Deng Shuyan, Bian Ruiqing, Liang Jiacheng
Institute of Architecture and Civil Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China.
College of Civil Engineering, Dalian Minzu University, Dalian 116600, China.
Micromachines (Basel). 2023 Feb 1;14(2):371. doi: 10.3390/mi14020371.
To guarantee the transporting efficiency of microdevices associated with fluid transportation, mixing, or separation and to promote the heat transfer performance of heat exchangers in microelectronics, the hydrodynamic behaviors at unsteady and steady states, as well as the thermal characteristics at the steady state in a pressure-driven electrokinetic slip flow of power-law fluid in a microannulus are studied. To present a more reliable prediction, the slip phenomenon at walls and nonlinear rheology of liquid are incorporated. The modified Cauchy momentum equation applicable to all time scales and energy equations, are analytically solved in the limiting case of a Newtonian fluid and numerically solved for power-law fluids. The transient velocity profile, time evolution of flow rate, temperature profile, and heat transfer rate are computed at different flow behavior indices, electrokinetic width, slip lengths, and Brinkman numbers, thereby, the coupling effect of nonlinear rheology, slip hydrodynamics, and annular geometry on flow and thermal behaviors is explored. The unsteady flow takes a longer time to achieve the steady state for shear thinning fluids or greater slip lengths. The flow behavior index and slip length play a significant role in the flow rate and heat transfer performance. The relevant discussion can serve as a theoretical guide for the operation and thermal management of annular geometry-related flow actuation systems.
为确保与流体输送、混合或分离相关的微器件的输送效率，并提高微电子学中热交换器的传热性能，研究了微环隙中幂律流体在压力驱动电动滑移流中非稳态和稳态下的流体动力学行为以及稳态下的热特性。为了给出更可靠的预测，考虑了壁面处的滑移现象和液体的非线性流变学。适用于所有时间尺度的修正柯西动量方程和能量方程，在牛顿流体的极限情况下进行了解析求解，对幂律流体进行了数值求解。计算了不同流动行为指数、电动宽度、滑移长度和布林克曼数下的瞬态速度分布、流量随时间的演变、温度分布和传热速率，从而探讨了非线性流变学、滑移流体动力学和环形几何形状对流动和热行为的耦合效应。对于剪切变稀流体或更大的滑移长度，非稳态流动达到稳态所需的时间更长。流动行为指数和滑移长度对流量和传热性能起着重要作用。相关讨论可为环形几何形状相关流动驱动系统的运行和热管理提供理论指导。
