EFFECT OF VISCOUS DISSIPATION ON MIXED CONVECTION IN A VERTICAL CHANNEL WITH BOUNDARY-CONDITIONS OF THE 3RD KIND

The effect of viscous dissipation on fully-developed mixed convection is analysed for the laminar flow in a parallel-plate vertical channel whose walls exchange heat with an external fluid. Both conditions of e qual and of different reference temperatures of the external fluid are considered. First,:the simpler cases of either negligible Brinkman nu mber or negligible Grashof number are solved analytically. Then, the c ombined effects of buoyancy forces and of viscous dissipation are anal ysed by a perturbation series method. In the examined cases, the veloc ity field, the temperature field and the Nusselt numbers are evaluated . (C) 1998 Elsevier Science Ltd. All rights reserved.