Application of FLACS to develop a standard for explosion venting of empty vessels

Abstract

Explosion venting is the most commonly used method to mitigate consequences of gas explosions. Therefore, research has been ongoing to establish adequate venting criteria for gas explosion. The existing standards are based on analytical models and empirical correlations. However, there are conflicts between the recommendations because of different factors influencing the peak overpressure that have been considered into such criteria or not. Therefore, in this thesis work, a modified recommendation of venting criteria in gas explosion was proposed under assumption that one of the factors giving significant impact on overpressure was controlled. To obtain a wide range of data to support the proposed modification, various cases of vented gas explosions were simulated by using a CFD tool, FLACS. Furthermore, turbulence generation at equipment inside the enclosure and acoustic resonance were not taken into consideration to meet the assumption. Accordingly, FLACS which does not take into account the effect of acoustic resonance was used as the main tool to run the vented gas explosion simulations. The proposed recommendation based on acquired results from FLACS simulations is less conservative than the existing recommendation suggested by Bradley & Mitcheson [1978], which has made reference to the aforementioned factors. Hence, it is expected that this work might help develop a guideline for explosion venting by proposing a modified safe recommendation in vent areas. However, the guideline shall specify that proper measures have to be implemented to eliminate the factors mentioned above.