CN108413641B - Frame and pulse tube type free piston Stirling refrigerator - Google Patents

Frame and pulse tube type free piston Stirling refrigerator Download PDF

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Publication number
CN108413641B
CN108413641B CN201810437952.8A CN201810437952A CN108413641B CN 108413641 B CN108413641 B CN 108413641B CN 201810437952 A CN201810437952 A CN 201810437952A CN 108413641 B CN108413641 B CN 108413641B
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piston
compression
expansion
heat exchanger
expansion piston
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CN108413641A (en
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陈曦
何韩军
朋文涛
杨文量
霍晴舟
杨巨沁
刘旭
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University of Shanghai for Science and Technology
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University of Shanghai for Science and Technology
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/14—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves

Abstract

According to the invention, the frame comprises a flange, an expansion piston pipe, a compression piston pipe and a base, wherein the expansion piston pipe is a straight pipe, one end of the expansion piston pipe is connected with the disc, the other end of the expansion piston pipe is a free end and is used for connecting a pulse pipe of the refrigerator, the expansion piston pipe is internally provided with a cylindrical heat exchange cavity and a cylindrical expansion piston cavity, the heat exchange cavity is communicated with the pulse pipe, the heat exchange cavity and the expansion piston cavity are coaxial and communicated, the compression piston pipe is a straight pipe and is arranged in the base, one end of the compression piston pipe is connected with the flange, the other end of the compression piston pipe is a free end, the compression piston pipe is internally provided with a cylindrical compression piston cavity, the compression piston cavity is coaxial and communicated with the expansion piston cavity and is parallel to the axis of the compression piston cavity, the disc is provided with a plurality of through, the expansion piston chamber has an inner diameter greater than the heat exchange chamber, which is the same as the pulse tube.

Description

Frame and pulse tube type free piston Stirling refrigerator
Technical Field
The invention belongs to the field of refrigeration, and particularly relates to a rack and pulse tube type free piston Stirling refrigerator.
Background
The low-temperature refrigerator is used for refrigeration as an important method for obtaining low temperature, and is widely applied to the fields of aviation, military, superconductivity, communication, electronics, metallurgy, industrial gas liquefaction, biological medical treatment and the like. Especially in recent years, the vigorous development of the aerospace industry in China makes the application requirements of the cryogenic refrigerator on aerospace more and more obvious, and the cryogenic refrigerator is more and more widely applied to superconductors, infrared detectors and low-temperature liquefaction of gas.
GLACER (general Laboratory Active Cryogenic ISS experimental regenerator) is a first low-temperature storage device developed by NASA (national air terminal for refrigeration) at-80 ℃ and can be simultaneously used for two platforms of a space station and an airship, a free piston Stirling refrigerator is adopted for refrigeration, and the refrigeration temperature of 4 ℃ to-95 ℃ can be realized in an air mode; in the water cooling mode, low-temperature storage of 4 ℃ to-160 ℃ can be realized. To further improve the low temperature storage capacity during on-track and up and down, NASA developed a single module cell size (273x460x522mm) low temperature storage product Polar in cooperation with birmingham university, alabama. The device also adopts the free piston Stirling refrigerator as a cold source, can realize low-temperature storage at minus 80 ℃ and sample transportation, and has the maximum storage volume of 12.7L.
Because space refrigeration has strict requirements on energy consumption, the improvement of the efficiency of the refrigerator is always the mainstream research direction of the space refrigerator, the mainstream space refrigerator at present is mainly a Stirling refrigerator and a pulse tube refrigerator, the theoretical refrigeration efficiency of the Stirling refrigerator and the pulse tube refrigerator is compared, and the efficiency of the pulse tube refrigerator working at the same temperature limit is always lower than that of the Stirling refrigerator from the thermodynamic perspective.
The pulse tube refrigerator has lower efficiency than the Stirling refrigerator mainly because the pulse tube refrigerator 'feeds back' the expansion work of gas to the compression cavity unlike the structure that the Stirling refrigerator has an expansion piston, and the expansion work at the hot end of the pulse tube is mainly dissipated to the environment in the form of heat through a phase modulation mechanism such as an inertia tube, a small hole and the like, so that the pulse tube refrigerator has lower efficiency.
Disclosure of Invention
In order to improve the refrigeration efficiency of the pulse tube refrigerator while ensuring the advantages of the pulse tube refrigerator, the sound-power recovery type pulse tube refrigerator is produced. For the occasion with small cold quantity requirement, the sound power dissipated by the pulse tube refrigerator in the phase modulation mechanism is very small, the significance of sound power recovery is not very obvious, for the high-power pulse tube refrigerator refrigerated in a medium-high temperature area, the sound power dissipated by the hot end is very considerable, and the effective recovery of the part of sound power is hopeful to greatly improve the refrigeration efficiency. Therefore, the sound power recovery type pulse tube refrigerator has higher research value in the aspect of large cooling capacity in the middle temperature region.
One of the objectives of the present invention is to provide a new frame and pulse tube type free piston stirling cooler for a free piston stirling cooler.
The present invention provides a housing for a free piston stirling cooler, having the characteristics of: the flange is in a disc shape, one side face of the flange is provided with a concentric disc, the other side face of the flange is connected with the base, the base is in a cylindrical shape, one end of the base is connected with the flange, the other end of the base is a free end, the central line of the base is coincident with the central line of the flange, the expansion piston pipe is a straight pipe, one end of the expansion piston pipe is connected with the disc, the other end of the expansion piston pipe is a free end and is used for connecting a pulse pipe of a refrigerator, a cylindrical heat exchange cavity and a cylindrical expansion piston cavity are arranged in the expansion piston pipe, the heat exchange cavity is communicated with the pulse pipe, the heat exchange cavity and the expansion piston cavity are coaxial and communicated, the compression piston pipe is a straight pipe and is arranged in the base, one end of the compression piston pipe is connected with the flange, the other end of the compression piston pipe is a free, the disc is provided with a plurality of through holes for communicating the compression piston cavity with the outside, the inner diameter of the compression piston cavity is larger than that of the expansion piston cavity, the inner diameter of the expansion piston cavity is larger than that of the heat exchange cavity, and the inner diameter of the heat exchange cavity is the same as that of the pulse tube.
In the frame for the free piston stirling cooler provided by the invention, the frame can also have the following characteristics: wherein the number of the through holes is between 3 and 9.
In addition, in the frame for the free-piston stirling cooler provided by the invention, the frame can also have the following characteristics: wherein, be provided with a plurality of connection screw on the free end of base.
In addition, in the frame for the free-piston stirling cooler provided by the invention, the frame can also have the following characteristics: the axis of the through hole is parallel to the axis of the compression piston pipe, and the cross section of the through hole is an arc groove.
The invention provides a pulse tube type free piston Stirling refrigerator which is characterized by comprising a frame, wherein the frame is any one of the frames.
In addition, the pulse tube type free piston stirling cryocooler provided by the present invention is characterized by further comprising a linear motor, wherein the linear motor comprises an outer yoke, an inner yoke and a mover, the outer yoke and the inner yoke are respectively arranged on the frame, a gap is formed between the outer yoke and the inner yoke, and the mover is arranged in the gap.
In addition, the pulse tube type free piston stirling cryocooler provided by the invention is characterized by further comprising a compression unit, wherein the compression unit is provided with a compression piston and a compression piston spring, the compression piston spring is fixedly connected with the rack through a connecting piece, the compression piston is arranged in the piston tube, one end of the compression piston is connected with the rotor and the compression piston spring, and the other end of the compression piston is a free end.
In addition, the pulse tube type free piston Stirling refrigerator provided by the invention is characterized by also comprising an expander unit, wherein the expander unit comprises an expansion piston, an expansion piston spring, an expansion piston rod, a primary hot end heat exchanger, a secondary hot end heat exchanger, a heat regenerator, a pulse tube and a cold end heat exchanger, the primary hot end heat exchanger is cylindrical and is sleeved on the outer wall of the expansion piston tube and arranged on the end surface of a small circular disc, one end of the pulse tube is connected with the expansion piston tube, the other end of the pulse tube is connected with the cold end heat exchanger, the heat regenerator is cylindrical and is arranged on the outer side of the pulse tube, one end of the heat regenerator is connected with the cold end heat exchanger, the other end of the heat regenerator is connected with the primary hot end heat exchanger, the secondary hot end heat exchanger is arranged in a heat exchange cavity, the expansion piston is arranged in the expansion piston, the other end of the expansion piston passes through the compression piston and the compression piston spring and then is connected with the expansion piston spring, the compression piston, the expansion piston, the compression piston cavity and the expansion piston cavity form a compression cavity, the expansion piston, the secondary hot end heat exchanger, the expansion piston cavity and the heat exchange cavity form an expansion cavity, and the compression cavity and the expansion cavity are coaxially arranged.
Action and Effect of the invention
The coaxial pulse tube type free piston Stirling refrigerator comprises a driving unit, a compression unit and an expander unit.
The coaxial pulse tube type free piston Stirling refrigerator cancels the longer low-temperature expansion piston of the traditional free piston Stirling refrigerator and is replaced by the work recovery expansion piston working in a shorter room temperature area. The expansion cylinder of the free piston Stirling refrigerator becomes a pulse tube of a pulse tube cold finger, a laminar flow guider is arranged at the cold end of the pulse tube, and a secondary hot end heat exchanger is arranged at the hot end of the pulse tube. The change combines the advantages of the free piston Stirling refrigerator and the pulse tube refrigerator, and eliminates pumping loss, shuttle loss and axial heat conduction loss caused by the low-temperature expansion piston by eliminating the expansion piston which moves at a high frequency at a cold end and a hot end. The problem of sound power recovery of the pulse tube refrigerator is solved by arranging the shorter room-temperature expansion piston at the hot end, and therefore when the sound power of the cold end is completely recovered, the theoretical efficiency of the novel pulse tube type free piston Stirling refrigerator is Carnot cycle efficiency. Meanwhile, the low-temperature expansion piston is eliminated, so that the manufacturing difficulty of the refrigerating machine is reduced, and the quality of the whole machine is reduced.
Drawings
FIG. 1 is a schematic cross-sectional view of a pulse tube type free piston Stirling cryocooler according to one embodiment of the present invention;
FIG. 2 is a perspective view of a frame in an embodiment of the invention;
FIG. 3 is a view from the direction A of FIG. 2;
FIG. 4 is a cross-sectional view C-C of FIG. 3;
FIG. 5 is a schematic cross-sectional perspective view of a frame in accordance with an embodiment of the present invention;
FIG. 6 is a schematic cross-sectional view of a pulse tube type free piston Stirling cryocooler according to a second embodiment of the present invention;
FIG. 7 is a perspective view of a second embodiment of the present invention;
FIG. 8 is a view from the direction B of FIG. 7;
FIG. 9 is a cross-sectional view taken along line D-D of FIG. 8;
FIG. 10 is a schematic cross-sectional view of an integrated airframe according to a fourth embodiment;
FIG. 11 is a schematic cross-sectional view of an embodiment five integrated airframe;
FIG. 12 is a schematic cross-sectional view of a pulse tube type free piston Stirling cooler according to a sixth embodiment of the present invention;
FIG. 13 is a schematic cross-sectional perspective view of a frame in accordance with a sixth embodiment of the present invention;
FIG. 14 is a cross-sectional schematic view of a frame in an embodiment of the invention; and
fig. 15 is a schematic cross-sectional view of a pulse tube type free piston stirling cooler with a segmented regenerator in an embodiment of the invention.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the following embodiments are specifically described in the following embodiments of the free piston stirling cryocooler of the coaxial pulse tube type with reference to the attached drawings.
Example one
As shown in fig. 1, the coaxial pulse tube type free piston stirling cooler includes a linear motor 1, a compression unit, an expander unit, an undamped dynamic vibration absorbing unit 4, a frame 50, and a housing 60.
As shown in fig. 2, 3, 4 and 5, the frame 50 includes a flange 52, a piston tube 51 provided in the flange 52 and a base 53,
the flange 52 is in a disc shape, one side of the flange is also provided with a concentric small disc 521, and the flange 52 is uniformly provided with a plurality of connecting through holes.
The base 53 is cylindrical, one end of the base is connected to one side of the flange 52, the other end of the base is a free end, the center line of the base 53 is overlapped with the center line of the flange 52, a plurality of connecting screw holes 531 are arranged on the free end of the base 53, and in the embodiment, the base 53 is four support legs arranged around the center line of the flange 52.
Piston tube 51 is the straight tube, sets up in flange 52 and with flange 52 coaxial line, outside one end opening is located the outside of little disc 521, and inboard one end opening is located base 53, has the cylindricality piston chamber in the piston tube 51, is provided with a plurality of through-holes 511 that are perpendicular to piston tube axis and pierce through the piston tube pipe wall on the piston chamber, and in the embodiment, the cross-section of through-hole 511 is the circular arc groove, and the quantity is 3.
The linear motor 1 comprises an outer yoke 11, an inner yoke 14 and a rotor, wherein the outer yoke 11 and the inner yoke 14 are respectively arranged on the frame, a gap is formed between the outer yoke and the inner yoke, the rotor is arranged in the gap, and the rotor comprises a permanent magnet 13 and a permanent magnet support 15.
As shown in fig. 1, the linear motor 1 mainly includes an outer yoke 11, a coil 12, a permanent magnet 13, an inner yoke 14, and a permanent magnet support 15, the mover includes a permanent magnet 13, a permanent magnet support 15, a connecting member 16, a fixing nut 18, a compression piston 19, and a compression piston plate spring 17 (1/3, which only takes the plate spring mass when calculating the mover mass), and the permanent magnet support 15 is connected to the permanent magnet 13, and is connected to the compression piston 19 and the connecting member 16 through a screw thread. The outer yoke iron 11 and the inner yoke iron 14 are made of soft magnetic materials, such as electrically pure iron and silicon steel sheets, and the permanent magnet 13 is made of permanent magnetic materials, such as Ru Fe B and Al Ni Co permanent magnetic materials. The outer yoke 11, the coil 12, the permanent magnet 13, and the inner yoke 14 are all annular and are arranged coaxially. The outer yoke 11 and the inner yoke 14 are respectively disposed on the frame 50, and a gap is formed between the outer yoke and the inner yoke, and the mover is disposed in the gap.
When the coil is energized with a direct current, the outer yoke iron 11 and the inner yoke iron 14 form a magnetic loop, thereby generating magnetic poles on the outer yoke iron 11 and the inner yoke iron 14. When alternating current is supplied to the coil, the permanent magnet 13 is subjected to alternating electromagnetic force to perform reciprocating linear motion. When the permanent magnet 13 makes reciprocating linear motion, the compression piston 19 is driven to make reciprocating linear motion, and the compression piston plate spring 17 provides axial reciprocating elastic force and radial support.
The compression unit comprises a connector 16, a compression piston plate spring 17, a fixing nut 18 and a compression piston 19. The compression piston plate spring 17 is connected with the connecting piece 16 through the fixing nut 18, the compression piston plate spring 17 is fixedly connected with the rack 50 through the connecting piece, the compression piston 19 is arranged in the piston cavity, one end of the compression piston is connected with the rotor and is connected with the compression piston spring 17, and the other end of the compression piston is a free end.
The expander unit comprises an expansion piston 21, an expansion piston plate spring 22, a piston rod 23, a primary hot end heat exchanger 26, a secondary hot end heat exchanger 33, a heat regenerator 25, a pulse tube 31, a cold end heat exchanger 24 and a cold finger shell 35.
The primary hot end heat exchanger 26 is cylindrical, is sleeved on the outer wall of the piston pipe 51 and is arranged on the end face of the small circular disc 521, the primary hot end heat exchanger 26 and the frame 50 are of a split structure, and the primary hot end heat exchanger 26 is in interference fit with the outer wall of the piston pipe 51.
One end of the pulse tube 31 is connected with one end of the outer side of the piston tube 51, the other end is connected with the cold-end heat exchanger 24,
the regenerator 25 is a cylinder with an annular section and is arranged outside the pulse tube 31, one end of the regenerator is connected with the cold-end heat exchanger 24, and the other end of the regenerator is connected with the first-stage hot-end heat exchanger 26.
The secondary hot end heat exchanger 33 is arranged in the pulse tube 31 and located at the joint of the pulse tube 31 and the piston tube 51, the secondary hot end heat exchanger 33 and the frame 50 are of a split structure, and the secondary hot end heat exchanger 33 is in interference fit with the inner wall of the piston tube 51.
The expansion piston 21 is arranged in the piston tube 51, the expansion piston plate spring 22 is fixedly connected with the frame 50 through a connecting piece, one end of the piston rod 23 is connected with the expansion piston 21, the other end of the piston rod passes through the compression piston 19 and the compression piston plate spring 17 and then is connected with the expansion piston plate spring 22,
compression piston 19, expansion piston 21 and piston chamber constitute the compression chamber, and compression piston 19, second grade hot junction heat exchanger 33 and piston chamber constitute the expansion chamber, and the expansion chamber is coaxial arrangement with the compression chamber.
The cold finger shell 35 is arranged outside the first-stage hot end heat exchanger 26, the heat regenerator 25 and the cold end heat exchanger 24, the shell 60 is arranged outside the frame 50 and the expander unit, and the shell 60, the cold finger shell 35 and the frame 50 are connected into a whole through connecting pieces.
The undamped dynamic vibration absorbing unit 4 is connected with the housing 60 and is arranged outside the housing 60 for damping the refrigerator.
The embodiment is suitable for the refrigerating temperature above 220K (-53 ℃), and can provide the refrigerating capacity of 50W-200W.
Example two
As shown in fig. 7, the coaxial pulse tube type free piston stirling cooler includes a linear motor 1, a compression unit, an expander unit, an undamped dynamic vibration absorbing unit 4, a frame 50B, and a housing 60.
As shown in fig. 8, 9 and 10, the frame 50B includes a flange 52B, an expansion piston tube 51B, a compression piston tube 54B and a base 53B,
the flange 52B is in a disc shape, one side surface of the flange 52B is provided with a concentric disc 521B, the other side surface is connected with the base 53B, and the flange 52B is uniformly provided with a plurality of connecting through holes.
The base 53B is cylindrical, one end of the base is connected to the flange 52B, the other end of the base is a free end, a center line of the base 53B coincides with a center line of the flange 52B, a plurality of connecting screw holes 531B are formed in the free end of the base 53B, and in the embodiment, the base 53B is four legs arranged around the center line of the flange 52B.
The expansion piston tube 51B is a straight tube with one end connected to the disc 521B and coaxial with the disc 521B and the other end being a free end for connection to a pulse tube of a refrigerator, and the expansion piston tube 51B has a cylindrical expansion piston chamber 511B therein.
The compression piston tube 54B is a straight tube, and is disposed in the base 53B, one end of the compression piston tube 54B is connected to the flange 52B and coaxial with the flange 52B, and the other end is a free end, and the compression piston tube 54B has a cylindrical compression piston cavity 541B therein, and the compression piston cavity 541B is coaxial and communicated with the expansion piston cavity 511B.
In parallel to the axis of the compression piston chamber 541B, a plurality of through holes 522B communicating the compression piston chamber 541B with the outside are provided in the disc 521B, and the number of the through holes 522B is between 3 and 9. In the embodiment, the cross section of the through hole 522B is an arc groove, and the number of the through holes is 4.
The compression piston chamber 541B has a larger inner diameter than the expansion piston chamber 511B, and the expansion piston chamber 511B has the same inner diameter as the pulse tube.
The linear motor 1 comprises an outer yoke 11, an inner yoke 14 and a rotor, wherein the outer yoke 11 and the inner yoke 14 are respectively arranged on the frame, a gap is formed between the outer yoke and the inner yoke, the rotor is arranged in the gap, and the rotor comprises a permanent magnet 13 and a permanent magnet support 15.
As shown in fig. 7, the linear motor 1 mainly includes an outer yoke 11, a coil 12, a permanent magnet 13, an inner yoke 14, and a permanent magnet support 15, the mover includes a permanent magnet 13, a permanent magnet support 15, a connecting member 16, a fixing nut 18, a compression piston 19, and a compression piston plate spring 17 (1/3, which only takes the plate spring mass when calculating the mover mass), and the permanent magnet support 15 is connected to the permanent magnet 13, and is connected to the compression piston 19 and the connecting member 16 through a screw thread. The outer yoke iron 11 and the inner yoke iron 14 are made of soft magnetic materials, such as electrically pure iron and silicon steel sheets, and the permanent magnet 13 is made of permanent magnetic materials, such as Ru Fe B and Al Ni Co permanent magnetic materials. The outer yoke 11, the coil 12, the permanent magnet 13, and the inner yoke 14 are all annular and are arranged coaxially. The outer yoke 11 and the inner yoke 14 are respectively disposed on the frame 50B with a gap therebetween, and the mover is disposed in the gap.
When the coil is energized with a direct current, the outer yoke iron 11 and the inner yoke iron 14 form a magnetic loop, thereby generating magnetic poles on the outer yoke iron 11 and the inner yoke iron 14. When alternating current is supplied to the coil, the permanent magnet 13 is subjected to alternating electromagnetic force to perform reciprocating linear motion. When the permanent magnet 13 makes reciprocating linear motion, the compression piston 19 is driven to make reciprocating linear motion, and the compression piston plate spring 17 provides axial reciprocating elastic force and radial support.
The compression unit comprises a connector 16, a compression piston plate spring 17, a fixing nut 18 and a compression piston 19. The compression piston plate spring 17 is connected with the connecting piece 16 through the fixing nut 18, the compression piston plate spring 17 is fixedly connected with the rack 50B through the connecting piece, the compression piston 19 is arranged in the compression piston cavity 541B, one end of the compression piston is connected with the rotor and connected with the compression piston spring 17, and the other end of the compression piston is a free end.
The expander unit comprises an expansion piston 21B, an expansion piston plate spring 22B, a piston rod 23B, a primary hot end heat exchanger 26B, a secondary hot end heat exchanger 33B, a heat regenerator 25B, a pulse tube 31B, a cold end heat exchanger 24B and a cold finger shell 35B.
The first-stage hot end heat exchanger 26B is cylindrical, is sleeved on the outer wall of the expansion piston pipe 51B and is arranged on the end face of the small circular disc 521B, the first-stage hot end heat exchanger 26B and the frame 50B are of a split structure, and the first-stage hot end heat exchanger 26B is in interference fit with the outer wall of the piston pipe 51B.
Pulse tube 31B has one end connected to one end of expansion piston tube 51B and the other end connected to cold side heat exchanger 24B.
Regenerator 25B is a cylinder with an annular cross section and is disposed outside pulse tube 31B, with one end connected to cold-end heat exchanger 24B and the other end connected to primary hot-end heat exchanger 26B. The heat regenerator 25B is made of any one of a polyester film, nylon and teflon, and in the embodiment, the heat regenerator 25B is made of a polyester film.
The secondary hot end heat exchanger 33B is arranged in the pulse tube 31B and is positioned at the joint of the pulse tube 31B and the expansion piston tube 51B, the secondary hot end heat exchanger 33B and the frame 50B are of a split structure, and the secondary hot end heat exchanger 33B is in interference fit with the inner wall of the expansion piston tube 51B.
The expansion piston 21B is arranged in the expansion piston pipe 51B, the expansion piston plate spring 22B is fixedly connected with the frame 50B through a connecting piece, one end of the piston rod 23B is connected with the expansion piston 21B, the other end of the piston rod passes through the compression piston 19 and the compression piston plate spring 17 and then is connected with the expansion piston plate spring 22B,
the compression piston 19, the expansion piston 21B, the compression piston chamber 541B, and the expansion piston chamber 511B constitute a compression chamber.
Expansion piston 21B, secondary warm end heat exchanger 33B and expansion piston chamber 511B form an expansion chamber. The expansion chamber and the compression chamber are coaxially arranged.
The cold finger shell 35B is arranged outside the primary hot end heat exchanger 26B, the heat regenerator 25B and the cold end heat exchanger 24B, the shell 60 is arranged outside the frame 50B and the expander unit, and the shell 60, the cold finger shell 35B and the frame 50B are connected into a whole through connecting pieces.
The radiator 27 is located outside the first-stage hot-end heat exchanger 26B and is arranged on the cold finger shell 35B, and the first-stage hot-end heat exchanger 26B transfers heat to the radiator 27 on the outer side through the cold finger shell 35B, and finally releases the heat to the environment.
The undamped dynamic vibration absorbing unit 4 is connected with the housing 60 and is arranged outside the housing 60 for damping the refrigerator.
The embodiment is suitable for the refrigerating temperature range of 120K-220K (-153 ℃ to-53 ℃), and can provide 20W-50W of refrigerating capacity.
EXAMPLE III
The other structure of this embodiment is the same as that of the embodiment, except that it further includes a flow director 32B disposed at one end of the pulse tube 31B and located inside the pulse tube 31B, and the flow director 32B is connected to the cold-side heat exchanger 24B.
Example four
The other structure of this embodiment is the same as that of the embodiment except that the secondary hot side heat exchanger 33B1 is an integral structure with the frame 50B. In the embodiment shown in fig. 10, the secondary hot side heat exchanger 33B1 is fabricated from aluminum as a whole with the frame 50B as 50B 1.
The integral structure of secondary hot side heat exchanger 33B1 and frame 50B effectively eliminates thermal contact resistance between secondary hot side heat exchanger 33B1 and frame 50B, and secondary hot side heat exchanger 33B1 may also function as a flow director.
EXAMPLE five
The other structure of this embodiment is the same as that of the fourth embodiment except that the primary hot side heat exchanger 26B2 is integral with the frame 50B. In the embodiment shown in fig. 11, the primary hot side heat exchanger 26B2, the secondary hot side heat exchanger 33B1, and the frame 50B are integrally formed of aluminum as 50B 2.
The integrated structure of first-stage hot side heat exchanger 26B2, second-stage hot side heat exchanger 33B1, and frame 50B1 effectively eliminates thermal contact resistance between first-stage hot side heat exchanger 26B2, second-stage hot side heat exchanger 33B1, and frame 50B, and at the same time, second-stage hot side heat exchanger 33B1 can also function as a flow director.
EXAMPLE six
As shown in fig. 12, the coaxial pulse tube type free piston stirling cooler includes a linear motor 1, a compression unit, an expander unit, an undamped dynamic vibration absorbing unit 4, a frame 50C, and a housing 60.
As shown in fig. 13 and 14, the frame 50C includes a flange 52C, an expansion piston tube 51C, a compression piston tube 54C and a base 53C,
the flange 52C is in a disc shape, one side surface of the flange 52C is provided with a concentric disc 521C, the other side surface is connected with the base 53C, and the flange 52C is uniformly provided with a plurality of connecting through holes.
The base 53C is cylindrical, one end of the base is connected to the flange 52C, the other end of the base is a free end, a center line of the base 53C coincides with a center line of the flange 52C, a plurality of connecting screw holes 531C are formed in the free end of the base 53C, and in the embodiment, the base 53C is four support legs arranged around the center line of the flange 52C.
The expansion piston pipe 51C is a straight pipe, one end of the expansion piston pipe is connected with the disc 521C and is coaxial with the disc 521C, the other end of the expansion piston pipe is a free end and is used for being connected with a pulse pipe of a refrigerator, the expansion piston pipe 51C is provided with a cylindrical heat exchange cavity 511C and a cylindrical expansion piston cavity 512C, the heat exchange cavity 511C is communicated with the pulse pipe, the heat exchange cavity 511C and the expansion piston cavity 512C are coaxial and communicated, the compression piston pipe 54C is a straight pipe and is arranged in the base 53C, one end of the compression piston pipe is connected with the flange 52C and is arranged in the center of the flange 52C, the other end of the compression piston pipe is a free end, the cylindrical compression piston cavity 541C is arranged in the compression piston pipe 54.
Parallel to the axis of the compression piston chamber 541C, a plurality of through holes 522C communicating the compression piston chamber 541C with the outside are provided on the disk, the number of the through holes 522C is between 3 and 9, in the embodiment, the cross section of the through hole 522C is an arc groove, and the number is 4.
The compression piston chamber 541C has a larger inside diameter than the expansion piston chamber 512C, the expansion piston chamber 512C has a larger inside diameter than the heat exchange chamber 511C, and the heat exchange chamber 511C has the same inside diameter as the pulse tube.
The linear motor 1 comprises an outer yoke 11, an inner yoke 14 and a rotor, wherein the outer yoke 11 and the inner yoke 14 are respectively arranged on the frame, a gap is formed between the outer yoke and the inner yoke, the rotor is arranged in the gap, and the rotor comprises a permanent magnet 13 and a permanent magnet support 15.
As shown in fig. 7, the linear motor 1 mainly includes an outer yoke 11, a coil 12, a permanent magnet 13, an inner yoke 14, and a permanent magnet support 15, the mover includes a permanent magnet 13, a permanent magnet support 15, a connecting member 16, a fixing nut 18, a compression piston 19, and a compression piston plate spring 17 (1/3, which only takes the plate spring mass when calculating the mover mass), and the permanent magnet support 15 is connected to the permanent magnet 13, and is connected to the compression piston 19 and the connecting member 16 through a screw thread. The outer yoke iron 11 and the inner yoke iron 14 are made of soft magnetic materials, such as electrically pure iron and silicon steel sheets, and the permanent magnet 13 is made of permanent magnetic materials, such as Ru Fe B and Al Ni Co permanent magnetic materials. The outer yoke 11, the coil 12, the permanent magnet 13, and the inner yoke 14 are all annular and are arranged coaxially. The outer yoke 11 and the inner yoke 14 are respectively disposed on the frame 50C, and a gap is provided between the outer yoke and the inner yoke, and the mover is disposed in the gap.
When the coil is energized with a direct current, the outer yoke iron 11 and the inner yoke iron 14 form a magnetic loop, thereby generating magnetic poles on the outer yoke iron 11 and the inner yoke iron 14. When alternating current is supplied to the coil, the permanent magnet 13 is subjected to alternating electromagnetic force to perform reciprocating linear motion. When the permanent magnet 13 makes reciprocating linear motion, the compression piston 19 is driven to make reciprocating linear motion, and the compression piston plate spring 17 provides axial reciprocating elastic force and radial support.
The compression unit comprises a connector 16, a compression piston plate spring 17, a fixing nut 18 and a compression piston 19. The compression piston plate spring 17 is connected with the connecting piece 16 through the fixing nut 18, the compression piston plate spring 17 is fixedly connected with the rack 50C through the connecting piece, the compression piston 19 is arranged in the compression piston cavity 541C, one end of the compression piston is connected with the rotor and connected with the compression piston spring 17, and the other end of the compression piston is a free end.
The expander unit comprises an expansion piston 21C, an expansion piston plate spring 22C, a piston rod 23C, a primary hot end heat exchanger 26C, a secondary hot end heat exchanger 33C, a heat regenerator 25C, a pulse tube 31C, a cold end heat exchanger 24C and a cold finger shell 35C.
The first-stage hot end heat exchanger 26C is cylindrical, is sleeved on the outer wall of the expansion piston pipe 51C and is arranged on the end face of the small circular disc 521C, the first-stage hot end heat exchanger 26C and the frame 50C are of a split structure, and the first-stage hot end heat exchanger 26C is in interference fit with the outer wall of the expansion piston pipe 51C.
One end of pulse tube 31C is connected to one end of expansion piston tube 51C and the other end is connected to cold end heat exchanger 24C, and cold end heat exchanger 24C is disposed at the end of cold finger shell 35C.
The regenerator 25C is a cylinder with an annular cross section and is disposed outside the pulse tube 31C, one end of the regenerator is connected to the cold-end heat exchanger 24C, and the other end of the regenerator is connected to the first-stage hot-end heat exchanger 26C. The heat regenerator 25C is made of any one of a polyester film, nylon and teflon, and in the embodiment, the heat regenerator 25C is made of a polyester film.
The secondary hot end heat exchanger 33C is arranged in the heat exchange cavity 511C and is positioned at the joint of the pulse tube 31C and the expansion piston tube 51C, the secondary hot end heat exchanger 33C and the frame 50C are of a split structure, and the secondary hot end heat exchanger 33C is in interference fit with the inner wall of the expansion piston tube 51C.
The expansion piston 21C is disposed in the expansion piston cavity 512C, the expansion piston plate spring 22C is fixedly connected to the frame 50C through a connecting member, one end of the piston rod 23C is connected to the expansion piston 21C, and the other end thereof passes through the compression piston 19 and the compression piston plate spring 17 and then is connected to the expansion piston plate spring 22C.
The compression piston 19, the expansion piston 21C, the compression piston cavity 541C, and the expansion piston cavity 512C constitute a compression cavity, the expansion piston 21C, the secondary hot-end heat exchanger 33C, the expansion piston cavity 512C, and the heat exchange cavity 511C constitute an expansion cavity, and the compression cavity and the expansion cavity are coaxially arranged.
The cold finger shell 35C is arranged outside the primary hot end heat exchanger 26C, the heat regenerator 25C and the cold end heat exchanger 24C, the shell 60 is arranged outside the frame 50C and the expander unit, and the shell 60, the cold finger shell 35C and the frame 50C are connected into a whole through connecting pieces.
The radiator 27 is located outside the first-stage hot-end heat exchanger 26C and is arranged on the cold finger shell 35C, and the first-stage hot-end heat exchanger 26C transfers heat to the radiator 27 on the outer side through the cold finger shell 35C and finally releases the heat to the environment.
The undamped dynamic vibration absorbing unit 4 is connected with the housing 60 and is arranged outside the housing 60 for damping the refrigerator.
The motion process of the expansion piston and the compression piston and the gas flow process are as follows:
the expansion piston plate spring 22C is fixed to the piston rod 23C, and the expansion piston 21C is connected to the piston rod 23C.
The expansion piston 21C is driven by pure air, and a refrigeration effect is generated by utilizing a displacement phase difference between the expansion piston 21C and the compression piston 19, and normally, the displacement of the expansion piston 21C leads the displacement of the compression piston 19 by about 70 to 100 degrees, and when the displacement phase difference is reduced to 50 to 60 degrees in a low temperature region (the cold head temperature is below-153 ℃). Since the linear motor is excited by sine alternating current, the motion of the expansion piston 21C and the compression piston 19 is also a continuous motion in a sine curve, but in order to explain the working principle, it is assumed that the expansion piston 21C and the compression piston 19 make intermittent jumping motion according to a cycle rule.
And (3) sound wave compression process: the expansion piston 21 stays still at the top dead center, the compression piston 19 moves upwards from the bottom dead center, at the moment, sound waves in the main compression cavity 29C are compressed and flow into the first-stage hot end heat exchanger 26C on the outer side of the cylinder, heat generated in the compression process is released to the first-stage hot end heat exchanger 26C, and the first-stage hot end heat exchanger 26C transfers the heat to the radiator 27 on the outer side through the outer shell and finally releases the heat to the environment. Ideally, the cylinder and the outer shell are completely heat-conducting, and meanwhile, the heat exchange area between the primary hot-end heat exchanger 26C and the radiator 27 is infinite, so that the temperature of the working medium is kept unchanged. In practice, however, isothermal compression is not possible and intermittent movement of the expansion piston 21C is not possible, the expansion piston 21C having already begun moving downward as the compression piston 19 moves upward.
The heat release process of the heat regenerator is as follows: the compression piston 19 moves to be fixed after the top dead center, the expansion piston 21C moves downwards, at the moment, sound waves pass through the heat regenerator 25C and are fully contacted with the filler in the heat regenerator 25C for heat exchange, heat is released into the heat regenerator 25C, at the moment, the temperature of the heat regenerator 25C is increased, and the temperature and the pressure of the sound waves are reduced. However, in the actual heat exchange process, the heat exchange process of the regenerator 25C is not constant in volume, and complete heat exchange between the sound wave and the filler of the regenerator 25C is not possible.
The sound wave laminar flow process: after passing through the cold side heat exchanger 24C, the gas passes through the flow director 32C and enters the pulse tube 31C in a laminar flow, pushing the gas in the pulse tube 31C towards the expansion chamber 28C. After the gas is compressed, the pressure and temperature rise. The generated heat is transferred radially through the secondary hot side heat exchanger 33C to the primary hot side heat exchanger 26C and ultimately to the radiator 27 and released to the environment. The gas in the expansion cavity 28C expands to do work to assist in pushing the expansion piston to the bottom dead center, and the work recovery compression cavity 34C becomes smaller, thereby playing a role in recovering acoustic work. In practice, the compression piston 19 does not remain at top dead center but moves downward with the expansion piston 21C, but it is noted that the two do not move in the same direction but the expansion piston leads the compression piston by a certain phase angle.
The sound wave refrigeration process: the expansion piston 21C starts to move upwards from the bottom dead center to the top dead center, the compression piston 19 moves to the bottom dead center, the expansion piston 21C pushes the sound waves in the expansion cavity 28C back to the pulse tube 31C, the gas expands in the pulse tube to absorb heat, a refrigeration effect is generated, and the lowest refrigeration temperature is reached at the top of the pulse tube 31C close to the flow guider 32C. The generated cold is led out to the cold environment through the cold end heat exchanger 24C. The acoustic wave working medium returns to the heat regenerator 25C along the original path and fully contacts with the filler for heat exchange, and returns to the main compression cavity 29C again to wait for the next compression after absorbing the heat in the heat regenerator 25C. The temperature and pressure of the acoustic wave increase and the temperature of regenerator 25C decreases in this process. In practice, the expansion piston 21C does not reach the top dead center when the compression piston 19 reaches the bottom dead center, but during the return to the top dead center, but it still leads the compression piston 19 in the phase of the displacement wave.
The embodiment is suitable for the refrigerating temperature of 120K (-153 ℃) and can provide the refrigerating capacity of 2W-20W.
Gas flow process detailed description:
as shown in figure 1, when the compression piston (19) moves towards the top dead center, gas in the compression cavity (29) is pressed into the first-stage heat exchanger (26) from an exhaust channel on the engine base, after heat generated in the compression process is released to the first-stage heat exchanger (26), gas working medium continuously moves upwards along the axial direction and flows through the regenerator, the temperature of the gas is reduced after the heat is released to the regenerator, the gas flows through the cold-end heat exchanger (24) and then enters the pulse tube (31) through the fluid director (32) in a laminar flow mode to move downwards along the axial direction, and the gas in the pulse tube (31) is pushed to the expansion cavity (28). After the gas is compressed, the pressure and temperature rise. The generated heat is transferred radially through the secondary heat exchanger (33) to the primary heat exchanger (26) and finally to the radiator (27) and released to the environment. The gas reaches the expansion cavity (28) and then expands to do work, and the expansion piston is pushed to move downwards to a point. When the expansion piston (21) moves to the lower dead point, the piston moves to the upper dead point under the action of the elastic force of the spring to push the gas in the expansion cavity (28) back to the pulse tube. The gas expands in the pulse tube to absorb heat, so that a refrigeration effect is generated, and the lowest refrigeration temperature is reached at the top of the pulse tube (31) close to the flow guider (32). After that, the gas flows through the cold-end heat exchanger and then returns to the regenerator again, absorbs the heat of the regenerator, continues to move downwards along the axial direction, passes through the hot-end heat exchanger and then returns to the compression chamber to wait for being compressed next time.
As shown in fig. 9, compared to the second frame 50 of the first embodiment with a plurality of radial holes, the second frame 50B of the second embodiment has a plurality of axially-opened kidney-shaped holes 522B as the air inlet passages, which can prevent the air from flowing in and out of the compression chamber by 90 ° rotation. The flow resistance loss of the gas working medium is greatly reduced, and the refrigerating performance of the refrigerator is improved. Simultaneously, because gas need not rotate 90 when passing in and out the compression chamber, can make gas pass through the regenerator with great velocity of flow, can know according to the heat transfer principle of convection heat transfer that the velocity of flow is big more, the surface heat transfer coefficient of gas-solid heat transfer is big more to the backheat effect of regenerator has been strengthened, has reduced the backheat loss of regenerator, promotes the refrigeration performance of refrigerator. Preferably, the cross-sectional area of 522B is about 40% to 60% of the cross-sectional area of the entire small truncated cone 521B.
The application of the three refrigerators in the first embodiment, the second embodiment and the sixth embodiment is compared.
As shown in fig. 1, 6, and 12, the three refrigerators in the first, second, and sixth embodiments correspond to refrigerator I, refrigerator II, and refrigerator III, respectively.
The PV work of the compression piston surface of the pulse tube type Stirling refrigerator is less than WPV＞＝P0AcXcPi fsin (theta) where P0 is the pressure wave amplitude, Ac is the cross-sectional area of the compression piston, Xc is the compression piston stroke, f is the operating frequency, and theta is the phase angle at which the displacement of the compression piston leads the pressure wave of the compression chamber. By the above formulaIt can be seen that the larger the compression piston cross-sectional area Ac, the greater the work input at the same Xc stroke.
The PV work of the surface of the expansion piston of the pulse tube type Stirling refrigerator is less than WPV＞＝P0AeXePi fsin (phi) where the pressure wave amplitude at P0, Ae is the cross-sectional area of the expansion piston, Xe is the expansion piston stroke, f is the operating frequency, and phi is the displacement phase angle of the expansion piston leading the compression piston. It can be seen from the above formula that the larger the cross-sectional area Ae of the expansion piston is, the larger the PV work on the surface of the expansion piston is, and the larger the refrigerating capacity of the refrigerator is.
The outer diameters of the compression pistons of the refrigerators I, II and III are the same, so that the input work of the motors is the same under the same compression piston stroke. The application occasions of the three refrigerators are compared under the same input power.
The outer diameter of the expansion piston of the refrigerator I is the same as the inner diameter of the pulse tube, the outer diameter of the expansion piston is the largest, and the expansion piston has larger PV work, so that the refrigerating capacity is larger. But the larger the inside diameter of the pulse tube, the higher the refrigeration temperature. Is suitable for the occasions with large cold quantity (50W-200W) in a high temperature region (above minus 53 ℃).
The outer diameter of the expansion piston of the refrigerator II is the same as the inner diameter of the pulse tube, but the outer diameter of the expansion piston is smaller than that of the pulse tube of the refrigerator I. Therefore, the expansion piston PV work of the refrigerator II is less than that of the refrigerator I, so the refrigerating capacity is less than that of the refrigerator I. But the inner diameter of the pulse tube is smaller than that of the refrigerator I, so the refrigerating temperature is lower than that of the refrigerator I. Is suitable for the occasions of medium-cold energy in the medium-temperature region (-153 to-53 ℃).
The outer diameter of the expansion piston of the refrigerator III is larger than the inner diameter of the pulse tube, the outer diameter of the expansion piston of the refrigerator III is the same as that of the refrigerator II, but the inner diameter of the pulse tube is smaller than that of the refrigerator II, and lower refrigerating temperature can be easily obtained by the smaller inner diameter of the pulse tube. Therefore, the refrigerator III is suitable for occasions with low cold capacity (less than 20W) in a low-temperature region (lower than-153 ℃).
EXAMPLE seven
The other structures of this embodiment are the same as those of this embodiment, except that a first filter layer is further disposed between the cold-end heat exchanger 24C and the heat regenerator 25C, and the first filter layer is in a cylindrical shape with an annular cross section and is made of a stainless steel wire mesh. The stainless steel wire has a wire diameter of 20 to 50 μm, and in the examples, the stainless steel wire has a wire diameter of 30 μm. The pressure drop of helium passing through the stainless steel wire layer is small, and the stainless steel wire layer has the characteristics of strong cold storage capacity and strong liquidity.
Example eight
The other structure of this embodiment is the same as that of the fourth embodiment, except that a second filter layer is further disposed between the primary hot-end heat exchanger 26C and the heat regenerator 25C, and the second filter layer is in the shape of a cylinder with an annular cross section and made of degreased wool. The diameter of the wool is 10-30 μm, and in the examples, the diameter of the wool is 20 μm. The wool layer has the characteristics of buffering assembly and adjusting assembly size.
As shown in fig. 15, the sectional heat regenerator is divided into three sections, which are respectively a stainless steel mesh, a polyester film and degreased wool from top to bottom, wherein the length ratio of the stainless steel mesh to the polyester film to the degreased wool is 1:8:1, and the void ratios of the stainless steel mesh, the polyester film and the degreased wool are respectively 70%, 50% and 70%.
Example nine
The other structure of this embodiment is the same as that of the sixth embodiment, except that the secondary hot side heat exchanger 33C is an integral structure with the frame 50C. In the embodiment, the second hot side heat exchanger 33C is integrally formed with the frame 50C from aluminum.
The integral structure of the secondary hot end heat exchanger and the frame effectively eliminates the thermal contact resistance between the secondary hot end heat exchanger 33C and the frame 50C, and meanwhile, the secondary hot end heat exchanger 33C can also play the role of a flow guider.
Example ten
The other structure of this embodiment is the same as that of the ninth embodiment, except that the primary hot side heat exchanger 26C and the frame 50C are of an integral structure. In the embodiment, the primary hot side heat exchanger 26C, the secondary hot side heat exchanger 33C, and the frame 50C are integrally made of aluminum.
The integrated structure of the first-stage hot end heat exchanger 26C, the second-stage hot end heat exchanger 33C and the frame 50C effectively eliminates thermal contact resistance between the first-stage hot end heat exchanger 26C, the second-stage hot end heat exchanger 33C and the frame 50C, and meanwhile, the second-stage hot end heat exchanger 33C can also play a role of a flow guider.
Effects and effects of the embodiments
The pulse tube type free piston Stirling refrigerator of the embodiment cancels the longer low-temperature expansion piston of the traditional free piston Stirling refrigerator and replaces the long low-temperature expansion piston with the work recovery expansion piston working in a shorter room temperature area. The expansion cylinder of the free piston Stirling refrigerator becomes a pulse tube of a pulse tube cold finger, a laminar flow guider is arranged at the cold end of the pulse tube, and a secondary hot end heat exchanger is arranged at the hot end of the pulse tube. The change combines the advantages of the free piston Stirling refrigerator and the pulse tube refrigerator, and eliminates pumping loss, shuttle loss and axial heat conduction loss caused by the low-temperature expansion piston by eliminating the expansion piston which moves at a high frequency at a cold end and a hot end. The problem of sound power recovery of the pulse tube refrigerator is solved by arranging the shorter room-temperature expansion piston at the hot end, and therefore when the sound power of the cold end is completely recovered, the theoretical efficiency of the novel pulse tube type free piston Stirling refrigerator is Carnot cycle efficiency. Meanwhile, the low-temperature expansion piston is eliminated, so that the manufacturing difficulty of the refrigerating machine is reduced, and the quality of the whole machine is reduced.
The above embodiments are preferred examples of the present invention, and are not intended to limit the scope of the present invention.

Claims (8)

1. A housing for a free piston Stirling cooler, the housing being formed entirely of aluminum, comprising:
a flange, an expansion piston pipe, a compression piston pipe, a first-stage hot end heat exchanger, a second-stage hot end heat exchanger and a base,
wherein the flange is in a disc shape, one side surface of the flange is provided with concentric discs, the other side surface is connected with the base,
the base is in a cylindrical shape, one end of the base is connected with the flange, the other end of the base is a free end, the central line of the base is superposed with the central line of the flange,
the expansion piston tube is a straight tube, one end of the expansion piston tube is connected with the disc, the other end of the expansion piston tube is a free end and is used for being connected with a pulse tube of a refrigerator, a cylindrical heat exchange cavity and a cylindrical expansion piston cavity are arranged in the expansion piston tube, the heat exchange cavity is communicated with the pulse tube, the heat exchange cavity and the expansion piston cavity are coaxial and communicated, the compression piston tube is a straight tube and is arranged in the base, one end of the compression piston tube is connected with the flange, the other end of the compression piston tube is a free end, a cylindrical compression piston cavity is arranged in the compression piston tube, and the compression piston cavity is coaxial and communicated with the expansion piston,
parallel to the axis of the compression piston cavity, a plurality of through holes which are communicated with the compression piston cavity and the outside are arranged on the disc,
the first-stage hot end heat exchanger is cylindrical and is arranged on the outer wall of the expansion piston pipe,
the secondary hot end heat exchanger is arranged in the expansion piston pipe,
the compression piston chamber has an inner diameter greater than an inner diameter of the expansion piston chamber, the expansion piston chamber has an inner diameter greater than an inner diameter of the heat exchange chamber, and the heat exchange chamber has an inner diameter the same as an inner diameter of the pulse tube.
2. A housing for a free piston stirling cooler in accordance with claim 1 wherein:
wherein the number of the through holes is between 3 and 9.
3. A housing for a free piston stirling cooler in accordance with claim 1 wherein:
wherein, be provided with a plurality of connection screw on the free end of base.
4. A housing for a free piston stirling cooler in accordance with claim 1 wherein:
the cross section of the through hole is an arc groove.
5. A pulse tube type free piston stirling cooler comprising:
a rack as claimed in any one of claims 1 to 4.
6. The pulse tube type free piston stirling cooler of claim 5 further comprising:
a linear motor is arranged on the base plate,
the linear motor comprises an outer yoke iron, an inner yoke iron and a rotor, the outer yoke iron and the inner yoke iron are respectively arranged on the rack, a gap is formed between the outer yoke iron and the inner yoke iron, and the rotor is arranged in the gap.
7. The pulse tube type free piston stirling cooler of claim 6 further comprising:
a compression unit for compressing the compressed air in the compressed air,
the compression unit is provided with a compression piston and a compression piston spring, the compression piston spring is fixedly connected with the rack through a connecting piece, the compression piston is arranged in the compression piston cavity, one end of the compression piston is connected with the rotor and is connected with the compression piston spring, and the other end of the compression piston is a free end.
8. The pulse tube type free piston stirling cooler of claim 5 further comprising:
an expander unit having a plurality of expander units,
the expander unit comprises an expansion piston, an expansion piston spring, an expansion piston rod, a primary hot end heat exchanger, a secondary hot end heat exchanger, a heat regenerator, a pulse tube and a cold end heat exchanger,
the first-stage hot end heat exchanger is cylindrical, is sleeved on the outer wall of the expansion piston pipe and is arranged on the end surface of the disc,
one end of the pulse tube is connected with the expansion piston tube, the other end of the pulse tube is connected with the cold-end heat exchanger,
the heat regenerator is cylindrical and arranged on the outer side of the pulse tube, one end of the heat regenerator is connected with the cold end heat exchanger, the other end of the heat regenerator is connected with the primary hot end heat exchanger,
the secondary hot end heat exchanger is arranged in the heat exchange cavity,
the expansion piston is arranged in the expansion piston pipe, the expansion piston spring is fixedly connected with the frame through a connecting piece, one end of the expansion piston rod is connected with the expansion piston, the other end of the expansion piston rod penetrates through the compression piston and the compression piston spring and then is connected with the expansion piston spring,
the compression piston, the expansion piston, the compression piston cavity and the expansion piston cavity form a compression cavity,
the expansion piston, the secondary hot end heat exchanger, the expansion piston cavity and the heat exchange cavity form an expansion cavity,
the compression chamber is disposed coaxially with the expansion chamber.
CN201810437952.8A 2018-05-09 2018-05-09 Frame and pulse tube type free piston Stirling refrigerator Active CN108413641B (en)

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CN1083970C (en) * 1995-01-24 2002-05-01 中国科学院低温技术实验中心 Reversible vessel refrigerator driven by conventional gas refrigerator
US5647217A (en) * 1996-01-11 1997-07-15 Stirling Technology Company Stirling cycle cryogenic cooler
JP3855225B2 (en) * 2001-10-19 2006-12-06 グローバル クーリング ビー ヴイ Free piston and Stirling equipment casing
CN101619687B (en) * 2009-08-11 2011-01-05 深圳市中科力函热声技术工程研究中心有限公司 Piston-free Stirling engine system
CN103062951B (en) * 2013-01-25 2015-03-25 浙江大学 Low-temperature J-T (Joule-Thomson) throttling cooler precooled by Stirling/pulse tube composite type cooler
CN103062952B (en) * 2013-01-30 2014-12-03 浙江大学 Pulse tube/Stirling gas coupling composite multi-stage refrigerator
CN104457009B (en) * 2014-11-27 2016-08-24 中科力函（深圳）低温技术有限公司 A kind of low temperature pulse tubes refrigeration machine using mixed structure
CN105066500B (en) * 2015-09-22 2017-10-31 中国科学院理化技术研究所 A kind of thermal drivers pulse tube cooler system

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