Accuracy improvement in evaluation of gas explosion overpressures in congestions with safety gaps

© 2014 Elsevier Ltd. This paper reports a comparison of simulations and published data from experiments carried out by TNO Prins Maurits Laboratory on geometric configurations that involved safety gaps of various separation distances. The Computational Fluid Dynamics (CFD) based software - FLACS is utilized to conduct the numerical simulations. In the majority of cases, good agreement is found between the simulated results and those obtained by experiment in both the donor and acceptor modules. However, a large discrepancy in the overpressures in the acceptor module is seen when the size of the separation gap approaches one or two times of the module size. A Data-dump technique is used in this study to reset the turbulence length scale for these cases with different separation distances, five sets of explosion scenarios are then numerically simulated and the overpressures are compared with experimentally measured explosion overpressures. The overall results indicate that the software with the Data-dump technique is still an extremely effective tool when it comes to the evaluation of gas explosion overpressures in areas with large separation gaps.