THEORETICAL STUDY OF HYDRODYNAMICS AND HEAT TRANSFER BY FREE 
CONVECTION OF NON-NEWTONIAN FLUIDS NEAR A COOLED SURFACE WITH 
REGARDFOR VARIABLE VISCOSITY

N. V. Selivanov and S. I. Kuz'min

UDC 536:24

We have made a theoretical study of the hydrodynamics and heat transfer
of non-Newtonian fluids near a cooled isothermal surface by laminar free
convection with regard for the change in the fluid viscosity with temperature.
A power rheological model has been used. The solutions to the systems
of differential equations for the boundary layer have been obtained numerically.
It has been shown that the strongest influence in the considered kinds
of convection is produced by the relative viscosity. Moreover, of great importance
is the nonlinearity index of the medium. With increasing rheological parameter
the influence of variable viscosity decreases. Criteria equations for calculating
the local and mean Nusselt numbers and friction coefficients have been obtained.

Astrakhan' State Technical University, 16a Tashkentskaya Str., Astrakhan', 414025,
Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 6, pp. 49-56,
November-December, 2006. Original article submitted February 8, 2005; revision
submitted July 4, 2005.