화학공학소재연구정보센터
Chemical Engineering Science, Vol.135, 52-60, 2015
Experiment and simulation of the shrinkage of falling film upon direct contact with vapor
An experiment is conducted to study the shrinkage of falling film in countercurrent direct contact with saturated vapor. The experiment indicates that falling film shrinks along its width. The degree of shrinkage decreases with increasing liquid inlet temperature and flow rate. To study the details of the phenomenon, a three-dimensional multiphase computational fluid dynamics (CM) model based on the method of volume of fluid (VOF) is developed. The model considers the variation of surface tension with temperature. The results of the simulation are consistent with the experimental data. Simulations reveal the temperature, velocity and tension surface profiles. The modified Marangoni number is compared to illustrate the influence of surface tension and demonstrates that the surface tension plays an important role in this phenomenon and the shrinkage of the film causes the heat transfer to decrease. This model is expected to be applied to the design of the industrial equipment with falling film. (C) 2015 Elsevier Ltd. All rights reserved