Numerical investigation for the heat and mass transfer between parallel flow of air and desiccant falling film in a fin-tube arrangement

A numerical investigation was conducted to study the heat and mass transfer between a falling film of calcium chloride desiccant solution and a parallel flow of air in a rectangular fin-tube arrangement. A control volume finite difference method was used to solve the governing equations for the air and the liquid desiccant solution subjected to the appropriate boundary conditions. A model was used to predict temperature distribution on the fin surface. In this model, two approaches were employed to determine the temperature distribution of the fin surface. The first approach utilized the analytical expression for the temperature distribution of a circular fin having the same area as the rectangular fin. The second approach used a finite difference algorithm to directly predict the temperature distribution of the rectangular fin surface. Both approaches were used to study the performance of the fin-tube arrangement for dehumidification of air at various operating conditions. The effects on the air dehumidification process, due to changing the inlet conditions of air and desiccant film; their mass flow rates; and the fin height were predicted. The results were used to developed correlations to predict the heat and mass transfer coefficients (on the airside) between the air and the liquid desiccant. These correlations can accurately be used to predict the outlet air and liquid desiccant conditions from the fin-tube arrangement. Correlations were developed to predict the rate of heat and mass transfer between the air and the desiccant film. Several numerical experiments showed agreement with the available data in literature.