目的 探究微流道中不同参数下微纳结构对流体边界滑移长度的影响。方法 基于有限元方法，对具有不同微纳结构形状、大小和间距的各模型进行仿真。基于NAVIER滑移基本条件，获得边界滑移长度求解理论模型，结合仿真结果以及相关参数，得到不同微纳结构下流道表面流体流动的边界滑移长度。结果 在各参数相同的情况下，方柱、圆柱和三棱柱3种微结构流道表面流体的边界滑移长度分别为22.7、23.1、22.9 μm。边长和间距不同，边界滑移长度存在差异，当微结构间距在1~12 μm时，微结构尺寸对边界滑移长度的影响较小，呈负相关;当微结构间距增大到12 μm以上时，边界滑移长度随着微结构尺寸的增加具有较大波动。当流道高度改变时，边界滑移长度在流道边长变化时始终保持稳定。当流道边长改变时，边界滑移长度随流道高度增大快速增加。在各参数相同的情况下，方柱、圆柱和三棱柱微结构表面流体的边界滑移长度随放置角度的增大分别在(22.7±0.1)、(23.1±0.1)和(22.9±0.1) μm范围内上下浮动。结论 不同微结构参数与流道参数的边界滑移长度存在显著差异。微流道表面的微结构形状、间距和流道高度会对边界滑移长度产生较为明显的影响。微结构的尺寸、放置角度、流道边长和驱动压强差对边界滑移长度的影响较小。

The study on the effect of micro-nanostructures on the slip length of fluid boundaries in microchannels plays a crucial role in the field of microfluidics. In microfluidics, there exists a close relationship between surface micro-nanostructures and boundary slip effects. The work aims to delve into the impact of micro-nanostructures with different parameters on the slip length of fluids in microchannels, providing a deeper understanding of flow behavior in microfluids. By utilizing the finite element method and simulation software, microchannel models with three different microstructure shapes (square, cylindrical, and triangular prisms) in Cassie state are established. Physical fields are selected, fluid material properties are defined, boundary conditions are set, meshes are generated, and geometric parameters are adjusted for each model with different micro-nanostructure shapes, sizes, and spacing. Integral calculation of channel flow rate is conducted by defining a two-dimensional cross-sectional area at the channel outlet. The variation in channel flow rate is then utilized to assess the magnitude of the slip length. Based on the basic condition of Navier slip, the relationship between pressure drop, volume flow rate, and slip length of two infinite parallel plates is determined to derive a theoretical model for slip length calculation. The simulated results and relevant parameters are incorporated into the model to ultimately obtain the slip length of fluid flow on channel surfaces with different micro-nanostructures.