Dynamic behaviour of a three fluid heat exchanger subjected to step change in inlet temperature of hot and cold fluids

Abstract

Purpose – The purpose of this paper is to analyse the dynamic behaviour of a three-fluid heat exchanger subjected to a step change in the temperature and velocity of the fluids at the inlet. Design/methodology/approach – The analysis is carried out using the finite element methodology, adopting the Galerkin’s approach, using implicit method for transient behaviour. Findings – The effect of step changes in the inlet temperature of hot and cold fluids show that an increase in the fluid inlet temperatures leads to increased outlet temperatures of all fluids and decreased hot fluid effectiveness. The exit temperatures of the fluids do not show any response initially for a certain period of time with the step changes. The time to reach steady state is independent of the step change in inlet temperature of the hot and the cold fluids. Research limitations/implications – The findings of this paper is limited to constant property situations. Practical implications – The findings will be useful in designing contro...