Speeding up of node potential method for ventilation network analysis

The authors have previously proposed a node potential method for ventilation network analysis which is used in all major coal mines in Japan. However, in the course of experience with this method it was found that two major problems must be solved for the calculation to be sped up: converge retardation by inadequate selection of an initial value of pressure to be given to the nodes and small resistances of the airway. The paper describes the improved method by which calculation time is reduced to about one second to one fourth that of the previously proposed method. The effect of natural ventilation pressure on the forced ventilation system and ventilation control in an emergency are discussed using the proposed method.