Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Entire DC Network
Design And Implementation Of Periodic Unsteadiness Generator For Turbine Secondary Flow Studies, Nathan James Fletcher
Design And Implementation Of Periodic Unsteadiness Generator For Turbine Secondary Flow Studies, Nathan James Fletcher
Browse all Theses and Dissertations
A primary source of periodic unsteadiness in low-pressure turbines is the wakes shed from upstream blade rows due to the relative motion between adjacent stators and rotors. These periodic perturbations can affect boundary layer transition, secondary flow, and loss generation. In particular, for high-lift front-loaded blades, the secondary flowfield is characterized by strong three-dimensional vortical structures. It is important to understand how these flow features respond to periodic disturbances. A novel approach was taken to generate periodic unsteadiness which captures some of the physics of turbomachinery wakes. Using stationary pneumatic devices, pulsed jets were used to generate disturbances characterized by …
Aerodynamics Of Fan Blade Blending, Clint J. Knape
Aerodynamics Of Fan Blade Blending, Clint J. Knape
Browse all Theses and Dissertations
Blending is a method of fan and compressor blade repair. The goal of the blending process is to remove stress concentration points such as cracks and nicks along the leading, trailing, or tip edges of the blade. The stressed areas are typically removed by grinding or cropping away the surrounding material. For integrally bladed rotor (IBR) disks, repairing a damaged blade is much more economical than replacing the entire disk. However, the change in shape of the blade will change the local aerodynamics and result in mistuning, both structurally and aerodynamically. In a worst case scenario, the change in the …
Using Cfd To Improve Off-Design Throughflow Analysis, Troy J. Lanchman
Using Cfd To Improve Off-Design Throughflow Analysis, Troy J. Lanchman
Browse all Theses and Dissertations
In turbomachinery design, complex internal flows give rise to significant losses and blockage whose effects are difficult to properly analyze without detailed computational fluid dynamics (CFD) methods or experiments. In a typical design method, CFD is used in conjunction with simpler throughflow or cascade codes to hasten the process. However, the lesser physical accuracy of the design codes demands the inclusion of models to improve the accuracy of the throughflow codes. This thesis aims to use CFD data to generate improved loss and blockage models for a 2D compressor throughflow code by matching throughflow data to CFD data using optimizations. …
Unsteady Effects Of A Pulsed Blowing System On An Endwall Vortex, Molly Hope Donovan
Unsteady Effects Of A Pulsed Blowing System On An Endwall Vortex, Molly Hope Donovan
Browse all Theses and Dissertations
The low-pressure turbine is an important component of a gas turbine engine, powering the low-pressure spool which provides the bulk of the thrust in medium- and high-bypass engines. It is also a significant fraction of the engine weight and complexity as it can comprise up to a third of the total engine weight. One way to drastically reduce the weight of the low-pressure turbine is to utilize high lift blades. To advance high-lift technology, the Air Force Research Laboratory (AFRL) designed the L2F blade profile, which was implemented in the linear cascade at AFRL/RQT’s low speed wind tunnel facility. The …