分类: 能源科学 >> 能源(综合) 提交时间: 2024-04-02
摘要: In this article, a numerical analysis is done on the temperature of 4 plate-shaped battery cells with phase change material (PCM) chambers around each one in a rectangular shape. The batteries are placed in a channel with air flow. The study is done transiently in a time of ten minutes. The batteries are of lithium ion type and the analysis is provided in two dimensions. The battery cells are arranged in the form of two single battery cells at the beginning, and end of the channel and two battery cells in the middle of the channel. These two middle batteries are placed in parallel. By changing the distance between the two middle batteries from two to three cm, this study is conducted to investigate the temperature of each of the four battery cells and changes in the amount of frozen PCM. Finally, the results showed that the temperature of the two batteries at the beginning and the end, increased continuously during the ten minutes of the study. At a distance of three cm from the middle batteries, the lowest temperature occurred on the first and last batteries, while at the same distance, the highest temperature occurred on the middle ones. At a distance of two cm from the middle batteries, the lowest amount of frozen PCM was observed, while at a distance of three cm from the middle batteries, the highest amount of frozen PCM was found on the first and last batteries.
分类: 机械工程 >> 机械工程其他学科 提交时间: 2024-04-02
摘要: In this study, first, an orthopedic plate was 3D printed with Polylactic acid (PLA) and coated with polycaprolactone (PCL)/Akermanite (AKT) nano-fibers. The composition included 8 wt.% of PCL and 3 wt.% of nAKT, while diameter of the PCL/AKT nano-fibers was approximately 253 nm ± 33 nm. Thermomechanical properties such as pressure, three-point bending flexural, and thermal conductivity of coated and non-coated specimens were examined and compared. In the next step, the bioactivity of the coated samples was evaluated following a 28-day immersion in simulated body fluid (SBF). Further, scanning electron microscope (SEM) images were taken to assess morphology of nanofibers and apatite formation on samples. By adding PCL to PLA, the maximum pressure force is enhanced by 16.83%. Further by adding nAKT to PLA+PCL sample, the maximum pressure force is enhanced by 4.72%. Further, by adding PCL to PLA, the maximum bending flexural force is enhanced by 21.06%. Further by adding nAKT to PLA+PCL sample, the maximum bending flexural force is enhanced by 21.39%. The results of this study are used to improve modeling of the orthopedic plates.
分类: 机械工程 >> 机械工程其他学科 提交时间: 2024-03-28
摘要: Increasing the transfer (HT) coefficient used in thermal industries is very important. Various methods are used to improve the efficiency of thermal heat HT so that maximum HT takes place in a smaller space. Ethylene glycol (EG) is generally used as an agent for convective HT. EG obtains energy from a hot source and discharges it to the required location. At present, the most consumption of EG is to produce engine cooling fluid. In the upcoming research, the TB of EG fluid in two-dimensional microchannels (MCs) has been investigated using molecular dynamics (MD) simulations, and the effect of variables such as MC dimensions and MC wall temperature (Temp) on the TB of the simulated fluid has been investigated. The results revealed that by increasing the Temp difference of the MC wall from 10 to 50 K, the maximum temperature (Max-Temp) and velocity (Max-Vel) of the target sample increased to 640.94 K and 0.024 Å/ps. It can be concluded that the increase in the cross-sectional area and the wall Temp difference leads to an increase in the HT rate in the MC.