Axial compressor research
- Axial compressor research (text version)
Steamlines showing the interaction betwen circumferential casing groove and flow in the blade tip region.
Axial compressors in gas turbines and aeroengines suffer from rotating stall at low mass flow and can cause a catastrophic drop in pressure ratio. Stall margin improvement studies investigate ways to enhance the ‘stability range’ either through active or passive means so that the engine can operate safely throughout its mission cycle.” Dr Vasudevan Kanjirakkad
Senior Lecturer in Experimental Thermofluid Mechanics
Rotating stall results from an instability of the compression stage or blade row at flow rates below a critical value (peculiar to each compressor). It is usually caused by a build-up of blockage within the blade passage. In many compressors the rotor blade tip region where the tip leakage flow or the tip leakage vortex causes a regions of low momentum fluid (or blockage) as the compressor pressure ratio is increased (and mass flow is reduced) during its operation. It is possible to alleviate the blockage by implementing active or passive casing treatment features.
In the present study the use of optimised circumferential grooves (due to their simplicity) is explored for improving ‘stall margin’, i.e., to extend safe operability of the compressor to lower mass flow regimes while still producing useful pressure rise. The optimisation is conducted using a physics-based parameter with the aid Machine Learning tools. Both experimental and computational work is undertaken both to understand the physics and to validate the concept.