基于正交试验的微通道翼形流场特征分析

Analysis of microchannel airfoil flow field characteristics based on orthogonal experiments

为抑制翼型的空化,提出了基于微通道技术的空化抑制方式,以NACA翼型为载体,并在其易发生空化区域设置局部微通道,利用正交试验的方法,设计了影响翼型空化的inlet 1来流速度、inlet 2微通道出口压力、微通道出口孔数与孔型等参数的混合水平正交试验,以数值仿真为手段寻求探究局部微通在不同因素及水平下各因素与水平对于低压区的抑制效果,通过极差分析得到各参数对空化影响的主次顺序和一组最优参数组合。研究表明:翼型来流速度是影响空化的最主要的因素,其次为微通道出口压力大小;采用多孔结构的微通道布局可以有效缩小低压区面积并抑制空化规模。综合对比发现,翼型来流速度15 m/s,微通道出口压力1.01×10^(5) Pa,采用单排方孔状的微通道出口结构的翼型为本文的最优方案。优化方案与原翼型相比空化面积减少90%以上,低压区面积减少一半,且流场与原始翼型的流场基本无变化。本试验结果对其他流体机械采用微通道抑制空化方法具有一定的参考价值。

In order to restrain the cavitation of airfoils,a cavitation suppression method based on microchannel technology was proposed.NACA airfoils were used as carriers and local microchannels were set up in the area prone to cavitation.By using the method of orthogonal test,the mixed horizontal orthogonal experiments were designed to affect the parameters of airfoil cavitation,such as inlet1 inlet velocity,inlet2 microchannel outlet pressure,number of microchannel outlet holes and pore shape.By means of numerical simulation,the suppression effects of different factors and levels of local microcommunication on the low pressure area under different factors and levels were explored.The primary and secondary order of the influences of parameters on cavitation and a set of optimal parameter combination were obtained through range analysis.The results show that the airfoil flow velocity is the most important factor affecting the cavitation,followed by the microchannel outlet pressure;The microchannel layout with porous structure can effectively reduce the low pressure area and restrain the cavitation scale.According to the comprehensive comparison,it is found that the final optimal scheme is the inlet speed of 15 m/s,the microchannel outlet pressure of 1.01×10^(5) Pa,and the airfoil with a single-row square hole-shaped microchannel exit structure.Compared with the original airfoil,the cavitation area of the optimization scheme is reduced by more than 90%,the area of low pressure area is reduced by a half,and the flow field is basically unchanged from that of the original airfoil.The test results have a certain reference value for other fluid machinery to use microchannels to suppress cavitation.