采煤工作面回风巷瓦斯气团漂移现象再探

针对采煤工作面回风巷中瓦斯气团进行长距离漂移而气团内部瓦斯浓度结构基本未发生变化这一现象,对瓦斯气团的产生区域、产生过程、在回风巷中的运移方式提出了一种假说,并且设计了一种试验方案用以验证该假说。利用瓦斯气团的运移特性,对瓦斯气团平均漂移速度的计算公式进行了优化,定义了瓦斯气团浓度衰减率这一概念,提出了一种用于吹散瓦斯气团降低回风巷中瓦斯气团浓度装置的设想。

Further exploration of the drifting phenomenon of the gas mass in the return airway of the coal mining goaf

The paper intends to bring about a hypothesis on the area and process of the gas mass production and its migration mode in the returning airway whereas the internal concentration structure of the gas mass does not change substantially with the gas concentration being decreased slowly. Literally speaking,the above hypothesis can be restated that the gas mass generating area in the return airway of the coal mining face is mainly the coal wall surface and the goaf area,whereas greater gas mass can be formed by the mutual fusion of the tiny gas mass or bubbles under the influence of the surrounding air condition to some extent.Or more specifically speaking,the mutual fusion of the tiny gas mass or bubbles under the influence of the surrounding air can be made to go on in the 2 areas with the help of the air current into the return airway. Actually,no obvious change has been made in the internal concentration structure of the gas mass after the longdistance drift. To get to know the inherent regularity of the longdistance drift,we have laid out an experimental scheme to verify the above said hypothesis. It goes like that,in the internal concentration structure,some gas concentration ought to be higher than the average value of the gas concentration in the return airway as is monitored for a long time. According to the gas mass special features described above,the drift velocity of the multiple groups of gas mass can be calculated by assigning a certain weight to each drift speed and then superimpose the drift speeds of the weight processing to obtain the optimized gas mass average drift velocity. And,the calculation formula of the average drift velocity of gas mass can be optimized to reduce the calculation error of the average drift velocity of gas mass further. At this,it would be convenient to introduce a concept of the gas mass concentration attenuation rate,which is the rate of the change of the gas mass concentration reduction. Thus,the suggested value can reflect the degree of the effect of the gas air mass control( i. e.,ventilation effect) in the return airway. The prevention and control measures for the long-distance drift of the gas agglomerates can further be proposed from the 2 angles: the first is to reduce the concentration of the gas that is escaped from the gas generation zone;and,second,is that the gas mass can be blown away,but the mass of the blown gas can be thought to be relatively easy to implement a kind of technical means,and in turn,the idea of an air blown gas mass device can thus be proposed.