加入纳米颗粒的相变悬浮液黏性和热导率特性

Viscosity and Thermal Conductivity Characteristics of Microencapsulated Phase Change Material Suspensions Added with Nano-particles

提出了在相变悬浮液中添加TiO2纳米颗粒以提高其热导率的概念,并使用旋转流变仪和热物性仪测量了这种新型悬浮液流变特性和热导率。研究结果表明,对于体积浓度为10%的相变悬浮液,当加入的纳米颗粒质量浓度不超过5%(体积浓度1.18%)时,低剪切率下悬浮液表现出非牛顿流体的特性,高剪切率下仍可视为牛顿流体。相变悬浮液的黏性随纳米颗粒浓度增加而增加,当纳米颗粒质量浓度为5%时,相变悬浮液的黏性提高约23%。相变悬浮液的热导率随着纳米颗粒浓度的增加而增加,当纳米颗粒质量浓度为5%时,相变悬浮液热导率提高约7.3%。

Nano-particles TiO2 is introduced to suspensions micro-encapsulated phase change materials （MPCM）. Thermal conductivity and viscosity of this kind of novel suspensions are investigated experimentally using rheometers and thermal property meters. It＇s revealed that when the mass concentration of the nano-particles is less than 5%,MPCM suspensions of 10% show non-Newtonian characteristics under low shear rates. Under high shear rates,however,the suspension could be considered to be a Newtonian fluid. The viscosity of the MPCM suspensions increases as the concentration of nano-particles increases. Viscosity increment of the MPCM suspensions is about 23% when the mass concentration of the nano-particles is 5%. Thermal conductivity increment of the MPCM suspension is about 7.3% when the mass concentration of the nano-particles is 5%.