Turbine Design to Mitigate Forcing (POSTPRINT)
Technical paper 9 Jun 2011-19 Sep 2012
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AEROSPACE SYSTEMS DIR
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A demonstrated ability to make accurate flowfield predictions leads to the possibility of controlling levels of unsteadiness through aerodynamic design. Here the physics of the flowfield that gives rise to unsteady interaction in a stage-and-one-half experimental high pressure turbine designed at AFRL is discussed with reference to available codevalidation data. Then, several design techniques are applied either to reduce the magnitude or alter the phase of unsteady interactions within the turbine in order to mitigate aerodynamic forcing. These include the shaping of both the rotating and stationary airfoil profiles as well as a novel flow-control method that involves steady blowing from the pressure side of the downstream stationary airfoil row. In addition, the effects of downstream vane asymmetric spacing and vane-tovane clocking are also assessed. While at present the application of these concepts to the turbine in question is strictly analytical, experimental validation of many of these methods to reduce unsteadiness is now underway in a full-scale rotating, transonic turbine experiment at AFRL.
- Fluid Mechanics