Nikhilkumar D. Abhangi¹, G. M. Deheri¹

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 245-260, 2009, DOI:10.3970/fdmp.2009.005.245

Abstract Efforts have been directed to study and analyze the behavior of a magnetic-fluid-based squeeze film between curved rough circular plates when the curved upper plate (with surface determined by an exponential expression) approaches the stationary curved lower plate (with surface governed by a secant function). A magnetic fluid is used as the lubricant in the presence of an external magnetic field oblique to the radial axis. The bearing surfaces are assumed to be transversely rough and the related roughness is characterized via a stochastic random variable with non-zero mean variance and skewness. The associated Reynolds equation is averaged with respect… More >

J. Roszmann¹, Y.C. Liu¹, S. Dost^1,2, B. Lent¹, S. Grenier³, N. Audet³

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 231-244, 2009, DOI:10.3970/fdmp.2009.005.231

Abstract The article presents the results of a combined numerical and experimental study of the effect of rotating magnetic field on impurity transport in a zone refining system. An impurity (selenium) with a segregation coefficient close to unity was targeted. The three-zone system previously developed was used for experiments and numerical simulations. The numerical simulations were performed for tellurium (Te) and cadmium (Cd) molten zones, but the experiments could only be carried out for the Te-system. More >

M.M. Shemirani¹, M.Z. Saghir²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 211-230, 2009, DOI:10.3970/fdmp.2009.005.211

Abstract A three-dimensional numerical modeling of Ge0.98Si0.02crystal growth is conducted to investigate the effect of g-jitter along with rotating magnetic field on the heat and mass transfer in the solvent region. It was found that the speed in the flow under the low frequency g-jitter is in the nano-centimeter per second and is too weak to have any impact on the silicon concentration in the process of crystallization near the growth interface. Different magnetic field intensities for different rotational speeds were examined. It was also found that rotating magnetic field not only did not suppress the convection but also generated an… More >

R. Abdeljabar¹

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.2, pp. 193-210, 2009, DOI:10.3970/fdmp.2009.005.193

Abstract A theoretical model has been developed to predict the expansion of a salty gradient (i.e. the interface) layer under natural diffusion. The salty gradient layer is initially sandwiched between two homogeneous miscible layers of varying salinity, which may or may not have the same thickness. The model describes the concentration profile of the salty gradient layer (expressed by analytical solutions of the diffusion equation) as the boundaries of this interfacial layer move into the adjacent (hitherto homogeneous) regions. The lifetime of the adjacent layers is also predicted. An experimental study for a configuration with salty water below and distilled water… More >

L. Bennamoun¹, A. Belhamri², A. Ali Mohamed

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.2, pp. 177-192, 2009, DOI:10.3970/fdmp.2009.005.177

Abstract This study focuses on the interplay between drying kinetics (encountered in typical industrial processes and particularly in the context of solar drying) and the possible variation of external (e.g., environmental) conditions. Theoretical models of these behaviours are introduced. Experimental results confirmed by simulation are also presented. Variation of the thermo physical properties of air is taken into account in terms of variation of viscosity, density and coefficient of diffusion. In particular, this coefficient is calculated from experimental data and expressed as a function of the wet bulb air temperature. When external conditions are modified and, as a natural consequence, also… More >

M.R. Arab^1,2, E. Semma³, B. Pateyron¹, M. El Ganaoui¹

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.2, pp. 161-176, 2009, DOI:10.3970/fdmp.2009.005.161

Abstract In this work, flows in porous media are simulated by using a Lattice Boltzmann Method (LBM). A model D2Q9 with a single collision operator is proposed. This method is applied on 2D digital images obtained by a Scanning Electron Microscope technique (SEM), and followed by a special treatment in order to obtain an image of synthesis that is finally read by the numerical code. The first results tested on two-dimensional configurations show the reliability of this strategy in simulating with a good accuracy phenomena of heat and mass transport. The numerical study is extended to the prediction of physical parameters… More >

Norihan M. Arifin¹, Ioan Pop²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.2, pp. 149-160, 2009, DOI:10.3970/fdmp.2009.005.149

Abstract A linear stability analysis is used to investigate the onset of Marangoni convection in a three-layer system comprising an incompressible fluid saturated porous layer over which lies a layer of the same fluid and below which lies a solid layer. The lower boundary is subjected to a fixed heat flux, while the upper free surface of the fluid is non-deformable. At the interface between the fluid and the porous layer, the Beavers-Joseph slip condition is used and the Darcy law is employed to describe the flow in the porous medium. The asymptotic analysis of the long-wavelength is performed and the… More >

Aouachria Z¹

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.2, pp. 137-148, 2009, DOI:10.3970/fdmp.2009.005.137

Abstract This work treats heat and mass transfer by natural convection along a vertical wall in porous media imbibed by fluid, using an integral method. The problem governing parameters are the buoyancy ratio,N, and the Lewis number, Le The results for the local Nusselt and Sherwood numbers are presented for a large range of these parameters. The concentration and thermal boundary layer thickness are also determined. We observe that our results are in good agreement with those obtained by Bejan and Khair (1985). More >

Munther Issa K,ah¹, Jean-Luc Meunier²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.2, pp. 123-136, 2009, DOI:10.3970/fdmp.2009.005.123

Abstract Multi walled carbon nanotubes (MWCNTs) were synthesized on different graphite types covered with thin layer of nickel catalyst by catalytic chemical vapour deposition using acetylene as hydrocarbon source. The produced carbon nanotubes were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The shape, quantity and diameter of the MWCNTs are shown to be affected by the type of the graphite substrate, the growth temperature and the hydrocarbon source flow rate. The diameters of the produced MWCNTs were ranged between 43 and 80 nm for pyrolytic (PYROID) and polycrystalline (AXF-5Q) graphite, respectively when the… More >

K.V. Pagalthivarthi¹, P.K. Gupta²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.1, pp. 93-122, 2009, DOI:10.3970/fdmp.2009.005.093

Abstract The objective of the present work is to predict erosive wear in multisize dense slurry flow in a rotating channel. The methodology comprises numerical prediction of two-phase flow which is accomplished using the Galerkin finite element method. The wear models for both sliding wear and impact wear mechanisms account for the particle size dependence. The effect of various operating parameters such as rotation rate, solids concentration, flow rate, particle size distribution and so forth has been studied. Results indicate that wear rate in general increases along the pressure-side of the channel with rotation rate, overall solids concentration, flow rates etc.… More >