MIXED CONVECTIVE FLOW AND HEAT TRANSFER THROUGH A HORIZONTAL CHANNEL WITH SURFACE MOUNTED OBSTACLES

Mixed convective flow and heat transfer has been performed in a horizontal channel with built-in obstacles on one of the channel walls. The channel blockage is taken to be 20%. Two-dimensional time-dependent Navier-Stokes and energy equations are solved in a Cartesian coordinate system using higher order discretization. Time integration of the governing equations reveals the critical Reynolds number of unsteadiness to be between 525 and 550. The effect of Richardson number on unsteady flow at a fixed Reynolds number of 600, at which the flow is unsteady laminar, has been investigated. The Richardson number, the parameter of interest of the present study, is varied between -1.0 and 1.0. The fluid chosen for the present study is air whose Prandtl number is 0.7. The flow and heat transfer show good correlation, and intense mixing with complex flow structures has been observed downstream of the obstacle. The heat transfer is found to be higher for the positive buoyancy while no significant variation is observed for negative buoyancy or Richardson number.