Work Package 5

Heat Transfer in Turbine Interducts
WP5 is focused on heat-transfer in turbine interducts, that is the ducts used to connect the high and lowpressure turbines. These interducts are subjected to very high heat-loads and it is often necessary to cool them or equip them with heat-resistant shields etc. A better understanding of the heat-transfer in these ducts would allow companies to reduce cooling requirements and/or to use cheaper materials. This, in turn, would of course increase the overall turbine performance and reduce costs.

The FP6 project AIDA, which started in February 2004, will develop and validate a new class of aggressive turbine interducts. It will also look a novel techniques like passive flow control devices (riblets etc.) to avoid separation in “super-aggressive” ducts. In order to use these new ducts in future engines it is also necessary to have a good knowledge about the heat-loads they are subjected to. However, AIDA only addresses the aerodynamic properties of these new ducts. By using the existing test-rigs from AIDA for heat-transfer measurements in the AITEB-2 project, it would be possible to relatively cheaply also address the essential heat-transfer aspects of this new class of aggressive turbine interducts and to therefore cover this important aspect of an enabling technology for future high by-pass ratio aero engines.

The main objectives of the work in WP5 are to:
  • Create an experimental database of heat-transfer in turbine interducts using the large-scale lowspeed test-rig built within AIDA. This rig includes a turbine upstream of the duct in order to create realistic inflow conditions into the duct.
  • Gain increased understanding of the mechanisms affecting duct heat-transfer by studying:
    • The flow-physics in these ducts and how this influences the heat transfer
    • Effects from up-stream components (transient wakes, vortices...)
    • Influence from inlet swirl
    • Effects from cooling/purge/leakage flows in the duct or upstream of the duct
    • Effects from secondary flows and struts/vanes in the duct
    • Influence from vanes downstream of the duct
  • Develop and validate design correlations for heat-transfer in turbine interducts
  • Develop and validate detailed analysis methods based on CFD
  • Assess impact on heat-transfer from novel designs like ducts with passive flow-control devices.