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针对传统的接触式瞬时速度测量方法的局限性,采用非接触测量技术激光多普勒测速仪(LDA)及粒子成像测速仪(PIV)对平直巷道及断面突扩后风流状态进行试验测试。在巷道试验模型条件下,PIV技术可以瞬时获得巷道突扩流场信息,平直巷道速度流线基本呈平滑直线,突扩隅角有大涡存在,并且涡流区测风方向极不稳定,而且风速很低,风速平均值在0.1~0.2 m/s波动,表明在煤矿井下测风时可以有条件地忽略涡流区。LDA技术测试得到巷道断面各点统计平均流速,由于受突扩涡流及二次流的影响,平直巷道断面风速从壁面以跃迁方式“突变”达到均值,断面风速分布呈近似均等的动态波浪线分布而非准抛物线型分布。结果表明,LDA与PIV测量技术联合应用可以测试以湍流为特征的巷道流场风流变化情况。
In order to overcome the limitation of the traditional method of contact instantaneous velocity measurement, LDA and PIV are used to test the wind flow in straight roadway and sudden expansion. Under the condition of tunnel test model, PIV technology can obtain instantaneous sudden expansion flow field information of tunnel, the straight streamline flow line is basically smooth and straight line, there is a large eddy in the sudden expanding corner, and the direction of wind measurement in the eddy current is very unstable The wind speed is very low and the average wind speed fluctuates from 0.1 m / s to 0.2 m / s, which indicates that the eddy current zone can be neglected conditionally when measuring wind in the coal mine. The average velocity of each point of the roadway cross section was obtained by LDA test. Due to the influence of sudden expansion vortex and secondary flow, the wind speed of straight roadway section reached the mean value by the transition mode "mutation Wavy distribution rather than parabolic distribution. The results show that the combined application of LDA and PIV measurement technology can test the turbulent flow characteristics of the roadway flow changes.