Numerical analysis of thermodynamic behaviour of falling film outside a horizontal tube

Abstract Falling film evaporation and condensation on horizontal tubes have been widely employed in the field of chemical, petroleum refining and desalinization. A numerical investigation on the thermodynamic behaviour of falling film outside a horizontal tube is presented. Based on the analysis of falling film state around a horizontal tube, a mathematical model is proposed, which takes into account the effect of jet impingement at the tube top on falling film behaviour. The numerical local heat transfer coefficients agree well with the experimental, which proves the reliability of the developed model. The variation of the local heat transfer coefficients and film thickness with flow density and evaporation temperature is simulated and analysed.