An analytical solution for a cyclic regenerator in the warm-up period in presence of an axially dispersive wave

Abstract

Regenerative heat exchangers are important components of energy intensive sectors such as chemical process, power, metallurgical and cryogenic industry. The challenge of simulating regenerators accurately is considerable in view of the transient cyclic process taking place in it. The simulation of warm-up period is even more challenging due to the change in temperature profiles after each cycle. In the present work a modern technique based on the “axial dispersion model” has been utilized to simulate the regenerative heat exchanger both in the warm-up and pseudo-steady state operation. The advantage of this model is that it takes all the flow maldistribution and backmixing effects into consideration instead of idealizing the flow to be so called “plug flow”. In contrast to previous studies with dispersion, in the present study the dispersion is considered to propagate with a finite propagation velocity following a hyperbolic law which is physically more consistent. The effect of different parameters on the cyclic response has been brought out and the results have been verified by comparing results of a rotary regenerator available in literature. The technique utilized in the present study can act as a tool for modelling regenerators where non-uniformity in flow distribution is significant.