Vienna University of Technology/AT
The main objective in the design of modern turbomachinery is to achieve high efficiencies at a broad operating range at minimum total costs. Within this context, flow control has the potential for significant impact on the performance of modern turbomachinery. The definition of flow control is the use of a small modification to change the behaviour of the main flow. This modification can be realised without (passive flow control) or with an external source (active flow control). Furthermore, this adjustment can be established by an actuator which is part of a control loop together with an appropriate sensor (reactive flow control). Typical examples for flow control are passive or active compressor stability enhancement methods, like tip injection or casing treatment. Endwall contouring in high-pressure turbines and boundary layer control in low-pressure turbines are typical examples for flow control to reduce endwall or profile losses. Finally, turbomachinery noise can be reduced by controlling the behaviour of blade wakes at stator-rotor interaction. Computational fluid dynamics (CFD) has become an important tool in the design and optimisation process of turbomachinery flow control systems. The main challenges on the CFD methods are great differences in geometry length scales in the order of two magnitudes. Furthermore, the inherently unsteady turbomachinery flow can be laminar, turbulent or even transitional. Frequently, Mach numbers are high enough that compressibility effects play an important role.
The objective of this Mini-Symposium is to present recent advancements on CFD in turbomachinery flow control. The main focus is on the development and application of approaches to capture the complex physics arising from turbomachinery flow control in a realistic manner.