Laminar mixed convection in a channel with a built-in semi-circular cylinder under the effect of cross-buoyancy

Abstract

Effects of cross-buoyancy mixed convection on flow and heat transfer characteristics of a long semi-circular cylinder (long in neutral direction) in a confined channel have been investigated in the laminar regime. The numerical results have been presented and discussed for the range of conditions as Reynolds number (Re)=1–40, Richardson number (Ri)=0–4, Prandtl number (Pr)=0.71–50 and blockage ratio (β)=16.67%–50%. The drag coefficient increases with increasing Richardson number and/or blockage ratio. The average Nusselt number is showing a maximum relative enhancement of approximately 45% for Ri=4 with respect to corresponding forced convection value (Ri=0). The average Nusselt number increases with increase in Prandtl number and shows a maximum relative enhancement of approximately 1136% for Pr=50 with respect to corresponding value at Pr=0.71. On the other hand, the maximum relative variation of the total drag coefficient is found to be approximately 55% for Ri=4 with respect to corresponding value at Ri=0. Finally, the simple heat transfer correlation is obtained for the proceeding range of control parameters.