Effects of Shear Dependent Viscosity and Variable Thermal Conductivity on the Flow and Heat Transfer in a Slurry

Energies

Ling Miao¹  Mehrdad Massoudi² 

[1] Department of Mechanical Engineering and Material Science, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA 15213, USA; E-Mail:;U. S. Department of Energy, National Energy Technology Laboratory (NETL), 626 Cochrans Mill Road, P.O. Box 10940, Pittsburgh, PA 15236, USA

关键词: non-linear fluids;    variable viscosity;    variable thermal conductivity;    coal slurry;    non-Newtonian fluids;   

DOI  :  10.3390/en81011546

来源: mdpi

【 摘 要 】

In this paper we study the effects of variable viscosity and thermal conductivity on the heat transfer in the pressure-driven fully developed flow of a slurry (suspension) between two horizontal flat plates. The fluid is assumed to be described by a constitutive relation for a generalized second grade fluid where the shear viscosity is a function of the shear rate, temperature and concentration. The heat flux vector for the slurry is assumed to follow a generalized form of the Fourier’s equation where the thermal conductivity k depends on the temperature as well as the shear rate. We numerically solve the governing equations of motion in the non-dimensional form and perform a parametric study to see the effects of various dimensionless numbers on the velocity, volume fraction and temperature profiles. The different cases of shear thinning and thickening, and the effect of the exponent in the Reynolds viscosity model, for the temperature variation in viscosity, are also considered. The results indicate that the variable thermal conductivity can play an important role in controlling the temperature variation in the flow.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.