چکیده مقاله
The mine face fire caused by methane combustion is an important incident that undermines the mine safety Depending onits magnitude and intensity, fire may damage the mine's auxiliary ventilation system, thus exacerbating the consequences With the help of computational fluid dynamics, this study investigates the effects of air curtain damage on the smokebehavior and temperature stratification in an active mine face First, by modeling the Ingason–Hansen fire experiment, thenumerical model was validated, attaining excellent convergence between the numerical and experimental results Next, a250 kW fire was simulated in the mine face using square cells as large as 5% of the characteristic fire diameter Fivedifferent scenarios were considered to investigate the damage inflicted on the air curtain by the fire, including the referencescenario S0 —assuming no damage—and the first S1 , second S2 , third S3 , and fourth S4 scenarios, in which 17, 50,67, and 83 % of the air curtain is damaged, respectively Based on the simulation results, the required pressure difference isnot supplied between the cold air inside the curtain and the hot smoke outside when the air curtain length is reduced,undermining the chimney effect and allowing the smoke to fill up the model In cases where more than 50% of the aircurtain remains unaffected by fire, temperature strata can be separated into two distinct regions, namely the near fire area—with stable stratification—and the areas further away—where hot and cold streams mix However, a clear temperaturegradient is established along the vertical axis, resulting in a non uniform temperature profile with a higher temperature nearthe ceiling and a lower temperature at the bottom The same process holds until the boundary between clean air and smoke,and the smoke free area When the length of the air curtain is reduced fewer than 50%, the chimney effect is canceledaltogether, but temperature strata remain unaffected near the fire However, further away from the fire, the smoke coolsdown, the vertical temperature profile of the model levels out, the entire model fills up with smoke, and temperaturestratification is disrupted, leaving no chance for operators to escape from the mine face
کلیدواژهها
نویسندگان
behzad Niknam
MSc mining engineering Amirkabir University
شیوه ارجاع
Niknam, behzad,1398,Numerical Simulation of the Effect of Damage to the Air Curtain on the SmokeBehavior and Temperature Stratification during Fire in Mine Faces,The 13th Iran Tunnel Conference,Tehran
ارائهشده در
مجموعه مقالات سیزدهمین کنفرانس تونل ایران28 آبان 1398 · تهران