Falling film evaporation on a vertical corrugated plate conduit in MED

Falling film evaporators are widely used in desalination, refrigeration, petroleum refining, chemical industries, etc. In falling film evaporators used in multi-effect distillation system, the latent heat released by the condensing steam is transferred to the liquid falling over the tubes which results in convective evaporation. This paper presents a two dimensional CFD study of falling film evaporation on a vertical corrugated conduit for low temperature multi-effect distillation (LT-MED) application. Two-phase flow simulation is carried out by using finite volume method based FLUENT 14.0 with turbulence model of k-ω equations with shear stress transport (SST). Sinusoidal corrugation with three different dimensions is selected for the study. Evaporation and heat transfer during falling film evaporation are included through user defined functions (UDFs). Present numerical results are compared with the results of horizontal tube falling film evaporation from the literature. An enhancement of 50% in film heat transfer coefficient is observed. Effects of Reynolds number and number of corrugations on heat transfer coefficient are presented.