Investigation of peripheral vortex reverse flow (PVRF) combustor for gas turbine engines

Abstract

In a reverse flow combustor air is injected from the exit side so that the bulk gas flow reverses its direction while exiting the combustor. In the combustor investigated here, a dominant peripheral vortex away from the exit is stabilized by carefully choosing the location of the air jet. Combustion is stabilized due to internally recirculated hot product gases in this peripheral vortex. The fuel is injected in the peripheral vortex region at high velocity and rapid mixing of injected fuel with the oxidizer results in avoidance of hot spot regions and leads to overall lean combustion and low pollutant emissions. Due to reverse flow geometry, along with the presence of the peripheral vortex, favourable residence time distribution of gases is achieved (shown numerically). This resulted in lower CO emissions (confirmed experimentally). In the non-premixed mode, fuel injection port is either placed on the exit/air port side (named as RS configuration) or on the opposite side of the exit/air port (named as RO configuration). The combustor operating in RO configuration displayed wider lean operational limit, and lower CO emissions as compared to the RS configuration, while NOx emissions were almost same in both the cases.