Jet Fan Ventilation in Very Deep Cuts: A Preliminary Analysis.

摘要

Future coal mining systems will possess the ability to cut from crosscut to crosscut where advances could exceed 100 ft. However, limitations arise when ventilating such mining systems. In deep advance mining, there will be no workers at the face to manually advance ventilation tubing or curtain. Traditional methods also provide no means for maintaining face ventilation after the miner backs out. Bureau of Mines research is looking at means to provide effective ventilation at cut depths beyond the current limit of 40 ft. A number of innovative ventilation schemes are currently being considered. One such method is the use of a jet fan to ventilate a deep cut. A jet fan is simply a freestanding fan using little or no ducting to direct the ventilation flow. Jet fan testing in a 90 ft. entry revealed that higher exit velocities and greater penetration depth occurred when confining the flow with an exhaust nozzle. Additional testing also indicated that 2,200 cfm of fresh air was delivered to the face 90 ft. distant when a check curtain was used to limit entrainment around the fan. Without the curtain, the quantity dropped to only 1,000 cfm.