No abstract

A two-dimensional unsteady flow model was established by Realizable k-ε turbulence model and SIMPLE algorithm, which was applied to conduct numerical simulation of sudden leakage and diffusion of coal gas in the plant area. Then, time-dependent distribution laws of coal gas under different influencing factors were analyzed. The results showed that as the leaking mouth diameter, internal pressure and wind speed increase, the concentration was roughly the same near the mouth; coal gas that was 3m away from the mouth diffuses more quickly and the area covered within explosion limit of coal gas expanded to some extent. For different gas medium, converter gas spread more widely than coke oven gas. The former accumulated on the ground, the latter accumulated above the ground.

In order to do research on dynamic characteristics of auger miner’s working mechanism, three-dimensional entity model was built by software Pro/E, some components of working mechanism were made flexible and corresponding Modal Neutral Files were created by software ANSYS. Through the date exchange among Pro/E, ANSYS and ADAMS, dynamical simulation model of working mechanism was built in ADAMS environment. ADAMS/vibration, a plugin in ADAMS, can solve the dynamical simulation model and obtain dynamic characteristics of working mechanism. The establishment of the model can lay the foundation for the research on dynamic characteristics of working mechanism. The resolved results of the model can provide reference for structural design and performance improvements of working mechanism.

According to the international standard, main problems lying in the process of hazardous zone classification were emphatically analyzed. The source of release was determined in light of its release frequency and duration, namely the continuous source, primary source and secondary source. Considering the effect of release rate, LEL, density, ventilation, obstacles, and meteorological conditions on the classification of the hazardous area, it could be found that the hazardous zone would expand as the release rate increased with lower explosion limit. The gas that was heavier than air covered larger hazardous areas than the lighter gas. Besides, ventilation might speed up the diffusion so as to reduce the scope the hazardous zone; obstacles prevented the diffusion so that concentration of partial gas increased and then the danger level increased; wind at high speed quickened the diffusion to decrease the range of dangerous area. Finally, explosion-proof electrical equipment was selected rationally according to the type of explosive gas and temperature group.