Study On The Gas Flow Characteristics And Refrigeratior Performance Of The Fiber-based Regenerator In A Micro-scale Pulse Tube Cryocooler

Pulse tube cryocoolers (PTC) are widely applied in the fields such as aeronautics and astronautics, electric information engineering, biomedical engineering and so on, due to its advantages of no moving parts at the cold end, high stability and reliability, and long working life. However, as the miniaturization of PTC is required in certain situations which have spatial constraint, the optimization of the system and parts structure is a big challenge.This thesis focuses on the miniaturization of PTC. A novel pulse tube cryocooler using holey optical fibers as the regenerator structure is proposed. Based on the literature summary of refrigerator miniaturization, optical fiber technology and the flow characteristics in microchannels, the simulation of gas flow in fibers is studied with N-S equations and slip flow boundary conditions respectively. The pressure distribution under various magnitudes of mass flow rate is numerically calculated. In the meantime, an experimental system for gas flow in microtubes, especially in glass fibers (d<50μm) and holey optical fibers (d<10μm) is set up to measure the friction factor and pressure drop. Finally, the refrigeration characteristics of the cryocooler proposed is discussed. A software mainly based on thermoacoustic theories is recompiled to simulate the working conditions of the holey fiber regenerator and compare it with that of stainless steel mesh regenerator (635mesh). The feasibility of the regenerator for micro-PTC is verified.