Paper2

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International Journal of Scientific Engineering and Technology Volume No.2, Issue No.2, pg : 56-72

(ISSN : 2277-1581) 1 Feb. 2013

Radiation and Thermo - Diffusion Effects on Mixed Convective Heat and Mass Transfer Flow af a Viscous Dissipated Fluid over a Vertical Surface in the Presence of Chemical Reaction with Heat Source D Chenna Kesavaiah1, P V Satyanarayana2, S Venkataramana3 1 Department of H & BS, Visvesvaraya College of Engineering & Technology, Greater Hyderabad, A.P, India chennakesavaiah@gmail.com 2 Fluid Dynamics Division, School of Advanced Science, VIT University, Vellore - 632 014, T N, India 3 Department of Mathematics, S V University, Tirupati - 517 502, A.P, India ABSTRACT

very light molecular weight  H 2 , He  and the medium

The present work analyzes the influence of chemical reaction on MHD mixed convection heat and mass transfer for a viscous fluid past an infinite vertical plate embedded in a porous medium with radiation and heat generation. The dimensionless governing equations for this investigation are solved analytically using two - term harmonic and non-harmonic functions. The effects of various parameters on the velocity, temperature and concentration fields as well as the skin-friction coefficient, Nusselt number are presented graphically and Sherwood number is presented numerically.

molecular weight

Keywords: Radiation, mass transfer, chemical reaction, heat source and concentration I. INTRODUCTION The phenomenon of heat and mass transfer has been the object of extensive research due to its applications in Science and Technology. Such phenomena are observed in buoyancy induced motions in the atmosphere, in bodies of water, quasisolid bodies such as earth and so on. This assumption is true when the concentration level is very low. Therefore, so ever, exceptions the thermal diffusion effects for instance, has been utilized for isotropic separation and in mixtures between gases with IJSET@2013

 N2

air) the diffusion – thermo

effects was found to be of a magnitude just it cannot be neglected. The heat and mass transfer simultaneously affecting each other that will cause the cross diffusion effect. The heat transfer caused by concentration gradient is called the diffusion-thermo or Dufour effect. On the other hand, mass transfer caused by temperature gradients is called Soret or thermal diffusion effect. Thus Soret effect is referred to species differentiation developing in an initial homogenous mixture submitted to a thermal gradient and the Dufour effect referred to the heat flux produced by a concentration gradient. The Soret effect, for instance has been utilized for isotope separation, and in mixture between gases with very light molecular weight

 H2 , He

and of medium molecular weight  N2 , air 

Soret effect [thermal-diffusion] refers to mass flux produced by a temperature gradient. These effects are neglected on the basis that they are of a smaller order of magnitude than the effects described by Fourier’s and Fick’s laws. In view of the importance of this diffusion – thermo effect. Similarity equations of the momentum energy and concentration equations are derived by introducing a time dependent length scale. Malsetty et. al [19] have studied the effect of both the Soret coefficient and Dufour coefficient on the double diffusive Page 56


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