ABSTRACT
By applying the mixed-length theories, the paper discusses that the main factors influencing on cross-gas migration mass-transferring velocity are the cross-and longitudinal pulsing velocity of airflow in tunnel. In theory, the paper analyzes that rotary jet can greatly enhance the cross-and longitudinal pulsing velocity of airflow in every place of whole cross section of tunnel, intensify cross-gas migration mass-transferring, effectively eliminate the local gas accumulation. It has proved that rotary jet can make methane concentration in airflow even distributing rapidly. On the basis of theoretical analysis and practical observation, there are three kinds of effects that rotary jet discharges the local accumulating gas, that is, the effect of gas periodically diluted, dispelled and discharged into main airflow in tunnel, the gentle discharging effect of rotary jet discharging the local accumulating gas and the effect of methane concentration even distributing rapidly in airflow. The method of rotary jet discharging the local accumulating gas is really safety, dependable, economical and validly. It has been proved by the field experiment.
