突扩巷道模型内流场的PIV实验

FlowField Test in a Expansion Roadway Model by PIV

为改善实验方法,推进矿井通风基础理论研究,将粒子图像测速技术(PIV)引入矿井通风研究领域。介绍了PIV的工作原理、系统组成和示踪粒子的选取原则。以粒径为0. 2～2μm的光扩散剂做示踪粒子测试了巷道突扩模型内的流场结构。结果表明,井巷风流遇断面突扩后会产生大范围的回流,同时在主流与回流区之间会产生小尺度的二次涡系,即回流区为多涡并存的情况,主流与各尺度涡间产生激烈的能量交换造成能量损失;二次涡系形成的区域风流极度紊乱,影响风速测试;整个回流区明显低于主流流速,有毒有害气体和粉尘可长期滞留在涡旋内形成安全隐患。实验表明,与传统的单点接触式测量方法相比,PIV可以获得更多的湍流流动细节,有助于人们更加深入的认识井巷内气体流动的本质。

In order to improve the experimental methods and the basic theory of mine ventilaition, particle image velocimetry was import to the research field of mine ventilation. The operating principle , system composition and selection principle of tracer particle was introduced. Light diffusing agent whose particle size was between 0. 2 to 2 μm has been used as tracer particles in the measurement of the flow field structure of suddenexpansion roadway . It was found that,backflow and the smaller second-vortex will appear when the air flowpassed the sudden expansion roadway and energy loss occur by energy exchange between the mainstream anddifferent size of vortex. The flow was very disorder impacted by vortex and its difficult for velocity measurement. Toxic or harmful gases will detain in the vortex because the velocity of backflow was significantly lowerthan the main stream. The results indicated that more accurate flow field information could be acquired by PIVthan the traditional experimental method,which is helpful to realize the essence of roadway flow field.