In this paper, a theoretical and numerical study is carried out to describe the thermal behavior of a U-tube heat exchanger. In order to predict the steady temperature distributions of both fluids and wall, some analytical solutions are provided, stressing the effects of the main physical and geometrical parameters on the heat exchanger behavior.
A new model is formulated on the basis of the analytical solutions. A numerical code is also proposed, based on a step-by-step solution of an energy balance equation system. Solutions referred to a reference experimental test are obtained by the analytical and the numerical method. Their comparison shows a satisfactory agreement.