Prediction of the Reduced Explosion Pressure During Vented Gas Explosions Using a One-Dimensional Combustion Model in Combination with the Efflux Function

Abstract

Pressure venting is a common method in process industry to limit the overpressure during a gas phase explosion to the design pressure of a vessel. The ability to predict the reduced explosion pressure for a given vent area is crucial in the design of venting devices. In preceding publications by BASF, a model to predict the reduced explosion pressure was introduced. The model describes the pressure development inside the vessel using a zero-dimensional approach for the explosion. The mass reduction due to the vented gases is calculated from the Efflux function. To improve the accordance of the predicted explosion pressures with experimental data, the existing model is refined in the present work by applying a one-dimensional model to represent the flame propagation along the vessela centreline. This increases the accuracy of the predicted reduced explosion pressures compared to the previous version, especially for large vent areas. The explosion is described by an iterative routine for the combustion process and the induced flow velocities and turbulence. The integration of the effect of increased turbulence due to the flow of vented gases on the burning velocity was found to be crucial.