MIXED CONVECTION HEAT TRANSFER FROM VERTICALLY SEPARATED HORIZONTAL CYLINDERS WITHIN CONFINING WALLS

Abstract

This paper presents a numerical study of mixed convection heat transfer around two vertically separated horizontal cylinders within confining adiabatic walk. Parametric simulations are performed to assess the effect of the cylinder spacing B / D, of the distance between the parallel plates L / D, and of the Gr / Re² ratio on the heat transfer and fluid flow. Results have shown that for L / D ≥ 1.5, increasing B / D increases, in all cases, the overall heat transfer coefficient. On the other hand, an enlargement of the channel decreases the overall Nusselt number for L / D ≤ 3.0 and Gr / Re² ≤ 1.0 and increases it for L / D ≤ 3.0 and Gr / Re² ≥ 10.0. For L / D > 3.0 the effect of the parallel adiabatic walls on the heat transfer is imperceptible regardless of the magnitude of the Gr /Re² ratio.