Chekifi. T^1,2, Dennai. B¹, Khelfaoui. R¹

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 205-220, 2015, DOI:10.3970/fdmp.2015.011.205

Abstract Droplet generation, splitting and sorting are investigated numerically in the framework of a VOF technique for interface tracking and a finite-volume numerical method using the commercial code FLUENT. Droplets of water-in-oil are produced by a flow focusing technique relying on the use of a microchannell equipped with an obstacle to split the droplets. The influence of several parameters potentially affecting this process is investigated parametrically towards the end of identifying "optimal" conditions for droplet breakup. Such parameters include surface tension, the capillary number and the main channel width. We show that the capillary number plays a crucial role in determining… More >

Shuce Zhang¹, Xueheng Tao^1,2,3, Jinshi Lu^1,2, Xuejun Wang^1,2, ZhenhuaZeng⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 143-155, 2015, DOI:10.3970/fdmp.2015.011.143

Abstract Three different kinds of nozzles, normally used in industrial processes for the cleaning of material surface by means of water jets at high pressure (a Cylindrical Contracting, a Taper Contracting and Stepped nozzle), are numerically simulated with the express intent to optimize the related efficiency (cleaning effectiveness). Although some of them are found to display interesting properties, simulation results indicate that a helix nozzle displays the best jetting performances. It is shown that, as compared to improvements obtained by simply changing the jetting angle, revolving the fluid released from the helix nozzle can be used to create a grinding wheel… More >

S. Hamimid^1,2, M. Guellal¹

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.3, pp. 377-393, 2014, DOI:10.3970/fdmp.2014.010.377

Abstract Combined laminar natural convection and surface radiation in a differentially heated square cavity has been investigated by a finite volume method through the concepts of staggered grid and SIMPLER approach. A power scheme has been also used in approximating advection–diffusion terms, determining the view factors by means of analytical expressions. The effect of emissivity on temperature and velocity profiles within the enclosure has been analyzed. In addition, results for local and average convective and radiative Nusselt numbers are presented and discussed for various conditions. More >

T. Sanada¹, K. Ando², T. Colonius²

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.4, pp. 329-340, 2011, DOI:10.3970/fdmp.2011.007.329

Abstract When a droplet impacts a solid surface at high speed, the contact periphery expands very quickly and liquid compressibility plays an important role in the initial dynamics and the formation of lateral jets. The high speed impact results in high pressures that can account for the surface erosion. In this study, we numerically investigated a high speed droplet impacts on a solid wall. The multicomponent Euler equations with the stiffened equation of state are computed using a FV-WENO scheme with an HLLC Riemann solver that accurately captures shocks and interfaces. In order to compare the available theories and experiments, 1D,… More >

S. Homma¹, M. Yokotsuka¹, T. Tanaka¹, K. Moriguchi¹, J. Koga¹, G. Tryggvason²

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.3, pp. 231-240, 2011, DOI:10.3970/fdmp.2011.007.231

Abstract We develop a three-fluid front-tracking method in order to simulate the motion of an axisymmetry compound droplet, which consists of three immiscible fluids separated by two different interfaces. The two interfaces of the compound droplet are represented by two different sets of the front-tracking elements immersed on the Eulerian grid mesh, where the velocities and the pressure are calculated. The density and viscosity profiles with jumps at the interfaces are successfully determined from the location and the connection information of the front-tracking elements. The motion of a compound droplet is simulated on axisymmetric cylindrical coordinates. The results show that the… More >

Ahmed Meskini, Mostafa Najam, Mustapha El Alami

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.1, pp. 97-110, 2011, DOI:10.3970/fdmp.2011.007.097

Abstract A numerical mixed convection investigation was carried out to study the enhancement of heat transfer in a square cavity with identical heated rectangular blocks adjacent to its upper wall, and submitted to a vertical jet of fresh air from below. The configuration so defined is an inverted "T"-shaped cavity presenting symmetry with respect to a vertical axis passing by the middle of the openings. The governing equations have been solved using the finite difference method. The parameters of this study are: Rayleigh number 10⁴ ≤ Ra ≤ 10⁶, Reynolds number 1 ≤ Re ≤ 1000, the opening width C=0.15, the… More >

A. Kidess¹, N. Armour¹, S. Dost^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.1, pp. 29-56, 2011, DOI:10.3970/fdmp.2011.007.029

Abstract When a metallic liquid is subject to strong magnetic body forces, the issues of convergence and numerical stability may arise in numerical simulations. Handling of magnetic body force terms needs care. In this work we have studied two open codes and discussed the related issues. Magnetic force and mass transport terms were added to these codes. Handling the stability issues was discussed. The developed systems were validated by two benchmark cases. Then, the dissolution process of silicon into the germanium melt was selected as an application. The objective was the numerical study of the dissolution process with and without the… More >

F. Mechighel^1,2, M. El Ganaoui¹, M. Kadja², B. Pateyron³, S. Dost⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.4, pp. 313-330, 2009, DOI:10.3970/fdmp.2009.005.313

Abstract A numerical study has been carried out to investigate the three-dimen -sional buoyant flow in a parallelepiped box heated from below and partially from the two sidewalls (a configuration commonly used for solidification problems and crystal growth systems). Attention has been paid, in particular, to phenomena of symmetry breaking and transition to unsteady non-symmetric convection for a low Prandtl number fluid (Pr=0.01). The influence of an applied horizontal magnetic field on the stability properties of the flow has been also considered. Results obtained may be summarized as follows: In the absence of magnetic field and for relatively small values of… 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 >

M. Sekhon¹, N. Armour¹, S. Dost^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.9, No.4, pp. 331-351, 2013, DOI:10.3970/fdmp.2013.009.331

Abstract Liquid Phase Diffusion (LPD) growth of Si_xGe_1-x single crystals has been numerically simulated under zero gravity. The objective was to examine growth rate and silicon concentration distribution in the LPD grown crystals under diffusion dominated mass transport prior to the planned LPD space experiments on the International Space Station (ISS). Since we are interested in predicting growth rate and crystal composition, the gravitational fluctuation of the ISS (g-jitter) was neglected and the gravity level was taken as zero for simplicity.
A fixed grid approach has been utilized for the simulation. An integrated top-level solver was developed in OpenFOAM to carry… More >