Novel flow analysis of regenerator under oscillating flow with pulsating pressure

A new model for the oscillating flow combined with pulsating pressure in cryocooler regenerators is developed to overcome inaccuracy of the conventional flow model based on steady flow friction factor. The new model is based on two non-dimensional parameters and one-dimensional governing equations. One of the parameters is the oscillating flow friction factor represented by the amplitudes of the pressure drop and the flow rate. The idea of the other important parameter originates from a volume averaged continuity equation, which includes the characteristic of randomly oriented matrix geometry. This parameter is named as Breathing factor, which implies that the regenerator breathes against the main oscillating flow. Empirical correlations of the parameters are obtained for screen regenerators. It is revealed that the phase angles of the pressure drop and the mass flow rate in regenerators are well predicted by introduction of the Breathing factor.