微通道纳米强化相变微胶囊悬浮液流动与传热实验

文章设计了微通道流动与传热实验平台, 针对定制的 $ Fe_{3}O_{4} $ 纳米颗粒强化相变微胶囊悬浮液 (microencapsulated phase change material slurry, MPCS) 开展循环流动实验, 分别从微通道压降、摩擦阻力系数、对流换热系数、微通道板温度等 4 个方面探究 MPCS 在微通道中的流动与传热特性。实验结果表明: MPCS 在微通道中的压降随质量分数的增加而增大, 且明显高于去离子水; 与之相比, $ Fe_{3}O_{4} $-MPCS 在微通道中的压降并无显著变化。此外, 微尺度流动可能更有利于在 Re 较小时产生湍流; MPCS 的对流换热系数高于去离子水, 且随 Re 及质量分数的增大而增大, 微通道的板温度更低, 表现出更好的冷却效果; 相同质量分数的 $ Fe_{3}O_{4} $-MPCS 具有更高的对流换热系数, 传热性能更佳; 在低 Re 下较低的热流密度更有利于传热, 在 Re 较高时高热流密度下传热效果更佳。

In this paper, a microchannel flow and heat transfer platform was designed to carry out circulation flow experiments on customized $ Fe_{3}O_{4} $ nanoparticle enhanced micro-encapsulated phase change material slurry ( $ Fe_{3}O_{4} $-MPCS). The flow and heat transfer characteristics of MPCS in microchannel were experimentally researched from four aspects: pressure drop, friction resistance coefficient, convective heat transfer coefficient and microchannel plate temperature. The results show that the pressure drop of MPCS in microchannel increases with the increase of mass fraction, which is significantly higher than that of deionized water. In contrast, the pressure drop of $ Fe_{3}O_{4} $-MPCS in microchannel has no obvious change. In addition, microscale flow may be more conducive to the emergence of turbulence with smaller Re. It is shown that the convective heat transfer coefficient of MPCS is higher than that of deionized water, and increases with the increase of Re and mass fraction. The microchannel plate temperature is correspondingly lower, indicating better cooling effect. $ Fe_{3}O_{4} $-MPCS with the same mass fraction has a higher convective heat transfer coefficient and better heat transfer performance. The experimental results also indicate the influence of heat flux density on heat transfer performance. When Re is low, lower heat flux density is more conducive to heat transfer; when Re is high, higher heat flux density is better for heat transfer.