CN1175225C - Space cryogenic refrigerator combining radiation cooling and pulse tube cooling - Google Patents

Abstract

The present invention discloses a cryogenic refrigerator with a reheating space, which combines radiation refrigeration and pulse tube refrigeration. The present invention comprises a pressure wave generator inlaid on a radiation refrigerating plate, and a metal plate which is provided with a hot end heat exchanger, a bidirectional air inlet, a small hole opening, an adjustable bidirectional air inlet valve and a small hole valve, wherein the bidirectional air inlet is communicated with the pressure wave generator, a heat regenerator and the hot end heat exchanger of a pulse tube; the small hole opening is communicated with the hot end heat exchanger of the pulse tube, and an air base; the adjustable bidirectional air inlet valve and the small hole valve are mutually communicated. The air base is communicated with the hot end heat exchanger of the pulse tube through the small hole valve. The pressure wave generator and the heat regenerator are communicated with the hot end heat exchanger of the pulse tube through the bidirectional air inlet valve. Because the present invention adopts radiation refrigeration to serve as a cold source of pulse tube refrigeration, the present invention solves the problem that a cold source needs to be added to the pulse tube refrigeration at the aspect of space application. Radiation refrigeration is adopted to refrigerate the pressure wave generator, so as to further reduce the temperatures of compressed gas and the pressure wave generator, which meets the requirement of low energy consumption of the space of the pressure wave generator.

Description

Space cryogenic refrigerator combining radiation cooling and pulse tube cooling

1. Technical field

The invention belongs to the field of regenerative gas low-temperature refrigeration, and in particular relates to a low-temperature range for generating a temperature from room temperature to a liquid nitrogen temperature zone, and is especially suitable for radiation refrigeration and cooling of space infrared detection and remote sensing elements in the aerospace field that require low temperature. A space cryogenic refrigerator combined with a pulse tube refrigeration phase.

2. Background technology

With the development of detectors and space remote sensing technology, infrared detectors have developed from units to line arrays and area arrays, and the cooling capacity required is also increasing. In order to cool infrared detectors more conveniently, effectively and reliably, various forms of cryogenic refrigerators have emerged. The uniqueness of the space environment (vacuum environment, no convective heat transfer) and the different technical requirements of various spacecraft when performing their respective tasks have put forward special requirements for low temperature acquisition technology, that is, small size, light weight, Low temperature refrigerator with long life, high reliability and low energy consumption. The space refrigerators used in the past mainly include: radiation refrigeration, solid refrigeration, adiabatic demagnetization refrigeration, He ₃ dilution refrigeration, mechanical refrigeration (such as Stirling refrigeration), etc. They have their own advantages and disadvantages, such as the small cooling capacity (about mW level) and high cooling temperature (90K ~ 100K) in the application of radiant cooling space, the vibration of the cold head parts of the Stirling refrigerator, and various types of mechanical refrigeration. Due to problems such as the space auxiliary cold source of the aircraft, they cannot fully meet the needs of space missions.

In 1963, the pulse tube (also known as pulse tube) refrigerator was jointly invented by Americans Gifford and Longsworth. After that, cryogenic workers used various types of pressure wave generators (ie compression machine) to replace low-frequency rotary valves and high and low pressure air sources to produce periodically changing pressure fluctuations, and achieved certain results. Since 1984, the former Soviet Union Mikulin (Mikulin) improved the pulse tube refrigerator with small holes and gas storage and the two-way intake pulse tube refrigerator improved by Zhu Shaowei of Xi'an Jiaotong University in 1990, so that the application of pulse tube refrigerator The prospects are even brighter. The refrigerator is composed of a pressure wave generator, a regenerator, a cold-end heat exchanger, a laminar fluidization element, a pulse tube, a hot-end heat exchanger, a gas store, a small hole, and a two-way inlet valve.

Compared with other traditional small mechanical cryogenic refrigerators, such as: Stirling refrigerator, G-M refrigerator, pulse tube refrigerator has unique advantages:

1. Because it cancels the mechanical low-temperature ejector (that is, the cold-end moving piston) and replaces it with gas reciprocating in the tube, it solves the problem of low-temperature sealing;

2. Since there are no moving parts at low temperature, the whole system only needs one power source (pressure wave generator), so the vibration source can be kept away from the working place, and the working noise is reduced. At the same time, the interference of the vibration of the cold head on the cooling element is also reduced. Greatly reduced, the position of the body is not subject to directional constraints;

3. The cancellation of the moving piston at the cold end also no longer requires a complex mechanical transmission system such as the corresponding drive device, phase matching, and support, so the structure is very simple, and the dust particles generated by the moving parts are also obvious. Reduce, thereby reducing the blockage of the internal flow channel, so that the reliability of the operation of the refrigerator and the working life are fundamentally significantly improved;

4. The reduction of moving parts makes the whole refrigerator easy to process, easy to manufacture and low in cost.

It is precisely because of the above characteristics that it is guaranteed that it can successfully complete the cooling requirements of target components or components in many high-tech fields, especially in line with the requirements of long life, high reliability, and low temperature infrared devices involved in aerospace and space technology. The strict requirements of no vibration and no interference are a major advancement in space mechanical low-temperature refrigeration technology, representing the future and development direction of space mechanical refrigeration technology, with great potential for development.

The basic principle of the pulse tube refrigerator is to use the high and low pressure gas to fill and deflate the cavity of the pulse tube to obtain the cooling effect. The function of the regenerator is to accumulate the cooling capacity obtained in the previous cycle, and transfer it to the inflow gas of the next cycle to gradually reduce the temperature of the cold end of the pulse tube. Its refrigeration process is as follows:

1. The high-pressure gas generated by the pressure wave generator flows through the regenerator, the cold-end heat exchanger, and the laminar flow element to enter the pulse tube in the form of laminar flow, and gradually pushes the gas in the tube to move to the closed end, and at the same time makes it squeezed pressure, the pressure rises, the temperature rises, and the temperature of the gas at the closed end of the pulse tube reaches the highest value;

2. The hot-end heat exchanger arranged at the closed end takes away the heat, so that the temperature and pressure of the gas in the tube are slightly lowered due to heat release;

3. When the gas in the system is located at the low-pressure gas source, the gas in the pulse tube gradually expands toward the pressure wave generator in a laminar flow, and the gas expands and depressurizes to obtain low temperature;

4. Then, the pressure wave generator generates a high-pressure air source, and the above cycle is repeated.

At present, the operating frequency of most pulse tube refrigerators is low (1Hz-20Hz), and auxiliary cooling measures (water cooling, air cooling or other low-temperature cold sources) are required to reduce the pressure of the compressed gas at the hot end of the pressure wave generator and the pulse tube. temperature, thereby further expanding to produce a low temperature environment and cooling capacity. The commonly used auxiliary cooling source is the air cooling method relying on the natural convection and forced convection of the outside atmosphere, or the water cooling method relying on an external cooling water source, or adding a set of refrigeration units, etc. Without exception, these cooling methods require another medium (atmosphere, water, low-temperature medium, refrigerant, etc.) as a refrigerant. However, the uniqueness of the peripheral space environment (vacuum environment, no convective heat transfer) and the strict requirements on the volume and quality of the space refrigerator make it necessary for the pulse tube refrigerator to solve the problem of the auxiliary cold source of the space in order to meet the practical requirements of the space. Require.

3. Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art, and to provide a combined refrigeration mode, which combines "passive" radiation refrigeration and "active" pulse tube refrigeration, in which radiation refrigeration and pulse tube refrigeration are combined. The low-temperature refrigerator makes full use of the characteristic of radiation refrigeration that does not need to rely on any intermediate medium for heat transfer, and serves as a cold source for cooling high-temperature airflow, making pulse tube refrigeration technology more practical in terms of space.

In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: comprising a pressure wave generator, the pressure wave generator is embedded on the radiation cooling plate, and its characteristic is that the radiation cooling plate is also embedded with a metal plate, and a heat sink is arranged on the metal plate. end heat exchanger, two-way air inlet and small orifice, the two-way air inlet is connected with the pressure wave generator, regenerator and pulse tube hot end heat exchanger, and the small orifice is connected with the pulse tube hot end heat exchanger and The gas storage is connected to each other, and an adjustable two-way inlet valve and a small hole valve connected to each other are also arranged on the metal plate. The gas storage is connected to the pulse tube hot end heat exchanger through the small hole valve, and the pressure wave generator and the return The heat exchanger communicates with the heat exchanger at the hot end of the pulse tube through a two-way inlet valve, the regenerator communicates with the heat exchanger at the pulse tube through a heat exchanger at the cold end, and the pulse tube communicates with the heat exchanger at the hot end of the pulse tube set on the metal plate. Unicom.

Another feature of the present invention is: the radiation cooling plate is provided with an inner hole equal to the outer diameter of the pressure wave generator, and the pressure wave generator is embedded in the inner hole by welding; The matching inner hole of the plate, the metal plate is embedded in the inner hole by welding; the pressure wave generator, the metal plate and the radiation cooling plate are an integral structure; the small hole valve, the two-way inlet valve and the pulse tube hot end heat Set on the metal plate; the metal plate is made of copper metal plate or other metal materials with good thermal conductivity; the radiation cooling plate is made of honeycomb material with high absorption rate or other new materials with high absorption rate; the two-way air intake valve and small hole valve pass through The lift distance is adjusted by the fine thread; the two-way intake valve and the small hole valve are respectively provided with sealing rings.

In the present invention, the small hole valve, the two-way intake valve and the pulse tube hot-end heat exchanger are processed on a copper block, thereby reducing the dead volume of the system, improving the refrigeration efficiency, and making the structure of the refrigerator more compact and more efficient. It meets the structural requirements of space refrigerators.

4. Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic structural view of the radiation cooling plate 11 of the present invention;

FIG. 3 is a schematic diagram of the structure of the metal plate 12 of the present invention.

5. Specific implementation

The structural principle and working principle of the present invention will be further described in detail below in conjunction with the drawings and embodiments.

Referring to Figures 1, 2, and 3, the present invention is designed with an inner hole 13 equal to the outer diameter of the pressure wave generator 1 shell and an inner hole 14 matched with the metal copper plate 12 on the radiation cooling plate 11, the radiation cooling plate 11, The pressure wave generator 1 and the metal copper plate 12 are integrated by welding, so that the pressure wave generator 1, the regenerator 2 and the pulse tube hot end heat exchanger 5 can be cooled by the cold energy generated by the radiation cooling plate 11 The function of the high temperature gas, the pulse tube hot end heat exchanger 5, the two-way air inlet 9 and the small orifice 6 are arranged on the metal plate 12. This design reduces the dead volume of the system, improves the refrigeration efficiency, and also To make the structure of the refrigerator more compact, the two-way air inlet 9 communicates with the pressure wave generator 1, the regenerator 2 and the pulse tube hot-end heat exchanger 5, and the small orifice 6 communicates with the pulse tube hot-end heat exchanger 5 and Gas storehouse 8 is communicated with each other, is also provided with mutually interconnected adjustable two-way air intake valve 10 and small hole valve 7 on metal plate 12, and two-way air intake valve 10 and small hole valve 7 regulate lift distance by fine thread, and then Change the flow rate of the valve and play the role of gap sealing at the same time. The two-way inlet valve 10 and the small hole valve 7 are respectively provided with a sealing ring 15 and a sealing ring 16. 5-phase communication, the pressure wave generator 1 and the regenerator 2 are connected with the heat exchanger 5 at the hot end of the pulse tube through the two-way inlet valve 10, and the regenerator 2 is connected with the pulse tube 4 through the heat exchanger 3 at the cold end. The pulse tube 4 communicates with the pulse tube hot end heat exchanger 5 arranged on the metal plate 12 .

The working mechanism of the present invention is basically the same as that of the pulse tube refrigerator, the only difference is that the present invention uses the radiation cooling plate 11 as the cold source of the traditional pulse tube refrigerator, that is, the radiation cooling plate 11 generates cold energy to cool the pressure wave Generator 1, regenerator 2, pulse tube hot-end heat exchanger 5 and high-temperature gas at the hot end of pulse tube 4, thereby replacing other auxiliary cooling systems such as air cooling or water cooling commonly used in traditional pulse tube refrigerators.

Concrete work process of the present invention is as follows:

1. The pressure wave generator 1 generates periodic alternating pressure fluctuations and absorbs part of the cold generated by the radiation cooling plate 11, thereby reducing the gas temperature at the outlet of the pressure wave generator 1;

2. When the pressure wave generator 1 is in the exhaust state, the gas pressure of the pressure wave generator 1 is higher than the gas pressure in the pulse tube 4, so that the high-pressure gas generated by the pressure wave generator 1 flows into the system and is further radiated The metal red copper plate 12 cooled by the cold plate 11 is cooled, and the temperature is lowered, and then flows into the regenerator 2, and the high-temperature gas in the regenerator 2 further absorbs the cooling capacity stored in the filler of the regenerator 2 in the previous cycle, and the temperature is further lowered , then, the gas flows through the cold end heat exchanger and the laminarization element 3, through the cold end heat exchanger and the laminarization element 3, the gas enters the pulse tube 4 in the form of laminar flow, and gradually pushes the gas in the tube to heat the pulse tube The end heat exchanger 5 moves and is squeezed at the same time, the pressure rises, the temperature rises, and the temperature of the gas at the hot end of the pulse tube 4 reaches the highest value;

3. Then, the high-temperature gas is cooled by the metal copper plate 12 cooled by the radiation cooling plate 11 in the heat exchanger 5 at the hot end of the pulse tube, so that the temperature and pressure of the gas in the pulse tube 4 are slightly lowered due to heat release;

4. When the pressure wave generator 1 is in the inhalation state, the pressure wave generator 1 is in a low-pressure state lower than the pressure of the pulse tube 4, so that the gas in the pulse tube 4 flows gradually toward the pressure wave generator 1 in a laminar flow. Moving and expanding, the gas expands and depressurizes to obtain a low temperature. The gas temperature reaches the lowest at the cold end heat exchanger of the pulse tube 4 and the laminarization element 3 and generates cold energy. Usually, the cooled electronic components are installed in the cold end heat exchanger And the position of the laminarization element 3 absorbs the cold energy released by the cold end heat exchanger 3 and is cooled.

5. Then, the low-temperature gas continues to flow to the pressure wave generator 1. When it flows through the regenerator 2, the filling of the regenerator is further cooled by the low-temperature gas flowing in, the temperature of the filling is reduced, and the temperature of the low-temperature gas gradually rises to the normal temperature ;

6. Finally, the pressure wave generator 1 starts to compress and exhaust to generate a high-pressure gas source, and repeat the above cycle.

The present invention is a compound refrigeration method of "passive" radiation refrigeration and "active" pulse tube refrigeration, without any other auxiliary cooling devices (such as water cooling, air cooling, cooling unit); the pressure wave generator 1 is cooled by radiation refrigeration , on the one hand, the temperature of the compressed gas is reduced, and on the other hand, the operating temperature of the pressure wave generator 1 is also reduced, thereby reducing power consumption, thereby improving the overall efficiency of the refrigerator; the combination of radiation refrigeration and pulse tube refrigeration In this way, the two are integrated to meet the requirements of miniaturization in space applications; the radiation cooling plate 11 and the pulse tube hot-end heat exchanger 5 are integrated to reduce the heat conduction resistance between the two and improve the The heat exchange efficiency between the two, thereby further improving the efficiency of the refrigerator; the small hole valve 7 and the two-way inlet valve 10 and the pulse tube hot end heat exchanger 5 are made into a whole, which reduces the dead volume of the system and improves The refrigeration efficiency of the system is improved; the "passive" radiation refrigeration is used as the cold source, which solves the problem that the auxiliary cooling system cannot dissipate heat due to the absence of convective heat transfer in the near vacuum environment of the peripheral space; removes other auxiliary " The active cooling device adopts a simple radiation cooling method to simplify the system; utilizes the special cold background (about 3K) of the peripheral space to perform radiation heat exchange, and adopts the "passive" radiation cooling as a high-temperature cold source to Cooling of high temperature compressed gas.

The present invention is not only applicable to the direct composite refrigerator of pulse tube refrigeration and radiation refrigeration applied in space, but also applicable to the refrigeration mode (including direct contact coupling mode and indirect contact coupling mode) of space refrigeration coupled with pulse tube refrigeration and radiation refrigeration ) or other forms of pulse tube refrigerators or other refrigerators combined with radiation cooling applied to space cooling, or other refrigerators combined with various forms of radiation cooling plate structures applied to space cooling, or It is the application of radiant cooling to cool other parts of the refrigerator (such as gas storage).

Compared with the prior art, the present invention solves the problem of an additional cold source for the space application of the pulse tube refrigerator, has the advantages of compact structure, high refrigeration efficiency, etc., and meets the requirement of space practicality.

Claims (9)

1, the space Cryo Refrigerator that a kind of radiation refrigeration is mutually compound with pulse tube refrigeration, comprise pressure wave generator [1], pressure wave generator [1] is embedded on the spoke cold drawing [11], it is characterized in that: also be inlaid with sheet metal [12] on the spoke cold drawing [11], sheet metal [12] is provided with hot end heat exchanger [5], bidirection air intake mouth [9] and microstome [6], bidirection air intake mouth [9] and pressure wave generator [1], regenerator [2] and pulse tube hot end heat exchanger [5] are connected, microstome [6] is connected with pulse tube hot end heat exchanger [5] and air reservoir [8], on sheet metal [12], also be provided with the adjustable bidirection air intake valve [10] and the little ports valve [7] of mutual UNICOM, air reservoir [8] links by little ports valve [7] and pulse tube hot end heat exchanger [5], pressure wave generator [1] and regenerator [2] link by bidirection air intake valve [10] and pulse tube hot end heat exchanger [5], regenerator [2] links by cool end heat exchanger [3] and pulse tube [4], and pulse tube [4] links with the pulse tube hot end heat exchanger [5] that is arranged on the sheet metal [12].

2, the radiation refrigeration according to claim 1 space Cryo Refrigerator mutually compound with pulse tube refrigeration, it is characterized in that: said spoke cold drawing [11] is provided with the endoporus [13] that equates with the external diameter of pressure wave generator [1] cylindrical, and pressure wave generator [1] is embedded in the endoporus [13] by welding.

3, the radiation refrigeration according to claim 1 space Cryo Refrigerator mutually compound with pulse tube refrigeration, it is characterized in that: also be provided with the endoporus [14] that matches with sheet metal [12] on the said spoke cold drawing [11], sheet metal [12] is embedded in the endoporus [14] by welding.

4, the radiation refrigeration according to claim 1 space Cryo Refrigerator mutually compound with pulse tube refrigeration, it is characterized in that: said pressure wave generator [1], sheet metal [12] and spoke cold drawing [11] are an one-piece construction.

5, the radiation refrigeration according to claim 1 space Cryo Refrigerator mutually compound with pulse tube refrigeration, it is characterized in that: said little ports valve [7], bidirection air intake valve [10] and pulse tube hot end heat exchanger [5] are co-located on the sheet metal [12].

6, the radiation refrigeration according to claim 1 space Cryo Refrigerator mutually compound with pulse tube refrigeration is characterized in that: said sheet metal [12] is the sheet of metallic material of red copper sheet metal or other good thermal conductivity.

7, the radiation refrigeration according to claim 1 space Cryo Refrigerator mutually compound with pulse tube refrigeration is characterized in that: said spoke cold drawing [11] adopts the cellular material of high-absorbility or the new material of other high-absorbility.

8, the radiation refrigeration according to claim 1 space Cryo Refrigerator mutually compound with pulse tube refrigeration is characterized in that: said bidirection air intake valve [10] and little ports valve [7] are regulated lift by fine thread.

9, the radiation refrigeration according to claim 1 space Cryo Refrigerator mutually compound with pulse tube refrigeration is characterized in that: the said O-ring seal [15,16] that is respectively arranged with on bidirection air intake valve [10] and little ports valve [7].

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