旋转径向射流排放积聚瓦斯热成像实验分析

根据传热、传质和动量传递的相似理论分析，提出在紊流流场中当传热传质相似当量比满足一定要求并恒定为某一值时，可利用热成像仪测定紊流流场中的热量运移规律及温度场分布规律，模拟瓦斯浓度场中的瓦斯运移规律及其瓦斯浓度场分布的变化规律．根据热相似模拟实验，旋转射流风机不仅可以有效地驱散上隅角的积聚瓦斯，而且可以使瓦斯浓度分布更均匀．实验结果表明：旋转射流的旋转频率必须根据瓦斯涌出量和每个旋转周期排放瓦斯量确定；射流速度越大，驱散上隅角积聚瓦斯的效果越好；旋转径向射流对局部积聚瓦斯的运移是一个不断稀释、驱散并排向巷道主风流的过程．风机每旋转一圈完成一次对上隅角部分高浓度瓦斯的稀释和排出过程．如此周而复始，形成一种柔性排放瓦斯效应．当射流速度达3～5m／s时，可提高风流的扩散系数2～4倍，有效射程可达10m以上，有效地驱散了工作面上隅角的积聚瓦斯。

Experimental Study of Rotary Radial Jet Dispersing Accumulating Gas by Heat-Imaging

On the basis of the similar theory analysis of heattransmission, mass-transmission and momentum-transmission, it is put forward that the changing laws of heat-transmission and the distribution of temperature field can be used to simulate the changing laws of methane-transmission and the distribution of methane concentration field when the analogical equivalent ratio of heat transmission and mass transmission in turbulent flow field meets a certain requirement and keeps as a certain value. According to the heat similar simulation experiment, rotary radial jet not only can effectively eliminate the local gas accumulation in upper corner,but also can make methane concentration even distribution in airflow rapidly. The experimental results show that the rotation frequency of the rotary radial jet must be determined by the amount of emitting methane and the amount of methane discharged every circle; the faster the speed of the rotary radial jet is, the better the result of dispelling methane accumulation in upper corner. The migration and discharging process of gas accumulation dispelled by the rotary radial jet in the upper corner of working face is a course of constantly diluting, dispelling and draining methane to main airflow of tunnel. The fanner finishes a course of diluting and draining high concentration methane of upper corner while rotating a circle. While the rotation is circulated, a flexible discharging methane effect can be formed. When the speed of the rotary radial jet reaches 3~5 m/s, the diffusing coefficient of airflow can be increased 2~4 times, and effective range can exceed 10 m. Therefore, the gas accumulation in upper corner can be eliminated effectively.