疏水表面流体流动特性的格子Boltzmann方法模拟

摘要

采用格子Boltzmann方法研究了微形貌对固体表面润湿性的影响，在此基础上进一步模拟了具有微形貌的疏水表面通道内的流体流动，从法向速度、剪应力、滑移速度等角度分析了疏水表面的流场特性，揭示了疏水表面滑移流动的产生机制。结果表明，疏水表面的滑移流动是由低表面能作用和微形貌共同引起的。具有微形貌的疏水表面比光滑疏水表面具有更好的减阻效果，原因在于微形貌能够驻留气体，形成的气液自由剪切面加剧了疏水表面的滑移流动，最大滑移速度可以达到主流平均速度的50%左右。%The influence of microcosmic topography on the surface wettability is investigated using a lattice Boltzmann method, and then the liquid flow over hydrophobic surfaces with microcosmic topography is sim-ulated in a microchannel. From aspect of normal velocity, shear stress and slip velocity, the flow field char-acteristics of hydrophobic surfaces are analyzed and the generation mechanism of hydrophobic surfaces’ slip flow is revealed. The simulation results show that hydrophobic surfaces’ slip flow is caused by the low surface energy effect and microcosmic topography together. Hydrophobic surfaces with microcosmic topog-raphy have a better drag reduction effect than smooth hydrophobic surfaces. The reason is that the micro-cosmic topography can retain gas and generate gas-liquid free shear surfaces, which can enhance hydropho-bic surfaces’ slip flow and make the maximum slip velocity reach about 50% of the average speed of main-stream.