ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
VISCOUS DISSIPATION EFFECTS ON HEAT TRANSFER FROM TURBULENT FLOW WITH HIGH PRANDTL NUMBER FLUIDS
Resumo
A comprehensive surface renewal type model,
namely, the surface rejuvenation model,is employed
to determine the viscous dissipation effect on heat
transfer from turbulent flow with high Prandtl
number fluids. In this work, the probability
distributions for the stochastic variables which
include the approach distance, the contact time,
the residence time, and the initial temperature
profile of the incoming eddies near the wall
region are utilized. The Nusselt number,
recovery factor, and temperature profile are
obtained in integral forms which are then solved
numerically. The ratio of Nusselt numbers in the
presence of viscous effect to that in the absence
of dissipation is presented in terms of Brinkman
number, Prandtl number and Reynolds number for
both cases of wall heating and cooling. Comparisons
of the predicted recovery factor for turbulent
pipe flow are also made based on the present
model, previous eddy diffusivity models and the
elementary surface renewal model for a wide range
of Prandtl number.