Swirl-Counter-Swirl Microjets for the Thermoacoustic Instability Suppression

Problem: -The extent of the flame along the longitudinal axis of the combustor -NOx emissions of the combustor Technology: The invention provides a passive method of mitigating high-amplitude, discrete-frequency, self-sustaining pressure oscillations within a certain window of operating conditions for a swirl stabilized combustor operating in the lean premixed mode. In the current design, fuel and air are mixed upstream of a choke plate, and the flow passes through a swirler before passing through a sudden expansion into the main combustion chamber. Swirl stabilization reduces the extent of the flame, measured along the longitudinal axis, compared to a bluff-body or expansion stabilized flame, allowing for the design of more compact combustors. Lean premixed combustion allows for a significant reduction in NOx emissions, making cleaner, more environmentally friendly combustors feasible. Christopher Noble crn@mit.edu