MIXED CONVECTION FROM HORIZONTAL TUBE BANKS BETWEEN 2 VERTICAL PARALLEL PLATES

The weighted residuals method is applied to analyze mixed convection h eat transfer in 3 x 3 in-line horizontal tube bundles placed between t wo vertical parallel plates. The flow regime of Reynolds numbers up to 500 and Grashof number up to 53,000 is investigated. The local data o f different geometries (nondimensional streamwise and transverse cylin der-to-cylinder spacing S-p/d = 2, 3 and S-h/d = 2, 3) are reported. D ata for both pure forced and mixed convection are presented for purpos es of comparison. It is shown that the thermal performance of the fron t sector of downstream cylinders is strongly affected by the presence of the upstream cylinders, while the backward sector of downstream cyl inders remains basically uninfluenced by the upstream cylinders. The a verage Nusselt number for the array increases 20-30% when the nondimen sional streamwise spacing is increased 50%; however, fewer tubes would be contained in a fixed channel length.