scholarly journals Conjugate Effects of Heat and Mass Transfer on Natural Convection Flow Across an Isothermal Horizontal Circular Cylinder With Chemical Reaction

2007 ◽  
Vol 12 (2) ◽  
pp. 191-201 ◽  
Author(s):  
Md. A. Hye ◽  
Md. M. Molla ◽  
M. A. H. Khan
Keyword(s):  
Boundary Layer ◽  
Natural Convection ◽  
Chemical Reaction ◽  
Transfer Rate ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Species Concentration ◽  
Local Skin ◽  
Boundary Layer Equations ◽  
Wide Range

Natural convection flow across an isothermal cylinder immersed in a viscous incompressible fluid in the presence of species concentration and chemical reaction has been investigated. The governing boundary layer equations are transformed into a system of non-dimensional equations and the resulting nonlinear system of partial differential equations is reduced to a system of local non-similarity boundary layer equations, which is solved numerically by a very efficient implicit finite difference method together with the Keller-box scheme. Numerical results are presented by the velocity, temperature and species concentration profiles of the fluid as well as the local skin-friction coefficient, local heat transfer rate and local species concentration transfer rate for a wide range of chemical reaction parameter γ (γ = 0.0, 0.5, 1.0, 2.0, 4.0), buoyancy ratio parameter N (N = −1.0, −0.5, 0.0, 0.5, 1.0), Schmidt number Sc (Sc = 0.7, 10.0, 50.0, 100.0) andPrandtl number Pr (Pr = 0.7, 7.0).

Magnetohydrodynamic Natural Convection Flow on a Sphere in Presence of Heat Generation

2005 ◽  
Vol 10 (4) ◽  
pp. 349-363 ◽  
Author(s):  
Md. M. Molla ◽  
M. A. Taher ◽  
Md. M. K. Chowdhury ◽  
Md. A. Hossain
Keyword(s):  
Natural Convection ◽  
Heat Generation ◽  
Numerical Solutions ◽  
Convection Flow ◽  
Surface Shear Stress ◽  
Natural Convection Flow ◽  
Surface Shear ◽  
Local Skin ◽  
Boundary Layer Equations ◽  
Keller Box Method

The present work describes the effect of magnetohydrodynamic natural convection flow on a sphere in presence of heat generation. The governing boundary layer equations are first transformed into a non-dimensional form and the resulting nonlinear system of partial differential equations arethen solved numerically using the Keller-box method. Here we have focused our attention on the evolution of the surface shear stress in terms of local skin friction and the rate of heat transfer in terms of local Nusselt number, velocity distribution as well as temperature distribution for a selection of parameter sets consisting of heat generation parameter Q (= 0.0, 0.5, 1.0, 2.0) and the magnetic parameter M (= 0.0, 0.2, 0.5, 0.8, 1.0). Numerical solutions have been considered for Prandtl number Pr (= 0.7, 1.0, 2.0).

Viscous dissipation in external natural convection flows

1969 ◽  
Vol 38 (1) ◽  
pp. 97-107 ◽  
Author(s):  
B. Gebhart ◽  
J. Mollendorf
Keyword(s):  
Boundary Layer ◽  
Natural Convection ◽  
Viscous Dissipation ◽  
Power Law ◽  
Surface Condition ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Wide Range ◽  
Prandtl Numbers ◽  
General Aspects

The effects of viscous dissipation are considered for external natural convection flow over a surface. A class of similar boundary-layer solutions is given and numerical results are presented for a wide range of the dissipation and Prandtl numbers. Several general aspects of similarity conditions for flow over surfaces and in convection plumes are discussed and their special characteristics considered. The general equations including the dissipation effect are given for the non-similar power law surface condition.

scholarly journals Effects of pressure work on natural convection flow around a sphere with radiation heat loss

2010 ◽  
Vol 15 (3) ◽  
pp. 287-298
Author(s):  
T. Akhter ◽  
M. A. Alim
Keyword(s):  
Natural Convection ◽  
Heat Loss ◽  
Nonlinear Partial Differential Equations ◽  
Convection Flow ◽  
Radiation Heat ◽  
Natural Convection Flow ◽  
Local Skin ◽  
Pressure Work ◽  
Boundary Layer Equations ◽  
Radiation Heat Loss

The effects of pressure work with radiation heat loss on natural convection flow on a sphere have been investigated in this paper. The governing boundary layer equations are first transformed into a non-dimensional form and the resulting nonlinear partial differential equations are then solved numerically using finite-difference method with Keller-box scheme. We have focused our attention on the evaluation of shear stress in terms of local skin friction and rate of heat transfer in terms of local Nusselt number, velocity as well as temperature profiles. Numerical results have been shown graphically and tabular form for some selected values of parameters set consisting of radiation parameter Rd, pressure work parameter Ge, surface temperature parameter θw and the Prandtl number Pr.

Two-phase natural convection flow of a dusty fluid

2015 ◽  
Vol 25 (7) ◽  
pp. 1542-1556 ◽  
Author(s):  
Sadia Siddiqa ◽  
M. Anwar Hossain ◽  
Suvash C Saha
Keyword(s):  
Boundary Layer ◽  
Natural Convection ◽  
Prandtl Number ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Two Phase ◽  
Metal Mixture ◽  
Content Type ◽  
Dusty Fluid ◽  
Wide Range

Purpose – The purpose of this paper is to conduct a detailed investigation of the two-dimensional natural convection flow of a dusty fluid. Therefore, the incompressible boundary layer flow of a two-phase particulate suspension is investigated numerically over a semi-infinite vertical flat plate. Comprehensive flow formations of the gas and particle phases are given in the boundary layer region. Primitive variable formulation is employed to convert the nondimensional governing equations into the non-conserved form. Three important two-phase mechanisms are discussed, namely, water-metal mixture, oil-metal mixture and air-metal mixture. Design/methodology/approach – The full coupled nonlinear system of equations is solved using implicit two point finite difference method along the whole length of the plate. Findings – The authors have presented numerical solution of the dusty boundary layer problem. Solutions obtained are depicted through the characteristic quantities, such as, wall shear stress coefficient, wall heat transfer coefficient, velocity distribution and temperature distribution for both phases. Results are interpreted for wide range of Prandtl number Pr (0.005-1,000.0). It is observed that thin boundary layer structures can be formed when mass concentration parameter or Prandtl number (e.g. oil-metal particle mixture) are high. Originality/value – The results of the study may be of some interest to the researchers of the field of chemical engineers.

scholarly journals Viscous Dissipation Effects on MHD Natural Convection Flow along a Sphere

1970 ◽  
Vol 36 ◽  
pp. 44-48 ◽  
Author(s):  
Md. M Alam ◽  
MA Alim ◽  
Md. MK Chowdhury
Keyword(s):  
Nusselt Number ◽  
Natural Convection ◽  
Viscous Dissipation ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Local Skin ◽  
Boundary Layer Equations ◽  
Box Scheme ◽  
Dissipation Parameter ◽  
Local Skin Friction

In this paper, we describe the viscous dissipation effects in magnetohydrodynamic (MHD) natural convection flow on a sphere. The natural convection laminar flow from a sphere immersed in a viscous incompressible optically thin fluid in the presence of magnetic field has been investigated. The governing boundary layer equations are first transformed into a non-dimensional form and the resulting nonlinear system of partial differential equations are then solved numerically using a very efficient finite-difference method with Keller-box scheme. Here we have focused our attention on the evolution of shear stress in terms of the local skin friction and the rate of heat transfer in terms of local Nusselt number, velocity profiles as well as temperature profiles for some selected parameters consisting of magnetic parameter M, viscous dissipation parameter N and the Prandlt number Pr.Keywords: Viscous dissipation, magnetohydrodynamics, natural convection, Nusselt number. Journal of Mechanical Engineering Vol.36 Dec. 2006 pp.44DOI = 10.3329/jme.v36i0.810

scholarly journals Joule heating effect on magnetohydrodynamic natural convection flow along a vertical wavy surface

2012 ◽  
Vol 9 (1) ◽  
pp. 11-24 ◽  
Author(s):  
Nazma Parveen ◽  
M A Alim
Keyword(s):  
Natural Convection ◽  
Joule Heating ◽  
Skin Friction Coefficient ◽  
Wavy Surface ◽  
Convection Flow ◽  
Surface Shear Stress ◽  
Natural Convection Flow ◽  
Surface Shear ◽  
Boundary Layer Equations ◽  
Marine Engineering

In this paper, the effect of Joule heating on magnetohydrodynamic natural convection flow of viscous incompressible fluid along a uniformly heated vertical wavy surface has been investigated. The governing boundary layer equations with associated boundary conditions for this phenomenon are converted to nondimensional form using a suitable transformation. The equations are mapped into the domain of a vertical flat plate and then solved numerically employing the implicit finite difference method, known as the Keller-box scheme. Effects of pertinent parameters, such as the Joule heating parameter (J), Prandtl number (Pr), magnetic parameter (M) and the amplitude of the wavy surface ? on the surface shear stress in terms of the skin friction coefficient (Cfx), the rate of heat transfer in terms of local Nusselt number (Nux), the streamlines and the isotherms are discussed. A comparison with previously published work is performed and the results show excellent agreement. DOI: http://dx.doi.org/10.3329/jname.v9i1.5954 Journal of Naval Architecture and Marine Engineering 9(2012) 11-24

Radiation effect on natural convection boundary layer flow over a vertical wavy frustum of a cone

2009 ◽  
Vol 223 (7) ◽  
pp. 1605-1614 ◽  
Author(s):  
M M Molla ◽  
M A Hossain ◽  
R S R Gorla
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Natural Convection ◽  
Boundary Layer Flow ◽  
Average Rate ◽  
Local Heat Transfer ◽  
Convection Boundary Layer ◽  
Local Skin ◽  
Wide Range ◽  
Layer Flow

The effect of thermal radiation on a steady two-dimensional natural convection laminar boundary layer flow of a viscous incompressible optically thick fluid over a vertical wavy frustum of a cone has been investigated. The boundary layer regime when the Grashof number Gr is large is considered. Using appropriate transformations, the basic governing equations are transformed into a dimensionless form and then solved numerically employing two efficient methods, namely: (a) implicit finite difference method together with Keller-box scheme and (b) direct numerical scheme. Numerical results are presented by streamline, isotherms, velocity and temperature distribution of the fluid, as well as the local shearing stress in terms of the local skin-friction coefficient, the local heat transfer rate in terms of local Nusselt number, and the average rate of heat transfer for a wide range of the radiation—conduction parameter or Planck number Rd and the surface heating parameter θw.

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