LAMINAR VISCOUS DISSIPATION IN RECTANGULAR DUCTS

In this paper, a theoretical study is conducted, calculating the tempe rature distribution in the cross-section of a rectangular duct, under the conditions of newtonian and incompressible fluid, fully developed laminar now and steady-state regime. The governing equations are solve d resorting to the finite Fourier transform. The temperature distribut ions are obtained. The results concerning the temperature distribution in a square duct are shown by tables and figures, and a comparison be tween the present solution and some literature contributions is also p resented. The viscous dissipation is responsible for a power generatio n that, for a particular Brinkman number (Br-q = 1/Phi or Br-w = +/-i nfinity), allows the wall heat flux to vanish. At last, the effects of viscous dissipation and wall heat flux are presented in some graphs, as a function of the duct aspect ratio. (C) 1998 Elsevier Science Ltd.