单组份气体在松散煤体中扩散规律试验研究

Experimental Study on Diffusion Law of Single-component Gas in Loose Coal

惰化气体多以单一组分的形式应用到惰化保护工作中,而惰化气体在松散煤体内扩散情况对惰化保护效果有直接影响,为了合理设置惰化气体喷口,使惰化气体充分扩散到煤体中易燃区域,在截面为1.50 m×1 m,高为0.6 m的试验台内放置松散煤体,在煤体内放置氧气浓度传感器,以氧气为示踪气体,研究单组分气体在煤体中的扩散情况,试验结果以气体浓度场的分布情况给出。结果显示:气体在松散煤体中会优先向位于喷口上方的煤层中扩散;在强制对流区域,松散煤体内部孔隙结构和煤粒粒径对气体的扩散规律影响较小,松散煤体底部中心区域易形成低气体浓度区;松散煤体中气体浓度变化曲线随时间呈现出指数函数变化线型。

In the inert protection,the form of inert gas’composition is single,and the diffusion condition of inert gas has a direct effect on the inert protection.In order to set up gas jets reasonably and ensure inert gas has a sufficient diffusion condition in the combustible area,the loose coal is placed in a test bed whose cross section is 1.50 m×1 m and height is 0.6 m,and oxygen concentration sensors are set in the loose coal.Oxygen is used as the tracer gas to reflect the diffusion regular in the loose coal,and the results are shown by the gas concentration filed.The results show that gas in loose coal will preferentially diffuse into the coal seam above the gas jet;in forced-convection area,the pore structure and particle size of loose coal have less impact on the regular of gas diffusion;the central area at the bottom of loose coal mass is apt to form a low gas concentration area;the variation curve of gas concentration in loose coal shows an exponential function variation curve with time.