M. Kriaa¹, M. El Alami^1,2, M. Najam¹, E. Semma³

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.2, pp. 125-140, 2011, DOI:10.3970/fdmp.2011.007.125

Abstract In this paper a numerical study of natural convection in a two dimensional convergent channel, with or without rectangular block, is carried out. The block is placed at the channel outlet and its thermal conductivity is set equal to that of air. One of channel planes is heated at constant temperature T_H. The other one is maintained cold at T_C < T_H. The governing equations are solved using a finite volume method and the SIMLEC algorithm for the velocity-pressure coupling is used. Special emphasis is given to detail the effect of the block size and Rayleigh number on the dynamics… More >

Shadia J Ikhmayies¹, Naseem M. Abu El-Haija², Riyad N. Ahmad-Bitar³

FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 219-232, 2010, DOI:10.3970/fdmp.2010.006.219

Abstract Large area and highly uniform polycrystalline ZnO thin films have been produced by a spray pyrolysis (SP) technique resorting to a customized system (spraying) on glass substrates at temperature Ts= 450℃. This study deals with the related investigation about the influence of heat treatment (in nitrogen atmosphere) on the resulting properties (electrical, optical and structural) of such films. Properties are analyzed by means of I-V plots, transmittance curves, X-Ray diffractograms (XRD) and scanning electron microscope (SEM) micrographs. Results show that the resistivity of the films decreases from about 200W.cm for the as-deposited films to about 95W.cm for annealed films. XRD… More >

A. B. Mahmud Hasan^1,2, S.M. Guo¹, M.A. Wahab¹

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.4, pp. 399-410, 2009, DOI:10.3970/fdmp.2009.005.399

Abstract The effects of gas flow channel design were studied experimentally for increasing fuel cell performance and fuel optimization. Three types of gas flow channels (serpentine, straight and interdigitated) were designed on the basis of water flooding due to electrochemical reactions, electro-osmotic drag, etc. Experimental results indicate that the best cell performance can be obtained by arranging interdigitated gas flow channel at the anode side and serpentine gas flow channel at the cathode side. Detailed analysis on complex two phase water generation and electrochemical phenomena behind those results were analyzed in this work to find out the best design for gas… More >

Ahmed Mezrhab¹, Hassan Naji²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 283-296, 2009, DOI:10.3970/fdmp.2009.005.283

Abstract The objective of this paper is to assess the effectiveness of the coupled Lattice Boltzmann Equation (LBE) and finite volume method strategy for the simulation of the interaction between thermal radiation and laminar natural convection in a differentially heated square cavity. The vertical walls of the cavity are adiabatic, while its top and bottom walls are cold and hot, respectively. The air velocity is determined by the lattice Boltzmann equation and the energy equation is discretized by using a finite volume method. The resulting systems of discretized equations have been solved by an iterative procedure based on a preconditioned conjugate… More >

R. Djebali^1,2, M. El Ganaoui^2,3, H. Sammouda¹, R. Bennacer⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 261-282, 2009, DOI:10.3970/fdmp.2009.005.261

Abstract The simplified thermal lattice Boltzmann model (STLBM) developed by Peng, Shu and Chew (2003) is used in this work to simulate low-Rayleigh-number natural convection in a heated rectangular cavity on a uniform grid. It is shown how by resorting to the double populations approach both hydrodynamic and thermal fields can be effectively simulated. Furthermore, a general benchmark is carried out to account for the effect of different parameters in relatively wide ranges. Results are compared with previous works available in the literature. 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 >

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 >

M. El Alami¹, E. A. Semma^2,3, M. Najam¹, R. Boutarfa²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.1, pp. 23-36, 2009, DOI:10.3970/fdmp.2009.005.023

Abstract This study is devoted to the investigation of natural convection in a two dimensional horizontal channel with rectangular heated blocks at the bottom. The aspect ratio of the channel is A = L'/H' = 5. The blocks are heated with a constant temperature while the upper plane of the channel is cold. The governing equations are solved using a finite volumes method and the SIMPLEC algorithm is used for the treatment of the pressure-velocity coupling. Special emphasis is given to detail the effect of the Rayleigh number and blocks height on the heat transfer and the mass flow rate generated… More >

G. Accary¹, S. Meradji², D. Morvan², D. Fougère²

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.4, pp. 263-270, 2008, DOI:10.3970/fdmp.2008.004.263

Abstract In the literature, only few references have dealt with mixed-convection flows in the low Mach number approximation. For this reason, in the present study we propose to extend the standard 3D benchmark for mixed convection in a rectangular channel heated from below (Medale and Nicolas, 2005) to the case of large temperature variations (for which the Boussinesq approximation is no longer valid). The Navier-Stokes equations, obtained under the assumption of a low Mach number flow, are solved using a finite volume method. The results, corresponding to the steady-state case of the benchmark, lead to the idea of launching a call… More >

Huawei Han¹, Kamiel S. Gabriel²

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.4, pp. 287-298, 2006, DOI:10.3970/fdmp.2006.002.287

Abstract Data on air-water co-current two-phase annular flow in a tube with an inner diameter of 9.525 mm (3/8 in) were previously collected at both microgravity u-g and normal gravity (1-g) conditions. The data contained measurements of pressure drop, in addition to previously published data of liquid film thickness. This paper presents the results and analysis of the influence of flow pressure gradient on interfacial wave properties of annular flow at both microgravity and normal gravity. The examined wave properties include wave base thickness, wave height (or roughness height), wave spacing, wave speed and wave frequency. It was found that, the… More >