Analysis of Pulse Tube Refrigerator using CFD

Abstract

The present thesis is a detail endeavors of numerical investigation of an Inertance pulse tube refrigerator(IPTR) and Gifford-McMahon (GM) pulse tube followed by corresponding optimization of various geometrical and operating parameters including demonstration of a novel modification in existing GM pulse tube know how by proposing a piston arrangement on the double inlet connecting pipe.
To start with, a benchmark IPTR model has been analyzed numerically using 2Daxisymmetric model followed by 3D assembly. Subsequently, the parametric optimizations have been carried out to estimate the optimal operating and geometrical parameters, independently followed by in combination, which recommends an optimal IPTR having lowest temperature approximately 22% lower than the initial IPTR under investigation.
Next, a benchmark GM pulse tube, which had been experimentally investigated, has been taken for numerical investigation, where the demonstrated numerical result agrees to experimental result adequately, however, a novel numerical scheme based on user define function (UDF) and a sinusoidal temperature profile has been proposed, which reduces the computational overhead significantly and permits to optimize the valve openings, where the observed temperature at cold heat exchanger becomes approximately half with respect to initial one.
At last, a novel concept has been proposed to enhance the performance of a GM pulse tube by introducing a frictionless piston on the path of double inlet connecting pipe. The
conceptual proof has been investigated using fluid structure interaction, which is first in its own domain, where the lowest temperature at CHX has been observed to be 23.8 K.