局部近似平面V型沟槽减阻特性数值模拟研究

Simulation Analysis on Drag Reduction Performance of Characteristic Parameters of V-Groove on Local Approximate Plane

随着仿生表面工程技术的发展,表面微织构的减阻特性被越来越多地研究,但其应用却受到物体复杂的表面形状等条件限制,单一的微织构并不适用于全局,进行整体分析计算成本较大。为解决这个问题,采用离散的思想,将复杂曲面分成局部近似平面考虑,探究微织构在局部近似平面上的减阻特性。基于边界层理论提出一套微织构的高度和位置设计方法,并在近似平面表面布置不同形状、深度、宽度、间距的V型沟槽结构,利用计算流体力学方法模拟近似平板表面的气流流动,探究各种特征参数对于V型沟槽在近似平面上减阻效果的影响。经过分析得出,在流速为25m/s时,得到深度0.2mm、宽度0.3mm的三角形微织构沟槽具有最佳减阻效果,达到5.51%,最佳无量纲参数y+=13.86。在进行微织构设计时,无量纲参数保持在14左右具有最佳的减阻效果。减阻微织构的宽深比必须小于1.5,且间距越小,其减阻效果越明显。

With the development of biomimetic surface engineering technology,the drag reduction characteristics of surface microtexture have been studied more and more,but its application is limited by the complex surface shape of the object and other conditions.A single microtexture is not applicable to the overall situation,and the overall analysis will consume a large amount of computing costs.In order to solve this problem,this paper adopts the idea of discrete,divides the complex surface into local facet to consider,and explores the drag reduction characteristics of micro-texture on local facet.Based on boundary layer theory,a design method of micro texture height and position is proposed,and in a small flat surface layout of different shape,depth,width and spacing of V–groove structure,using the method of computational fluid dynamics simulation of airflow in the small flat surface,various characteristic parameters for V–groove on the choice of drag reduction effects are explored.After analysis,the following rule can be obtained.When the flow velocity is 25m/s,the triangular micro-texture groove with depth of 0.2mm and width of 0.3mm has the best drag reduction effect,reaching 5.51%and the best dimensionless parameter y+=13.86.In microtexture designing,the dimensionless depth parameter is kept at about 14,which has the best drag reduction effect.The width to depth ratio of the drag reduction microtexture must be less than 1.5,and the smaller the spacing,the more obvious the drag reduction effect.