Design and construction of a pressure wave cryogenic refrigerator.

A pressure wave refrigerator (PWR) works on the principle of energy transfer through a shock wave. As in a shock tube, sudden entry of a gas at high pressure into a receiving tube generates a shock wave which moves forward and simultaneously, an expansion wave moves in the reverse direction producing refrigeration. Compared with turbo-expanders, a PWR can operate at much lower rotational speed and at lower flow rates. Moreover, these are cheaper, simpler in design and operationally more reliable. Several attempts are being made worldwide for constructing PWRs. In this paper, we present the progress made in design and development of a PWR at Indian Institute of Technology (IIT) Kharagpur, India. A numerical model is developed to predict the performance of a PWR. A motor driven rotary valve is designed and fabricated inhouse. Details of the setup, critical issues and preliminary performance are discussed in the paper.