七孔探针测量剪切流场的误差分析和实验验证

摘要

Finite diameters of seven-hole probes will bring systematic errors in the measurement in shearing flow. In this paper, the calibra-tion of the coefficient matrix of the three-dimensional seven-hole probe in steady ilow held is carried out by numerical simulation. It is studied that several factors, such as velocity gradient, probe diameter and roll angle, cause systematic error in the measure-ment of parallel shearing flow field by numerical simulation. In the experiment of seven-hole probe measurement of the shearing flow field, it is determined the spatial resolution of the seven-hole probe in shearing flow fields. "Critical diameter" is defined and the error distribution of seven-hole probes is established in this paper in the measurement of shearing flow fields under the allow-ance of error.%有限直径的七孔探针在测量剪切流场时,会引入系统误差.本文通过数值模拟的方法,建立三维七孔探针模型,研究了平行流场的速度梯度、七孔探针直径、滚转角等因素对测量结果的影响,并进行误差分析.在实验中,本文选用典型的平行剪切流场——圆管射流——验证误差分析的结果.通过七孔探针测量剪切流场的实验,确定七孔探针对于剪切流场的空间分辨率.提出了七孔探针的“临界直径”的概念,并且绘制了误差随速度梯度和探针直径变化的曲面示意图,用以选择合适尺寸的七孔探针.