七孔探针测量剪切流场的误差分析和实验验证

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.

Experimental research and error analysis on seven-hole probe measurements of shearing flow field

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 flow field 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.