Prediction of Equivalence Oscillation under Unchoked Injection Condition in Lean Premixed Combustion

Abstract

Combustion instabilities are encountered in many applications related to power generation, propulsion and boiler systems. During past centuries, it is difficult to understand the instability mechanism and reduce the combustion instability completely though lots of researches have been conducted various points of view. Especially, very low frequency are big problems because a higher frequency oscillation is attenuated by a resonator in many attempts, but a lower frequency oscillation, which has around of 10Hz, is difficult to be reduced by a resonator. The report has showed that main cause of 10Hz mode is spatially modulated equivalence ratio fluctuation. We could make a comparative study of the modulated equivalence ratio using commercial code “STAR-CD v3.2”