Effectiveness of vortex generator jets and wall suction on separated flows in serpentine-duct diffuser

The present study describes the effectiveness of different flow control methods applied to a serpentine intake. Due to the geometry of the duct and diffusing nature of flow, the duct performs poorly as an intake, delivering low pressure and distorted air to the compressor. The problem can be alleviated by employing flow control on the duct. In this study, two types of flow control, namely steady vortex generator jets and boundary layer suction, have been applied and detailed measurements carried out. The performance of the duct has been evaluated with respect to static pressure recovery, total pressure loss and circumferential distortion at the exit. The amount of mass flow required to be added or removed for each method is also considered. It was found that the application of suction showed a greater improvement in total pressure recovery and reduction in circumferential distortion intensity compared to vortex generator jets. A combination of suction and vortex generator jets showed an improved performance compared to application of either. The improvements are attributed to reduction in flow separation region due to suction and a decrease in the effect of secondary flow due to vortex generator jets.