Method for determining length extreme value of downstream inclined shaft of purification and ventilation system in inclined shaft slag conveying process

The invention discloses a method for determining the length extreme value of a downstream inclined shaft of a purification ventilation system in the inclined shaft slag conveying process. An air purifier is installed in the inclined shaft, the two ends of the air purifier are an air inducing section and an injection section respectively, the air inducing section is arranged opposite to the bottom of the inclined shaft, and the injection section is arranged opposite to an inlet of the inclined shaft; by means of an air inducing section, an injection section, upstream air flow, air flow to be purified, purified air flow and unpurified air flow of the air purifier, flow dividing flowing and converging flowing of the air flow are achieved; the calculation formula of the length extreme value of the downstream inclined shaft is # imgabs0 #, wherein Q0 is the volume of backflow dirty air of the tunnel face, m < 3 >/s; c = C/delta is the ratio of the comprehensive influence factor of the smoke flow to the design conc