Hydrodynamic resistance parameters of regenerator filler materials at cryogenic temperatures

Abstract Prototypical cryocooler regenerators were assembled with several common regenerator filler materials and were tested under periodic helium flow at room and cryogenic temperatures. The mass flow and pressure drop data were analysed to determine the friction factor, Darcy Permeability and Forchheimer coefficients. The results are compared to previous investigations, and the relevance of room-temperature models and correlations to cryogenic temperatures is assessed. It is shown that within the range of parameters tested, room-temperature hydrodynamic parameters such as friction factor can be used at cryogenic temperatures. Empirical correlations with improved accuracy are developed for the friction factor for each of the tested filler materials.