Simulation of turbulent combustion in a self-aerated domestic gas oven

Abstract

Characteristics of the partially-premixed flames are numerically studied in a self-aerated domestic gas oven. The fuel (methane) and air are introduced into the premixing chamber from different inlets and, therefore, the non-premixed formulation of the reactive scalars is possible to use. The Reynolds-averaged transport equations are solved with the k-ε turbulence model to assess the mixing efficiencies of the primary and the secondary aeration processes in the burner and combustion chamber with relevance to the flashback and flame blow-off issues. The results reveal that the most important flow feature in the chamber is the vortical motion above the fuel jets, which recirculates hot flue gases into the flame zone and reduces the burning intensity and the peak flame temperature. The concentration of flue gases passing to the compartment appears to be sufficiently diluted by the secondary aeration so that the contamination of food by the exhausts is prevented. The positions of the intake and outlet slots of the combustion chamber are also discussed for the appraisal of the effectiveness of the secondary aeration, the characteristics of the air streams driving the flow in the chamber as well as the uniformity of the temperature of the cooking compartment and flue gases.