http://dspace.ensta.edu.dz/jspui/handle/123456789/134 Tue, 24 Mar 2026 15:38:48 GMT 2026-03-24T15:38:48Z http://dspace.ensta.edu.dz/jspui/handle/123456789/282 Title: Simultaneous hydrodynamic and thermal flow development of a thermodependent viscoplastic fluid Authors: LABSI, Nabila; BENKAHLA, Youb Khaled; BOUTRA, Abdelkader; BRUNIER, E Abstract: Numerical analysis of simultaneously developing forced convection laminar flow and heat transfer of a viscoplastic fluid has been carried out. This fluid is incompressible and of thermodependent rheological properties. It consists on the sloe fruit juice with low pulp and pectin contents, which obeys the rheological law of Bingham and for which we adopt the Papanastasiou model to describe its behaviour. The flow takes place in an isothermal circular pipe. In order to validate the computing code, parametric computations were performed to investigate the effect of Reynolds, Prandtl and Bingham numbers on heat transfer. The effect of wall-to-inlet temperature difference on velocity and temperature profiles, Nusselt number and apparent friction factor was then analysed, by taking into account the temperature dependency of the fluid’s plastic viscosity and yield stress, for both heating and cooling situations. The results show on one hand, that the variability of the plastic viscosity provides more effect on hydrodynamic and thermal characteristics than the variability of the yield stress. On the other hand, the effect of variable plastic viscosity is more pronounced on the friction factor than on the Nusselt numbers Description: Article,International Review of Chemical Engineering IRECHE,volume 10 (2), 2016 Fri, 01 Jan 2016 00:00:00 GMT http://dspace.ensta.edu.dz/jspui/handle/123456789/282 2016-01-01T00:00:00Z http://dspace.ensta.edu.dz/jspui/handle/123456789/281 Title: Lattice Boltzmann Analysis of the Heat Transfer in Cubical Enclosures Authors: AMEZIANI, Djamel Eddine; BENNACER, Rachid; BELMEDANI, Mohamed; BOUTRA, Abdelkader Abstract: The purpose of this work is to study hydrodynamic and thermal characteristics of air contended into a differentially heated cubic cavity. Due to their importance in the characterization of heat transfer in this kind of configuration, the effect of some parameters is analyzed. It consists in the Rayleigh number and the aspect ratio. In order to resolve the governing equations, the Lattice-Boltzmann method coupled with finite difference method is used Description: Article,Defect and Diffusion Forum, volume 326-328 (2012) pp 536-541 Sun, 01 Jan 2012 00:00:00 GMT http://dspace.ensta.edu.dz/jspui/handle/123456789/281 2012-01-01T00:00:00Z http://dspace.ensta.edu.dz/jspui/handle/123456789/280 Title: Heat and flow properties of a temperature dependent viscoplastic fluid including viscous dissipation Authors: LABSI, Nabila; BENKAHLA, Youb Khaled; BOUTRA, Abdelkader; AMMOURI, Abdellah Abstract: The present study concerns the numerical analysis using the finite volume method, of laminar forced convection flow of a viscoplastic fluid. The flow takes place in a circular pipe maintained at uniform wall temperature. The fluid consists of the sloe fruit juice with low pulp and pectin contents which obeys the rheological model of Bingham. The Nusselt number and the friction factor when both viscous dissipation and variability of the viscosity upon temperature for heating and cooling cases are taken into account are calculated and compared to those obtained for an isothermal flow when viscous dissipation is neglected. The results show that neglecting both viscous dissipation and the temperature dependency of viscosity leads to underestimate heat transfer and pressure drop Description: Article,Journal of Food Process Engineering,volume 36, 2013, pp. 450-461. Sun, 01 Jan 2012 00:00:00 GMT http://dspace.ensta.edu.dz/jspui/handle/123456789/280 2012-01-01T00:00:00Z http://dspace.ensta.edu.dz/jspui/handle/123456789/279 Title: Study of Convective heat transfer in a square cavity filled with a viscoplastic fluid by taking into account viscous dissipation Authors: LABSI, Nabila; BENKAHLA, Youb Khaled; BOUTRA, Abdelkader Abstract: The present work is devoted to the numerical study of forced, natural and mixed convective heat transfer inside a square cavity filled with a non-Newtonian viscoplastic fluid described by the Bingham rheological model. The upper and bottom walls of the enclosure are thermally insulated, while the remaining walls are mobile and differentially heated. In order to solve the general coupled equations, a code based on the finite volume method is used and has been validated after comparison of the present results with those from the literature. Viscous dissipation effects on hydrodynamic and thermal properties are analyzed for various values of the Richardson number. The results show that the Richardson number affects the hydrodynamic characteristics as well as heat transfer in a cavity filled with a viscoplastic fluid and leads to a flow structure modification different from that obtained for a Newtonian fluid. The same observation is done concerning the effect of the Brinkman number. Indeed, it has been noted that neglecting the viscous dissipation results in a significant underestimation of heat transfer in an enclosure, especially in the case of natural heat transfer convection Description: Article,Journal of Heat Transfer Research,volume 44(7), 2013, pp. 645-663 Tue, 01 Jan 2013 00:00:00 GMT http://dspace.ensta.edu.dz/jspui/handle/123456789/279 2013-01-01T00:00:00Z