Predicting the safety zone and fire dynamics of Heptane multiple pool fire in a square dike using Flamelet Generated Manifold model

Abstract

The pool fire-triggered domino events in chemical and process industries result in multi-fold damages with the worst severity. Consequence analysis of Multiple Pool Fire (MPF) through Quantitative Risk Assessment (QRA) is highly essential to save the workers and machinery beforehand. This research aims to develop a computational methodology for predicting the safety zone and fire dynamics of MPF in various meteorological environments using ANSYS Fluent. The present paper predicts the fire dynamics of heptane stored in four tanks within a square dike of 2.7m×2.7m. The simulations are performed using the unsteady Flamelet Generated Manifold (FGM) and Discrete Ordinate (DO) radiation model within the framework of the Large Eddy Simulation (LES) turbulence model. The Moss-Brookes soot model is deployed for capturing the soot formation. The hexahedral mesh with local refinement is utilized to resolve the flame characteristics. To attain the optimal mesh, an extensive grid-independence study is conducted. The experimented still air condition along with the worst-case scenario are modelled to evaluate the safety zone using flame surface irradiation. The proposed Computational Fluid Dynamics (CFD) methodology is validated using the predicted temperature profile, O2 and CO2 mass fraction within 2.2% error of experimental findings. The safety distance is predicted using the radiative heat flux values of CFD models. The validated CFD model consisting of FGM approach with LES turbulence model, can be a robust methodology to determine the safety perimeter of an industrial MPF during crosswind situations, with the aim of averting human casualties and property damage in advance.