A one metre diameter, four stage model of a high pressure steam turbine has been rebladed with blades designed using 3-D flow calculations. The objective is to reduce the endwall losses and hence increase the efficiency. The resulting blades are highly three-dimensional in shape and give a substantial increase in efficiency compared with the previous design based on state-of-the-art two-dimensional blading. Measurements of the detailed steady and unsteady flow pattern in the turbine have been obtained. The current project on this turbine involved applying the same ideas to a more highly loaded design with emphasis on exploiting the unsteady effects in the flow. This project is supported by Siemens Power Generation, UK Ltd

John Denton (Carmen Kachel)

The I P Turbines of most Rolls-Royce engines have very low aspect ratio stator combined with a high aspect ratio rotor. This gives rise to very strong secondary flows in the stator which then interact in an unsteady manner with the rotor. A full scale (1.2m diameter) low speed model of an I P turbine has been built and is being used to study the flow in such machines. Both time averaged and unsteady flow measurements are being made and are being compared to steady and unsteady 3D CFD solutions. The objective is to understand the extra loss generated by the unsteady flows and to redesign the turbine to try to reduce this.

John Denton, Eric Curtis Graham Pullan

3D flow calculations are being used to investigate new designs of fan blading for large aero engines. Features such as blade sweep and lean are being investigated as well as the detailed choice of blade profiles and hub and casing shapes. As part of a collaborative European project (RESOUND), efforts are directed at designing fans with reduced noise generation.

John Denton, Liping Xu