Design and Optimization of Cryogenic Regenerators: A Review

Objectives: The principles of cryogenic regenerator operation, its design and optimization procedures are reviewed in this paper. Recent and ongoing developments of these regenerators are highlighted. Due to the non linear behaviour of geometry and operating parameters with performance parameters, design and optimization of regenerator performance has not been possible in conventional mathematical terms. Methods: Methodologies of design to determine the volume having maximum heat transfer ability with minimum losses are listed. The optimization in terms of mathematical, analytical and experimental approaches with their inherent difficulties is discussed. Findings: The regenerator mesh with a lower hydraulic diameter in the cold region and a larger hydraulic diameter in hot region will lead to lower regenerator losses. Thus a regenerator consisting of layers of different matrix geometry would have a better performance than a regenerator with single mesh geometry. Regenerators that incorporate heat transfer components in a parallel orientation with respect to the oscillating flow theoretically provide a better performance than screen mesh regenerators. An optimum regenerator would have a continuous variation in its hydraulic diameter along the length of the tube. Applications: This review is expected to be a catalogue of principles needed for effective simulation, design, and optimization of regenerators for cryogenic refrigerators. The optimum regenerator has the potential to significantly improve the performance of cryogenic refrigerators and make them suitable for more applications.