Experimental and computational performances of heat exchangers functioning in wet regime by using the film method

摘要

In this paper, we present a method of calculation by partial or total condensation of the water vapour contained in the humid air, over the smooth or finned tubes-heat recuperators. This study presents an implementation of the film method in a computer code developed here. The mathematical model used is validated by our experimental approach, using tubes bundles in staggered and aligned arrangements. The temperature of the humid air varies between 100℃ and 350℃. The determination of the fin portion, which functions in wet regime was carried out by the calculation of temperature field over a circular fin. The heat transfer coefficient by convection around the fin is supposed to be constant. The computer code predicts the heat flux exchanged in a range of 20% and 5%, in wet and dry regime, respectively. The apparent heat transfer coefficient by condensation can exceed 10 times the value of the heat transfer coefficient.