TRANSIENT-RESPONSE OF FINITE WALL CAPACITANCE HEAT-EXCHANGER WITH PHASE-CHANGE

In this study the transient response of counterflow and parallel-flow heat exchangers having finite wall capacitance is investigated. Three configurations are considered: the flat-plate exchanger with phase cha nge in either channel and the shell-and-tube exchangers with phase cha nge either in the tube or in the shell. The transient response of thes e configurations results from sudden change in the inlet temperature o f the one-phase fluid or from sudden exposition of the shroud to ambie nt conditions. The thermal behavior of the exchanger is described by d etecting the transient variations in the temperature of the one-phase fluid and in the quality of the two-phase fluid within the exchanger. Closed-form expressions for these parameters are presented. These expr essions can be used to evaluate different design parameters required b y heat exchanger designers.