ABSTRACT

This article reports the heat transfer data obtained from experimenting a novel functionalized nanodiamond (fND) colloid. In this functionalization technique, the nanodiamonds are coupled with molecules of the host fluid via carboxylic bonds, leading to a de-aggregated and fully stable nanodiamond colloid. The colloid flows through a conduction cold plate where the system cools the electronic component, leading to the resultant heat dissipation. This surface modification on the fully functionalized nanodiamonds ensures ultimate stability of the colloidal suspension of nanodiamond particles. The heat transfer experiments were performed with different concentrations of nanodiamond (0.05, 0.10, and 0.20 wt.%) and under a turbulent flow regime (6,400 < Re < 17,000). The closed-loop heat transfer apparatus utilizes a pump equipped with a variable frequency drive to study the pumping power at various flow rates and fND concentrations. The experimental results of this paper show the remarkable effect of low-concentrated fND additives on enhancing the heat-transfer coefficient of the deionized water. The results show up to a 70% enhancement in the heat transfer coefficient compared to the base fluid at the same pumping power using a 0.20 wt.% fND. The nanodiamond colloid has shown no sedimentation after remaining stored over two years after synthesis.

摘要

本文报告了通过实验一种新型功能化纳米金刚石 (fND) 胶体获得的传热数据。在这种功能化技术中，纳米金刚石通过羧基键与主体流体的分子偶联，从而产生解聚且完全稳定的纳米金刚石胶体。胶体流经系统冷却电子元件的传导冷板，从而导致散热。这种对全功能化纳米金刚石的表面改性确保了纳米金刚石颗粒胶体悬浮液的最终稳定性。传热实验是在不同浓度的纳米金刚石（0.05、0.10 和 0.20 wt.%）和湍流状态下（6,400 < Re < 17,000）进行的。闭环传热装置利用配备变频驱动器的泵来研究不同流速和 fND 浓度下的泵送功率。本文的实验结果表明，低浓度的fND添加剂对提高去离子水的传热系数有显着的效果。结果表明，与使用 0.20 wt.% fND 的相同泵送功率的基础流体相比，传热系数提高了 70%。纳米金刚石胶体在合成后储存超过两年后没有显示出沉淀。结果表明，与使用 0.20 wt.% fND 的相同泵送功率的基础流体相比，传热系数提高了 70%。纳米金刚石胶体在合成后储存超过两年后没有显示出沉淀。结果表明，与使用 0.20 wt.% fND 的相同泵送功率的基础流体相比，传热系数提高了 70%。纳米金刚石胶体在合成后储存超过两年后没有显示出沉淀。