In order to make cleaner aircraft engines, there is a drive to have lower pollutant levels. This requires aero gas turbine engines to operate in fuel-lean conditions, which lead to unwanted large-amplitude flow oscillations in the combustion chamber. The oscillations are catastrophic to the engine components, leading to sudden failure or reduction in their working life. These oscillations are sustained by the energy produced during the combustion process. In our lab, we focus to understand and therefore devise control methods to mitigate or reduce these combustions-driven oscillations. In this process, we also find a way to reduce the noise emitted by the engine.
We are also working on the development of advanced low pollutant emission combustors in which fuel and air are injected as high-velocity jets. These combustors do not have conventional swirlers and the combustion is stabilized by a carefully tailored flow field, controlled product gas recirculation, and rapid mixing of fuel/oxidizer inside the combustor. Novel flow field configurations have been tested for operation with both gaseous and liquid fuels and ultra-low NOx and CO emissions have been demonstrated under laboratory conditions.
We along with our students perform investigations in our in-house developed test rigs, which are instrumented with state of art measuring instruments. Our study is mainly focused to understand the fundamental mechanism, causing the combustion-driven oscillations and mitigation of pollutants emissions. We perform experiments in a wide variety of configurations, starting from a simple Bunsen-type burner to a realistic gas turbine type annular combustor and novel combustor configurations. We also have a strong team performing numerical investigations to support our experimental findings.
Overall our lab focuses on the development of next-generation cleaner and quieter combustors.