Conically Stabilized Turbulent Premixed Lean-Flames Sustainability

Abstract

Lean combustion is a very well-known technology for low carbon and NOx emissions and yet relatively high combustion efficiency. On the other hand, lean combustion flames may blow off in absence of well-designed flame stabilizers. This article presents an experimentally validated modelling approach to study lean premixed flames anchored on a conical bluff body. The structure of an unconfined premixed propane-air flame, stabilized on a conical bluff body, has been computationally examined for conditions of 0.8 to near blow off equivalence ratio (Ø). Reynolds number of about 30,600 is considered based on the conveying pipe’s diameter (10.4cm) and upstream velocity (4.5m/s). the effect of radiation heat losses on flame stability is examined as well as the flow and temperature profiles. Experiments were performed to measure the flame’s spatial temperature profile in order to validate the developed computational models. Our model’s result portrayed a good agreement with experimental measurements. As expected, calculated temperature profiles show that reduction in Ø reduces flame temperature. Results also show that the open-base cone generate a larger recirculation zone – which favours flame stability – than the closed-base cone. Overall, this article highlights the potential of computational models in providing greater insights in the study of flames sustainability nearby the lean combustion limit.