Browsing by Author "Bailey, Justin Mark"

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    Full Scale Experimental Transonic Fan Interaction with a Boundary Layer Ingesting Total Pressure Distortion
    Bailey, Justin Mark (Virginia Tech, 2017-01-05)
    Future commercial transport aircraft will feature more aerodynamic architectures to accommodate stringent design goals for higher fuel efficiency, reduced cruise and taxi NOx emissions, and reduced noise. Airframe designs most likely to satisfy the first goal feature architectures that lead to the formation of non-uniform flow introduced to the engine through boundary layer ingesting (BLI) inlets, creating a different operational environment from which the engines were originally designed. The goal of this study was to explore the effects such non-uniform flow would have on the behavior and performance of a transonic fan in a full scale engine test environment. This dissertation presents an experimental study of the interaction between a full scale transonic fan and a total pressure distortion representative of a boundary layer ingesting serpentine inlet. A five-hole pneumatic probe was traversed directly in front of and behind a fan rotor to fully characterize the inlet and outlet fan profile. The distortion profile was also measured at the aerodynamic interface plane (AIP) with an SAE standard total pressure rake, which has historically been accepted as the inlet profile to the fan. This provided a comparison between the present work and current practice. Accurate calculation of local fan performance metrics such as blade loading, pressure rise, and efficiency were obtained. The fan inlet measurement profile greatly enhanced the understanding of the fan interaction to the flow distortion and provided a more complete explanation of the fan behavior. Secondary flowfield formation due to the accelerated flow redistribution directly upstream of the fan created localized bulk co- and counter- rotating swirl regions that were found to be correlated with localized fan performance phenomena. It was observed that the effects of the distortion on fan performance were exaggerated if the assumed fan inlet profiles were data taken only at the AIP. The reduction in fan performance with respect to undistorted inlet conditions is also explored, providing insight into how such distortions can be compared to baseline conditions. The dissertation closes with several recommendations for improving distortion tolerant fan design in the context of experimental research and development.
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    The Influence of Development and Fan/Screen Interaction on Screen-Generated Total Pressure Distortion Profiles
    Bailey, Justin Mark (Virginia Tech, 2014-02-03)
    The rising interest in fan performance in the presence of total pressure distortion, a topic of fundamental interest for integrated airframe/engine architectures, has led to increased research in ground based testing environments. Included in these studies is the generation of simulated total pressure distortion profiles using wire mesh screens. Although the inlet duct development of total pressure distortion patterns has been studied in a historical context when distortion effects on engine performance were first of interest, these were typically simplified experimental studies for low-speed flows. To aid in the understanding of total pressure distortion development approaching a transonic fan face, a series of experiments were conducted to detail the development of such a profile downstream of the screen plane in the absence and presence of fan effects. Presented is an extensive experimental set to detail (1) the evolution of a screen-generated total pressure distortion profile as it develops in a constant diameter inlet duct and (2) the effect that a single stage transonic fan has on the distortion development. Included is a detailed analysis of the distortion profile characteristics for increasing development length, and the behavioral changes of the profile when fan blockage is present near the screen plane. Recommendations are made regarding the placement of total pressure distortion screens relative to the fan face, and insights are given into the expected profile evolution. This work is a contributing part of an ongoing systematic investigation of fan performance when subjected to screen-generated total pressure inlet distortion.