Efficient propulsion – cost and environmental savings
In order to improve the computational fluid dynamics (CFD) modelling methods used in the design of HP turbines, one must understand the complex aero-thermal phenomena generated in turbines. The EU-funded ‘Turbine aero-thermal external flows 2’ (TATEF2) project was undertaken to study the most important external air and heat flows, to create a database enabling improved CFD methods and thus to optimise the design process for increased efficiency with reduced cost and risk of failure. First, the researchers evaluated aero-thermal efficiency and losses related to inlet temperature distortion and inlet air swirling effects. They extended this with a study enabling high confidence measurements of overall HP turbine efficiency for the first time and were able to determine the main cause of turbine loss. Furthermore, they carried out fundamental film cooling studies with powerful optical infrared thermography techniques, enabling excellent thermal and local resolution not previously possible. The studies also led to the creation of two databases of aero-thermal performance characteristics of a cooling film to validate CFD methods and extend understanding of flow physics. Finally, the investigators improved CFD code based on the previous studies, enhancing calculations for both turbulence and heat transfer, the latter of which decreased computation time by one third. In summary, the TATEF2 project resulted in better understanding of the complex aerodynamics and heat transfer in basic film cooling and of HP turbine stage behaviour, which led to significant improvements in CFD modelling methods. In addition to better performance of aero-engines, implementation of the results should decrease the environmental impact of air transportation that currently contributes significantly to global warming. Greener air travel is good for consumers, good for industry and good for the planet.
