Effects of Geometrical Dimension on Mixed Convection Heat Transfer in Cavities

In this paper, mixed forced and natural convection heat transfer in a rectangular cavity has been numerically studied. the cavity receives a uniform heat flux from one side and is ventilated with a uniform external flow. The external flow enters the cavity from the heated side and leaves the cavity from the opposite side. The velocity and temperature fields and heat transfer rate are determined by solving the two-dimensional continuity, momentum and energy equations. In this research, steady-state flow with constant Reynolds number, Re=100, is considered. Rayleigh number is in the range of 0≤Ra≤107. First, the results are presented for a cavity with constant aspect ratio, AR=2, and four different inlet and exit opening positions. Then cases with a fixed opening position and different aspect ratios including 0.1, 0.25, 1, 4 and 10 are modeled. In the cavities with opening in the bottom or cavities with aspect ratios less than one, the results show weak effects of natural convection on heat transfer. This research has been done for air as a working fluid (Pr=0.71). In some cases, the results are compared with those from previous studies. Keywords: Convection, Natural, Forced, Cavity, Rayleigh, Ventilate