Browsing by Author "Chan, Choon Kit"

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A molecular dynamics study of the effect of initial pressure on the mechanical resilience of aluminum polycrystalline
(Elsevier, 2024) Salahshour, Soheıl; Jasim, Dheyaa J.; Alizadeh, As'ad; Chan, Choon Kit; Salahshour, Soheil; Hekmatifar, Maboud
Polycrystalline materials are essential in engineering due to their ability to withstand various forces, heat, and environmental conditions. The arrangement of atoms within these crystals significantly affects their mechanical properties. This study used molecular dynamics simulations to explore how initial pressure affects the mechanical resilience of aluminum polycrystals. Aluminum composite materials, known for their strength, flexibility, and environmental sustainability, are the focus of this investigation. We particularly investigated stress- strain reactions at 1, 2, and 3 bar initial pressures. Reduced free volume causes atomic migration to be hampered as pressure increases, therefore affecting mean square displacement and diffusion coefficient. The results show that ultimate strength and Young's modulus of the polycrystalline samples were 30 and 6.64 GPa at 1 bar pressure. Moreover, the results demonstrated a notable decrease in mechanical performance by increasing pressure; the ultimate strength and Young's modulus of the polycrystalline samples diminished to 5.66 GPa and 22.43 GPa, respectively, at 3 bar. Furthermore, the heat flux increased by rising initial pressure in the Al- polycrystalline sample due to the compression of material that reduced atomic distances. This improved atomic arrangement facilitated more efficient heat transfer. These insights are essential for engineering applications, as they establish a foundation for the production of aluminum components that maintain structural integrity in the face of extreme conditions.
Citation Count: 0
Numerical investigation of the effect of the number of fins on the phase-change material melting inside a shell-and-tube cylindrical thermal energy storage
(Elsevier, 2024) Rashid, Farhan Lafta; Salahshour, Soheıl; Alizadeh, As'ad; Al-Obaidi, Mudhar A.; Salahshour, Soheil; Chan, Choon Kit
A numerical analysis of the fin count that affects phase change material (PCM) melting within a cylindrical shell-and-tube thermal energy storage (TES) is provided. Using the ANSYS/FLUENT 16 tool, the enthalpy-porosity combination was quantitatively evaluated. PCMs made of paraffin wax were used in this experiment (RT42). The results of this investigation show that fins significantly affect melting, which reduces the time required to finish the operation. Since melting relies on natural convection, which has a sluggish rate of heat transfer, the process takes longer when there are no fins. The melting process takes 900 min to finish. The melting fraction grew monotonically with the number of fins, and the curve had an initial sharp trend followed by a gradual one. When more PCMs transitioned from a solid state to a liquid state over time, the pace at which they melted decreased, and the thermal resistance between the solid-liquid interface and the heat transfer surface increased. With the same heat storage effect, the maximum time difference was 236 min, and the biggest time difference was caused by the number of fins at 81.4 %. The total melting time was greatly affected by the number of fins in the design.