Numerical study of the evaporative cooling of liquid film in laminar mixed convection tube flows

A numerical study is reported to investigate the evaporative cooling of liquid film falling along a vertical tube. A marching procedure is employed for solution of the equation of mass momentum, energy and concentration in the flow. Numerical results for air-water system are presented. The effects of flow conditions on the film cooling mechanism are discussed. Results show that a better liquid film cooling is noticed for a system having a higher inlet liquid temperature T_L0, a higher gas flow Reynolds number Re or a lower liquid flow rate Γ₀. Additionally, the results indicate that the convection of heat by the flowing water film becomes the main mechanism for heat removal from the interface.