Accession Number : ADA608202


Title :   Unsteady Aerodynamic Interaction in a Closely Coupled Turbine Consistent with Contra-Rotation


Descriptive Note : Interim rept. 4 Aug 2012-4 Aug 2014


Corporate Author : AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AEROSPACE SYSTEMS DIR


Personal Author(s) : Ooten, Michael K ; Clark, John P ; Anthony, Richard ; Lethander, Andrew


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a608202.pdf


Report Date : Aug 2014


Pagination or Media Count : 167


Abstract : A significant design concern for turbomachinery parts is forced vibrational response due to unsteady pressure fields. Shortened component lives, increased maintenance costs, and catastrophic engine failure can result due to unmitigated vibrational stresses. Geometry changes, increased airfoil count and wall thickness, and the inclusion of damping systems are a few of the current strategies employed by designers in order to move modal frequencies out of the engine running range or reduce the vibrational stresses on the airfoil. However, these techniques have a negative impact on performance, system weight, and/or life cycle cost. The focus of the study presented here was to investigate the reaction between the blade and downstream vane of the stage-and-a-half High Impact Technologies (HIT) Research Turbine via CFD analysis and experimental data. Code Leo?a Reynolds-Averaged Navier-Stokes (RANS) flow solver with the two-equation Wilcox 1998 k-ω turbulence model?was used as the numerical analysis tool for comparison for all of the experiments conducted, which includes two- and three-dimensional geometries and both time-averaged and time-accurate simulations. The rigorous blade and downstream vane interaction study was accomplished by first testing the midspan and quarter-tip two-dimensional geometries of the blade in a linear transonic cascade. The effects of varying the incidence angle and pressure ratio on the pressure distribution were captured both numerically and experimentally. This was used during the stage-and-one-half post-test analysis to confirm that the target corrected speed and pressure ratio were achieved. Then, in a full annulus facility, the first vane itself was tested in order to characterize the flow field exiting the vane that would be provided to the blade row during the rotating experiments. Finally, the full stage-and-a-half Research Turbine was tested in the full annulus cascade with a data resolution not seen in any studies to date.


Descriptors :   *AERODYNAMICS , *TURBINES , *TURBOMACHINERY , AIRFOILS , ANGLE OF INCIDENCE , BLADES , CATASTROPHIC CONDITIONS , CODING , COMPARISON , CONSISTENCY , CORRECTIONS , COSTS , COUNTING METHODS , COUPLING(INTERACTION) , DAMPING , ENGINES , EXPERIMENTAL DATA , FACILITIES , FAILURE , FLOW FIELDS , GEOMETRY , IMPACT , LIFE CYCLE COSTS , MAINTENANCE , MEAN , MODELS , NUMERICAL ANALYSIS , PARTS , PRESSURE , PRESSURE DISTRIBUTION , RATIOS , REDUCTION , RESOLUTION , RESPONSE , ROTATION , STRATEGY , STRESSES , TARGETS , TEST AND EVALUATION , TOOLS , TURBULENCE , VELOCITY , VIBRATION , WALLS , WEIGHT


Subject Categories : Hydraulic and Pneumatic Equipment


Distribution Statement : APPROVED FOR PUBLIC RELEASE