MIXED CONVECTION FROM HORIZONTAL TUBE BANKS BETWEEN TWO VERTICAL PARALLEL PLATES

Abstract

The weighted residuals method is applied to analyze mixed convection heal transfer in 3 × 3 in-line horizontal tube bundles placed between two vertical parallel plates. The flow regime of Reynolds numbers up to 500 and Grashof number up to 53,000 is investigated. The local data of different geometries (nondimensional streamwise and transverse cylinder-to-cylinder spacing S_p / d = 2,3 and S_h / d = 2, 3) are reported. Data for both pure forced and mixed convection are presented for purposes of comparison. It is shown that the thermal performance of the front sector of downstream cylinders is strongly affected by the presence of the upstream cylinders, while the backward sector of downstream cylinders remains basically uninfluenced by the upstream cylinders. The average Nusselt number for the array increases 20–30% when the nondimensional streamwise spacing is increased 50%; however, fewer tubes would be contained in a fixed channel length.