Ni Yu, Fan Jianren, Hu Yacai
State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, P, R, China.
Nanoscale Res Lett. 2011 Feb 28;6(1):183. doi: 10.1186/1556-276X-6-183.
This study is a numerical study on the coagulation as well as the sedimentation effect of nanofluids using the Brownian dynamics method. Three cases are simulated, focusing on the effects of the sizes, volume fraction, and ζ potentials of nano-particles on the formation of coagulation and sedimentation of nanofluids. The rms fluctuation of the particle number concentration, as well as the flatness factor of it, is employed to study the formation and variation of the coagulation process. The results indicate a superposition of coagulation and sedimentation effect of small nano-particles. Moreover, it is stable of nanofluids with the volume fraction of particles below the limit of "resolution" of the fluids. In addition, the effect of ζ potentials is against the formation of coagulation and positive to the stability of nanofluids.
本研究是一项使用布朗动力学方法对纳米流体的凝聚以及沉降效应进行的数值研究。模拟了三种情况，重点关注纳米颗粒的尺寸、体积分数和ζ电位对纳米流体凝聚和沉降形成的影响。采用颗粒数浓度的均方根波动及其平坦度因子来研究凝聚过程的形成和变化。结果表明小纳米颗粒的凝聚和沉降效应叠加。此外，当颗粒体积分数低于流体“分辨率”极限时，纳米流体是稳定的。另外，ζ电位的作用不利于凝聚的形成，对纳米流体的稳定性有积极影响。
