Falling film heat transfer analysis on a bank of horizontal tube evaporator

Heat transfer analysis of falling film evaporation on a bank of horizontal tubes is investigated in this study. Liquid falling from one tube to the next lower one is considered as a thin liquid jet impinging on the top of the tube with a uniform free falling velocity. The hydrodynamic and thermal solutions are obtained by a finite difference method. In these solutions the heat transfer coefficients are modified to account for waviness. Liquid film thickness and local and average heat transfer coefficients are obtained for the constant heat flux and isothermal boundary conditions. Convective heat transfer effects are shown to be dominant as Peclet number increases. Heat transfer coefficients for the tubes in a tube bank decrease from the first tube onwards until the fully developed region is reached. The present predictions agree favorably with the reported heat transfer data.