A 2D CFD model investigation of the impact of obstacles and turbulence model on methane flame propagation

The formation of explosive gas zones (EGZs) from flammable vapors, gases, or dust pose safety hazards to many industries. In many cases, explosions may occur in confined areas with obstacles in the path of flame expansion. By studying the effects of obstacle shape, turbulence model, and spark location on flame propagation and turbulence, a more complete understanding of the flame and fluid dynamics interaction has been achieved. Reynolds Averaged Navier-Stokes (RANS) models were tested to determine if these simplified turbulence models could capture the flame dynamics and propagation velocities using fewer computational resources compared to the higher fidelity Large Eddy Simulation (LES) turbulence model. Results showed that square obstacles caused faster flame propagation compared to hexagons and circles. The square had an average flame propagation velocity 26 % faster than the circle, and the hexagon was 16 % faster than the circle using a k-omega model. Modeling results indicate variation of spark location by as small as 10 % of the obstacle diameter can result in a difference of the flame propagation. Findings on turbulence model accuracy and computational time along with shape comparison can be applied in future modeling of large systems, providing crucial information for safety planning and explosion prevention. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

Studying the effects of obstacle shape, turbulence model, and spark location on flame propagation and turbulence has provided a more complete understanding of the flame and fluid dynamics interaction. Results showed that square obstacles caused faster flame propagation compared to hexagons and circles. Variation of spark location by as small as 10 % of the obstacle diameter can result in a difference in flame propagation.