ABSTRAKT

A steady two-dimensional volume of fluid (VOF) simulation of laminar film condensation of vapor with and without a noncondensable gas inside a 1-mm horizontal minichannel is presented. The uniform interface temperature and wall temperature are fixed as boundary conditions, and the flow pattern is expected to be annular. The numerical simulation results display the evolution of the liquid−gas interface, Nu, and heat flux. It is found that the global effect of gravity is negligible. Moving downstream the minichannel, the liquid film grows rapidly near the entrance and then remains unchanged in the rest of the minichannel till the end. Higher inlet velocity and wall temperature of the minichannel lead to the augmentation of the average Nu value of condensation. The existence of a noncondensable gas makes the heat flux to decrease sharply compared to that vapor condensation, while a higher inlet velocity will aggravate this effect. Meanwhile, the noncondensable gas with smaller thermal conductivity would give rise to greater reduction of heat flux as a result of the higher thermal resistance in the noncondensable gas layer.