Browsing by Author "Ren, Jiaxuan"

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Citation Count: 0
Battery thermal management system by employing different phase change materials with SWCNT nanoparticles to obtain better battery cooling performance
(Elsevier, 2024) Ren, Jiaxuan; Salahshour, Soheıl; Bagheritabar, Mohsen; Abdul-Redha, Hadeel Kareem; Al-Bahrani, Mohammed; Singh, Sandeep; Toghraie, D.
Maintaining a stable temperature within a battery is essential for optimizing the performance of battery thermal management systems. Phase change materials (PCMs) have demonstrated potential in achieving this stability. This study investigates the use of single-walled carbon nanotubes (SWCNTs) dispersed in three PCMs with varying fusion temperatures to regulate the temperature of a lithium-ion battery (LIB) during discharge, a common scenario in electric vehicles. A Computational Fluid Dynamics (CFD) approach was utilized to simulate the liquid-solid transition of the PCMs, incorporating buoyancy forces in the liquid phase surrounding the LIB. The study examined the effects of different C-rates (1, 2, and 3), SWCNT volume fractions (0, 2, and 4 %), and three types of PCMs (RT27, RT35, and RT58) across multiple simulation scenarios to evaluate their impacts on LIB temperature and PCM melting fraction. Results indicate that nano-enhanced PCMs, which exhibit superior convection effects in the liquid phase, significantly enhance battery cooling performance. Specifically, at a C-rate of 1, using a 4 % volume fraction of nanoparticles in the PCM reduces the battery temperature by an average of 4.138 K compared to cases without nanoparticles. Additionally, while nanoparticles are generally reported to have a minor effect on cooling and melting processes, this study reveals that considering the beneficial effects of SWCNTs and the physical properties of the selected PCMs, the cooling performance of LIBs improves by 4.69 percentage points for the scenario with a C-rate of 3, RT58, and phi = 0.02. In this particular case, the melting process is more pronounced in the top half of the battery, where the increased velocity magnitude of the melted region contributes to enhanced battery cooling.
Citation Count: 0
Investigating the initial pressure effect on Brownian displacement, thermophoresis, and thermal properties of graphene/ water nanofluid by molecular dynamics simulation
(Elsevier, 2024) Ren, Jiaxuan; Salahshour, Soheıl; Sajadi, S. Mohammad; Nasajpour-Esfahani, Navid; Salahshour, Soheil; Sabetvand, Rozbeh
The concept of nanofluid includes suspensions containing nanoparticles, metallic and non-metallic materials. Nanofluids have many potentials in different environments and conditions that make them exist in industries and food industries. Considering their high thermal conductivity, the nanoparticles increased the fluid's thermal conductivity, one of the basic heat transfer parameters, when distributed in the base fluid. The present research investigated the thermal properties, Brownian motion, and thermophoresis of water/ graphene nanofluid affected by different ratios of initial pressure (1, 2, 3 and 5 bar) by molecular dynamics simulation. This study reported the changes in heat flux, thermal conductivity, average Brownian displacement, and thermophoresis. The results depict that by increasing the initial pressure from 1 to 5 bar, average Brownian displacement and thermophoresis values decrease from 06.3 and 23.88 to 2.91 and 23.53 angstrom, respectively. Also, by raising the initial pressure (1 to 5 bar), the heat flux and thermal conductivity after 10 ns decrease from 39.54 and 0.36 to 35.12 W/m2 and 0.28 W/m.K, and the maximum temperature reduces from 1415 K to 1033 K. These results can be useful in different industries, especially for improving the thermal properties of different nanofluids.
Citation Count: 0
A molecular dynamics study of the external heat flux effect on the atomic and thermal behavior of the silica aerogel/ paraffin /CuO nanostructure
(Pergamon-elsevier Science Ltd, 2024) Ren, Jiaxuan; Salahshour, Soheıl; Al-Bahrani, Mohammed; Jasim, Dheyaa J.; Al-Rubaye, Amir H.; Salahshour, Soheil; Alizad, A.
Investigating the nanostructure's atomic and thermal properties (TP) might help enhance energy conversion and storage technologies. This is particularly important when considering phase change materials (PCM) and their use in thermal energy storage systems. However, understanding the behavior of nanostructure's atomic and thermal components in response to temperature (Temp) changes is critical, as is improving its heat transfer capacities for a wide range of applications by examining the effect of external heat flux (EHF). As a result, the major goal of this research was to determine the effect of EHF on the atomic and TP of silica aerogel (SA)/ paraffin/CuO nanostructures. This investigation was done using molecular dynamics (MD) simulation and LAMMPS software. To achieve this, a study was undertaken into the effect of EHF of different magnitudes (0.01, 0.02, 0.03, and 0.05 W/m2) on the maximum (Max) density (Dens), velocity (Vel), and Temp, as well as HF, thermal conductivity (TC), and charging and discharging time. The results show that when the EHF increased to 0.05 W/m2, the Max Dens value decreased to 0.0754 atoms per square centimeter. Furthermore, the Max Temp and Vel increased to 1018.82 K and 0.0139/fs, respectively. Increased external heat discharge improved the thermal effectiveness of simulated construction. Increasing the EHF raised the TC and HF to 95.93 W/m2 and 1.93 W/mK, respectively. Finally, the results of this simulation are expected to improve understanding of nanostructure TP and their potential applications in improved energy conversion and storage technologies.