Frontiers in Heat and Mass Transfer (FHMT), 8, 39 (2017) DOI: 10.5098/hmt.8.39 Global Digital Central ISSN: 2151-8629 1 EFFECTS OF VARIABLE VISCOSITY AND VARIABLE THERMAL CONDUCTIVITY ON HYDROMAGNETIC DUSTY FLUID FLOW DUE TO A ROTATING DISK Jadav Konch * and G. C. Hazarika Department of Mathematics, Dibrugarh University, Dibrugarh-786004, Assam, India ABSTRACT This paper investigates momentum, heat and mass transfer characteristics of a hydromagnetic Newtonian dusty fluid flow due to a rotating disk with radiation and viscous dissipation. The main objective of this paper is to study effects of temperature dependent viscosity and thermal conductivity on flow, temperature and species concentration. Radiation and viscous dissipation effects are also taken into account. Saffman model for dusty fluid is considered for the problem. The partial differential equations governing the flow are converted into ordinary differential equations employing similarity transformations. The resulting highly nonlinear coupled ordinary differential equations are solved numerically using shooting technique with fourth order Runge-Kutta integration scheme. The influence of variable fluid viscosity, variable thermal conductivity, fluid particle interaction, magnetic interaction and radiation parameters as well as Eckert number are presented graphically and discussed for velocity, temperature and species concentration profiles. Numerical values of the wall shear stress, rate of heat transfer (in terms of Nusselt number) and rate of mass transfer (in terms of Sherwood number) are obtained, analyzed and presented in tabular form. Keywords: Dusty fluid, variable viscosity, variable thermal conductivity, radiation, rotating disk, shooting method. * Corresponding Author Email: jadavkonch@gmail.com 1. INTRODUCTION The study of a two-phase gas-particle flow has a wide range of applications in power plant piping, combustion, petroleum transport, waste water treatment, corrosive particles in engine oil flow and formation of raindrops. Its relevance is also seen in the field of smoke emission from vehicles, agriculture and food technologies. Motivated by the applications of a two-phase flow, Saffman (1962) has initiated and formulated the governing equations for the flow of dusty fluid and discussed the stability of a laminar flow of a dusty gas. In this model, he considered that the dust particles were uniformly distributed. Michael and Miller (1966) discussed the motion of dusty gas occupying the semi infinite space above a rigid plane boundary. Nayfeh (1966) studied oscillating dusty flow through a rigid pipe. Gupta and Gupta (1976) discussed the flow of a gas containing solid particles in a channel with arbitrary time varying pressure. The flow of a dusty fluid in the boundary layer over a semi-infinite flat plate was analyzed by Datta and Mishra (1982). Ramamurthy (1990) investigated the effects of free convection on the Stokes problem for the flow of dusty fluid in an infinite vertical plate. Attia (2006) analyzed unsteady MHD Couette flow and heat transfer of dusty fluid with variable physical properties. Palani and Kim (2010) obtained the approximate solution for the flow of a dusty-gas along a semi-infinite vertical cylinder. Gireesha et al. (2011; 2012; 2013) discussed interesting results on the flow of dusty fluid due to linear and exponential stretching of porous and nonporous sheet with various effects like radiation, source/sink parameter, viscous dissipation etc. Manjunatha (2015) studied the effect of radiation on MHD flow and heat transfer of dusty fluid over a stretching cylinder in a porous medium. The study of dusty viscous fluid flow under the influence of various physical conditions has been carried out by several researchers or authors. This interest stems from the fact that the flow and heat transfer of magnetohydrodynamic boundary layer flow finds its applications in wide range of science and technology like MHD power generation, purification of crude oil, cooling of nuclear reactors, centrifugal separation of matter from fluid and in several astrophysical situations. The theory of rotating fluid is highly important due to its occurrence in various natural phenomena and for its applications in various technological situations. The broad subjects of oceanography, meteorology, atmospheric sciences, and limnology all contain some important and essential features of rotating fluid. Further, the fluid flow problems of rotating fluid have attracted many scholars and there appeared a number of studies in literature viz. Tiwari and Kamal Singh (1983) analyzed viscous incompressible hydromagnetic boundary layer flow of dusty fluid over a semi-infinite plate. Prasada Rao and Krishna (1981) investigated the Hall Effect on unsteady hydromagnetic flow. The effects of Hall current on unsteady MHD flow past a rotating disk was studied by Kanch and Jana (1999). Debnath et al. (1979) studied the Hall effects on the unsteady hydromagnetic flow of a rotating fluid system over a porous plate. Turkyilmazoglu (2009; 2010) studied the steady laminar flow of viscous, incompressible, electrically-conducting fluid over a rotating disk in the presence of a transverse magnetic field. The problem of heat transfer from a rotating disk maintained at a constant temperature for various values of Prandtl number in steady state was considered by Millsaps and Pohlhausen (1952). Heat transfer characteristic of MHD steady flow of a viscous incompressible electrically conducting fluid past a rotating disk with Hall current, viscous dissipation and Ohmic heating were studied by Sibanda and Makinde (2010). They found that magnetic field opposed fluid motion due to the Lorentz force generated by the magnetic field. It is interesting that in the above flow problems generated by a rotating disk, fluids are considered in pure form. But, it is well known Frontiers in Heat and Mass Transfer Available at www.ThermalFluidsCentral.org