Loi de reponse d'un echangeur thermique soumis a des echelons de temperature aux entrees

Abstract In this paper we try to characterize the transient behaviour of parallel or counterflow heat exchangers when the two inlets are submitted at the same time to steps of temperature. The analysis lies on a two-parameter model for the temperature response, including a time lag tr and a time constant τ. By the mean of a time-dependent energy balance, we obtain an analytical expression of τ. Many special cases deduced from the general formulation are considered. This study is completed by a parametric analysis. Experimental investigations realized in various situations show a good agreement with theoretical results.