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In this paper, we present a numerical three-dimensional study of coupled heat and mass transfer by natural convection occurring in a trapezoidal cavity. Our objective is to evaluate numerically the thermal and hydrodynamic behaviour of this system. It is assumed that the cavity vertical walls are thermally isolated and impermeable, and we imposed on the lower surface a constant high temperature and concentration. The upper surface is supposed to be cooled at a constant temperature and has a zero concentration.Governing equations are solved by a finite-volume technique and provide the temperature, concentration and velocity fields in binary mixture air-water vapor system. The obtained results show that the flow configuration depends strongly on the α angle inclination of the upper wall. The influence of the cavity dimensions on heat and mass transfer rates is also examined. In particular, as the aspect ratio increases, multi-cellular flow patterns start to form.

This paper studies heat transfer during rapid heat cycle injection molding process. Actually, the mold is heated and cooled with channels in which steam or water circulates. The purpose of this numerical study is to improve the design of heating/cooling system to ameliorate the quality of the polymer part and the cycle productivity. Transfers in mold, translating thermal phenomena are predicted by the finite volume method and the fractional area volume obstacle representation in cyclic transient regime. It was found that the steady cycle is obtained rapidly (after two or three cycles) for the rapid heat cycle molding process when compared to conventional injection molding. The mathematical modeling was developed to explore the effect of control temperature system characteristics on temperature uniformity of the cavity surface and thermal response efficiency. The three-dimensional simulation results show the limitations of the conventional system when compared to the conformal configuration. This research study also compares three conformal thermal control systems, and shows that the heating energy consumption can be greatly decreased (about 27%) with the amelioration of the temperature distribution by means of the improvement of the channel layout.