A New Simple Dynamic Model of Steam Liquid Heat Exchangers Based on Their Static and Structural Characteristics

Abstract

The dynamic characteristics of heat exchangers are described by partial differential equations .But the expressions are rather complicated and not well suited for practical use, so it is necessary to develop a simple lumped-parametered model to estimate the dynamic behavior of systems with heat exchangers and also to design optimal control systems. The aim of this paper is to present a relatively simple dynamic model for steam liquid heat exchangers via the method of weighted residuals (MWR). A 2nd-order MWR model is derived with a good approximation, which is represented by the three parameters, i.e. k_p which depends upon the steam and liquid temperature in steady state, τ_p which is the residence time of the liquid, and k_s which is the ratio between the shell-side time constant and τ_p. The results of an experimental study are also represented to validate the analytical results.