Far-field pressure prediction of a vented gas explosion from storage tanks by using new CFD simulation guidance

An extension of previous work to predict the far-field overpressures of vented gas explosions from small-medium scale storage tanks is presented. Four actual vented explosion experiments with different methane-air mixture concentrations were conducted. The recorded internal and external pressures from the tests were compared with the predictions from the Multi-Energy Method (MEM) model and Baker-Strehlow-Tang (BST) model. The limitations of these two empirical models in predicting the vented gas explosion pressures are discussed. Compared to the empirical model predictions, a combined CFD modelling approach (FLACS simulation plus ANSYS Fluent simulation) yields respectable accuracy in far-field overpressure prediction. The flame speed and initial mechanical energy, which are incorrectly assumed in the MEM and BST models, are taken into account in this study. Furthermore, this study simplifies previous work by using FLACS simulations for internal pressure estimation and a newly derived correlation for far-field pressure estimation. In addition to the peak pressure estimation, the equations to calculate the pressure-time history duration and shape are proposed. Computational efficiency and prediction accuracy are both achieved in the proposed approach for far-field overpressure predictions.