Modeling non-stationary gas admixture flow in excavations under recirculating airing

Assessment of emergencies in return air system design

“…All those supplementary fans are the recirculating fans since leaks in the excavation system inevitably lead to formation of closed circuits (the air is drawn by a fan without going out to the surface). Some part of return air, which should contain significantly less detrimental impurities than critical concentration, is reused [1,2]. Recirculating ventilation permitted by safety regulations in potash and rock salt mines [3] can be organized using a draught producer placed in vent cross cuts between excavations.…”

“…The main mine fan (MMF) due to depression ∆P produces and supports the airflow ) 0 ( 1 Q through the mine, i.е., through air and downcast shafts. The total airflow resistance of the shafts, MMF channel, and sections of haulage and air roadways up to the place of the to-be cross-cut with recirculating fan is denoted as 1 R , and 4 R is the resistance from this place to a poorly ventilated section, including this section resistance. The recirculating ventilation is meant to increase air supply to the poorly ventilated area.…”

Numerical modeling of air flows in mines under emergency state ventilation

“…To take account of air mass, correct the second law of networks (2). The work of pressure force, ΔA (J), to displace air flow along a mine working with cross-section S (m 2 ) and length ΔL (m), for distance ΔL (m), is spent to overcome friction force F (N) and kinetic energy k E Δ (J) of the said air flow: …”

“…Formula (8) is included in the code "AeroSet". The calculation of smoke and heat propagation in a mine is analogous to the algorithm of perfect displacement during modeling of contamination spreads from [2]. It is accounted for variable air flows by revaluation of air densities, thermal drops of ventilation pressure and air distribution at every time step.…”