Natural convection heat and mass transfer in partially heated vertical parallel plates

Abstract

A combined numerical and theoretical investigation of laminar natural convection heat and mass transfer in open vertical parallel plates with unheated entry and unheated exit is presented. Both boundary conditions of uniform wall temperature/uniform wall concentration (UWT/UWC) and uniform heat flux/uniform mass flux (UHF/UMF) are considered. Results of dimensionless induced volume rate Q, average Nusselt number Nu E and Sherwood number Sh E are obtained for air flow under various buoyancy ratio N, Grashof number Gr L, Schmidt number Sc and combinations of unheated entry, heated section and unheated exit length. Theoretical solutions for Q, Nu E and Sh E for both UWT/UWC and UHF/UMF cases are derived under fully developed conditions. The numerical solutions are shown to approach asymptotically the closed form solutions for fully-developed flow. The presence of unheated entry and unheated exit severely affects the heat and mass transfer rates. In addition, the correlation equations of Q, Nu E and Sh E for both boundary conditions are presented.