LES modelling of explosion propagating flame inside vented chambers with various built-in solid obstructions

This paper presents large eddy simulations (LES) of the transient interaction between propagating turbulent premixed flames and solid obstructions mounted inside a laboratory scale combustion chamber. Interactions between the flame movement and the obstacles found to create both turbulence by vortex shedding and local wake/recirculation whereby the flame is wrapped in on itself, increasing the surface area available for combustion and the rate of local reaction rate. Accounting the influence of such local events in order to predict overall flame spreading speed, flame behaviour and the generated overpressure as a measure of reaction rate are extremely useful in combustion analysis in order to develop new models. The rise in the reaction rate due to the local nature of the flow and the increase in overall pressure due to the enhanced turbulence flame interactions as the flame travels through the unburned fuel air mixture are presented and discussed. The main focus of the current work is to establish the LES technique as a good numerical tool to calculate turbulent premixed propagating flames of propane/air mixture having equivalence ratio of 1.0, which is of practical importance in analysing explosion hazards and gas turbine combustors.