scholarly journals Laminar free convection with variable fluid properties in vertical ducts having uniform wall temperature.

1985 ◽  
Vol 51 (471) ◽  
pp. 3582-3588 ◽  
Author(s):  
Toshio AIHARA ◽  
Shigenao MARUYAMA ◽  
Jun-Seop CHOI
Keyword(s):  
Free Convection ◽  
Wall Temperature ◽  
Uniform Wall Temperature ◽  
Variable Fluid Properties ◽  
Fluid Properties ◽  
Uniform Wall

Influence of Uniform Blowing/Suction on the Free Convection of Non-Newtonian Fluids Over a Vertical Cone in Porous Media With Thermal Radiation and Soret/Dufour Effects: Uniform Wall Temperature/Uniform Wall Concentration

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Chuo-Jeng Huang
Keyword(s):  
Mass Transfer ◽  
Free Convection ◽  
Thermal Radiation ◽  
Heat And Mass Transfer ◽  
Power Law ◽  
Wall Temperature ◽  
Newtonian Fluids ◽  
Vertical Cone ◽  
Uniform Wall Temperature ◽  
Uniform Wall

This work studies numerically the combined heat and mass transfer of uniform blowing/suction, non-Newtonian power-law fluid, and thermal radiation effects on free convection adjacent to a vertical cone within a porous medium in the presence of Soret/Dufour effects. The surface of the vertical cone has a uniform wall temperature and uniform wall concentration (UWT/UWC). The Rosseland diffusion approximation is employed to describe the radiative heat flux. A nonsimilarity analysis is performed, and the transformed governing equations are solved by Keller box method (KBM). The effects of these major parameters of the Dufour parameter, Soret parameter, Lewis number, buoyancy ratio, power-law index of the non-Newtonian fluids, blowing/suction parameter, and thermal radiation parameter on the heat and mass transfer characteristics have been carried out. In general, for the case of blowing, both the local Nusselt number and the local Sherwood number decrease. This trend reversed for suction of fluid. The physical aspects of the problem are discussed in detail.

scholarly journals Second Law Analysis of Laminar Flow in a Circular Pipe Immersed in an Isothermal Fluid

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Vishal Anand ◽  
Krishna Nelanti
Keyword(s):  
Laminar Flow ◽  
Entropy Generation ◽  
Circular Tube ◽  
Dimensionless Temperature ◽  
Bejan Number ◽  
Uniform Wall Temperature ◽  
Thermal Boundary Conditions ◽  
Fluid Properties ◽  
Isothermal Fluid ◽  
Uniform Wall

Entropy generation and pumping power to heat transfer ratio (PPR) of a laminar flow, for a circular tube immersed in an isothermal fluid, are studied analytically in this paper. Two different fluids, namely, water and ethylene glycol, are chosen to study the influence of fluid properties on entropy generation and PPR. The expressions for dimensionless entropy generation, Bejan number and PPR are derived in a detailed way and their variations with Reynolds number, external Biot number, and the dimensionless temperature difference are illustrated. The results of the analysis are compared with those for a laminar flow in a circular tube with uniform wall temperature boundary condition. Finally, a criterion is established to determine which type of thermal boundary conditions is more suitable for a particular fluid, with respect to its influence on entropy generation.

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