Development and Experimental Test of an Analytical Model of the Orifice Pulse Tube Refrigerator

Abstract

The promise of high reliability and high refrigeration capacity is responsible for a recent surge of interest in pulse tube refrigeration. This work involves the development of an analytical model describing behavior of the orifice pulse tube to gain a better understanding of the refrigeration process. Due to oscillating gas flow, the system is described in terms of average enthalpy flow with such simplifying assumptions as an ideal gas and sinusoidal pressure variation. Phasor analysis is used to represent the temperature, pressure, and mass flow rate waves in vector form. Also discussed in this paper is the verification of the model in which analytical predictions are compared to experimental measurements. The results confirm predictions by the model that refrigeration power is proportional to the average pressure, the pulse frequency, the mass flow ratio, and the square of the dynamic pressure ratio. Also, a temperature probe was devised to measure the average temperature profile and dynamic temperature in the tube. As a result of simplifying assumptions, magnitudes of refrigeration power from the model are between 3 and 5 times greater than experimental values.

Research funded by NASA Ames Research Center under contract no. A-34964C(RCW). Contribution of the National Bureau of Standards, not subject to copyright.