In this study, the combustion noise is passively mitigated using ring shaped porous inert media (PIM). Kerosene, simulating fuel commonly used in jet engines, is combusted in a swirl-stabilized combustor. In this combustor, the flame stabilizes within the recirculation zone downstream of the dump plane. The ring shaped PIM is placed on the dump plane of the combustor to alter the flow field in an advantageous manner. Multiple PIM rings of same OD but different ID are stacked together to form various geometric configurations. For each PIM configuration, a parametric study is conducted by varying the atomizing air to liquid mass ratio and heat release rate. Sound pressure levels (SPLs) and CO and NO, emissions are measured for combustion with no PIM and with PIM. Results show that the PIM insert mitigates the combustion noise, and that the converging PIM configuration provides the most noise reduction overall the full frequency range.
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