基于激光多普勒测速技术的突扩巷道流场风速分布研究

Study on the distribution law of the wind speed in the sudden enlarged roadway based on LDA

利用非接触测量技术激光多普勒测速仪(LDA)测试得到了突扩巷道流场断面风流分布特征。实验表明,突扩前平直巷道断面内风流呈对称分布,突扩后上下隅角形成回流漩涡区,且为不对称分布;从断面纵对称轴上风速分布来看,回流区内断面风速呈现出“Ω”型分布趋势,而断面横对称轴上风速分布对称性良好,未受断面突扩影响;全断面风速等值线为环状分布曲线,受矩形管道湍流二次流影响,在突扩巷道断面角域处风流速度分布呈现出略有凸起的形式。研究表明,非接触LDA测速技术为复杂的矿井通风巷道流场湍流特性研究提供了实验手段。

The distribution characteristics of the airflow field have obtained by Laser Doppler Anemometer (LDA) in the cross-section of the sudden enlarged roadway,which belongs to the non-contact measurement te chnology to solve the limitations of traditional contact instantaneous velocity measurement.Experiments show that the airflow di stribution is symmetrical in the straight roadway before the sudden enlarged roadway,and the backflow zones exist in the upper an d lower corner of the sudden extension with asymmetric distribution;From the view of the wind speed distribution of the cro ss-section on the longitudinal axis,the wind speed of the cross-section shows the “Ω” type distribution trend in the backflow zone ,while the wind speed distribution is symmetrical on the horizontal axis,which is not affected by the sudden enlarged section;The wind speed contours show a ring-like distribution in the full section.And the wind speed distribution characteristics present a slightly prot ruding form at the corners of the cross section in the sudden enlarged roadway because of the turbulent secondary flow in rectangular p ipe.The study illustrates LDA as a non-contact measurement technology provides a feasible experimental means for the study of t he complex turbulent characteristics of the flow field in the mine ventilation t unnel.