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dc.contributor.authorMebrouk, Ridha
dc.contributor.authorBoudenn, Abderrahim
dc.contributor.authorKabar, Yassine
dc.date.accessioned2017-10-22T11:36:27Z
dc.date.available2017-10-22T11:36:27Z
dc.date.issued2017-07-04
dc.identifier.urihttp://hdl.handle.net/123456789/136130
dc.description.abstractThis thesis presents the results of two studies: the first concerns natural turbulent convection in a rectangular cavity heated from the bottom wall and filled with a nanofluid and the second relates to the investigation of conjugate heat transfer in a fin-and-tube heat exchanger. The cavity of the first study is tall and has a heat source embedded on its bottom wall, while its left, right and top walls are maintained at a relatively low temperature. The working fluid is a water based nanofluid having three nanoparticle types: alumina, copper and copper oxide. The influence of pertinent parameters such as the Rayleigh number, the type of nanofluid and solid volume fraction of nanoparticles on the cooling performance is studied. Steady forms of two dimensional Reynolds-Averaged-Navier-Stokes equations and conservation equations of mass and energy, coupled with the Boussinesq approximation, are solved by the control volume based discretisation method employing the SIMPLE algorithm for pressure-velocity coupling. Turbulence is modeled using the standard k-ε model. The Rayleigh number, Ra, is varied from 2.49x1009 to 2.49x1011. The volume fractions of nanoparticles were varied in the interval 0≤φ≤ 6% . Stream lines, isotherms, velocity profiles and Temperature profiles are presented for various combinations of Ra, the type of nanofluid and solid volume fraction of nanoparticles. The results are reported in the form of average Nusselt number on the heated wall. It is shown that for all values of Ra, the average heat transfer rate from the heat source increases almost linearly and monotonically as the solid volume fraction increases. Finally the average heat transfer rate takes on values that decrease according to the ordering Cu, CuO and Al2O3. In the second study we determined the heat transfer and friction characteristics of a realistic fin-andtube heat exchanger . The computations assume steady-state heat transfer and fluid flow. Nusselt number and friction factor characteristics of the heat exchanger are presented for various values of Reynolds numbers. The energy conservation and the heat conduction equations in 3 dimensions have been solved in the fluid and the solid respectivelyalong with the mass and momentum conservation equations in order to determine these characteristics. Both laminar and turbulent flow regimes are considered. The effect of turbulence modeling was investigated using three different models (the one equation Spalart-Allmaras turbulence model, the standard k-ε model and the RSM model). The computations allowed the determination of the dynamic and thermal fields. Model validation was carried out by comparing the calculated friction factor f and Colburn j-factor to experimental results found in the literature. The plotted results showed a qualitatively good agreement between numerical results and experimental data. The results obtained also showed that the simplest of the three turbulence models tested(i.e. SpalartAllmaras) gives the closest values to the experimental datafr_FR
dc.language.isofrfr_FR
dc.publisherجامعة الإخوة منتوري قسنطينةfr_FR
dc.subjectConvection turbulentefr_FR
dc.subjectSimulation numériquefr_FR
dc.subjectNanofluidefr_FR
dc.subjectEnceinte chauffée par le basfr_FR
dc.subjectConvection forcéefr_FR
dc.subjectEchanges turbulentsfr_FR
dc.subjectEchangeur de chaleurfr_FR
dc.subjectTransfert thermique conjuguéfr_FR
dc.subjectTurbulent convectionfr_FR
dc.subjectNumerical simulationfr_FR
dc.subjectTurbulent exchangesfr_FR
dc.subjectHeat exchangerfr_FR
dc.subjectConjugate heat transferfr_FR
dc.subjectNanofluidfr_FR
dc.subjectEnclosure heated from belowfr_FR
dc.subjectForced convectionfr_FR
dc.subjectالحمل المضطربfr_FR
dc.subjectالمحاكاة العددیةfr_FR
dc.subjectنانومائعfr_FR
dc.subjectتجویفات مسخنة من الأسفلfr_FR
dc.subjectالحمل القسريfr_FR
dc.subjectالتبادل المضطربfr_FR
dc.subjectالمبادلات الحراریةfr_FR
dc.subjectنقل الحرارة المترافقةfr_FR
dc.titleEtude paramétrique des échanges convectifs turbulents dans les configurations d’intérêt pratiquefr_FR
dc.typeThesisfr_FR


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