Turbulent lean premixed flame responseto the imposed inlet oscillatingvelocity and effect of the equivalence ratio and inlet temperature on it

In the present study, the flame response and the effect of equivalence ratio and inlet temperature on the flame response are numerically investigated using Weller flamelet combustion and LES turbulent models. The results show that with increasing excitation amplitude at a constant frequency, theheat release ratio increases; the increment is smaller at higher frequencies. Due to the combustor geometry, two recirculating zones are formed. Any change in the amplitude and frequency can affect these recirculation zones, especially the central recirculation zone. At the low frequencies (below 50Hz), increasing the excitation amplitude affects flame transfer functioninconsiderably, because of no influence of the recirculation zoneson the heat release. At higher frequencies, an increase in the amplitude has a more influence on value of flame transfer function. It is shown that by increasing the amplitude, up to frequency of 140 Hz, the phase of flame transfer function slightly reduced, while this is intensified with increasing the equivalence ratio or flame inlet temperature. Furthermore, by increasing the equivalence ratio or inlet temperature of the flame, heat release ratio and the flame transfer function are reduced.