Browsing by Author "Kolsi, Lioua"

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Citation Count: 0
Investigation of the effect of model structure type on the thermal performance of phase change materials through molecular dynamics simulation
(Elsevier, 2024) Aich, Walid; Salahshour, Soheıl; Sultan, Abbas J.; Ghabra, Amer Ali; Eladeb, Aboulbaba; Kolsi, Lioua; Baghaei, Sh.
Using molecular dynamics (MD) simulation, the thermal efficacy of phase change materials (PCMs) in solar energy applications and solar thermal energy storage was evaluated. In order to achieve this objective, an investigation was conducted into the structure's temperature (Temp), velocity, and density profiles, heat flux, thermal conductivity, charge and discharge time, and thermal stability. Three models of tube, shell, and shell-tube were adopted to scrutinize the atomic behavior and thermal performance (TP) of PCMs. The results show that the maximum density of the tube model, shell model, and shell-tube model was 0.042, 0.036, and 0.033 atom/A 3 , respectively. Other numerical results showed that the maximum velocity for the three structures of tube model, shell model, and shell-tube model under the initial Temp of 300 K was 0.0066 & Aring;/fs, 0.0059 & Aring;/fs, and 0.0054 & Aring;/fs, respectively. The structure in the tube model manifested more optimal atomic behavior compared to other models. The TP of simulated structures revealed that the heat flux of the samples reached 5.69, 4.85, and 4.15 W/m 2 , respectively. Finally, the thermal conductivity of the structures approached 1.35, 1.32, and 1.31 W/m.K, respectively. The results suggested that the tube model had the most thermal stability and showed the optimal thermal behavior in the simulation. The findings of this study, particularly the optimal atomic behavior and thermal stability of the tube model, can be useful in designing and optimizing PCMs for solar energy applications. In general, this research had the potential to significantly advance the field of solar energy system efficiency and cost-effectiveness.
Citation Count: 2
A numerical study of catalytic combustion of methane-air in excess oxygen and deficient oxygen environments with increasing initial pressure: A molecular dynamic approach
(Elsevier, 2024) Rajhi, Wajdi; Salahshour, Soheıl; Sabri, Laith S.; Mohammed, Malik M.; Becheikh, Nidhal; Kolsi, Lioua; Sabetvand, Roozbeh
In the low -temperature range, catalytic combustion results in few emissions of nitrogen oxide and happens without a visible flame. This work investigates the effect of initial pressure (IP) on catalytic methane -air combustion (CMAC) in a microchannel using the molecular dynamics (MD) method. Palladium particles with an atomic ratio of 4 % were used as a catalyst. The study also investigates the CMAC in two environments: excess oxygen (EO) and deficient oxygen (DO). The research investigates the changes in density (Den), velocity (Velo), temperature (Temp) profiles, heat flux (HF), thermal conductivity (TC), and combustion efficiency (CE). The results of the MD simulation indicate that the maximum values of Den and velocity decrease as the IP increases to 10 bar. This reduction was more pronounced in the EO medium than in the DO medium. The maximum values of density and velocity decrease to 0.105 atom/& Aring; and 0.17 & Aring;/ps, respectively, in the EO medium. These values decrease to 0.080 atom/& Aring; and 0.20 & Aring;/ps, respectively, in the DO medium. Additionally, the HF and TC values decrease in both mediums, with the EO medium showing values of 1839 W/m 2 and 1.01 W/m.K, and the DO medium showing values of 1869 W/ m 2 and 1.04 W/m.K. If there was a DO medium, the atoms and particles of the system had a greater ability to heat transfer to different parts. Therefore, TC and HF are more in this case.