Browsing by Author "Ghezal, A."

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    Analytical and numerical study of the evaporation on mixed convection in a Vertical rectangular cavity
    (2017) Ihdene, M.; Ben Malek, T.; Aberkane, Sofiane; Mouderes, M.; Spiterri, P.; Ghezal, A.
    We consider an ascending laminar air flow in a vertical channel formed by two parallel flat plates wetted by a thin water film and under different temperature and concentration conditions. The study includes a numerical finite volume method for the treatment of the double diffusion problem, where the analytical solution is given to the thermal diffusion. The analytical study showed that the reversed flow is observed only under some wall temperature conditions and also for certain values of Re/Gr. The reversed flow is also strongly dependent on the aspect ratio A, which is based on the cross section of the channel. Indeed, the results show than this dependence is very strong for values less than a certain critical one equal to 2.22. In the absence of the mass transfer the results showed that the evaporation rate remains null along the channel, decreases when the mass gradient is favorable and it finally vanishes at x=15. However, the evaporation rate increases in the case of an unfavorable mass gradient, to cancel at position x=20, then merges with the curve representing the forced convection. In the absence of heat transfer the evaporation rate is less important and amounts to fifty percent of the double diffusion. The results obtained by the analytical and numerical methods are compared each other and with those of a similar works and a good agreement was found
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    An investigation of highly pressurized transient fluid flow in pipelines
    (2012) Ouchiha, Z.; Loraud, J. C.; Ghezal, A.; Kessal, M.; Benzaoui, A.; Ghiaasiaan, M.
    This paper discusses transient processes in natural gas pipelines. The method of characteristics (MOC) is applied for the analysis of two transient categories, where the governing one-dimensional, hyperbolic conservation equations are linearized and solved without neglecting any of their term. First, we present a parametric study of the pressurized flow encountered when pipelines are utilized for the transportation or the temporary storage of natural gas. The non-ideal compressibility of natural gas is included in the model and its impact on the thermo-hydraulic processes is elucidated. Second, we model the hydrodynamics of a pipeline whose downstream boundary is a periodic discharge rate. The results show that, in response to these boundary conditions, the pressure distribution in the pipeline also undergoes periodic variations. Furthermore, our simulation results confirm the usefulness of MOC for numerical simulation of flow phenomena in pipelines