Optimal design of thermal performance of an orifice pulse tube refrigerator

Abstract

In this paper, simultaneous influence of low and high pressure of helium compressor, frequency, opening coefficient of orifice valve and waiting time of rotary valve on the cooling capacity and “coefficient of performance” (COP) of a single-stage orifice pulse tube refrigerator is studied. “Box–Behnken design” model is opted here to create a design data matrix by utilizing the above design variables and responses (i.e., cooling capacity and COP). A numerical model is used to estimate the responses from the design variables, and effects of each design variable on the responses are studied through “analysis of variance.” Finally, input variables are ranked according to their ability to change the outputs by using the sensitivity analysis. A regression equation, which establishes a functional relationship between the design variables and response, is maximized by using “particle swarm optimization” method. ANN model is also applied to find the relationship between design variables and responses. Furthermore, by using the optimal range of inputs, an experimental investigation is carried out. Novelty of this article includes the study of simultaneous influences of aforementioned input variables on COP and cooling capacity, and also the sensitivity analysis. It has been observed that the cooling power and COP are increased by 10.8% and 0.76%, respectively, after optimization within the range of selected input parameters.