The asymptotic behaviour of laminar forced convection in a circular tube, for a Newtonian fluid at constant properties, is analysed by taking into account the viscous dissipation effects. The axial heat conduction in the fluid is neglected. A sufficient condition for the existence of a fully developed region is determined. This condition includes, for instance, any asymptotically vanishing axial distribution of the wall heat flux, uniform wall temperature, convection with an external fluid. The asymptotic temperature field and the asymptotic value of the Nusselt number are determined analytically, for every boundary condition which allows a fully developed region. In particular, it is proved that, whenever the wall heat flux tends to zero, the asymptotic Nusselt number is zero. Copyright © 1996 Elsevier Science Ltd.
Effect of viscous dissipation on the asymptotic behaviour of laminar forced convection in circular tubes / Zanchini E.. - In: INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER. - ISSN 0017-9310. - STAMPA. - 40:1(1996), pp. 169-178. [10.1016/S0017-9310(96)00076-2]
Effect of viscous dissipation on the asymptotic behaviour of laminar forced convection in circular tubes
Zanchini E.
1996
Abstract
The asymptotic behaviour of laminar forced convection in a circular tube, for a Newtonian fluid at constant properties, is analysed by taking into account the viscous dissipation effects. The axial heat conduction in the fluid is neglected. A sufficient condition for the existence of a fully developed region is determined. This condition includes, for instance, any asymptotically vanishing axial distribution of the wall heat flux, uniform wall temperature, convection with an external fluid. The asymptotic temperature field and the asymptotic value of the Nusselt number are determined analytically, for every boundary condition which allows a fully developed region. In particular, it is proved that, whenever the wall heat flux tends to zero, the asymptotic Nusselt number is zero. Copyright © 1996 Elsevier Science Ltd.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.