ABSTRACT

The novelty of microencapsulated phase change material slurry (MPCMS) in the microchannel is a proven technique for enhancing the heat transfer due to its combination of high latent heat transfer and surface area. In this experimental investigation, the paraffin is encapsulated with silica and titanium shells, and its thermal performance is compared with three different configurations like straight, dimple-cavity, and rib-groove microchannel heat sinks. The operating parameters are mass flow rate of 200–400 ml/min with Reynolds number (Re) 400–1350, heat flux of 10, 20, and 30 W/cm², and 1% and 2% of mass fraction (concentration of the MPCM in DI) with constant inlet sub-cooling 25°C. From the results, at Re. 780 and heat flux of 20 W/cm², the Nusselt number (Nu) shows an improved performance of 6.5% with Ti-1 in the straight channel configuration, when compared to plain DI. Further, Nu enhancement is up to 11.5% in the dimple-cavity and 26.9% in the rib-groove microchannel heat sinks under the same conditions. To clarify the effectiveness of MPCMS in three configurations, the measurement of COP is conducted. The results reveal that the heat transfer outweighs the required pumping power in all three configurations. Overall, the Rib-groove microchannel shows enhanced heat transfer of 131.6% than straight channel heat sinks and 47.85% higher than the dimple-cavity channel using Ti-1.

摘要

微通道中微封装相变材料浆料 (MPCMS) 的新颖性是一种经过验证的增强传热的技术，因为它结合了高潜热传递和表面积。在本实验研究中，石蜡被二氧化硅和钛壳封装，其热性能与直型、凹窝腔和肋槽微通道散热器等三种不同配置进行了比较。操作参数是 200–400 ml/min 的质量流量，雷诺数 (Re) 400–1350，10、20 和 30 W/cm ²的热通量，以及 1% 和 2% 的质量分数（浓度DI 中的 MPCM），入口过冷度恒定为 25°C。从结果来看，在 Re。780 和 20 W/cm ^{2的热通量}, 努塞尔数 (Nu) 显示与普通 DI 相比，Ti-1 在直通道配置中的性能提高了 6.5%。此外，在相同条件下，Nu 增强在凹坑腔中高达 11.5%，在肋槽微通道散热器中高达 26.9%。为了阐明 MPCMS 在三种配置中的有效性，进行了 COP 测量。结果表明，在所有三种配置中，传热都超过了所需的泵浦功率。总体而言，肋槽微通道的传热性能比直通道散热器高 131.6%，比使用 Ti-1 的凹坑通道高 47.85%。