چكيده به لاتين
In current study, the effect of three main methods, i.e. utilizing metal foam, fins, and nanoparticles on improving the performance of PCM in a certain geometry and conditions are investigated and compared. The effects of parameters such as porosity and PPI of metal foam on the heat transfer enhancement in the PCM are investigated, also the idea of using a partial metal foam instead of using a full metal foam in order to weight reduction is studied. The material of the fins, nanoparticles, and metal foam are assumed to be copper. The PCM used is n-eicosan with a melting temperature of 309.55-309.65 K. The geometry of passive thermal management system of the 18650 lithium-ion battery is used in current simulation. The performance of PCM in two main applications, thermal management system (with the aim of reducing the battery temperature) and the thermal energy storage unit (assuming the battery as a source of energy with constant heat generation rate) are investigated. While examining the performance of PCM as a battery thermal management system results showed that the addition of nanoparticles into PCM in both 4.6W and 9.2W heat generation rates had insignificant effect on thermal control system performance. Using fins in 4.6W and 9.2W heat generation rates, led to battery mean temperature reduction of 2 and 4K, respectively. Also the results indicated that the addition of fins did not always lead to system performance improvement. In the studied configurations, it revealed that the thermal control system had better performance with 3 fins than 5 fins. Using metal foam in 4.6W and 9.2W heat generation rates led to battery mean temperature reduction of 4 and 6K, respectively. The change in porosity from 95% to 85% did not lead to significant change on thermal management system performance. It is seemed using metal foam has more effect than utilizing fins and nanoparticles on improvement of the performance of PCM in TMS. In examining the performance of PCM as the thermal energy storage unit, results indicated that using metal foam reduced the melting time. Also results showed that, while using metal foam reducing porosity and PPI of metal foam are the two parameters decreasing PCM melting time. In current study it is seemed that in overall conditions using fins is more proper to improve the performance of PCM in thermal energy storage unit rather than using metal foam or nanoparticles. In the some certain conditions the idea of using partial foam can be effective.
