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Ducted fan inlet/exit and rotor tip flow improvements for vertical lift systems.

机译：改进了垂直提升系统的风道风扇进/出口和转子叶尖流量。

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摘要

The current research utilized experimental and computational techniques in 5" and 22" diameter ducted fan test systems that have been custom designed and manufactured. Qualitative investigation of flow around the ducted fan was also performed using smoke flow visualizations. Quantitative measurements consisted of 2D and 3D velocity measurements using planar and Stereoscopic Particle Image Velocimetry (PIV and SPIV), high resolution total pressure measurements using Kiel total pressure probes and real time six-component force and torque measurements. The computational techniques used in this thesis included a recently developed radial equilibrium based rotor model(REBRM) and a three dimensional Reynolds-Averaged Navier Stokes (RANS) based CFD model.;A radial equilibrium based rotor model (REBRM) developed by the author was effectively integrated into a three-dimensional RANS based computational system. The PIV measurements and computational flow predictions using (REBRM) near the fan inlet plane were in a good agreement at hover and forward flight conditions. The aerodynamic modifications resulting from the fan inlet flow distortions in forward flight regime were clearly captured in 2D PIV results. High resolution total pressure measurements at the downstream of the fan rotor showed that tip leakage, rotor hub separation, and passage flow related total pressure losses were dominant in hover condition. However, the losses were dramatically increased in forward flight because of inlet lip separation and distortion.;A novel ducted fan inlet flow conditioning concept named "Double Ducted Fan" (DDF) was developed. The (DDF) concept has a potential to significantly improve the performance and controllability of VTOL UAVs and many other ducted fan based vertical lift systems. The new concept that will significantly reduce the inlet lip separation related performance penalties used a secondary stationary duct system to control "inlet lip separation" occurring especially at elevated forward flight velocities. The (DDF) is self-adjusting in a wide forward flight velocity range. DDFs corrective aerodynamic in influence becomes more pronounced with increasing flight velocity due to its inherent design properties.;RANS simulations of the flow around rotor blades and duct geometry in the rotating frame of reference provided a comprehensive description of the tip leakage and passage flow in the flow environment of the two ducted fan research facilities developed throughout this thesis. The aerodynamic measurements and results of the RANS simulation showed good agreement especially near the tip region. A number of novel tip treatments based on custom designed pressure side extensions were introduced. Various tip leakage mitigation schemes were introduced by varying the chordwise location and the width of the extension in the circumferential direction. The current study showed that a proper selection of the pressure side bump location and width were the two critical parameters in influencing the success of the tip leakage mitigation approach. Significant gains in axial mean velocity component were observed when a proper pressure side tip extension was used. It is also observed that an effective tip leakage mitigation scheme significantly reduced the tangential velocity component near the tip of the axial fan blade. Reduced tip clearance related flow interactions were essential in improving the energy efficiency and range of ducted fan based vehicle. Full and inclined pressure side tip squealers were designed. Squealer tips were effective in changing the overall trajectory of the tip vortex to a higher path in radial direction. The interaction of rotor blades and tip vortex was effectively reduced and aerodynamic performance of the rotor blades was improved. The overall aerodynamic gain was a measurable reduction in leakage mass flow rate. This leakage reduction increased thrust significantly. Full and inclined pressure side tip squealers increased thrust obtained in hover condition by 9.1 % and 9.6 % respectively. A reduction or elimination of the momentum deficit in tip vortices is essential to reduce the adverse performance effects originating from the unsteady and highly turbulent tip leakage flows rotating against a stationary casing. The novel tip treatments developed throughout this thesis research are highly effective in reducing the adverse performance effects of ducted fan systems developed for VTOL vehicles. (Abstract shortened by UMI.).
机译：当前的研究在定制设计和制造的直径为5“和22”的管道风机测试系统中采用了实验和计算技术。还使用烟气流动可视化技术对风管风扇周围的流动进行了定性研究。定量测量包括使用平面和立体粒子图像测速（PIV和SPIV）进行2D和3D速度测量，使用Kiel总压力探头进行高分辨率总压力测量以及实时六分量力和扭矩测量。本文使用的计算技术包括最近开发的基于径向平衡的转子模型（REBRM）和基于三维雷诺平均Navier Stokes（RANS）的CFD模型。有效地集成到基于RANS的三维计算系统中。在悬停和向前飞行条件下，使用风扇入口平面附近的（REBRM）进行PIV测量和计算流量预测非常一致。在2D PIV结果中清楚地记录了在前向飞行状态下由风扇进气流变形引起的空气动力学变化。风机转子下游的高分辨率总压力测量结果表明，在悬停条件下，叶尖泄漏，转子轮毂分离以及与通道流量有关的总压力损失占主导地位。然而，由于进气口唇缘的分离和变形，损失在前向飞行中显着增加。；开发了一种新型的管道风扇进气流量调节概念，称为“双导管风扇”（DDF）。 （DDF）概念具有显着提高VTOL无人机和许多其他基于管道风扇的垂直举升系统的性能和可控性的潜力。新的概念将大大减少与进气口唇部分离相关的性能损失，该技术使用了辅助固定导管系统来控制“进气口唇部分离”，特别是在前向飞行速度升高时。 （DDF）可在很宽的向前飞行速度范围内进行自我调节。由于其固有的设计特性，DDF的校正空气动力学影响随着飞行速度的增加而变得更加明显。RANS对旋转叶片周围流动和参考几何结构中管道几何形状的RANS模拟提供了对叶尖泄漏和通道流动的全面描述。贯穿本论文开发的两个管道风机研究设施的流动环境。空气动力学测量和RANS模拟的结果显示出很好的一致性，尤其是在尖端区域附近。引入了许多基于定制设计的压力侧延伸的新型尖端治疗。通过改变弦向位置和延伸部在周向上的宽度，引入了各种尖端泄漏缓解方案。当前的研究表明，正确选择压力侧凸块的位置和宽度是影响尖端泄漏缓解方法成功与否的两个关键参数。当使用适当的压力侧尖端延伸时，观察到轴向平均速度分量的显着增加。还观察到有效的叶尖泄漏缓解方案显着减小了轴向风扇叶片叶尖附近的切向速度分量。减少与叶尖间隙相关的流动相互作用对于提高基于管道风扇的车辆的能源效率和航程至关重要。设计了全压力和倾斜压力侧吸嘴。剥皮器尖端可有效地将尖端涡旋的整体轨迹更改为沿径向的更高路径。有效地减少了转子叶片与尖端涡旋的相互作用，并改善了转子叶片的空气动力学性能。总的空气动力学增益是泄漏质量流率的可测量的降低。这种泄漏减少明显增加了推力。满载和倾斜的压力侧吸嘴在悬停状态下获得的推力分别增加了9.1％和9.6％。减小或消除尖端涡旋中的动量不足对于减少源于相对于固定壳体旋转的不稳定且高度湍流的尖端泄漏流产生的不利性能影响至关重要。在整个论文研究中开发出的新型尖端处理方法在减少为VTOL车辆开发的管道风扇系统的不利性能影响方面非常有效。 （摘要由UMI缩短。）。

著录项

  • 作者

    Akturk, Ali.;

  • 作者单位

    The Pennsylvania State University.;

  • 授予单位 The Pennsylvania State University.;
  • 学科 Engineering Aerospace.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 260 p.
  • 总页数 260
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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