Determination of Airway Resistance Using Airflow Distribution

The most widely adopted method for determining airflow resistance in a mine is that based upon the measurement of airflow rate and pressure drop. However, as the measurement of pressure is time-consuming and prone to inaccuracy, in practice it is impossible to always maintain up-to-date data concerning airflow resistan ces for every change in the mine structure using this method.On the other hand, as the measurement of airflow is easier than that of pressure and is regularly made for the purpose of safety, there is a large volume of data on airflow available in every mine. Therefore, if it is possible to calculate airflow resistance using only airflow data, this will contribute to an improvement in the accuracy of airflow resistance determination and also to a reduction in labor involved in ventilation measurement. This would lead to greater precision in ventilation network analysis.From this point of view, the authors have examined the possibility of calculating airflow resistance using airflow data only. This has led to the following conclusions:(1) Unique values for resistance cannot be calculated using only a single set of airflow data;(2) Unique resistances can be calculated by using two or three sets of airflow data that have been measured under different conditions of ventilation.Subsequently, two different methods are shown for calculating airway resistances. One uses the principle of the node potential method and the other uses the mesh method principle. If the airflow data are correct, both methods give correct values of resistance.