A STRATIFIED FLOW MODEL FOR ADIABATIC LOSSES IN REGENERATIVE THERMAL DEVICES

A model has been developed for regenerative thermal devices such as St irling engines and refrigerators, in which while the heat exchangers a re modeled as fully isothermal, the flow in the cylinders and dead spa ces. is modeled as adiabatic, one-dimensional, and stratified Pressure is assumed to be spatially uniform, so that the two remaining conserv ation laws refer to mass and energy. Tt is shown that under the propos ed assumptions, the conservation laws can be integrated in closed form with respect to the space variable, leaving only time integration to be performed numerically. As a result, the numerical integration is ve ry cost-effective, sufficiently so that the resulting program can be u sed to chart large portions of the parameter space relatively quickly on widely available engineering workstations.