been widely used in aerospace missions in the above temperature range, but the efficiency of the Stirling pulse tube refrigerator at deep low temperature (<10K) is still extremely low, one of the main reasons is that the volume specific heat capacity of helium increases sharply in the temperature range below 15K However, the specific heat capacity of commonly used regenerative fillers (such as lead shot, stainless steel, etc.) decreases significantly. Although magnetic regenerative fillers (ErNi, etc.) have a higher peak volume specific heat capacity, the peak only exists in the phase transition temperature region. , resulting in a sharp decrease in the efficiency of the deep low temperature regenerator (as shown in Figure 4), which in turn leads to the extremely low efficiency of the Stirling pulse tube refrigerator in the liquid helium temperature region, so it is necessary to look for a high specific heat capacity at a deep low temperature (<10K). The regenerative packing is a key to solve the inefficiency of current pulse tube refrigerators in the liquid helium temperature zone. The patent document with the application number CN200910100286.X discloses a high-frequency regenerator using stainless steel fiber regenerating material and its refrigerator. The high-frequency regenerator using stainless steel fiber regenerating material is filled with wire diameter The high-frequency regenerator is composed of stainless steel fibers of 2mm-15mm. The working frequency in the 300-80K temperature zone is 150HZ-1000HZ, and the working frequency in the 80K-35K temperature zone is 100HZ-1000HZ. This new type of high-frequency regenerator can be applied not only to single-stage pulse tube refrigerators in the 80K temperature zone, but also to multi-stage thermally coupled or gas-coupled pulse tube refrigerators in the 35K temperature zone. The stainless steel fiber has a smaller wire diameter than the traditional stainless steel wire mesh, which can form a smaller fluid channel, which can make the regenerator work in the 300K-80K temperature range, 150-1000HZ high-frequency working condition, or at 80K-35K temperature Zone, 100-1000HZ high-frequency working conditions, work efficiently. But as mentioned above, at deep low temperature (<10K), the specific heat capacity of the heat recovery material will drop significantly, which greatly affects the refrigeration efficiency of the heat recovery device and the pulse tube refrigerator.

Contents of the invention

The invention provides a deep-low temperature regenerator using helium as the heat-regenerating medium. By adopting the heat-regenerating packing of the sealed heat exchange structure filled with helium, the temperature of the regenerating material at deep low temperature (<10K) is significantly improved. ) under the specific heat capacity, which improves the cooling efficiency of the regenerator and the pulse tube refrigerator.

The present invention also provides another pulse tube refrigerator adopting the above-mentioned deep-low temperature regenerator, which can efficiently reach the working temperature range of 10K or lower.

A deep low temperature regenerator using helium as the heat recovery medium, comprising a tube shell with a hot end flow hole and a cold end flow hole, and a regenerative filler placed in the tube shell, the regenerative filler It has a gas flow channel connecting the flow hole of the hot end with the flow hole of the cold end, and the heat recovery filler is a sealed heat exchange structure filled with helium.

The sealed heat exchange structure can be selected from a variety of structures. For ease of installation and processing, preferably, the sealed heat exchange structure includes:

Several sets of heat exchange tubes for filling helium;

A plurality of first fixing parts for sealing and fixing one end of each group of heat exchange tubes, and a plurality of second fixing parts for sealing and fixing the other end of each group of heat exchange tubes;

The first fixing part and the second fixing part are provided with connecting passages connecting the heat exchange tubes in the corresponding set of heat exchange tubes with each other. By providing connecting channels on the first fixing part and the second fixing part, it is ensured that each heat exchanger in a group of heat exchange tubes forms a whole. The connecting channel can adopt a groove structure, and can also adopt a pipe structure. For example, the first fixing piece and the second fixing piece can adopt a tubular structure with a cavity. At this time, notches corresponding to the heat exchange tubes are processed on the tubular structure, and the heat exchange tubes are fixed by welding or other fixing methods. The end side wall is sealed and fixed to the hole wall of the notch.

Preferably, each group of heat exchange tubes is arranged in a ring, several groups of ring-shaped heat exchange tubes are arranged concentrically, and the gas flow passage is left between adjacent groups of heat exchange tubes. When the technical scheme is adopted, the heat exchange in the regenerator is guaranteed to be uniform, and the heat exchange efficiency is improved.

Preferably, the sealed heat exchange structure further includes: at least one connecting arm connecting all the first fixing parts or all the second fixing parts to each other, and at least one connecting arm is provided with an air-filled tube connecting all the connecting channels All heat exchange tubes are inflated through the inflation pipeline. The connecting arm realizes the fixing of a plurality of first fixing parts or a plurality of second fixing parts, and at the same time, the setting of the gas charging pipeline ensures that each group of heat exchange tubes forms a whole, which facilitates the control of system parameters.

As another preferred solution, the sealed heat exchange structure is: heat exchange tubes arranged in a meander in the axial direction of the tube shell and arranged in a helical line in the circumferential direction of the tube shell, and at least one gas-filled tube is arranged on the heat exchange tube mouth.

In order to improve heat exchange performance, preferably, the heat exchange tubes are copper tubes. The heat transfer coefficient of the copper tube is still high at deep low temperature (<10K), which further improves the heat transfer performance of the regenerator.

The volumetric specific heat capacity of helium at different temperatures and pressures is shown in Figure 5. It can be seen from the figure that there is a peak in the volumetric specific heat capacity of helium at different pressures, and the peak corresponds to a critical temperature. Below this critical temperature, helium The volume specific heat capacity of gas increases with the increase of temperature, and above the critical temperature, the volume specific heat capacity of helium decreases with the increase of temperature; at the same time, it can be seen from Figure 5 that the peak value of the volume specific heat capacity of helium is It increases as the pressure decreases, and the peak value is much higher than that of the magnetic regenerating material in Figure 4.

The above characteristics show that helium as a refrigerant is an extremely ideal heat recovery medium. Through reasonable structural design, helium can be sealed in a closed space structure (such as a copper tube), and the space structure can be Used as a high-efficiency heat recovery filler, the helium in it is used as a heat recovery medium to exchange heat with helium as a refrigerant to achieve high efficiency heat recovery performance. At the same time, according to the charging pressure of the pulse tube refrigerator, it is also possible to select and fill the helium gas of a suitable pressure in the closed space structure, so as to realize that in the working temperature range, the volume specific heat capacity of the helium gas used as the heat recovery medium is higher than that used as the refrigeration gas. Working fluid helium. For example, the commonly used filling pressure of pulse tube refrigerators in the liquid helium temperature zone is 1 to 1.5 MPa. Taking 1.0 MPa as an example, it can be seen from Figure 5 that the temperature corresponding to the peak volume specific heat capacity of helium at 1.0 MPa is about 7.5 K. Through experimental measurement and numerical simulation, the temperature distribution in the regenerator can be obtained. In the temperature range below 7K, helium with a filling pressure lower than 1.0MPa can be selected as the regenerating medium, because in this temperature range The volumetric specific heat capacity of helium increases as the pressure decreases. At a temperature higher than 7K, helium with a filling pressure higher than 1.0MPa is selected as the heat recovery medium, because the volumetric specific heat capacity of helium increases with the pressure at this temperature. As the temperature rises, the volumetric specific heat capacity of helium as the heat recovery medium in the entire temperature range (4-10K) is higher than that of helium as the refrigerant, thereby achieving efficient heat recovery and ultimately increasing the temperature range of liquid helium. Performance of pulse tube refrigerators. At the same time, compared with the magnetic regenerative materials commonly used in the liquid helium temperature zone, helium has the advantages of low price, easy acquisition, and no influence of magnetic fields.

Based on the above-mentioned deep low temperature regenerator using helium as the heat recovery medium and the existing pulse tube refrigerator technology, the present invention provides two kinds of pulse tube refrigerators. The refrigeration efficiency of the following two pulse tube refrigerators is relatively high, Both can efficiently reach the working temperature range of 10K and lower.

A pulse tube refrigerator, comprising a first-stage pre-cooling pulse tube refrigerator unit and a second-stage low-temperature pulse tube refrigerator unit, the first-stage pre-cooling pulse tube refrigerator unit and the second-stage low-temperature pulse tube refrigerator unit Both adopt low-frequency compressor units; the regenerator of the second-stage low-temperature pulse tube refrigerator unit includes a second-stage pre-cooling section regenerator, a second-stage pre-cooling section regenerator cold-end heat exchanger, The second-stage mid-temperature section regenerator and the second-stage low-temperature section regenerator; the first-stage pre-cooling pulse tube refrigerator unit and the second-stage low-temperature pulse tube refrigerator unit are connected to the first-stage precooling The heat bridge between the first-stage cold-end heat exchanger of the pulse tube refrigerator unit and the cold-end heat exchanger of the second-stage pre-cooling section regenerator is thermally coupled; the second-stage low-temperature section regenerator is the above-mentioned The deep low temperature regenerator using helium as the regenerating medium described in any technical solution. The composition of the low-frequency compressor unit is an existing technology, and generally includes a compressor, an aftercooler, a low-pressure control valve, and a high-pressure control valve.

The first-stage pre-cooling pulse tube refrigerator unit includes a first-stage low-frequency compressor unit, a first-stage regenerator, a first-stage cold-end heat exchanger, a first-stage pulse tube, and a first-stage pulse tube The hot-end heat exchanger and the first-stage phase-adjusting mechanism, the first-stage phase-adjusting mechanism includes: the first-stage gas storage, which communicates with the first-stage pulse tube hot-end heat exchanger through the pipeline; the first The first-stage small hole valve is arranged on the pipeline between the first-stage gas storage and the first-stage pulse tube hot-end heat exchanger; The unit is in communication with the pipeline between the first-stage regenerator, and the other end is in communication with the pipeline between the first-stage orifice valve and the first-stage pulse tube hot-end heat exchanger.

The second-stage low-temperature pulse tube refrigerator unit includes a second-stage low-frequency compressor unit, a second-stage pre-cooling section regenerator, a second-stage pre-cooling section regenerator cold-end heat exchanger, and a second-stage low-frequency compressor unit connected in sequence. The mid-temperature section regenerator, the second-stage low-temperature section regenerator, the second-stage cold-end heat exchanger, the second-stage pulse tube, the second-stage pulse tube hot-end heat exchanger, and the second-stage phase adjustment mechanism, the The second-stage phase adjustment mechanism includes: a second-stage gas storehouse, which communicates with the second-stage pulse tube hot-end heat exchanger through a pipeline; a second-stage small hole valve, which is arranged between the second-stage air storehouse and the On the pipeline between the second-stage pulse tube hot end heat exchanger; the second-stage two-way intake valve, one end of which is connected to the pipe between the second-stage low-frequency compressor unit and the second-stage precooling section regenerator The other end communicates with the pipeline between the second-stage small hole valve and the second-stage pulse tube hot end heat exchanger.

The first-stage phasing mechanism and the second-stage phasing mechanism can also use other phasing mechanisms with the same phasing function to adjust the mass flow and pressure wave phase in the corresponding regenerator to ensure the stable and efficient operation of the system .

In order to further improve the refrigeration performance, the thermal bridge (TB) simultaneously precools the phase adjustment mechanism and the pulse tube hot end heat exchanger of the second-stage low-temperature pulse tube refrigerator unit.

When using a low-frequency compressor unit, generally a two-stage structure can be used to reach the working temperature range of 10K and below 10K. When a high-frequency compressor unit is used, for example, when a linear compressor is used, under the current conditions, it is difficult for the two-stage structure to reach the working temperature range below 10K, so in order to ensure the more effective work of the regenerator of the present invention, as Preferably, a pulse tube refrigerator includes a first-stage pre-cooling pulse tube refrigerator unit, a second-stage pre-cooling pulse tube refrigerator unit, and a third-stage low-temperature pulse tube refrigerator unit; the second-stage pre-cooling pulse tube refrigerator unit The tube refrigerator unit includes a second-stage pre-cooling section regenerator, a second-stage pre-cooling section regenerator cold-end heat exchanger, and a second-stage low-temperature section regenerator connected in sequence; the third-stage low-temperature pulse tube The heat recuperator in the refrigerator unit includes the heat exchanger of the first pre-cooling section of the third stage, the heat exchanger of the cold end of the heat exchanger of the first pre-cooling section of the third stage, the heat exchanger of the second pre-cooling section of the third stage, and the heat exchanger of the second pre-cooling section of the third stage, which are connected in sequence. Heater, third-stage second pre-cooling section regenerator cold-end heat exchanger, third-stage low-temperature section regenerator; the first-stage pre-cooling pulse tube refrigerator unit, second-stage pre-cooling pulse tube refrigeration The machine unit and the third-stage low-temperature pulse tube refrigerator unit are connected to the first-stage cold-end heat exchanger of the first-stage pre-cooling pulse-tube refrigerator unit, the second-stage pre-cooling section regenerator cold-end heat exchanger, and The first-stage heat bridge between the cold-end heat exchangers of the first pre-cooling section regenerator of the third stage performs a thermal coupling, and is connected to the cold-end heat exchanger of the second pre-cooling section regenerator of the third stage and the first-stage heat exchanger. The second-stage heat bridge of the second-stage cold end heat exchanger of the second-stage precooling pulse tube refrigerator unit performs secondary thermal coupling; the third-stage low-temperature section regenerator is provided by any one of the above technical solutions The above-mentioned deep low temperature regenerator using helium as the regenerating medium.

The first-stage pre-cooling pulse tube refrigerator unit, the second-stage pre-cooling pulse tube refrigerator unit and the third-stage low-temperature pulse tube refrigerator unit all include a phase adjustment mechanism, and the phase adjustment mechanism is composed of an air bank and It consists of an inertia tube arranged between the gas store and the corresponding pulse tube hot end heat exchanger.

In order to further reduce the working temperature range of the low-temperature section of the third-stage low-temperature pulse-tube refrigerator unit, as a preference, the pulse-tube hot-end heat exchanger and the phase adjustment mechanism in the third-stage low-temperature pulse-tube refrigerator unit are simultaneously connected with the second-stage low-temperature pulse-tube refrigerator unit. stage thermal bridge connection.

As a further preference, the first thermal bridge (TB1) simultaneously precools the phase adjustment mechanism and the pulse tube heat exchanger of the second-stage precooling pulse tube refrigerator unit; the second thermal bridge (TB2) At the same time, the phase adjustment mechanism and the heat exchanger of the pulse tube hot end of the third-stage low-temperature pulse tube refrigerator unit are precooled.

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

The deep-low temperature regenerator of the present invention has a higher volumetric specific heat capacity when helium is used in the temperature range below 10K and 10K, and helium filled in a closed space is used as the regenerating medium, which is different from the use of traditional regenerating fillers (such as Compared with deep-low temperature regenerators such as rare earth magnetic regenerating materials), the present invention can realize high-efficiency heat exchange in the liquid helium temperature zone, and has the advantages of low price, easy acquisition, and no influence of magnetic field, so that helium is used as the The cryogenic regenerator with the heat recovery medium can obtain higher efficiency, thereby improving the performance of the cryogenic pulse tube refrigerator.

Description of drawings

Fig. 1a is a structural schematic diagram of an embodiment of a deep-low temperature regenerator using helium as a regenerating medium according to the present invention.

Fig. 1b is a schematic structural view of the lower end cover of the deep-low temperature regenerator shown in Fig. 1a.

Fig. 2 is a structural schematic diagram of an embodiment of a pulse tube refrigerator for a deep low temperature regenerator using helium as a heat recovery medium according to the present invention.

Fig. 3 is a structural schematic diagram of another embodiment of the pulse tube refrigerator of the cryogenic regenerator using helium as the heat recovery medium of the present invention.

Figure 4 shows the relationship between the volumetric specific heat capacity and temperature of various regenerator fillers.

Figure 5 shows the volumetric specific heat capacity of helium at different temperatures and pressures.

In the above attached drawings:

SC, tube shell; UC, upper end cover; T, heat exchange tube; DC, lower end cover; FC, gas flow channel; CP, gas charging line; 1, hot end orifice; 2, cold end orifice; 3, groove 4. The first fixing part; 5. The second fixing part; 6. The connecting arm; 7. The connecting channel;

C1, first-stage compressor; C2, second-stage compressor; C3, third-stage compressor; AC1, first-stage aftercooler; AC2, second-stage aftercooler; LV1, first-stage compression LV2, low-pressure control valve of the second-stage compressor; HV1, high-pressure control valve of the first-stage compressor; HV2, high-pressure control valve of the second-stage compressor; DO1, two-way intake valve of the first stage; DO2, The second-stage two-way intake valve; O1, the first-stage small hole valve; O2, the second-stage small-hole valve; R1, the first-stage gas storage; R2, the composition of the second-stage gas storage; R3, the third-level gas storage ; HX1, first-stage regenerator hot-end heat exchanger; HX2, first-stage cold-end heat exchanger; HX3, first-stage pulse tube hot-end heat exchanger; HX4, second-stage regenerator hot-end heat exchanger Heater; HX5, second-stage pre-cooling section regenerator cold-end heat exchanger; HX6, second-stage cold-end heat exchanger; HX7, second-stage pulse tube hot-end heat exchanger; HX8, third-stage return Heater hot end heat exchanger; HX9, third stage first precooling section regenerator cold end heat exchanger; HX10, third stage second precooling section regenerator cold end heat exchanger; HX11, third stage stage cold end heat exchanger; HX12, third stage pulse tube hot end heat exchanger; He-Re, deep low temperature regenerator; He-Re2, second stage low temperature section regenerator; He-Re3, third stage Low-temperature section regenerator; RG1, first-stage regenerator; RG21, second-stage pre-cooling section regenerator; RG22, second-stage medium-temperature section regenerator; RG23, second-stage low-temperature section regenerator; RG31 , third-stage first pre-cooling section regenerator; RG32, third-stage second pre-cooling section regenerator; PT1, first-stage pulse tube; PT2, second-stage pulse tube; PT3, third-stage pulse tube ; TB, thermal bridge; TB1, first-level thermal bridge; TB2, second-level thermal bridge; I1, first-level inertia tube; I2, second-level inertia tube; I3, third-level inertia tube.

detailed description

Example 1

As shown in Figure 1a and Figure 1b: a deep low temperature regenerator He-Re using helium as the heat recovery medium includes: a tube shell SC with a hot end flow hole 1 and a cold end flow hole 2, and a The regenerative packing in the shell SC has a gas flow channel FC connecting the hot end flow hole 1 and the cold end flow hole 2, and the regenerative packing is a sealed heat exchange structure filled with helium. The shell SC is a stainless steel tube.

The sealed heat exchange structure includes: an upper end cover UC, a lower end cover DC, and several groups of heat exchange tubes T fixed between the upper end cover UC and the lower end cover DC for filling helium. The heat exchange tube T is a copper tube. Each set of heat exchange tubes T is arranged in a ring shape; multiple sets of ring heat exchange tubes T are arranged concentrically. Between two adjacent sets of heat exchange tubes T is a gas flow channel FC.

As shown in Figure 1(b), the lower end cover DC is composed of an annular second fixing member 5 and a connecting arm 6 that fixes a plurality of annular second fixing members 5 to each other. Each second fixing part 5 is used to fix a group of annular heat exchange tubes T, and the second fixing part 5 is provided with a connecting channel 7 communicating with each heat exchange tube T in the group of heat exchange tubes T. The top surface of the second fixing member 5 is provided with a notch 3 communicating with the connecting channel 7. The number of notches 3 corresponds to the number of heat exchange tubes T. The bottom side wall of the heat exchange tube T and the edge of the notch 3 are sealed by welding during installation. Fixing; cold end flow holes 2 are formed between two adjacent second fixing pieces 5 .

The structure of the upper end cover UC is basically the same as that of the lower end cover DC. The upper end cover UC is provided with a first fixing part 4, and the first fixing part 4 and the second fixing part 5 have the same structure and are used for sealing and fixing with the top of the heat exchange tube T. ; A hot end flow hole 1 is formed between two adjacent first fixing parts 4; in order to facilitate the completion of inflation, one of the connecting arms 6 on the lower end cover DC is provided with an inflation pipeline CP connecting all the connecting channels.

When filling helium, fill the inside of the heat exchange tube T through the inflation pipeline CP, and when the pressure of the helium is stable, it is sufficient to seal the end of the inflation pipeline CP.

Example 2

As shown in Figure 2, a two-stage low-frequency pulse tube refrigerator using helium as the heat recovery medium for a deep low-temperature regenerator includes: a first-stage compressor C1, a first-stage aftercooler AC1, a first-stage The first stage compressor low pressure control valve LV1, the first stage compressor high pressure control valve HV1, the first stage regenerator RG1, the first stage cold end heat exchanger HX2, the first stage pulse tube PT1, the first stage pulse tube hot end The first-stage pre-cooling pulse tube refrigerator unit composed of heat exchanger HX3, the first-stage two-way inlet valve DO1, the first-stage orifice valve O1, the first-stage gas storage R1, the thermal bridge TB, and the second-stage Compressor C2, second-stage aftercooler AC2, second-stage compressor low-pressure control valve LV2, second-stage compressor high-pressure control valve HV2, second-stage pre-cooling section regenerator RG21, second-stage pre-cooling section Regenerator cold-end heat exchanger HX5, second-stage mid-temperature section regenerator RG22, second-stage low-temperature section regenerator He-Re2, second-stage cold-end heat exchanger HX6, second-stage pulse tube PT2, second-stage The second-stage low-temperature pulse tube refrigerator unit composed of the second-stage pulse tube hot-end heat exchanger HX7, the second-stage two-way inlet valve DO2, the second-stage orifice valve O2 and the second-stage gas storehouse R2.

The structure of the second-stage low-temperature regenerator He-Re2 is the same as that of the deep-low temperature regenerator He-Re using helium as the heat recovery medium in Example 1. The working temperature range of the second-stage low-temperature regenerator He-Re2 is 10K and below 10K, which is filled with helium as a heat recovery medium.

The connections of the above components are as follows:

The first-stage compressor C1, the first-stage aftercooler AC1, the first-stage compressor high-pressure control valve HV1 and the first-stage compressor low-pressure control valve LV1 are sequentially connected in series to form a circulation loop of the first-stage low-frequency compressor unit; The inlet of the first-stage regenerator RG1 is connected with the pipeline between the high-pressure control valve HV1 of the first-stage compressor and the low-pressure control valve LV1 of the first-stage compressor; The first-stage cold-end heat exchanger HX2, the first-stage pulse tube PT1, the first-stage pulse tube hot-end heat exchanger HX3, the first-stage orifice valve O1, and the inlet of the first-stage gas storage R1 are connected; the first-stage two-way inlet One end of the gas valve DO1 is connected with the pipeline between the first-stage regenerator RG1 and the first-stage low-frequency compressor unit, and the other end of the first-stage two-way inlet valve DO1 is connected with the first-stage orifice valve O1 and the first-stage pulse tube The pipelines between the hot end heat exchangers HX3 are connected.

The second-stage compressor C2, the second-stage aftercooler AC2, the second-stage compressor high-pressure control valve HV2 and the second-stage compressor low-pressure control valve LV2 are connected in sequence to form the second-stage low-frequency compressor unit; the second-stage precooling The regenerator RG21 of the second stage is sequentially connected with the cold end heat exchanger HX5 of the regenerator of the second precooling section, the regenerator RG22 of the second stage of the middle temperature section, the regenerator He-Re2 of the second stage of the low temperature section, and the second stage of regenerator through the pipeline. The first-stage cold-end heat exchanger HX6, the second-stage pulse tube PT2, the second-stage pulse tube hot-end heat exchanger HX7, the second-stage orifice valve O2 and the second-stage gas storage R2 are connected; the second-stage two-way intake valve One end of DO2 is connected to the pipeline between the second-stage low-frequency compressor unit and the second-stage precooling section regenerator RG21, and the other end of the second-stage two-way intake valve DO2 is connected to the second-stage orifice valve O2 and the second-stage The pipelines between the pulse tube hot end heat exchangers HX7 are connected.

The first-stage pre-cooling pulse tube refrigerator unit and the second-stage low-temperature pulse tube refrigerator unit are connected through the first-stage cold-end heat exchanger HX2 and the second-stage pre-cooling section regenerator cold-end heat exchanger HX5 The thermal bridge TB is thermally coupled to realize the precooling of the first-stage cold-end heat exchanger HX2 to the second-stage pre-cooling section regenerator cold-end heat exchanger HX5.

The operation process of the two-stage low-frequency pulse tube refrigerator of the deep low temperature regenerator using helium as the heat recovery medium in this embodiment is as follows:

In the initial stage, the low-pressure regulating valve LV1 of the first-stage compressor and the high-pressure regulating valve HV1 of the first-stage compressor are both closed, and the gas becomes high-temperature and high-pressure gas after being compressed by the first-stage compressor C1, and the high-temperature and high-pressure gas flows through the first The after-cooler AC1 cools down to room temperature. When the gas pressure is higher than the set value, the high-pressure regulating valve HV1 of the first-stage compressor opens, and the high-pressure room temperature gas flows out from the high-pressure valve HV1 of the first-stage compressor and is divided into two streams. , one stream passes through the first-stage regenerator RG1 and exchanges heat with the filler in it to lower the temperature and enters the subsequent related components, and the other stream enters the subsequent related components through the first-stage two-way intake valve DO1, so that the entire system is uniform In a high-pressure state, the high-pressure regulating valve HV1 of the first-stage compressor is closed, and the low-pressure regulating valve LV1 of the first-stage compressor is opened. The gas is divided into two streams from the first-stage gas storage R1 through the first-stage orifice valve O1. The first-stage two-way intake valve DO1 returns to the first-stage compressor C1 through the first-stage compressor low-pressure regulating valve LV1, and the other one passes through the first-stage pulse tube PT1, and the first-stage regenerator RG1 finally passes through the first-stage The compressor low-pressure regulating valve LV1 returns to the first-stage compressor C1, thereby completing a cycle. During the cycle, there is a temperature difference between the gas entering and leaving the first-stage cold-end heat exchanger HX2, thereby generating a refrigeration effect. The first stage The cooling capacity is taken from the first-stage cold-end heat exchanger HX2 through the thermal bridge TB to pre-cool the gas entering the second-stage low-temperature section regenerator.

In the initial stage, the low-pressure regulating valve LV2 of the second-stage compressor and the high-pressure regulating valve HV2 of the second-stage compressor are closed, and the gas becomes high-temperature and high-pressure gas after being compressed by the second-stage compressor C2, and the high-temperature and high-pressure gas flows through the second The after-stage cooler AC2 is cooled to room temperature. When the gas pressure is higher than the set value, the high-pressure regulating valve HV2 of the second-stage compressor is opened, and the high-pressure room temperature gas flows out from the high-pressure valve HV2 of the second-stage compressor and is divided into two streams. , one stream passes through the second-stage pre-cooling section regenerator RG21 and is cooled to the first-stage refrigeration temperature by the second-stage pre-cooling section regenerator cold-end heat exchanger HX5 connected to the thermal bridge TB at its cold end, Then it enters the subsequent related components, and the other one enters the subsequent related components through the second-stage two-way intake valve DO2, so that the whole system is in a high-pressure state, and then the high-pressure regulating valve HV2 of the second-stage compressor is closed, and the second-stage compression The low-pressure regulating valve LV2 of the compressor is opened, and the gas is divided into two streams from the second-stage gas storage R2 through the second-stage orifice valve O2. The second-stage compressor C2, the other one passes through the second-stage pulse tube PT2, the second-stage low-temperature section regenerator He-Re2, the second-stage medium-temperature section regenerator RG22, the second-stage pre-cooling section regenerator cooling The end heat exchanger HX5 and the regenerator RG21 of the second-stage pre-cooling section finally return to the second-stage compressor C2 through the low-pressure regulating valve LV2 of the second-stage compressor, thereby completing a cycle. There is a temperature difference in the gas in the heat exchanger HX6 at the cold end of the stage, which produces a cooling effect.

Example 3

As shown in Figure 3, a high-frequency pulse tube refrigerator using helium as the heat-regenerating medium for a deep-low temperature regenerator includes a first-stage compressor C1, a first-stage regenerator hot-end heat exchanger HX1, The first-stage regenerator RG1, the first-stage cold-end heat exchanger HX2, the first-stage pulse tube PT1, the first-stage pulse tube hot-end heat exchanger HX3, the first-stage inertia tube I1, and the first-stage gas storage R1 The first-stage pre-cooling pulse tube refrigerator unit consists of the first-stage thermal bridge TB1, the second-stage compressor C2, the second-stage regenerator hot-end heat exchanger HX4, and the second-stage pre-cooling section regenerator RG21, second-stage pre-cooling section regenerator cold-end heat exchanger HX5, second-stage low-temperature section regenerator RG23, second-stage cold-end heat exchanger HX6, second-stage pulse tube PT2, second-stage pulse tube The second-stage pre-cooling pulse tube refrigerator unit composed of the hot end heat exchanger HX7, the second-stage inertia tube I2, and the second-stage gas storage R2, the second-stage thermal bridge TB2, and the third-stage compressor C3, the second-stage Three-stage regenerator hot-end heat exchanger HX8, third-stage first pre-cooling section regenerator RG31, third-stage first pre-cooling section regenerator cold-end heat exchanger HX9, third-stage second pre-cooling Section regenerator RG32, third stage second precooling section regenerator cold end heat exchanger HX10, third stage low temperature section regenerator He-Re3, third stage cold end heat exchanger HX11, third stage pulse The third-stage low-temperature pulse tube refrigerator unit composed of tube PT3, third-stage pulse tube hot-end heat exchanger HX12, third-stage inertial tube I3, and third-stage gas storage R3.

The structure of the third-stage low-temperature regenerator He-Re3 is the same as that of the deep-low temperature regenerator He-Re using helium as the heat recovery medium in Example 1. The working temperature zone of the third-stage low-temperature regenerator He-Re3 is 10K and below 10K, which is filled with helium as a heat recovery medium.

The connections of the above components are as follows:

The first-stage compressor C1 is sequentially connected with the first-stage regenerator hot-end heat exchanger HX1, the first-stage regenerator RG1, the first-stage cold-end heat exchanger HX2, the first-stage pulse tube PT1, and the first-stage regenerator through pipelines. The first-stage pulse tube hot end heat exchanger HX3, the first-stage inertia tube I1 and the first-stage gas storage R1 are connected;

The second-stage compressor C2 connects with the hot-end heat exchanger HX4 of the second-stage regenerator, RG21 of the second-stage pre-cooling section regenerator, and the cold-end heat exchanger HX5 of the second-stage pre-cooling section regenerator through pipelines , the second-stage low-temperature section regenerator RG23, the second-stage cold-end heat exchanger HX6, the second-stage pulse tube PT2, the second-stage pulse tube hot-end heat exchanger HX7, the second-stage inertia tube I2 and the second-stage Gas storage R2 connection;

The third-stage compressor C3 is sequentially connected with the heat exchanger HX8 at the hot end of the third-stage regenerator, the regenerator RG31 of the first pre-cooling section of the third stage, and the cold end of the regenerator of the first pre-cooling section of the third-stage through pipelines. Heat exchanger HX9, regenerator RG32 in the second pre-cooling section of the third stage, heat exchanger HX10 at the cold end of the regenerator in the second pre-cooling section of the third stage, He-Re3 in the third-stage low-temperature section, and The first-stage cold-end heat exchanger HX11, the third-stage pulse tube PT3, the third-stage pulse tube hot-end heat exchanger HX12, the third-stage inertial tube I3, and the third-stage gas storage R3 are connected.

The first-stage cold-end heat exchanger HX2, the second-stage pre-cooling section regenerator cold-end heat exchanger HX5, and the third-stage first pre-cooling section regenerator cold-end heat exchanger HX9 are respectively the first-stage thermal bridge TB1 Connecting, the cold-end heat exchanger HX10 of the third-stage second precooling section regenerator and the second-stage cold-end heat exchanger HX6 of the second-stage pre-cooling pulse tube refrigerator unit are respectively connected with the second-stage thermal bridge TB2.

The working process of the high-frequency pulse tube refrigerator of the deep-low temperature regenerator using helium as the heat recovery medium in this embodiment is as follows:

In the high-pressure stage, the high-temperature and high-pressure gas compressed by the first-stage compressor C1 flows through the hot-end heat exchanger HX1 of the first-stage regenerator, and then cools down to room temperature, and then is heated with the regenerative filler in the first-stage regenerator RG1. After heat exchange, the temperature drops, and then flows through the first-stage cold-end heat exchanger HX2, the first-stage pulse tube PT1, the first-stage pulse tube hot-end heat exchanger HX3, and the first-stage inertial tube I1 to enter the first-stage gas storage R1; then enters the low-pressure cycle, the gas from the first-stage gas storage R1 sequentially passes through the first-stage inertial tube I1, the first-stage pulse tube hot-end heat exchanger HX3, the first-stage pulse tube PT1, and the first-stage cold-end heat exchanger The heat exchanger HX2 and the first-stage regenerator RG1 return to the first-stage compressor C1 to complete a cycle. During the cycle, there is a temperature difference between the gas entering and leaving the first-stage cold-end heat exchanger HX2, so that the first-stage cold-end The cooling effect is generated at the heat exchanger HX2, and the cooling capacity here passes through the second-stage pre-cooling section heat exchanger cold-end heat exchanger HX5 connected to the first-stage heat bridge TB1 and the third-stage first pre-cooling section heat exchanger HX5 respectively. The heat exchanger cold end heat exchanger HX9 provides pre-cooling for the second-stage pulse tube refrigerator and the third-stage pulse tube refrigerator.

In the high-pressure stage, the high-temperature and high-pressure gas compressed by the second-stage compressor C2 flows through the hot-end heat exchanger HX4 of the second-stage regenerator and is cooled to room temperature, and then is cooled to room temperature with the regenerator RG21 in the second-stage pre-cooling section. The hot filler performs heat exchange, the temperature decreases, and then cools to the cold end temperature of the first-stage pulse tube refrigerator at the cold-end heat exchanger HX5 of the regenerator in the second-stage pre-cooling section, and then the low-temperature gas flows through the second stage in turn The low-temperature section regenerator RG23, the second-stage cold-end heat exchanger HX6, the second-stage pulse tube PT2, the second-stage pulse tube hot-end heat exchanger HX7, and the second-stage inertia tube I2 enter the second-stage gas storage R2; Then enter the low-pressure cycle, the gas from the second-stage gas storage R2 passes through the second-stage inertia tube I2, the second-stage pulse tube hot-end heat exchanger HX7, the second-stage pulse tube PT2, and the second-stage cold-end heat exchanger HX6 , The second-stage low-temperature section regenerator RG23, the second-stage pre-cooling section regenerator cold-end heat exchanger HX5, the second-stage pre-cooling section regenerator RG21 return to the second-stage compressor C2 to complete a cycle, During the circulation process, there is a temperature difference between the gas entering and leaving the second-stage cold-end heat exchanger HX6, so that a refrigeration effect is generated at the second-stage cold-end heat exchanger HX6, and the cooling capacity there is passed through the second-stage heat bridge TB2. The heat exchanger HX10 at the cold end of the recuperator in the second precooling section of the third stage provides precooling for the third stage pulse tube refrigerator.

In the high-pressure stage, the high-temperature and high-pressure gas compressed by the third-stage compressor C3 flows through the hot-end heat exchanger HX8 of the third-stage regenerator and is cooled to room temperature, and then is combined with the regenerator RG31 of the first pre-cooling section of the third stage. The regenerative filler is used for heat exchange, the temperature is lowered, and it is cooled to the cold end temperature of the first-stage pulse tube refrigerator at the cold-end heat exchanger HX9 of the first pre-cooling section of the third-stage regenerator, and then the gas enters the third-stage The regenerator RG32 in the second precooling section conducts heat exchange with the regenerating filler in it, the temperature drops, and cools down to the second stage pulse tube refrigeration at the cold end heat exchanger HX10 of the regenerator in the second precooling section of the third stage temperature of the cold end of the machine, and then flow through the third-stage low-temperature section regenerator He-Re3, the third-stage cold-end heat exchanger HX11, the third-stage pulse tube PT3, and the third-stage pulse tube hot-end heat exchanger HX12 , the third-level inertia tube I3 enters the third-level gas storage R3; then enters the low-pressure cycle, and the gas passes through the third-level inertia tube I3, the third-level pulse tube hot-end heat exchanger HX12, and the third-level gas storage R3 successively. The third-stage pulse tube PT3, the third-stage cold-end heat exchanger HX11, the third-stage low-temperature section regenerator He-Re3, the third-stage second pre-cooling section regenerator cold-end heat exchanger HX10, the third-stage The regenerator RG32 in the second pre-cooling section, the cold end heat exchanger HX9 of the regenerator in the first pre-cooling section of the third stage, and the regenerator RG31 in the first pre-cooling section of the third stage return to the third-stage compressor C3 to complete a Circulation, there is a temperature difference between the gas entering and leaving the third-stage cold-end heat exchanger HX11 during the cycle, thereby generating a refrigeration effect at the third-stage cold-end heat exchanger HX11.

In the above examples, the length and filling pressure of the third-stage low-temperature section regenerator He-Re3 and the second-stage low-temperature section regenerator He-Re2 need to be determined according to actual simulation experiments, that is, the third-stage low-temperature section regenerator The working temperature of He-Re3 and He-Re2 of the second-stage low-temperature section regenerator is 10K or below. According to the volume specific heat capacity of helium at different temperatures and pressures shown in Figure 5, the charging pressure of the pulse tube refrigerator For the reference pressure, select different charging pressures on both sides of the corresponding volume specific heat capacity peak at the reference pressure, so as to realize that the volume specific heat capacity of helium under the filling pressure in the entire working temperature zone is higher than that of the refrigerant helium under the reference pressure The specific heat capacity of the volume can finally realize the efficient heat exchange of the regenerator in this section.

Claims (9)

1. A deep low temperature regenerator using helium as the heat recovery medium, including a tube shell (SC) with a hot end flow hole (1) and a cold end flow hole (2), and a The regenerative filler in (SC), which has a gas flow channel (FC) connecting the hot end flow hole (1) and the cold end flow hole (2), is characterized in that the regenerative filler is Sealed heat exchange structure filled with helium inside; The sealed heat exchange structure is: a heat exchange tube arranged in a circuitous shape in the axial direction of the tube shell (SC) and arranged in a helical line in the circumferential direction of the tube shell (SC), and at least one gas charging port is provided on the heat exchange tube . 2. The deep low temperature regenerator using helium as the heat recovery medium according to claim 1, characterized in that the sealed heat exchange structure comprises: Several sets of heat exchange tubes (T) for filling helium; A plurality of first fixing parts (4) for sealing and fixing one end of each group of heat exchange tubes (T), and a plurality of second fixing parts (5) for sealing and fixing the other end of each group of heat exchange tubes (T) ; The first fixing part (4) and the second fixing part (5) are provided with connecting channels (7) connecting the heat exchange tubes in the corresponding set of heat exchange tubes (T) with each other. 3. The deep-low temperature regenerator using helium as the heat recovery medium according to claim 2, characterized in that each group of heat exchange tubes (T) is arranged in a ring, and several groups of heat exchange tubes (T) arranged in a ring It is concentrically arranged, and the gas flow channel (FC) is left between adjacent groups of heat exchange tubes (T). 4. The deep cryogenic regenerator using helium as the heat recovery medium according to claim 3, characterized in that the sealed heat exchange structure further comprises: all the first fixing parts (4) or all the second At least one connecting arm (6) fixed to each other by the fixing parts (5), and at least one connecting arm (6) is provided with an inflatable pipeline (CP) connecting all the connecting channels (7), through the inflatable pipeline (CP) ) to realize the inflation of all heat exchange tubes (T). 5. The deep cryogenic regenerator using helium as the heat recovery medium according to claim 3 or 4, characterized in that the heat exchange tubes are copper tubes. 6. A pulse tube refrigerator, comprising a first-stage precooling pulse tube refrigerator unit and a second-stage low-temperature pulse tube refrigerator unit; it is characterized in that, The regenerator of the second-stage low-temperature pulse tube refrigerator unit includes the second-stage pre-cooling section regenerator (RG21), the second-stage pre-cooling section regenerator cold-end heat exchanger (HX5), which are connected in sequence. The second-stage mid-temperature section regenerator (RG22) and the second-stage low-temperature section regenerator (He-Re2); The cold end of the first-stage pre-cooling pulse tube refrigerator unit realizes pre-cooling of the cold-end heat exchanger (HX5) of the regenerator of the second-stage pre-cooling section through a thermal bridge (TB); The second-stage low-temperature section regenerator (He-Re2) is the deep-low temperature regenerator using helium as the heat-regeneration medium according to any one of claims 1-5. 7. The pulse tube refrigerator according to claim 6, characterized in that the thermal bridge (TB) simultaneously controls the phase adjustment mechanism of the second-stage low-temperature pulse tube refrigerator unit and the pulse tube hot end heat exchanger Pre-cool. 8. A pulse tube refrigerator, comprising a first stage precooling pulse tube refrigerator unit, a second stage precooling pulse tube refrigerator unit and a third stage low temperature pulse tube refrigerator unit; it is characterized in that, The regenerator in the third-stage low-temperature pulse tube refrigerator unit includes the third-stage first pre-cooling section regenerator (RG31) connected in sequence, the third-stage first pre-cooling section regenerator cold end heat exchange heat exchanger (HX9), third-stage second pre-cooling section regenerator (RG32), third-stage second pre-cooling section regenerator cold end heat exchanger (HX10), third-stage low-temperature section regenerator (He -Re3); The cold end of the first-stage pre-cooling pulse tube refrigerator unit realizes the heat exchanger (HX9) of the cold end of the third-stage first pre-cooling section regenerator and the second-stage pre-cooling unit through the first-stage thermal bridge (TB1). The first-stage precooling of the cold end heat exchanger (HX5) in the second-stage precooling section of the cold pulse tube refrigerator unit; the cold end of the second-stage precooling pulse tube refrigerator The bridge (TB2) realizes the secondary precooling of the cold end heat exchanger (HX10) of the regenerator of the second precooling section of the third stage; The third-stage low-temperature section regenerator (He-Re3) is the deep-low temperature regenerator using helium as the heat-regeneration medium according to any one of claims 1-5. 9. The pulse tube refrigerator according to claim 8, characterized in that the first stage thermal bridge (TB1) simultaneously controls the phase adjustment mechanism and the pulse tube hot end of the second stage precooling pulse tube refrigerator unit The heat exchanger is pre-cooled; the second-stage heat bridge (TB2) simultaneously pre-cools the phase adjustment mechanism and the pulse-tube hot-end heat exchanger of the third-stage low-temperature pulse tube refrigerator unit.