Fri, September 30, 4pm – 5pm
Room: A2-002, University of Limerick ()
Description Emergence of combustion instabilities in smouldering combustion: a homogenisation approach Experimentally, it is known that, under microgravity conditions, a thin porous material burning in the same (downstream) or opposite (upstream) direction to an inlet oxidising wind develops unexpected combustion instabilities. The instabilities originate from a destabilizing effect of the oxidiser transport. In this talk, we start from a basic microscopic description of the combustion process and derive upscaled models by using the homogenisation method and proper choice of scaling arguments. The proposed model exhibits two modes (upstream and downstream modes) of the combustion instabilities, which are related to the direction of supply of the oxidising gaseous mixture. Eventually, we describe the two modes in 2D numerical simulations to demonstrate the close correspondence of our theoretical understanding with the qualitative results described in the experiments.