A device and method for evaluating the optimal phase matching of a pneumatic Stirling refrigerator

Abstract

The present invention discloses a device and method for evaluating the optimal phase matching of a pneumatic Stirling refrigerator. The linear compressor and the phase-adjusting Stirling cold finger in the device are connected by a connecting pipe; the pressure sensor is installed on the connecting pipe to measure the pressure wave at the outlet of the linear compressor; the displacement sensor is used to measure the displacement wave of the piston in the compressor and the cold finger; the control system controls and adjusts the displacement and phase relationship between the compressor and the piston in the Stirling cold finger by adjusting the input voltage amplitude and phase of the compressor and the expander drive motor, and obtains the optimal phase relationship under the optimal performance of the Stirling cold finger; the drive motor is removed, the displacement and phase relationship between the compressor and the piston in the pneumatic cold finger is tested, and whether the pneumatic Stirling refrigerator reaches the optimal phase relationship is evaluated. The advantages of the present invention are that the optimal phase relationship of the Stirling refrigerator can be obtained simply and quickly, whether the pneumatic Stirling reaches the optimal phase, and the design optimization efficiency of the Stirling refrigerator can be improved.

Description

Technical Field

[0001] The present invention relates to a regenerative cryogenic refrigerator, and more particularly to a device and method for evaluating the optimal phase matching of a Stirling refrigerator. Background Art

[0002] As high-temperature superconducting materials, infrared detection technology and cryogenic technology are increasingly used in energy, medical, aerospace and other fields, the application areas of cryogenic refrigerators are becoming wider and wider.

[0003] Stirling refrigerator is a typical type of regenerative cryogenic refrigerator, which can be divided into integral type and split type. Split Stirling refrigerator connects the compressor and the cold finger through a thin tube, and the two are placed completely independently. Compared with the integral type, the split type can effectively reduce the impact of compressor vibration and noise on the performance of the cold finger. The split Stirling refrigerator is a piston-displacer type refrigerator composed of two separate cylinders with reciprocating motion, and the expansion piston moves freely in the cylinder. Therefore, how the expansion piston maintains the correct stroke in the cylinder and how to maintain a suitable phase relationship with the movement of the compressor piston is the main problem of the split Stirling refrigerator. The expansion piston can be driven by an independent motor, and a complex electronic control system is used to accurately control the phase difference between the movement of the compressor piston and the expansion piston.

[0004] The expansion piston of the pneumatic split Stirling refrigerator is not driven by a motor. The entire refrigerator has only one motor, the compressor, so the weight and volume of the whole machine will be reduced, and the energy consumption is low, which has attractive application prospects in the fields of infrared and superconducting electronics. In this case, the displacer is driven by the periodic pressure wave generated by the compressor. The displacer and the supporting spring form a forced vibration system. The damping force generated can produce a suitable phase difference, so that the movement of the displacer leads the compression piston by a phase angle to produce refrigeration. How to evaluate the phase angle has always been a difficult point in the design of pneumatic refrigerators. Summary of the invention

[0005] In view of the above problems and needs existing in the prior art, the object of the present invention is to provide a device and method for evaluating the optimal phase matching of a pneumatic Stirling refrigerator. This method has high reliability and simple operation, and can effectively improve the efficiency of refrigerator design optimization.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A device for evaluating the optimal phase matching of a pneumatic Stirling refrigerator comprises a linear compressor, a connecting pipe, a phase-adjusting Stirling cold finger, a data acquisition and control system, a pressure sensor, a drive motor, a vacuum dewar, a refrigeration capacity test system, a drive power supply, a first displacement sensor of the compressor, a second displacement sensor of the compressor, a Stirling cold finger displacement sensor and a Stirling cold finger to be evaluated, wherein the phase-adjusting Stirling cold finger comprises a cold head, an expansion piston, a cylinder and a spring.

[0008] The linear compressor is connected to the phase-adjusting Stirling cold finger through a connecting pipe, and a pressure sensor is installed on the connecting pipe; the linear compressor adopts an opposed linear compressor, and the first displacement sensor of the compressor and the second displacement sensor of the compressor are respectively installed on both sides of the linear compressor; the cold head is installed with a refrigeration capacity test system to measure the refrigeration temperature and refrigeration capacity; the vacuum dewar is installed on the outside of the cylinder through a flange structure to ensure high vacuum during testing; the phase-adjusting Stirling cold finger is connected to the driving motor and supports the expansion piston through a spring; a Stirling cold finger displacement sensor is installed on the driving motor side; the pressure sensor, the first displacement sensor of the compressor, the second displacement sensor of the compressor, the Stirling cold finger displacement sensor, and the refrigeration capacity test system are connected with the data acquisition and control system for adjusting and monitoring the data of each measuring point.

[0009] The connecting pipe adopts a threaded connection between the linear compressor and the phase-modulating Stirling cold finger, which is convenient for disassembly and assembly and improves work efficiency.

[0010] The pressure sensor is connected to the connecting pipe through threads.

[0011] The driving motor is driven by a linear motor.

[0012] The Stirling cold finger to be evaluated is a pneumatic Stirling cold finger, which reciprocates through a spring-supported expansion piston.

[0013] In a possible implementation, the displacement sensor is a laser displacement sensor, wherein a lens is installed at the bottom of the housing of the linear compressor, the housing and the lens are connected through a flange structure, and the first displacement sensor of the compressor and the second displacement sensor of the compressor measure the displacement wave of the piston of the linear compressor through the lens;

[0014] The lens is made of sapphire glass material;

[0015] The Stirling cold finger displacement sensor uses the same method to measure the displacement wave on the cold finger side.

[0016] In another possible implementation, the displacement sensor is a metal induction linear displacement sensor.

[0017] A method for evaluating the optimal phase matching of a pneumatic Stirling refrigerator comprises the following steps:

[0018] 1) Real-time monitoring of the first displacement sensor of the compressor, the second displacement sensor of the compressor, the pressure sensor, the Stirling cold finger displacement sensor, and the refrigeration capacity test system is performed through the data acquisition system;

[0019] 2) The control system adjusts the input voltage amplitude and phase of the linear compressor and the drive motor to adjust the piston displacement X c , Expansion piston displacement X d ;

[0020] 3) Using a pressure sensor to measure the pressure wave P between the linear compressor and the phase-modulated Stirling cold finger in real time;

[0021] 4) The PV work output by the linear compressor is obtained based on thermodynamic calculations: A c is the cross-sectional area of ​​the linear compressor piston, ΔP c The maximum pressure P at the connecting pipe max With minimum pressure P min The difference between the two, θ represents the phase angle at which the pressure wave at the connecting pipe leads the piston displacement.

[0022] 5) Collect the temperature T at the cold head through the cooling capacity test system c and cooling capacity Q;

[0023] 6) Obtain the phase-modulated Stirling cold finger refrigeration performance: This performance is an important indicator for evaluating the refrigeration performance of Stirling refrigerators;

[0024] 7) The expansion piston phase angle is adjusted by the driving motor. When the COP is the optimal value, the displacement phase difference between the expansion piston and the linear compressor piston is

[0025] 8) Remove the drive motor and use pneumatic phase modulation instead of motor driven active phase modulation. Test the displacement and phase relationship between the piston in the compressor and the expansion piston in the pneumatic Stirling cold finger to be evaluated through the data acquisition system. The phase difference between the expansion piston displacement and the compressor piston displacement is α. Compare the phase difference and α, if the two phase differences are equal, the pneumatic Stirling refrigerator reaches the optimal phase relationship, otherwise it does not reach the optimal phase relationship.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention can simply and quickly obtain the optimal phase relationship of the Stirling refrigerator by actively adjusting the phase through motor drive; remove the driving motor, test the phase relationship between the compressor and the piston in the pneumatic cold finger, and evaluate whether the pneumatic Stirling reaches the optimal phase. This method is beneficial to improving the optimization efficiency of the Stirling cold finger design. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a system for evaluating the optimal phase matching of a pneumatic Stirling refrigerator provided for the implementation of the present invention;

[0029] Figure 2 A schematic diagram of a pneumatic Stirling refrigerator system to be evaluated for the implementation of the present invention;

[0030] Figure 3 Schematic diagram of testing piston displacement using a laser displacement sensor provided for implementation of the present invention.

[0031] The numbers in the figure are as follows: 1. Linear compressor; 101. Piston; 102. Casing; 103. Lens; 104. Flange structure; 2. Connecting pipe; 3. Phase-adjusting Stirling cold finger; 301. Cold head; 302. Expansion piston; 303. Cylinder; 304. Spring; 4. Data acquisition and control system; 5. Pressure sensor; 6. Drive motor; 7. Vacuum dewar; 8. Refrigeration capacity test system; 9. Drive power supply; 10. First displacement sensor of compressor; 11. Second displacement sensor of compressor; 12. Stirling cold finger displacement sensor; 13. Pneumatic Stirling cold finger to be evaluated. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0033] Combination Figure 1 As shown, this embodiment provides a device for evaluating the optimal phase matching of a pneumatic Stirling refrigerator, including a linear compressor 1, a connecting pipe 2, a phase-adjusting Stirling cold finger 3, a data acquisition and control system 4, a pressure sensor 5, a drive motor 6, a vacuum dewar 7, a refrigeration capacity test system 8, a drive power supply 9, a compressor first displacement sensor 10, a compressor second displacement sensor 11, a Stirling cold finger displacement sensor 12, and a pneumatic Stirling cold finger to be evaluated 13, wherein the phase-adjusting Stirling cold finger 3 includes a Stirling cold head 301, an expansion piston 302, a cylinder 303 and a spring 304.

[0034] In this embodiment, the linear compressor 1 is connected to the phase-modulated Stirling cold finger 3 through a connecting pipe 2, and a pressure sensor 5 is installed on the connecting pipe 2; the linear compressor 1 adopts an opposed linear compressor 1, and the first displacement sensor 10 of the compressor and the second displacement sensor 11 of the compressor are respectively installed on both sides of the linear compressor 1; the cold head 301 is installed with a refrigeration capacity test system 8 to measure the refrigeration temperature and refrigeration capacity; the vacuum dewar 7 is installed on the outside of the cylinder 303 through a flange structure 104 to ensure high vacuum during testing; the phase-modulated Stirling cold finger 3 is connected to the drive motor 6, and the expansion piston 302 is supported by a spring 304; a Stirling cold finger displacement sensor 12 is installed on the side of the drive motor 6; the first displacement sensor 10 of the compressor, the second displacement sensor 11 of the compressor, the pressure sensor 5, the Stirling cold finger displacement sensor 12, and the refrigeration capacity test system 8 are connected to the data acquisition and control system 4 for adjusting and monitoring the data of each measuring point.

[0035] In order to facilitate disassembly and assembly and improve work efficiency, the connecting pipe 2 is threadedly connected to the linear compressor 1 and the phase-modulating Stirling cold finger 3.

[0036] Taking into account the convenience of measurement, the pressure sensor 5 is connected to the connecting pipe 2 through threads.

[0037] In this embodiment, the pressure sensor 5 is a voltage sensor type, and its model is Kistler 5015A1000

[0038] In this embodiment, the driving motor 6 is driven by a linear motor.

[0039] In this embodiment, the Stirling cold finger 13 to be evaluated is a pneumatic Stirling cold finger, which reciprocates through a spring-supported expansion piston.

[0040] The displacement sensor testing method is described in detail below through specific embodiments.

[0041] In a possible implementation, the displacement sensor is a laser displacement sensor, wherein:

[0042] Combination Figure 2 As shown, a lens 103 is installed at the bottom of the housing 102 of the linear compressor 1, and the housing 102 and the lens 103 are connected through a flange structure 104. The first displacement sensor 10 of the compressor and the second displacement sensor 11 of the compressor measure the displacement wave of the piston 101 of the linear compressor 1 through the lens 103;

[0043] The Stirling cold finger displacement sensor uses the same method to measure the displacement wave on the cold finger side;

[0044] The lens 103 is made of sapphire glass.

[0045] In this embodiment, the laser displacement sensor adopts Ometron Type 83038.

[0046] In another possible implementation, the displacement sensor is a metal induction linear displacement sensor.

[0047] Next, combine Figure 1 As shown, the specific implementation method of the above device is described in detail.

[0048] 1) Real-time monitoring of the compressor first displacement sensor 10, the compressor second displacement sensor 11, the pressure sensor 5, the Stirling cold finger displacement sensor 12, and the refrigeration capacity test system 8 is performed through the data acquisition and control system 4;

[0049] 2) The control system adjusts the input voltage amplitude and phase of the linear compressor 1 and the drive motor 6 to adjust the displacement X of the piston 101 c , expansion piston 302 displacement X d ;

[0050] 3) measuring the pressure wave P between the linear compressor 1 and the phase-modulated Stirling cold finger 3 in real time through the pressure sensor 5;

[0051] 4) The PV work output by the linear compressor 1 is obtained according to thermodynamic calculation: A c is the cross-sectional area of ​​the piston 101 of the linear compressor 1, ΔP c The maximum pressure P at the connecting pipe 2 max With minimum pressure P min , θ represents the phase angle at which the pressure wave at the connecting pipe 2 leads the displacement of the piston 101.

[0052] 5) The temperature T at the cold head 301 is collected by the cooling capacity test system 8 c and cooling capacity Q;

[0053] 6) Get the refrigeration performance of the phase-modulated Stirling cold finger 3: This performance is an important indicator for evaluating the refrigeration performance of Stirling refrigerators;

[0054] 7) The phase angle of the expansion piston 302 is adjusted by the driving motor 6. When the COP is at the optimal value, the displacement phase difference between the expansion piston 302 and the piston 101 of the linear compressor 1 is

[0055] 8) Remove the drive motor 6 and use pneumatic phase adjustment instead of motor driven active phase adjustment. Test the displacement and phase relationship between the piston 101 in the compressor and the expansion piston 302 in the pneumatic Stirling cold finger 13 to be evaluated through the data acquisition system. At this time, the displacement phase difference between the expansion piston 302 and the piston 101 of the compressor is α. Compare the phase difference and α, if the two phase difference values ​​are equal, the pneumatic Stirling cold finger 13 to be evaluated reaches the optimal phase relationship, otherwise it does not reach the optimal phase relationship.

[0056] Finally, it is necessary to point out here that the above embodiments are only preferred specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A device for evaluating the optimal phase matching of a pneumatic Stirling refrigerator, comprising a linear compressor (1), a connecting pipe (2), a phase-adjusting Stirling cold finger (3), a data acquisition and control system (4), a pressure sensor (5), a drive motor (6), a vacuum dewar (7), a refrigeration capacity test system (8), a drive power supply (9), a first displacement sensor of the compressor (10), a second displacement sensor of the compressor (11), a Stirling cold finger displacement sensor (12) and a pneumatic Stirling cold finger to be evaluated (13), characterized in that: The phase-adjusting Stirling cold finger (3) comprises a cold head (301), an expansion piston (302), a cylinder (303) and a spring (304); the linear compressor (1) is connected to the phase-adjusting Stirling cold finger (3) via a connecting pipe (2), and a pressure sensor (5) is mounted on the connecting pipe (2); the pressure sensor (5) is connected to the connecting pipe (2) by threaded connection; the connecting pipe (2) is threadedly connected to the linear compressor (1) and the phase-adjusting Stirling cold finger (3); the linear compressor (1) is an opposed linear compressor, and a first displacement sensor (10) and a second displacement sensor (11) of the compressor are respectively mounted on two sides of the linear compressor (1); A refrigeration capacity test system (8) is installed on the cold head (301) for measuring refrigeration temperature and refrigeration capacity; a vacuum dewar (7) is installed on the outside of the cylinder (303) via a flange structure; a phase-modulated Stirling cold finger (3) is connected to a drive motor (6) and supports an expansion piston (302) via a spring (304); a Stirling cold finger displacement sensor (12) is installed on the side of the drive motor (6); the pressure sensor (5), a first displacement sensor (10) of the compressor of the refrigeration capacity test system (8), a second displacement sensor (11) of the compressor, and a Stirling cold finger displacement sensor (12) are connected to a data acquisition and control system (4) for adjusting and monitoring data at each measuring point.

2. The device for evaluating the optimal phase matching of a pneumatic Stirling refrigerator according to claim 1, characterized in that: The Stirling cold finger (13) to be evaluated is a pneumatic Stirling cold finger, which is supported by a spring to perform reciprocating motion on an expansion piston.

3. The device for evaluating the optimal phase matching of a pneumatic Stirling refrigerator according to claim 1, characterized in that: The first compressor displacement sensor (10) and the second compressor displacement sensor (11) are laser displacement sensors. The first compressor displacement sensor (10) and the second compressor displacement sensor (11) measure the displacement wave of the piston of the linear compressor (1) through a lens (103) installed at the bottom of the housing (102) of the linear compressor (1).

4. The device for evaluating the optimal phase matching of a pneumatic Stirling refrigerator according to claim 1, characterized in that: The Stirling cold finger displacement sensor (12) adopts a laser displacement sensor and measures the displacement wave on the cold finger side in the same way as the first compressor displacement sensor (10) and the second compressor displacement sensor (11).

5. The device for evaluating the optimal phase matching of a pneumatic Stirling refrigerator according to claim 1, characterized in that: The compressor first displacement sensor (10), the compressor second displacement sensor (11), and the Stirling cold finger displacement sensor (12) may also be metal induction linear displacement sensors.

6. A method for evaluating the optimal phase matching of a pneumatic Stirling refrigerator based on the device for evaluating the optimal phase matching of a pneumatic Stirling refrigerator according to claim 1, characterized in that The following steps are involved: 1) real-time monitoring of the pressure sensor (5), the refrigeration capacity test system (8), the first displacement sensor (10) of the compressor, the second displacement sensor (11) of the compressor, and the Stirling cold finger displacement sensor (12) by means of a data acquisition system; 2) The control system adjusts the input voltage amplitude and phase of the linear compressor (1) and the drive motor (6) to adjust the displacement X of the piston (101) c , Expansion piston (302) displacement X d ; 3) measuring the pressure wave P between the linear compressor (1) and the phase-modulated Stirling cold finger (3) in real time through a pressure sensor (5); 4) The PV work output by the linear compressor (1) is obtained according to thermodynamic calculation: A c is the cross-sectional area of ​​the piston (101) of the linear compressor (1), ΔP c is the maximum pressure P at the connecting pipe (2) max With minimum pressure P min θ represents the phase angle at which the pressure wave at the connecting pipe (2) leads the displacement of the piston (101); 5) The temperature T at the cold head (301) is collected by the cooling capacity test system (8) c and cooling capacity Q; 6) Get the phase-modulated Stirling cold index (3) refrigeration performance: This performance is an important indicator for evaluating the refrigeration performance of Stirling refrigerators; 7) The phase angle of the expansion piston (302) is adjusted by the driving motor (6). When the COP is at the optimal value, the displacement phase difference between the expansion piston (302) and the piston (101) is ; 8) The driving motor (6) is removed, and pneumatic phase modulation is used instead of motor-driven active phase modulation. The displacement and phase relationship between the piston (101) in the compressor and the expansion piston (302) in the pneumatic Stirling cold finger (13) to be evaluated is tested by a data acquisition system to evaluate whether the pneumatic Stirling refrigerator has reached the optimal phase relationship; at this time, the displacement phase difference between the expansion piston (302) and the displacement phase of the compressor piston (101) is α, and the phase difference is compared. and α, if the two phase differences are equal, the pneumatic Stirling refrigerator reaches the optimal phase relationship, otherwise it does not reach the optimal phase relationship.

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