Falling film flow of a viscoelastic fluid along a wall |
| |
| Authors: | Ling Miao Wei‐Tao Wu Nadine Aubry Mehrdad Massoudi |
| |
| Institution: | 1. Department of Mechanical Engineering, Carnegie Mellon University, , Pittsburgh, PA 15213, USA;2. Department of Mechanical Engineering, Northeastern University, , Boston, MA 02115, USA;3. U. S. Department of Energy, National Energy Technology Laboratory (NETL), , Pittsburgh, PA 15236, USA |
| |
| Abstract: | In this paper, we study the heat transfer in the fully developed flow of a viscoelastic fluid, a slag layer, down a vertical wall. A new constitutive relation for the stress tensor of this fluid is proposed, where the viscosity depends on the volume fraction, temperature, and shear rate. For the heat flux vector, we assume the Fourier's law of conduction with a constant thermal conductivity. The model is also capable of exhibiting normal stress effects. The governing equations are non‐dimensionalized and numerically solved to study the effects of various dimensionless parameters on the velocity, temperature, and volume fraction. The effect of the exponent in the Reynolds viscosity model is also discussed. The different cases of shear‐thinning and shear‐thickening, cooling and heating, are compared and discussed. The results indicate that the viscous dissipation and radiation (at the free surface) cause the temperature to be higher inside the flow domain. Copyright © 2013 John Wiley & Sons, Ltd. |
| |
| Keywords: | nonlinear fluids slag non‐Newtonian fluids variable viscosity falling film viscous dissipation radiation boundary condition gasification |
|
|
