底层隔板法流体壁面剪切力的测量研究

The research of measuring skin friction with a sublayer fence

针对流体壁面剪切力测量难度较大的问题,研制了一种流体壁面剪切力测量元件的底层隔板法,并采用理论推导、数值计算和实验相结合的方法对其性能进行研究。通过公式推导,分析了元件用于流体壁面剪切力测量的原理,找出壁面剪切力和隔板前后压力差的函数关系。实验结果表明:元件隔板前后差压与测得的流体剪切力的幂次方成正比。数值计算结果表明:测量元件的敏感尺寸是迎风薄片高度,高度越大,校准曲线斜率越小,幂次系数越小,而正比例系数越大。对底层隔板法壁面剪切力系数特性的研究,为探索其免标定应用方法奠定了基础。

In this paper,a new element measuring skin friction with a sublayer fence is made and the principle of measuring is analyzed.The theoretical analysis,numerical simulation and experimental research have been used.The derivation and discussion of the measurement formula of the sublayer fence show that the differential pressure of element has a function to the shear stress.The experiment results indicate that the differential pressure of element is proportional to the shear stress raised to some power.The numerical simulation results show that the key size is the height of fence.With the height of the fence becoming bigger,the slope of calibration curve becomes smaller,the power of the formula becomes smaller and the coefficient of the formula becomes bigger.The research to the characteristics of coefficients will lay the foundations for the using of the sublayer fence without calibration.