A Large-Scale Facility for Investigation of Intermediate Turbine Ducts: Design, Implementation and Initial Tests

Licentiatavhandling, 2006

Intermediate turbine ducts are used in modern multi-spool jet engines for guiding the flow from the high-pressure turbine to the low-pressure turbine. The demand for lighter, more efficient and more environmentally friendly aircraft engines requires the new jet engines to have higher by-pass ratios. This leads to a demand on the intermediate turbine ducts to be more "aggressive", i.e. to have larger radial offset, and to be shorter and more diffusing. Unfortunately the flow phenomena that occur in such ducts are both complicated and poorly understood, and current numerical tools are of limited value. Therefore, in order to make these ducts more aggressive, a better understanding of the flow inside intermediate turbine ducts is necessary. As part of an effort to overcome this problem a new, large-scale, low-speed turbine facility has been design and constructed at Chalmers University of Technology. This thesis describes the design of the facility, with an emphasis on the intermediate turbine duct section. The design is based on general guide-lines for low-speed wind tunnels together with CFD and FEA. The facility is expected to provide detailed understanding of the flow physics within these intermediate turbine ducts, as well as provide high-quality data for validation of numerical simulations. This thesis also contains initial measurements used for implementation of the measurement techniques to the facility.