Oscillatory flow in microporous media applied in pulse – tube and Stirling – cycle cryocooler regenerators

Pulse tube and Stirling cryocoolers are widely used in aerospace and other high-demand application. A key component in these systems is the regenerator, which is typically a microporous metallic structure that is subject to periodic flow of a cryogenic fluid. The thermal and hydrodynamic irreversibilities in the regenerator, which play crucial roles with respect to the efficiency of the aforementioned cycles, are poorly understood, however.