Deng Shuyan, Xiao Tan
Institute of Architecture and Civil Engineering, Guangdong University of Petrochemical Technology, Maoming 525011, China.
Micromachines (Basel). 2022 Mar 1;13(3):405. doi: 10.3390/mi13030405.
To achieve the optimum use and efficient thermal management of two-layer electroosmosis pumping systems in microdevices, this paper studies the transient hydrodynamical features in two-layer electroosmotic flow of power-law nanofluids in a slit microchannel and the corresponding heat transfer characteristics in the presence of viscous dissipation. The governing equations are established based on the Cauchy momentum equation, continuity equation, energy equation, and power-law nanofluid model, which are analytically solved in the limiting case of two-layer Newtonian fluid flow by means of Laplace transform and numerically solved for two-layer power-law nanofluid fluid flow. The transient mechanism of adopting conducting power-law nanofluid as a pumping force and that of pumping nonconducting power-law nanofluid are both discussed by presenting the two-layer velocity, flow rates, temperature, and Nusselt number at different power-law rheology, nanoparticle volume fraction, electrokinetic width and Brinkman number. The results demonstrate that shear thinning conducting nanofluid represents a promising tool to drive nonconducting samples, especially samples with shear thickening features. The increase in nanoparticle volume fraction promotes heat transfer performance, and the shear thickening feature of conducting nanofluid tends to suppress the effects of viscous dissipation and electrokinetic width on heat transfer.
为实现微器件中两层电渗泵系统的优化利用和高效热管理，本文研究了狭缝微通道中幂律纳米流体两层电渗流的瞬态流体动力学特性以及存在粘性耗散时的相应传热特性。基于柯西动量方程、连续性方程、能量方程和幂律纳米流体模型建立了控制方程，在两层牛顿流体流动的极限情况下通过拉普拉斯变换进行解析求解，并对两层幂律纳米流体流动进行数值求解。通过给出不同幂律流变学、纳米颗粒体积分数、电动宽度和布林克曼数下的两层速度、流速、温度和努塞尔数，讨论了采用导电幂律纳米流体作为驱动力的瞬态机制以及泵送非导电幂律纳米流体的瞬态机制。结果表明，剪切变稀导电纳米流体是驱动非导电样品，特别是具有剪切增稠特性样品的一种有前途的工具。纳米颗粒体积分数的增加促进了传热性能，导电纳米流体的剪切增稠特性倾向于抑制粘性耗散和电动宽度对传热的影响。
