Combustion noise characteristics of an experimental 2D trapped vortex combustor

The objective of present investigation is to understand the effects of various operating parameters on the combustion noise characteristics of a 2D trapped vortex combustor (TVC). Spectral analysis of the microphone signal indicates that the power spectral density (PSD) magnitude increases with primary air velocity (Vp) for both mainstream Reynolds number (Rems) 20 000 and 40 000 cases considered in this study. Combustion noise measurements reveal that the spectral amplitude of the combustor increases with cavity equivalence ratio (ϕc). Moreover, for a particular Vp case, the PSD magnitude is observed to be higher for Rems=20000 as compared to that of Rems=40000 case due to the quenching of mainstream flame in the latter case. For a particular mainstream Reynolds number, the noise level increases with the momentum flux ratio between cavity and mainstream flow. Analysis of results reveals that the noise level varies between 80 dB for non-merged flame and 100 dB for merged flame cases. An attempt has also been made to correlate the overall sound pressure level (OASPL) with the non-dimensional operating variables.