Condensation in the presence of non-condensable gases in a convergent 3D channel

In this study, a numerical study is arranged to simulate the condensation in the presence of non-condensable gases in a convergent three-dimensional channel. The presence of air, as a non-condensable gas, can significantly decrease the heat transfer. Therefore, this paper attempts to reduce the effects of this factor and enhance the heat transfer by controlling some geometrical and physical parameters. One of the most important geometrical parameters studied in this research is controlling the ratio of the output-width to input-width of the channel or the convergence angle. In addition, the values of temperature, velocity, relative humidity of the input flow, and the thickness and temperature of the aluminum wall of the channel are also investigated. Condensation is considered as a film in this study. Computational fluid dynamics (CFD) is used to simulate the present problem. The results show that the mass rate of condensation can be enhanced by about 45% for the channel with the convergence ratio of 0.3, compared with the convergence ratio of 1. Also, the input temperature is an effective parameter and the mass rate of condensation improves by just over 400% through increasing the input temperature in the range of 70 °C to 100 °C. The mass rate of condensation can enhance by about 530% by increasing the relative humidity in the range of 40%–100%.