Publications Scientifiques
Permanent URI for this communityhttps://dspace.univ-boumerdes.dz/handle/123456789/10
Browse
12 results
Search Results
Item Comparative analysis on heat transfer, between a steady and oscillating jet in a cavity(Inderscience Publishers, 2024) Iachachene, Farida; Mataoui, AminaThis paper numerically investigates the cooling of a heated rectangular cavity by a cold slot jet. The study aims to examine the effect of the jet location inside the cavity (Lf and Lh) and Reynolds number on heat transfer, using URANS turbulence modelling. Different flow behaviours, including oscillatory and steady flows, are generated depending on the jet location inside the cavity. The study identifies and discusses the optimal jet locations for achieving optimal cavity cooling. The results indicate that the lateral placement of the jet has a negligible effect on heat transfer across all cavity walls. Additionally, oscillatory flow consistently expands the heat exchange zone along all three walls, resulting in a wider effective exchange area compared to steady flow conditions. The study proposes optimised jet positions within the cavity for specific wall cooling requirements. By considering the optimal combination of jet height and impinging distance, the cooling performance can be optimised.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 Turbulent forced convective flow in a conical diffuser : hybrid and single nanofluids(Elsevier, 2023) Iachachene, Farida; Haddad, Zoubida; Arıcı, Müslüm; Jamei, Mehdi; Mataoui, AminaTurbulent forced convective flow of hybrid and single nanofluids in a conical diffuser is investigated numerically. Simulations are conducted for various Reynolds (Re=10000-70000) and different concentrations (ϕ=0-1.5 vol%) at equal ratio of TiO2:SiO2. The impact of using theoretical and experimental correlations for dynamic viscosity and thermal conductivity on turbulent forced convection of TiO2 showed that the mean Nusselt (Nu) number is considerably reduced with the use of the experimental model. However, when the theoretical model is used, Nu varies insignificantly. Addition of TiO2 nanoparticles decreases the heat transfer inside the diffuser, whereas addition of TiO2–SiO2 nanoparticles either enhances or decreases the heat transfer rate. Compared to the pure fluid, hybrid nanofluids show a maximum enhancement of 5% and a maximum decrease of 9.7% at ϕ= 0.5 vol% and ϕ= 0.5 vol% at Re=10000, respectively. However, TiO2 nanofluids show a maximum decrease of 19% at ϕ=1.5 vol% and Re= 30000. As Re increases, the deviations between TiO2 and SiO2-TiO2 nanofluids diminish. Moreover, the Gene Expression Programming model can accurately evaluate Nu versus Re number and nanoparticle concentrationItem 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, EiyadLow 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 separatelyItem The effect of nano encapsulated phase change materials and nanoparticles on turbulent heat transport : a conical diffuser scenario(Elsevier, 2022) Iachachene, Farida; Haddad, Zoubida; Arıcı, Müslüm; Abu-Nada, Eiyad; Sheremet, Mikhail A.The present work investigates turbulent flow of single and hybrid nanofluids filled in a conical diffuser. The heat transfer coefficients and pressure losses are analyzed at various Reynolds numbers and nanoparticle volume fractions. The diffuser is filled with Al2O3, nano encapsulated phase change material NEPCM, and NEPCM_Al2O3 nanofluids. The thermophysical parameters of all nanofluids were determined using a novel methodology based on the thermodynamic equilibrium data for binary liquid mixtures. A notable novelty in the current work is the introduction of an innovative method of hybrid nanofluids composed of nanoparticles with and without phase change material (PCM). When compared to the other nanofluids tested, the NEPCM nanofluid presented the lowest pressure loss and the greatest heat transfer improvement within the diffuser. The Nusselt number of NEPCM nanofluids is enhanced by 15%, while for NEPCM_Al2O3 and Al2O3 nanofluids is increased by 10% and 6%, respectively. Similarly, the pressure drop is greater as compared to the base fluid, where the pressure drop is increased by 1%, 3.5%, and 5% for NEPCM, Al2O3, and NEPCM_Al2O3 nanofluid, respectivelyItem Natural convection melting of phase change material in corrugated porous cavities(Elsevier, 2022) Iachachene, Farida; Haddad, Zoubida; Abu-Nada, Eiyad; Sheremet, Mikhail A.In this paper, a numerical study is carried out to examine the melting inside a wavy cavity under partial heating. A wide range of numerical computations have been performed to understand the effect of porosity, pore density, wall waviness, and heater location and intensity on the melting process. The results revealed that lower metal foam porosity resulted in higher melting rate and lower thermal storage capacity. However, pore density indicated no effect on melting performance for porosity in the range 80–96 %. When considering heater location at various porosities, its impact on melting performance is small at low porosity but becomes significant at higher porosity. Top–bottom partial heating can save almost 10 % of the melting time at ɛ = 0.96. Moreover, the PCM can store more energy, i. e. 11.36 %, when the heater location was changed from center or top–bottom position to top or bottom position at ɛ = 0.96. The results further showed that increasing the number of undulations can save 27.4 % of the melting time at ε = 0.96. Therefore, it can be concluded that higher energy storage and melting rate can be achieved by increasing the number of undulationsItem 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 Heat transfer prediction of a jet impinging a cylindrical deadlock area(American Society of Mechanical Engineers (ASME), 2014) Halouane, Yacine; Mataoui, Amina; Iachachene, FaridaItem Heat transfer related to a self-sustained oscillating plane jet flowing inside a rectangular cavity(IEEE, 2014) Iachachene, Farida; Matoui, A.; Halouane, YacineItem Turbulent heat transfer for impinging jet flowing inside a cylindrical hot cavity(Serbian Society of Heat Transfer Engineers, 2015) Halouane, Yacine; Mataoui, Amina; Iachachene, FaridaConvective heat transfer from an isothermal hot cylindrical cavity due to a turbulent round jet impingement is investigated numerically. Three-dimensional turbulent flow is considered in this work. The Reynolds stress second order turbulence model with wall standard treatment is used for the turbulence predictions the problem parameters are the jet exit Reynolds number, ranging from 2·104 to 105 and the normalized impinging distance to the cavity bottom and the jet exit Lf, ranging from 4 to 35. The computed flow patterns and isotherms for various combinations of these parameters are analyzed in order to understand the effect of the cavity confinement on the heat transfer phenomena. The flow in the cavity is divided into three parts, the area of free jet, and the area of the jet interaction with the reverse flow and the semi-quiescent flow in the region of the cavity bottom. The distribution of the local and mean Nusselt numbers along the cavity walls for above combinations of the flow parameters are detailed. Results are compared against to corresponding cases for impinging jet on a plate for the case of the bottom wall. The analysis reveals that the average Nusselt number increases considerably with the jet exit Reynolds number. Finally, it was found that the average Nusselt number at the stagnation point could be correlated by a relationship in the form Nu = f(Lf, Re)