Thermal performances of codirected cross-flow heat exchangers

An analysis of temperature-fields and heat transfer in a heat exchanger with codirected cross-flow configuration (see Fig. 1) and tube bundle of arbitrary size has been carried out. This kind of flow arrangement is very suitable for heat transfer between liquid flowing in finned tubes bundle while gas passing across them. The problem was treated analytically by using the method of weighted mean value of outside fluid temperature described in [1]. The solution of energy balance equations, valid for this case, is expressed by special polynomials which are appropriate for fast calculation of temperatures. They are analogous to other polynomials found in mathematical physics. As end result it has been established that for such crossflow arrangements, with an arbitrary number of tubes n in the bundle, given NTU value and the heat capacity rate ratio R, the relation for thermal effectiveness P has a simple explicit form.