Anomalous predictions of pressure drop and heat transfer in ducts of arbitrary cross-section with modified power law fluids |
| |
Authors: | S Park D-R Lee |
| |
Institution: | (1) Department of Mechanical Engineering Korea University, Seoul, Korea, KR;(2) School of Mechanical and Automotive Engineering Catholic University of Daegu Kyungbuk, Korea, KR |
| |
Abstract: | The apparent viscosities of purely viscous non-Newtonian fluids are shear rate dependent. At low shear rates, many of such
fluids exhibit Newtonian behaviour while at higher shear rates non-Newtonian, power law characteristics exist. Between these
two ranges, the fluid's viscous properties are neither Newtonian or power law. Utilizing an apparent viscosity constitutive
equation called the “Modified Power Law” which accounts for the above behavior, solutions have been obtained for forced convection
flows. A shear rate similarity parameter is identified which specifies both the shear rate range for a given fluid and set
of operating conditions and the appropriate solution for that range. The results of numerical solutions for the friction factor–Reynolds
number product and for the Nusselt number as a function of a dimensionless shear rate parameter have been presented for forced
fully developed laminer duct flows of different cross-sections with modified power law fluids. Experimental data is also presented
showing the suitability of the “Modified Power Law” constitutive equation to represent the apparent viscosity of various polymer
solutions.
Received on 21 August 2000 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|