Numerical simulation of exact two-dimensional governing equations for internal condensing flows

The paper outlines a two-dimensional computational methodology and presents results for laminar/laminar condensing flows inside mm- scale ducts. The methodology has been developed using MATLAB/COMSOL platform and is currently capable of simulating film-wise condensation for steady and unsteady flows. The results obtained are shown to be in agreement with an independently developed quasi-one-dimensional technique as well as a two-dimensional technique. The results are further validated with the help of vertical tube condensation experiments. The developed code is employed to investigate effects of transverse gravity on condensate motion inside a horizontal channel. It is found that in mm-scale channels, the flows in 0g are much different than flows in horizontal channels. The differences in film thickness, velocity profiles and pressure drops between horizontal and 0g channel are presented in this paper. The paper also investigates the response of the flow variables to inlet mass flow rate fluctuations for different cooling methods employed at the heat transfer surface