Cesare Hall

New propulsion system configurations have the potential to deliver significant reductions in aircraft emissions and fuel consumption. However, there are numerous technical challenges to their development. My research is aimed at overcoming the challenges that involve turbomachinery aerodynamics. The open rotor is a configuration of jet engine in which a gas turbine core drives a pair of counter-rotating propellers. A key issue is their noise generation. Recent research has developed new methods and improved our understanding of the aerodynamic features that influence open rotor performance and noise. Current studies include open rotor design and operation, and engine-airframe installation effects. Boundary Layer Ingestion (BLI) involves taking the low momentum viscous flow adjacent to the surface of an aircraft and reenergising it within the engine. This leads to more efficient propulsion. The difficulty is designing a propulsion system that can ingest highly non-uniform flow without suffering large losses in performance. Research using a low speed fan rig has identified the details of how boundary layer ingestion impacts fan efficiency. The effects on fan operability and aeromechanical forcing are also being studied. More conventional turbofan engines are moving to higher and higher bypass ratios. This means that the engine fans are larger and potentially more susceptible to particular operational problems. Research is underway into the design and performance of these fan systems.