scholarly journals Heatline Visualization of Natural Convection in a Porous Cavity Occupied by a Fluid With Temperature-Dependent Viscosity

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
K. Hooman ◽  
H. Gurgenci
Keyword(s):  
Porous Medium ◽  
Nusselt Number ◽  
Temperature Dependent ◽  
Exponential Form ◽  
Comprehensive Investigation ◽  
Temperature Dependent Viscosity ◽  
Temperature Relation ◽  
Mean Values ◽  
Viscosity Effect ◽  
Dependent Viscosity

Temperature-dependent viscosity effect in buoyancy driven flow of a gas or a liquid in an enclosure filled with a porous medium is studied numerically based on the general model of momentum transfer in a porous medium. The exponential form of viscosity-temperature relation is applied to examine three cases of viscosity-temperature relation: constant, decreasing, and increasing. Application of arithmetic and harmonic mean values of the viscosity is also investigated for their ability to represent the Nusselt number versus the effective Rayleigh number. Heat lines are illustrated for a more comprehensive investigation of the problem.

Predicting Inlet Temperature Effects on the Pressure-Drop of Heated Porous Medium Channel Flows Using the M-HDD Model

2004 ◽  
Vol 126 (2) ◽  
pp. 301-303 ◽  
Author(s):  
Arunn Narasimhan ◽  
Jose´ L. Lage
Keyword(s):  
Porous Medium ◽  
Pressure Drop ◽  
Inlet Temperature ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Viscosity Effects ◽  
Nonisothermal Flows ◽  
Nonlinear Temperature ◽  
Global Pressure ◽  
Dependent Viscosity

A Modified Hazen-Dupuit-Darcy (M-HDD) model, incorporating nonlinear temperature-dependent viscosity effects, has been proposed recently for predicting the global pressure-drop of nonisothermal flows across a heated (or cooled) porous medium channel. Numerical simulations, mimicking the flow of a liquid with nonlinear temperature-dependent viscosity, are presented now for establishing the influence of inlet temperature on the pressure-drop and on the predictive capabilities of the M-HDD model. As a result, new generalized correlations for predicting the coefficients of the M-HDD model are derived. The results not only demonstrate the importance of fluid inlet temperature on predicting the global pressure-drop but they also extend the applicability of the M-HDD model.

Unsteady Magnetohydrodynamic Mixed Convective Flow of a Reactive Casson Fluid in a Vertical Channel Filled with a Porous Medium

2021 ◽  
Vol 408 ◽  
pp. 33-49
Author(s):  
Lazarus Rundora
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Porous Medium ◽  
Fluid Flow ◽  
Vertical Channel ◽  
Casson Fluid ◽  
Convection Flow ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity

This article analyses the thermal decomposition in an unsteady MHD mixed convection flow of a reactive, electrically conducting Casson fluid within a vertical channel filled with a saturated porous medium and the influence of the temperature dependent properties on the flow. The fluid is assumed to be incompressible with the viscosity coefficient varying exponentially with temperature. The flow is subjected to an externally applied uniform magnetic field. The exothermic chemical kinetics inherent in the flow system give rise to heat dissipation. A technique based on a semi-discretization finite difference scheme and the shooting method is applied to solve the dimensionless governing equations. The effects of the temperature dependent viscosity, the magnetic field and other important parameters on the velocity and temperature profiles, the wall shear stress and the wall heat transfer rate are presented graphically and discussed quantitatively and qualitatively. The fluid flow model revealed flow characteristics that have profound ramifications including the increased heat transfer enhancement attributes of the reactive temperature dependent viscosity Casson fluid flow.

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