Browsing by Author "Emami,N."

Now showing 1 - 2 of 2

Citation Count: 0
Effect of temperature on the mechanical properties of aluminum polycrystal using molecular dynamics simulation
(Elsevier Ltd, 2024) Lin,P.; Basem,A.; Alizadeh,A.; Nasser,E.N.; Al-Bahrani,M.; Chan,C.K.; Emami,N.
The initial temperature has a considerable effect on aluminum polycrystals' physical stability and mechanical performance, with the possibility to optimize their mechanical properties for practical applications. Thus, using a molecular dynamics technique, the effect of temperature on the mechanical properties of aluminum polycrystals is studied. Stress-strain curves, ultimate strength, and Young's modulus were all measured at temperatures of 300, 350, 400, and 450 K. The findings from MD simulations show that the initial temperature significantly affects the physical stability and mechanical performance of designed aluminum polycrystals. The aluminum polycrystal experiences a numerical increase in ultimate strength and Young's modulus from 6640 to 74.072 to 7.055 and 79.226 GPa, respectively, when subjected to the optimal initial conditions of 350 K. With further increasing temperature to 450 K, ultimate strength and Young's modulus decrease to 6.461 and 74.413 GPa, respectively. The observed decrease in ultimate strength and Young's modulus of the aluminum polycrystal as the temperature increased from the optimal condition of 350 K–450 K can be attributed to the weakening of interatomic attraction forces at higher temperatures. This reduction in interatomic bonding strength resulted in decreased material stiffness and resistance to deformation, leading to lower ultimate strength and Young's modulus values. This study's novelty lies in its comprehensive assessment of the initial temperature's effects on the mechanical performance of aluminum polycrystals, providing valuable insights for practical applications and advancing beyond previous efforts in the literature. © 2024 The Authors
Citation Count: 0
Numerical simulation of the nanofluid flow and heat transfer in porous microchannels with different flow path arrangements using single-phase and two-phase models
(Elsevier B.V., 2024) Salahshour, Soheıl; M․ Ali,A.B.; Jasim,D.J.; Salahshour,S.; Akbari,O.A.; Emami,N.
Background: The fluid flow and nanofluid heat transfer are studied in this research through porous microchannels with different flow path arrangements in single-phase and two-phase modes (Mode I and Mode II). In Mode I, the flow inlet is located in the longitudinal direction of the microchannel (single-way path), while in Mode II, the flow inlet is placed in the transverse direction of the microchannel (two-way path). Methods: The finite volume method was utilized to simulate the flow and heat transfer. The porous medium is supposed homogeneous and isotropic with a porosity coefficient of 0.9 and it is assumed that the local thermal equilibrium is established between the fluid and the solid. The Eulerian-Eulerian mixture model is applied for modeling the two-phase flow. As demonstrated, mode II always has a higher heat transfer rate than mode I. However, in contrast, the pressure drop of mode I is lower than in mode II. Besides, using the two-phase model predicts a higher heat transfer rate than the single-phase model in all cases. Significant Findings: The percent increase of pressure in mode II compared to mode I in Re= 100 and 400 is obtained as 11.5 % and 20.8 %, respectively. At Re= 100 in mode I, the heat transfer percentage increases by 52.6 % from Da=1 compared to a case without the porous foam. Whilst, at Re= 400, the rise is found to be 45.5 %. In mode II, at Re=100, the heat transfer percentage increases by 63.9 % from Da= 1 compared to a case without the porous foam. Whilst, at Re= 400, the rise is found to be 43.3 %. Finally, Mode II microchannel has more heat transfer rate and pressure drop than Mode I. © 2024 The Author(s)