融冰沿气槽结构超疏水斜面下滑的解析数值分析

ANALYTICAL AND NUMERICAL ANALYSIS OF MELTING ICE SLIDING ALONG INCLINED SUPERHYDROPHOBIC SURFACE WITH AIR SLOT

文章提出了融冰沿气槽结构超疏水表面顺向下滑过程的物理几何模型.对融冰层液膜微剪切流进行分析,利用超疏水壁面“黏-滑”边界条件建立了微剪切流场的双Fourier级数方程,求得解析数值解,在此基础上研究了融冰层液膜微剪切流的速度分布及冰层下滑速度与超疏水表面气槽占比(a)、斜面倾角(α)以及融冰层液膜厚度(δ)之间的定量规律.研究结果表明,融冰层越薄或空气槽占比越大,融冰层微剪切流场偏离平板剪切流越显著;三相接触线处滑移速度梯度发生突变并达到峰值;a,α与δ的增大均会导致冰层超滑速度非线性增加,融冰层厚度增大到1之后超滑速度趋于渐近解析解函数.基于所取的参数值,a=0.95,δ=0.2以及a=0.9,δ=0.1时,由超疏水壁面结构导致的冰层下滑速度增量相对于总下滑速度的占比超过60%,此时冰层下滑速度主要来自超滑速度的贡献.文章的研究为当前超疏水除冰应用中的相关流体物理过程提供了参考.

A physical and geometric model for the sliding process of an melting ice along superhydrophobic(SH)surfaces with air slot structures in this article.By analyzing the micro-shear flows of molten liquid layers between the ice layer and SH surfaces,a double series equation(DSE)was established by using the"stick-slip"boundary condition of SH surface to obtain the analytical and numerical solutions for the micro-shear flows.Based on this,the velocity fields of the micro-shear flows and the sliding velocties of the ice layer under the different air slot ratios(a),the inclination angles(α)and the thickness of the molten liquid layers(δ)were investigated.The results indicate that the thinner the molten liquid layer or the larger the air slot ratio is,the more significant is the deviation of the micro-shear flow field on the SH surfaces from the planar shear flow.The slip velocity gradients have sudden changes and reach their peaks at triple contact lines.Increases of a,αandδwill lead to non-linear increases in the hyperslip velocities.Whenδ≥1,the hyperslip velocities tend to the values calculated from the function of asymptotically analytic solutions.Based on the parameter values taken in current study,it is found that the increments in ice sliding velocities account for more than 60%of the total sliding velocities at a=0.95,δ=0.2 and a=0.9,δ=0.1,which indicate that the ice sliding velocities mainly come from the contributions of hyperslip velocities.This study provides a reference for the fluid physical processes in current SH de-icing applications.