An expander unit and a pulse-tube free-piston Stirling refrigerator

Abstract

The invention discloses an expander unit and a pulse-tube type free piston Stirling refrigerator. The expander unit comprises an expansion piston, an expansion piston spring, an expansion piston rod,a first-stage head end heat exchanger, a second-stage head end heat exchanger, a regenerator, a pulse tube and a cold end heat exchanger; an expansion piston tube is a straight tube used for being connected with the pulse tube of a refrigerator and is internally provided with a cylindrical heat exchange cavity and a cylindrical expansion piston cavity; a compression piston tube is a straight tubeand is internally provided with a cylindrical compression piston cavity; the compression piston cavity is coaxial with the expansion piston cavity and communicates with the expansion piston cavity; parallel to the axis of the compression piston cavity, multiple through holes used for communicating the compression piston cavity with the external are formed in a disc; the inside diameter of the compression piston cavity is larger than the inside diameter of the expansion piston cavity; the inside diameter of the expansion piston cavity is larger than the inside diameter of the heat exchanger cavity; the inside diameter of the heat exchanger cavity is same as the inside diameter of the pulse tube; the expansion piston is arranged in the expansion piston tube; and the compression piston, the expansion piston, the compression piston cavity and the expansion piston cavity form a compression cavity.

Description

technical field [0001] The invention belongs to the refrigeration field, and in particular relates to an expander unit and a pulse-tube type free-piston Stirling refrigerator. Background technique [0002] As an important method to obtain low temperature, cryogenic refrigerator refrigeration is widely used in the fields of aviation, military, superconductivity, communication, electronics, metallurgy, industrial gas liquefaction, and biomedicine. Especially in recent years, the vigorous development of my country's aerospace industry has made the application requirements of cryogenic refrigerators in aerospace more and more obvious. [0003] GLACIER (General Laboratory Active Cryogenic ISSExperimentRefrigerator) is the first -80°C low-temperature storage device developed by NASA that can be used on two platforms of the space station and the spacecraft at the same time. It uses a free-piston Stirling refrigerator for cooling. Refrigeration temperature from 4°C to -95°C; in wat...

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Problems solved by technology

[0005] The reason why the efficiency of the pulse tube refrigerator is lower than that of the Stirling refrigerator is mainly because the pulse tube refrigerator does not have a structure such as the expansion piston of the Stirling refrigerator, which "feeds back" the expansion work of the gas to the compression chamber. The expansion work of the hot end is mainly dissipated to the environment in the form of heat through phase-modulating mechanisms such as inertial tubes and small holes, resulting in low efficiency of pulse tube refrigerators

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