Preliminary Aerodynamic Design of a Fan Stage for an Ultra High Bypass Ratio Engine
Preliminary Aerodynamic Design of a Fan Stage for an Ultra High Bypass Ratio Engine
复制标题
超高涵道比发动机风扇级的初步空气动力学设计
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
D. Giesecke
中科院分区：
文献类型：
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作者：
D. Giesecke;J. Friedrichs;D. Giesecke
在880协调研究中心（Sonderforschungsbereich 880）的框架内，正在开发一种环境友好型未来支线飞机的基本原理。因此，必须为目标参考飞机任务设计一种涵道比为17的发动机，从而提高推进效率。对于这类超高涵道比发动机，为了减少大进气道带来的不利的粘滞阻力影响，进气道的长度将会减小。在此背景下，将发动机安装位置选择在机翼上方，以达到一定的噪声屏蔽效果和来流矫直效果。为了研究流入情况和相互作用，必须开发一个合适的跨音速扇级。本文描述了从飞机规格到发动机性能模型和初步风扇级设计的设计过程。风机级的初步设计程序依赖于等熵简单径向平衡方程。叶片截面为三次厚度分布的抛物线平均值。在设计过程中，特别注意了超声速流接近旋翼前缘时产生的复杂激波结构。激波结构与所选择的入射角密切相关。首先，87%的峰值等熵效率与一个大的进出口管道实现。其次，数值模拟表明，在设计点，通过切断进口管道，使用隔离的短舱流动可以将等熵效率提高到近88%。总而言之，数值验证显示与设计规范一致的结果，因此，使用的方法。对翼上安装发动机的进一步流入调查将是正在进行的研究项目的一部分。
In the framework of the Coordinated Research Centre 880 (Sonderforschungsbereich 880) the fundamentals of an environmental friendly future regional aircraft are being developed. Therefore, an engine with a bypass ratio of 17 for the target reference aircraft mission has to be designed resulting in an increased propulsive efficiency. In order to reduce the adverse viscous drag effects of a large intake for such ultra high bypass ratio engines, the intake will be reduced in its length. With this background, the engine installation position was chosen above the wing to realize some noise shielding effects as well as inflow straightening effects. To investigate the inflow situation and interaction a suitable transonic fan stage has to be developed. The paper describes the design process starting from aircraft specifications to an engine performance model and a preliminary fan stage design. The preliminary fan stage design procedure relies on the isentropic simple-radial equilibrium equation. The blade sections are parabolic mean lines with cubic thickness distributions. During the design process special attention has been drawn on the supersonic flow approaching the rotor leading edge resulting in a complex shock structure. The shock structure goes hand-in-hand with the incidence chosen. Firstly, a peak isentropic efficiency of 87 percent was achieved with a large inand outlet duct. Secondly, numerical simulations using isolated nacelle flow by cutting away the inlet duct show an increase in isentropic efficiency to almost 88 percent at design point. To summarize, numerical verifications show consistent results with the design specification and hence, methodology used. Further inflow investigations in case of the on-wing mounted engine will be part of the on-going research project.