Effect of flow and reactive environment on acoustic characteristic of H2–CH4 inverse diffusion flame.

The acoustic characteristic of swirled and non-swirled turbulent inverse diffusion flame (IDF) for hydrogen-methane fuel is experimentally investigated with variation in Reynolds numbers (Re air) and equivalence ratios (Φ). For maintaining adequate working environment, noise characterization of hydrogen-methane fuel IDF is essential. Comparison of sound level indicates significant alteration in acoustic characteristics with change in Re air , Φ and swirl. The swirling IDF is noisier than the non-swirling IDF at the same Re air and Φ. The sound level increases by 9.9% for swirling and 10.2% for non-swirling IDFs with a surge in Re air. The variation of Φ (0.6 ≤ Φ ≤ 1.4) indicates that the noise of IDF with swirl is higher (an increase of 13.14%) than non-swirling IDF (an increase of 1.43%). Shearing of flow induced by swirl dominates sound generation. For swirling IDF, the rise in sound level is 3.67% when methane is blended with H 2 from 0% to 10%. • Effect of Swirl, momentum and hydrogen addition on acoustic of IDF is analysed. • Flow shear due to swirl increases noise levels. • Hydrogen addition enhances combustion dynamics and thus radiates large sounds. • Sound level of swirled IDF with hydrogen enhances by about 4%. [ABSTRACT FROM AUTHOR]