Publications Scientifiques

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Author: search.filters.author.Haddad, ZoubidaSubject: search.filters.subject.Heat transfer

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    Numerical investigation and optimization of melting performance for thermal energy storage system partially filled with metal foam layer: New design configurations
    (Elsevier, 2023) Haddad, Zoubida; Iachachene, Farida; Sheremet, Mikhail A.; ;Abu-Nada, Eiyad
    Low thermal performance of storage systems represents a barrier to their industrial/engineering application and commercialization. Among all the proposed methods, combination of phase change material with metal foams appears more promising due to the high thermal conductivity of metal foams. However, the insertion of metal foams reduces the PCM volume; hence, a lower amount of stored energy. The present numerical study thoroughly addresses this issue with a focus on the optimization of melting performance for thermal energy storage system partially filled with metal foam layer. A finite volume method based on the enthalpy–porosity technique has been adopted for the numerical simulations. The metal foam location, porosity, and nanoparticle volume fraction were optimized to explore their effects on the melting performance. The results showed that inserting the foam layer diagonally from the top left to the right bottom leads to the lowest melting time. Compared to pure PCM, the melting time increases by 77.7%, while the stored energy decreases by 6.7%. The optimum porosity was found to be 0.88 as it gives approximately the same amount of stored energy as that of pure PCM with a deviation of 4%. Adding nanoparticles to pure PCM increases the melting rate by approximately 8%, while it decreases the stored energy by almost 3%. It is concluded that hybrid systems, i.e., metal foam at an optimum porosity and nanoparticles is more efficient than using each technique separately
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    Poiseuille-Rayleigh-Bénard mixed convection flow in a channel : Heat transfer and fluid flow patterns
    (Elsevier, 2021) Taher, Rani; Ahmed, Mohamed Mohsen; Haddad, Zoubida; Abid, Cherifa
    In the present work, a numerical and experimental study of mixed convection of water flow in a horizontal channel subjected to a constant heat flux is presented. An experimental setup was constructed to delineate the fluid flow patterns inside the channel, while a numerical simulation was performed to study the heat transfer characteristics of the flow. This study is performed for Rayleigh and Reynolds numbers in the range of 104 ≤ Ra≤ 106 and 25≤ Re≤ 100, respectively. The present predicted results are in good agreement with the experimental ones. The longitudinal evolution rolls revealed the existence of four zones corresponding to the entry zone, establishment zone, destabilization zone, and turbulent zone. Moreover, numerical simulations showed that the Nusselt number for the mixed convection gives higher heat transfer coefficient compared to forced convection. In addition, new correlations for the Nusselt number have been developed for the first time for the establishment length, onset and established zones as a function of Rayleigh and Reynolds numbers
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    Rayleigh number effect on the turbulent heat transfer within a parallelepiped cavity
    (2011) Aksouh, Mohamed; Mataoui, Amina; Seghouani, Nassim; Haddad, Zoubida
    This purpose is about a 3-D study of natural convection within cavities. This problem is receiving more and more research interest due to its practical applications in the engineering and the astrophysical research. The turbulent natural convection of air in an enclosed tall cavity with high aspect ratio (Ar = = H/W = 28.6)is examined numerically. Two cases of differential temperature have been considered between the lateral cavity plates corresponding, respectively, to the low and high Rayleigh numbers: Ra = 8.6.10 5 and Ra = = 1.43.10 6. For these two cases, the flow is characterized by a turbulent low Reynolds number. This led us to improve the flow characteristics using two one point closure low-Reynolds number turbulence models: renormalization group κ-ε model and shear stress transport κ-ω model, derived from standard κ-ε model and standard κ-ω model, respectively. Both turbulence models have provided an excellent agreement with the experimental data. In order to choose the best model, the average Nusselt number is compared to the experiment and other numerical results. The vorticity components surfaces confirm that the flow canbe considered 2-D with stretched vortex in the cavity core. Finally, a correlation between Nusselt number and Rayleigh number is obtained to predict the heat transfer characteristics