Publications Internationales
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Item A comprehensive numerical study on melting performance in a storage cavity with partial metal foam integration: Design and economic assessment(Elsevier, 2024) Cheradi, Hanane; Haddad, Zoubida; Iachachene, Farida; Mansouri, Kacem; Arıcı, MüslümDespite remarkable technological progress aimed at improving thermal performance of storage systems, designing cost-effective thermal storage solutions still remains a challenge. Consequently, to address this gap, the current study provides a detailed numerical analysis of the melting performance within a storage cavity with partial metal foam integration, considering both design and economic aspects. Five distinct designs were considered to provide a comprehensive assessment of the melting process including non-porous and porous designs. Various factors such as foam position, foam shape and foam filling ratio were examined under different criteria. The results revealed that designs employing kite-shaped, triangular-shaped, square-shaped, and trapezoidal-shaped foam under optimal location resulted in melting time reduction of 74.8 %, 67.0 %, 50.9 %, and 42.8 %, respectively, in comparison to the non-porous design. The findings highlight the kit-shaped foam as the optimal foam shape, with a notable 7.8 % difference in melting times between designs with kite and triangular foams, and an 8.1 % disparity between designs with square and trapezoidal foams. From an economic assessment, it was found that the kit-shaped foam filling design, with a 1/3 filling ratio, proved to be cost-effective when the unit price ratio of the metal foam to PCM fell within the range of 4 to 12. Interestingly, for ratios below 4, the same design, with a 1/2 filling ratio, emerged as an economical solution. This study contributes to the field by providing quantitative insights into the design and economic viability of metal foam integrated thermal storage systems.Item 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, CherifaIn 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 numbersItem Investigation of the novelty of latent functionally thermal fluids as alternative to nanofluids in natural convective flows(Nature, 2020) Haddad, Zoubida; Iachachene, Farida; Abu-Nada, Eiyad; Ioan, PopThis paper presents a detailed comparison between the latent functionally thermal fluids (LFTFs) and nanofluids in terms of heat transfer enhancement. The problem used to carry the comparison is natural convection in a differentially heated cavity where LFTFs and nanofluids are considered the working fluids. The nanofluid mixture consists of Al2O3 nanoparticles and water, whereas the LFTF mixture consists of a suspension of nanoencapsulated phase change material (NEPCMs) in water. The thermophysical properties of the LFTFs are derived from available experimental data in literature. The NEPCMs consist of n-nonadecane as PCM and poly(styrene-co-methacrylic acid) as shell material for the encapsulation. Finite volume method is used to solve the governing equations of the LFTFs and the nanofluid. The computations covered a wide range of Rayleigh number, 104 ≤ Ra ≤ 107, and nanoparticle volume fraction ranging between 0 and 1.69%. It was found that the LFTFs give substantial heat transfer enhancement compared to nanofluids, where the maximum heat transfer enhancement of 13% was observed over nanofluids. Though the thermal conductivity of LFTFs was 15 times smaller than that of the base fluid, a significant enhancement in thermal conductivity was observed. This enhancement was attributed to the high latent heat of fusion of the LFTFs which increased the energy transport within the cavity and accordingly the thermal conductivity of the LFTFs.Item Rayleigh number effect on the turbulent heat transfer within a parallelepiped cavity(2011) Aksouh, Mohamed; Mataoui, Amina; Seghouani, Nassim; Haddad, ZoubidaThis 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 characteristicsItem A review on how the researchers prepare their nanofluids(Elsevier, 2014) Haddad, Zoubida; Abid, Chérifa; Oztop, Hakan F.; Mataoui, Amina