Liquid Film Falling on Horizontal Plain Cylinders: Numerical Study of Heat Transfer in Unsaturated Porous Media

In this article, numerical investigation of liquid film falling over three horizontal plain cylinders is presented. The flow Reynolds number of 50 to 3000 and cylinder diameters of 0.022 m, 0.123 m, and 0.1 m are employed. Numerical predictions are obtained using FLUENT, a proprietary computational fluid dynamics (CFD) code for 2D configurations of the three cylinders. The mathematical approach is based on the volume of fluid (VOF) method to account for two fluid phases, namely air and water. The research reported in this paper is motivated by the possibility of using detailed numerical simulations of the phenomena that occur in beds of irrigated porous media to cool horticultural produce. The effect of liquid flow rate (Reynolds number) and the cylinder diameter on heat transfer coefficient have been studied. It is found that increasing liquid flow rate or Reynolds number results in an increase in the heat transfer coefficients, and decreasing the cylinder diameter results in an increase in the heat transfer coefficient. The numerical results provide an insight into the cooling mechanisms within beds of unsaturated porous media. This research is part of an overall study of horizontal cylinders falling film flow and heat transfer.