Computational Study of Liquid Film Condensation with the Presence of Non-Condensable Gas in a Vertical Tube

Abstract

The main objective of this chapter is to study the liquid film condensation in a thermal desalination process, which is based on the phase change phenomenon. The external tube wall is subjected to a constant temperature. The set of the non-linear and coupled equations expressing the conservation of mass, momentum and energy in the liquid and gas mixtures is solved numerically. An implicit finite difference method is employed to solve the coupled governing equations for liquid film and gas flow together with the interfacial matching conditions. Results include radial direction profiles of axial velocity, temperature and vapour mass fraction, as well as axial variation of the liquid film thickness. Additionally, the effects of varying the inlet conditions on the phase change phenomena are examined. It was found that increasing the inlet-to-wall temperature difference improves the condensate film thickness. Decreasing the radius of the tube increased the condensation process. Additionally, non-condensable gas is a decisive factor in reducing the efficiency of the heat and mass exchanges. Overall, these parameters are relevant factors to improve the effectiveness of the thermal desalination units.

Numerical Study of Thin Film Condensation in Forced Convection in a Canal Whose Walls Are Covered with a Porous Material: Influence of ratio of form-Determination of Lengths of Entry

“…The condensation of vapor in a porous medium has received great interest in many theoretical and experimental researches [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Shekarriz and Plumb [1] analyzed the influence of the presence of the porous medium on the condensation of a film on the external wall of a horizontal tube.…”

“…The main variables controlling the film condensation process are revealed from the analysis, which define the relative importance of the interactive modes of wall conduction, free convection and film condensation. They ended up finding that the combined solution of the laminar film condensation problem is different from a Nusselt-type solution.The liquid film condensation in a thermal desalination process, which is based on the phase change phenomenon was examined by Charef A. et al [13]. The increase of the inlet-to-wall temperature difference between the inlet and the wall improves the thickness of the condensate film, has been noted.…”