差速式抽采瓦斯稀释混合器运行特性

针对煤矿抽采瓦斯混兑稀释通入热逆流氧化装置氧化处理的需要,采用漩涡强制混合的思路,设计了差速式抽采瓦斯稀释混合器。采用数值模拟方法研究了混合器后管道内CH4的浓度分布,并针对煤矿现场运行参数波动的实际情况,研究了内外管道速度比、入口CH4浓度等运行参数以及抽采瓦斯与空气流量调节系统对混合效果的影响。研究结果表明,混合器后CH4浓度从管路中心到壁面逐渐降低,CH4分布的均匀性逐渐提高;内外管道速度比越小,混合气体浓度分布就越均匀;抽采瓦斯浓度变大导致不均匀性系数增大,而采用抽采瓦斯及空气流量自动调节系统时抽采瓦斯浓度越高则不均匀性系数越小,采用抽采瓦斯及空气流量自动调节系统可确保差速式抽采瓦斯稀释混合器有效促进CH4均匀分布。

Operating Characteristics of Drained Coal Mine Methane Diluting Mixer with Velocity Difference

According to the need that the drained coal mine methane should be mixed,diluted and added into the thermal counterflow oxidation unit to oxidize,it designed the drained coal mine methane diluting mixer with velocity difference by using the idea of vortex forced mixing.Through the method of numerical simulation,it studied methane distribution in pipe after the mixer.For the actual situation of operating parameters fluctuations in coal mine site,it discussed the operating parameters,such as methane velocity ratio between inner and outer pipe,inlet methane density and so on,then it studied the effect that drained coal mine methane and air flow adjusting system to the mixing efficiency.Results showed that the concentration of methane decreased from the axis to the wall in pipes,the uniformity of methane distribution increased along the way;the smaller the ratio of inner velocity to outer velocity was,the more uniform the concentration field was;the non-uniform index increased with the increasing of inlet methane concentration;while,the non-uniform index decreased with the increasing of inlet methane concentration when it utilized the flow automatically adjusting system of inlet air and inlet methane.So it ensured the drained coal mine methane diluting mixer with velocity difference to promote methane distribution uniform effectively with the drained coal mine methane and air flow automatically adjusting system.