FORCED LAMINAR CONVECTION IN AN ARRAY OF STACKED PLATES

A numerical study of laminar flow and heat transfer in an array of stacked rectangular plates is presented. The array is placed in a uniform stream, and the plates are subjected to a constant surface heat flux. This flow configuration is relevant to a number of practical heat transfer devices with finned surfaces. The computations were performed using a finite volume solution of the steady, two-dimensional Navier-Stokes equations and energy equation. A numerical scheme that reduces numerical diffusion is used to discretize the equations. The dominant feature of the flow is the separation, and subsequent reattachment of, the boundary layer, which takes place at Reynolds numbers greater than about 75. The separation first occurs downstream of the leading edge of the plate, then as Re increases, the separation point moves upstream and remains fixed at the leading edge, and the reattachment length increases linearly with Re. The appearance and growth of the separation bubble are accompanied by a local thinning of the thermal boundary layer and a substantial heat transfer augmentation in the reattachment region, with local maximum heat transfer rates occurring slightly downstream of reattachment. The heat transfer augmentation is attenuated at higher blockage ratios (reduced spacing between plates) as a result of the reduction of the separation bubble size.