An analytic solution to the electric analog simulation of the regenerative heat exchanger with time-varying fluid inlet temperatures

Abstract

Direct simulation on an electric analog of heat transfer problems, has been extensively used, for obtaining approximate solutions. The electric simulation is based on discrete space continuous time differential equations, using electric capacitances and resistances with special devices for simulating convective terms and boundary conditions. (See ref. [16] in the text). In this paper, an analytic solution of the discretized space continuous time differential equations, describing the performance of the periodic-flow regenerative heat exchanger, is presented. With this method the cyclic periodic operation and the starting-up periods of the regenerator, having arbitrary fluid inlet and initial matrix temperatures, can be determined. Several cases with constant inlet fluid temperatures are given and the results are in a good agreement with those previously reported in the literature; the computations for the case of a starting-up period having linearly varying fluid inlet temperature are also presented, which compares well with the results given in a previous paper. Using the present method Hausen's simplified theory is tested and it is found to be justifiable.