Experimental Investigation On Pulse Tube Refrigerator Driven By A Standing-Wave Thermoacoustic Engine

A pulse tube refrigerator (PTR) driven by a thermoacoustic engine (TE) instead of mechanical compressor occupies two outstanding advantages. 1) It has no abrasion or vibration, due to no moving parts both at ambient and cryogenic temperatures. 2) It can be driven by low-grade thermal resources, such as waste heat, solar energy. So, a thermoacoustically driven pulse tube refrigerator could be a potential long-life cryocooler.In the beginning of this paper, the developments of researches on thermoacoustic engine, pulse tube refrigerator and thermoacoustically driven pulse tube are reviewed, respectively. The pulse tube refrigeration, the linear and non-linear thermoacoustics are introduced. The present work focuses on the following sections:1) According to the experimental data of a standing wave thermoacoustic engine, the simulation has been made to find out suitable dimensions of a PTR's regenerator, in order to improve the matching of PTR and TE. The effects of pressure ratio and acoustic power on performance of the PTR have been numerically simulated.2) According to the simulation results, the performance of the pulse tube refrigerator can be improved through the increase of pressure ratio and acoustic power. In experiments, pressure ratio and acoustic power have been enhanced by increasing heating power and the length of acoustic pressure amplifier. When the input heating power is 2kW, and the length of the acoustic pressure amplifier is 3.7m, the PTR achieves its lowest cooling temperature 54.5K. It also gets a cooling power of 214mW at the temperature of 60K, which has never been achieved before. 3) Both orifice valve and double-inlet valve can be introduced into the refrigerator as a phase shifter. However, the throttle effect which exists in the valve will cause irreversible loss to the system. In addition, a double-inlet PTR may easily generate a DC flow which greatly decreases the performance of the refrigerator. Thus in the experiment an inertance tube rather than a valve is used to shift phase, and a cooling temperature as low as 63.0K is achieved. Although this lowest cooling temperature is higher than that achieved by using a double-inlet valve, the cooling power obtained by the refrigerator with an inertance tube is higher than with a double-inlet valve, which demonstrates the excellence of inertance tube.