A semi-empirical model for retained condensate on horizontal pin-fin tube including the effect of vapour velocity

Abstract

During condensation process, the formation of condensate film is main resistance to retard heat transfer. This liquid condensate on horizontal pin-fin tube is known as condensate retention that generally blocks the lower part of tube and act as an insulation resulting in the form of resistance to heat transfer. Various, tube geometries experimentally tested with different pin-fin longitudinal and circumferential thickness and spacing, pin-fin height, internal and external tube diameters under the effect of vapour velocity are selected for model development. As it is extremely important to estimate the extent of condensate retention on such pin-fin tubes in order to make more effective horizontal pin-fin tubes in terms of heat transfer. The development of semi empirical correlations for condensate retention on pin-fin tubes as a function of vapour velocity (forced convection condensation) is proposed in this paper. Various geometric parameters and fluids are considered for model development. Accurate data are used for the model development. The proposed model which is based upon the dimensional analysis successfully predicts available data to within 5%. Relative standard deviation was about 2.44, 2.30 and 1.73 for water, ethylene glycol and refrigerant respectively. The development of such a semi empirical model is the first important step required for the development of full-scale heat transfer model of condensation heat transfer on horizontal pin-fin tubes during forced convection.