Prediction of the explosion severity of hybrid mixtures

Abstract

To clarify the relationship of explosion severity between the flammable gas, dust, and their mixtures, along with developing models for predicting the explosion severity of hybrid mixtures, four different kinds of hybrid mixtures with wide range of concentrations were selected in this study. The maximum explosion pressure as well as the maximum rate of pressure rise for these four hybrid mixtures were measured in a standard 20 L spherical chamber. It was obtained that addition of flammable gas to dust cloud increases both the maximum explosion pressure and the maximum rate of pressure rise. However, the increase in the maximum rate of pressure rise was more pronounced than that of the maximum explosion pressure, indicating that the influence of the flammable gas addition on the maximum rate of pressure rise of dust was more effective. Both the maximum explosion pressure and the maximum rate of pressure rise of the hybrid mixtures increased with an increase in the flammable gas concentration. At any flammable gas concentration, both the maximum explosion pressure and the maximum rate of pressure rise of the hybrid mixtures were smaller than those of the pure flammable gas but greater than those of the pure dust. That is to say, the explosion severity of hybrid mixtures was less than that of the flammable gas, but greater than that of dust. The maximum explosion pressure of the hybrid mixture increased linearly with an increase in the flammable gas equivalent ratio Ф. In addition, the maximum rate of pressure rise of the hybrid mixture increased following a second-order function by increasing the flammable gas equivalent ratio Ф. Building on this latest finding, two models were developed for predicting the maximum explosion pressure and the maximum rate of pressure rise of the hybrid mixtures with satisfactory predictive performances.