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Leonard D.J.,Pennsylvania State University | Lindau J.W.,Applied Research Laboratory Penn State
ASME/JSME/KSME 2015 Joint Fluids Engineering Conference, AJKFluids 2015 | Year: 2015

Steady-periodic multiphase Computational Fluid Dynamics (CFD) simulations were conducted to capture cavitation breakdown in a Francis hydroturbine due to largescale vaporous structures. A reduced-scale model and a full-scale prototype were investigated to display differences in vapor content and machine performance caused by lack of Reynolds and Froude similarity. The model scale efficiencies compared favorably (within 3%) to the experimental cavitation tests. The CFD model and prototype displayed distinct qualitative and quantitative differences as σ was reduced. A stage-by-stage analysis was conducted to assess the effect of cavitation on loss distribution throughout the machine. Furthermore, a formal mesh refinement study was conducted on efficiency and volume of vapor, with three mesh levels and Richardson extrapolation, to ensure convergence. © Copyright 2015 by ASME.

Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase I | Award Amount: 99.96K | Year: 2005

The proposed research would be a collaborative effort combining the gear testing expertise of Penn State's Gear Research Institute with the modeling and alloy design expertise of QuesTek Innovations. Engineers from the V22 manufacturer, Bell Helicopter, would be consulted to establish the desired property gradients in the designed alloy for improving the endurance of power transmissions built by Bell Helicopter. An increased strength of the core material will allow for increased power density compared to the existing gear alloys, and increased core toughness will provide improved damage tolerance. A new alloy will be designed to meet these criteria, and a 30 lb VIM/VAR prototype ingot will be produced. The core hardness, strength, and impact toughness of the prototype material will be measured. A preliminary carburization cycle will be developed during the phase I base and option programs using simulations. The contact fatigue resistance of a similar proprietary gear steel, C61, will be tested at Penn State to evaluate the rolling/sliding contact fatigue resistance of an alloy with an improved fatigue resistant microstructure during the phase I option program.

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