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S. Aggoune¹, C. Abid², E.H. Amara^1,3
FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 115-125, 2015, DOI:10.3970/fdmp.2015.011.115
Abstract This paper focuses on the vortex formation effect during the application of a laser-fusion cutting technique. This industrial technique is typically associated with the ejection of a film of molten stainless steel blown off by a subsonic laminar jet of nitrogen gas used to assist the process. Without taking into account the transverse movement of the workpiece, we consider a 4 mm thick stainless steel plate. The resulting molten metal flow is assumed to be laminar, steady, viscous and incompressible. The numerical results reveal vortex structures adjacent to the walls at the entrance of the kerf, and a pair of… More >

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ARTICLE

Yuan Chen¹, Honggang Duan¹, Fei Yu¹, Xingyu Zhao¹, Han Xu¹, Jun Gao^1,2
FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 127-142, 2015, DOI:10.3970/fdmp.2015.011.127
Abstract The dynamics of dispersed bubbles in a centrifugal separator are investigated with the aim to improve the efficiency of the system. The prototype separator consists of a rotor, a base, a diverting disc, a shaft, an oil trapping impeller, a central pipe, an inlet section for contaminated oil, an outlet section for purified oil and an air outlet. A hydrodynamic model is developed to predict the complex influence of parameters such as the centrifugal force and vacuum pressure. In particular, three different force models are selected to analyze the effect of the added mass and Basset forces (also including inertia,… More >

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1138

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ARTICLE

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 >

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2339

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ARTICLE

L. Belarche^1,2, B. Abourida¹, S. Smolen³
FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 157-170, 2015, DOI:10.3970/fdmp.2015.011.157
Abstract Natural convection in a cubical cavity, discretely heated is studied numerically using a three-dimensional finite volume formulation. Two heating square portions are placed on the vertical wall of the enclosure, while the rest of the considered wall is adiabatic. The opposite vertical wall is maintained at a cold uniform temperature and the other walls are adiabatic. Effects of the heating sections dimensions ε (0.15 ≤ ε ≤ 0.35) and the Rayleigh number Ra (10³ ≤ Ra ≤ 10⁷) on the fluid flow and the heat transfer within the cavity are studied. The obtained results show that the flow intensity and… More >

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Imen Mejri^1,2, Ahmed Mahmoudi¹
FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 171-195, 2015, DOI:10.3970/fdmp.2015.011.171
Abstract This paper examines natural convection in an open cavity with a sinusoidal thermal boundary condition. The cavity is filled with a water-Al₂O₃ nanofluid and subjected to a magnetic field. The Lattice Boltzmann method (LBM) is applied to solve the coupled equations of flow and temperature. The study has been carried out considering parameters in the following ranges: Rayleigh number of the base fluid, Ra = 10³ to 10⁶, Hartmann number varied from Ha = 0 to 60, phase deviation γ = 0, π4, π2, 3 π4 and π and solid volume fraction of nanoparticles between π = 0 and 6%.… More >

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Y.H. Liu¹, X.X. Xue², J.M.Shen¹
FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 197-204, 2015, DOI:10.3970/fdmp.2015.011.195
Abstract Blends of Polyethylene (PE) and modified-oil shale ash (MOSA) with different fractions of MOSA were prepared by the melting blend method. The effects of MOSA content on the rheological and mechanical properties of the blend were properly assessed via direct experimental analysis (more precisely, all rheological measurements were performed using a laboratory-scale XSS-300 torque rheometer with single screw extruder; the temperatures were maintained at 170°C, 180°C and 190°C under continuous extrusion). The prepared samples were observed to display a shear-thinning behaviour. Moreover, with increasing the MOSA content, we found the yield strength of the blends to increase, while its elongation… More >

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