J.J. Derksen¹, D. Eskin²

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.4, pp. 341-356, 2011, DOI:10.3970/fdmp.2011.007.341

Abstract Direct simulations of laminar solid-liquid flow in micro-channels with full resolution of the solid-liquid interfaces have been performed. The solids phase consists of simple agglomerates, assembled of monosized, spherical particles. The flow of the interstitial liquid is solved with the lattice-Boltzmann method. Solids and fluid dynamics are two-way coupled. The simulations keep track of the flow-induced forces in the agglomerates. The effects of agglomerate type (doublets, triplets, and quadruplets), solids loading, and channel geometry on (the statistics of the) flow and collision-induced forces have been investigated. By comparing these forces with agglomerate strength, we would be able to assess the… More >

Carole Planchette¹, Elise Lorenceau¹, Günter Brenn²

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.3, pp. 279-302, 2011, DOI:10.3970/fdmp.2011.007.279

Abstract This work is dedicated to a general description of collisions between two drops of immiscible liquids. Our approach is mainly experimental and allows us to describe the outcomes of such collisions according to a set of relevant parameters. Varying the relative velocity U as well as the impact parameter X we can build for each pair of investigated liquids a nomogram X,U showing three possible regimes: coalescence, head-on separation and off-center separation. In this paper, we also study the influence of the liquid properties, i.e. viscosity, density, surface and interfacial tensions using a set of aqueous glycerol solutions together with… More >

R. Abdeljabar¹

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.2, pp. 217-230, 2011, DOI:10.3970/fdmp.2011.007.217

Abstract In this paper, we discuss a new technique for desalination based on the principles of the Soret effect. In particular, the method stems from the peculiar behavior of the solute in a solution of sodium chloride (i.e. salty water layer) of uniform concentration being less or equal to 5wt% under the effect of an imposed temperature gradient with average temperature equal to 12oC. The Soret coefficient may be positive or negative according to whether the temperature of the solution is above or below 12oC. As two diffusion processes (one parallel to the temperature gradient and the other anti-parallel) can occur… More >

S. Srinivasan¹, M. Z. Saghir¹

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.2, pp. 201-216, 2011, DOI:10.3970/fdmp.2011.007.201

Abstract CFD simulations have been made to understand the impact of the vibrations of the ISS on the thermodiffusion process. Simulations were made for two ternary hydrocarbon mixtures and one binary associated mixture. While one of the ternary mixture was at a pressure of 35 MPa, the second ternary mixture as well as the binary mixture were at a pressure of 0.101325 MPa. The analysis of the results showed that imposing the ISS vibrations had a profound effect on the Soret effect in all three systems. More precisely, in all three mixtures, a single convective flow cell is established. Such a… More >

M. N. Noui-Mehidi¹

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.2, pp. 141-152, 2011, DOI:10.3970/fdmp.2011.007.141

Abstract The present work is concerned with a numerical study of the performance of a conical annular centrifugal contractor through the analysis of the flow properties when the apex angle is changed for different imposed axial flows. The calculations revealed the advantage of using conical annular centrifugal contractors compared to the cylindrical annular centrifuges. The study is conducted by a comparison analysis of the hydrodynamics of fluid flow in both conical and cylindrical contractors where moderate axial flows are imposed. In both systems the outer body is stationary while the inner rotor is maintained at constant speed. The calculations are achieved… More >

M. Chrigui^1,2, L. Schneider¹, A. Zghal², A. Sadiki¹, J. Janicka¹

FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.4, pp. 399-408, 2010, DOI:10.3970/fdmp.2010.006.399

Abstract This paper deals with the numerical simulation of droplet dispersion and evaporation within an LPP (Lean Premix Prevaporized) burner. The Eulerian-Lagrangian approach was used for this purpose, and a fully two way-coupling was accounted for. For the phase transition, a non-equilibrium evaporation model was applied that differs strongly from the equilibrium one where there are high evaporation rates. The non-equilibrium conditions were fulfilled in the investigated configuration, as the droplets at the inlet had a mean diameter of 50mm. The numerical results of water droplet velocities, corresponding fluctuations, and diameters were compared with experimental data. Good agreement was found. More >

Mohamed Rady¹, Eric Arquis²

FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 137-152, 2010, DOI:10.3970/fdmp.2010.006.137

Abstract In the present article, differential scanning calorimetry (DSC) and a modified T-history method have been used to study the phase changing behavior of granular composites. Further modifications and improvements of the two methods are employed to handle granular materials undergoing phase change over a temperature range. A simple procedure has been advised to obtain accurate results from the DSC measurements based on the estimation of the thermal resistance between the sample and its enclosure. The concept of enthalpy and its relationship with temperature has been employed in the T-history analysis to obtain enthalpy-temperature and apparent heat capacity curves similar to… 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 >

Shishir Sinha¹, Vinay Kumar²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 297-312, 2009, DOI:10.3970/fdmp.2009.005.297

Abstract High-capacity ion exchange resins based on Poly Methyl Methacrylate (PMMA) was developed during this study having higher mechanical strength, stable and, hydrophilic in nature compared to Poly styrene (PS) based systems. PMMA was cross-linked by Di Vinyl Benzene (DVB) to get macro porous PMMA-DVB resins by suspension polymerization. PMMA-DVB resins were surface modified by nitration followed by amination under appropriate temperature conditions. Change in the color of resin from white to pale yellow and pale yellow to golden yellow as well as characteristic peaks of NO2at 700 cm-1and 1400 cm-1and 3100-3200 cm-1for NH2group in FTIR spectroscopy confirmed the presence of… 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 >