CN-122015319-A - Low-vibration active phase modulation compound pulse tube Stirling refrigerator

CN122015319ACN 122015319 ACN122015319 ACN 122015319ACN-122015319-A

Abstract

The invention discloses a low-vibration active phase modulation compound pulse tube Stirling refrigerator, and belongs to the technical field of low-temperature refrigerators. The cold finger of the composite refrigerator integrates a first-stage Stirling component serving as a high-temperature stage and a second-stage pulse tube component serving as a low-temperature stage, and is characterized in that a phase modulation unit of the second-stage pulse tube component is formed by winding and fixing a second-stage inertia tube on the inner circle of a gas reservoir, the gas reservoir is integrally fixedly connected to a first-stage cold end heat exchanger, and the system efficiency is improved through low-temperature arrangement. Meanwhile, the motion states of the compressor piston and the primary discharger are monitored in real time and cooperatively controlled through the compressor displacement sensor and the cold finger displacement sensor, active accurate phase modulation is achieved, and the active vibration absorber is utilized for reverse compensation according to the motion feedback of the primary discharger, so that vibration output of the whole machine is remarkably counteracted. The invention realizes the unification of high efficiency, low vibration and high reliability, and is particularly suitable for application scenes such as space detection sensitive to vibration.

Inventors

JIANG ZHENHUA
DING LEI
TANG YIHAO
WANG SHUANG
HUANG ZHENG
Miao Zhejun
YANG BAOYU
WU YINONG

Assignees

中国科学院上海技术物理研究所

Dates

Publication Date: 20260512
Application Date: 20260409

Claims (10)

1. A low-vibration active phase modulation compound pulse tube Stirling refrigerator is characterized by comprising a driving compressor, a connecting tube, a compound refrigerator cold finger and an active vibration damper, wherein, The driving compressor is communicated with the gas cavity of the cold finger of the compound refrigerator in a sealing way through a connecting pipe so as to transmit pressure waves generated by compression to the cold finger of the compound refrigerator; The cold finger of the compound refrigerator comprises a primary Stirling component and a secondary pulse tube component which are integrated on the same axis, the secondary pulse tube component comprises a secondary inertia tube and an air reservoir which are used as a phase modulation unit, the air reservoir and the secondary inertia tube are integrated into an integral structure and are directly fixedly connected to a primary cold end heat exchanger of the primary Stirling component, so that the phase modulation unit is in a low-temperature environment provided by the primary cold end heat exchanger during operation; the active vibration damper is rigidly and fixedly connected with the cold finger of the compound refrigerator.
2. The low vibration active phase modulation compound pulse tube stirling cooler of claim 1, wherein the compressor piston assembly driving the compressor is resiliently supported within the compressor housing by a compressor leaf spring assembly, the compressor motor assembly is fixedly mounted to the compressor housing and drivingly connected to the compressor piston assembly for driving the compressor piston assembly to reciprocate, the compressor piston assembly, the compressor leaf spring assembly and the compressor motor assembly are disposed in opposition, and the compressor displacement sensor is disposed at the rear end of the piston assembly for detecting displacement thereof.
3. A low vibration active phase modulation compound pulse tube stirling cooler in accordance with claim 1 wherein the primary displacer of the primary stirling assembly is resiliently supported within the primary displacer housing by a cold finger leaf spring assembly, the mover portion of the cold finger phase modulation motor being drivingly connected to the primary displacer, and a cold finger displacement sensor disposed at the aft end of the primary displacer for sensing displacement thereof.
4. The low-vibration active phase-modulation composite pulse tube Stirling refrigerator according to claim 1, wherein the secondary pulse tube assembly adopts a coaxial structure, an annular secondary regenerator is surrounded and sleeved outside a tubular secondary pulse tube, and the low-temperature end of the secondary regenerator is connected with a secondary cold end heat exchanger.
5. The low vibration active phase modulation compound pulse tube stirling cooler of claim 1, wherein the secondary inertance tube is tightly coiled in the internal cavity of the air reservoir in a spiral shape, and the secondary inertance tube and the air reservoir are fixed into an integral structure by welding or high heat conduction adhesive.
6. A low vibration active phase modulation compound pulse tube stirling cooler in accordance with claim 1 wherein the balance mass of the active damper is resiliently supported within the damper housing by a damper leaf spring assembly, the mover portion of the damper motor being drivingly connected to the balance mass, and a self-sensing displacement sensor disposed at the primary ejector tail end for sensing the movement thereof.
7. A low vibration, active phase modulation, compound pulse tube stirling cooler in accordance with claim 2 further comprising a control system to which the compressor displacement sensor, cold finger displacement sensor, and self-sensing displacement sensor signals are all connected.
8. The low vibration active phase modulation compound pulse tube stirling cooler of claim 7, wherein the control system controls the drive voltages of the compressor motor assembly and the cold finger phase modulation motor based on the detection signals of the compressor displacement sensor and the cold finger displacement sensor, respectively, and controls the vibration reduction motor to drive the balance mass to generate a compensating motion opposite to the motion of the primary ejector based on the detection signals of the self-induced displacement sensor.
9. The low vibration active phase modulation compound pulse tube stirling cooler of claim 5, wherein the outer wall of the air reservoir is integrally coated with a thermally insulating layer comprising a plurality of layers of high reflectivity film.
10. The low vibration, active phase modulation, compound pulse tube stirling cooler of claim 7, wherein the control system is integrated with a unified control unit that synchronously processes the signals from the compressor displacement sensor, cold finger displacement sensor, and self-sensing displacement sensor and cooperatively outputs drive commands to the compressor motor assembly, cold finger phase modulation motor, and vibration reduction motor.

Description

Low-vibration active phase modulation compound pulse tube Stirling refrigerator Technical Field The invention belongs to the technical field of low-temperature refrigerators, and particularly relates to a low-vibration active phase modulation compound pulse tube Stirling refrigerator. Background The low-temperature refrigeration technology has an irreplaceable core effect in the fields of aerospace, quantum information, infrared detection, basic scientific research and the like. The regenerative cryo-refrigerator, in particular the stirling refrigerator and pulse tube refrigerator, is the main technical route in this field. Stirling refrigerators have high theoretical efficiency in medium temperature regions (e.g., 40K-80K) because of the active ejector at the cold end, which can realize efficient sound power recovery and phase adjustment. However, when the multi-stage Stirling structure is expanded to lower temperature (such as 10K-20K), the requirement on the matching precision of friction pairs is extremely high due to the increase of moving parts, and the risks of abrasion and clamping stagnation exist, so that the development of the multi-stage Stirling structure in space application requiring long service life and high reliability is seriously restricted. Pulse tube refrigerators fundamentally solve the reliability problem by eliminating the moving parts of the cold end completely, but their intrinsic efficiency is low due to the thermal dissipation of the acoustic work at the hot end of the pulse tube. Especially, the low-temperature level pulse tube, the traditional passive phase modulation modes such as a small hole-air reservoir or an inertia tube and the like are difficult to establish the optimal acoustic impedance matching and phase relation in the deep low-temperature regenerator, so that the overall efficiency of the multi-stage pulse tube refrigerator is obviously lower than that of the same-stage Stirling refrigerator, and the disadvantages of volume and weight are caused. To achieve both efficiency and reliability, compound refrigerator solutions (e.g., stirling-pulse tube compound) have been developed. Such schemes typically place the stirling cycle at a high temperature level to take advantage of its efficiency and the vascular cycle at a low temperature level to ensure reliability in the deep low temperature region. However, the existing compound scheme still faces two major bottlenecks, namely, firstly, the phase modulation precision and flexibility of the low-temperature-level pulse tube are insufficient, the further improvement of the overall efficiency is limited, and secondly, the reciprocating motion of the high-temperature-level Stirling discharger and the compressor can generate considerable mechanical vibration, which is unacceptable for carrying loads extremely sensitive to micro-vibration, such as a superconducting quantum interference device (SQUID). Prior art approaches have attempted to provide active phasing of the low temperature stage pulse tubes by means of separate phasing compressors or to dampen vibrations by means of additional counter-moving balancing masses. However, these schemes tend to be complex in system, loose in layout, difficult to control coupling, and not deeply optimized from the thermodynamic cycle level of the system, and difficult to achieve engineering goals of high efficiency, low vibration and high compactness simultaneously under limited space and power consumption constraints. Therefore, developing a compound refrigerator with compact structure, accurate phase modulation and remarkable vibration suppression effect becomes a key technical problem to be solved in the field. Disclosure of Invention The invention provides a low-vibration active phase modulation compound pulse tube Stirling refrigerator, which is characterized in that a cold finger of the compound pulse tube Stirling refrigerator is connected with a compressor through a connecting pipe, an oscillating helium working medium sequentially enters a first-stage ejector cavity and a second-stage cold accumulator cavity from the compressor through the connecting pipe, the refrigerating capacity is realized through gas expansion in the first-stage cold end heat exchanger cavity and the second-stage cold end heat exchanger cavity, the displacement of a compressor piston and the first-stage ejector is monitored and adjusted in real time through a compressor displacement sensor and a phase modulation displacement sensor, the accurate phase modulation control is realized, the low-vibration output is realized through an active vibration absorber, and the low temperature of the second-stage inertia tube and a gas reservoir is realized through arranging the second-stage inertia tube and the gas reservoir on the first-stage cold end heat exchanger, so that the refrigerating capacity is improved. In order to achieve the above purpose, the invention adopts the following technical scheme: A low-vibrat