Designing Low Pressure Turbines for Optimized Airfoil Lift
Designing Low Pressure Turbines for Optimized Airfoil Lift
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DOI：
10.1115/1.3148476
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发表时间：
2010-07
影响因子：
1.7
通讯作者：
J. Gier;M. Franke;N. Hübner;T. Schröder
中科院分区：
文献类型：
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作者：
J. Gier;M. Franke;N. Hübner;T. Schröder
在过去的10-15年里，人们一直在努力提高翼型升力，特别是在航空发动机低压涡轮中。这是有吸引力的，因为增加的翼型升力可以用于翼型数量减少，导致重量和硬件成本降低。因此，这项工作的挑战是保持高效率。根据翼型升力的基线水平，已经实现了20-50%的增加，并且至少部分地纳入现代涡轮机设计中。就效率而言，实际上存在一个最佳的翼型升力水平。升力水平低于此最佳值的翼型排会受到过多翼型的影响，这些翼型具有太多的润湿表面，特别是增加了后缘损失。由于翼型排内的高峰马赫数、翼型吸力面上较高的后部扩散和增加的二次流损失，升力水平高于该最佳值的翼型遭受不断增加的损失。由于燃料成本显著上升，以及人们对二氧化碳环境影响的认识，设计低压涡轮机以实现效率和重量之间的最佳权衡以实现最低的发动机燃料燃烧变得越来越重要。本文总结了最近和过去所做的工作，以解决翼型升力水平的主要影响和机制，相对于损失和效率作为确定最佳翼型升力选择的基础。
In the past 10-15 years, substantial effort has been spent on increasing the airfoil lift especially in aero-engine low pressure turbines. This has been attractive, since increased airfoil lift can be used for airfoil count decrease leading to weight and hardware cost reduction. The challenge with this effort consequently has been to keep the efficiency at high levels. Depending on the baseline level of airfoil lift, an increase of 20-50% has been realized and at least partly incorporated in modern turbine designs. With respect to efficiency there is actually an optimum level of airfoil lift. Airfoil rows at a lift level below this optimum suffer from an excessive number of airfoils with too much wetted suface and especially increasing trailing edge losses. Airfoils at lift levels above this optimum suffer from growing losses due to high peak Mach numbers inside the airfoil row, higher rear diffusion on the airfoil suction sides, and increased secondary flow losses. Since fuel cost have been rising significantly, as has been the awareness of the environmental impact of CO 2 , it becomes more and more important to design low pressure turbines for an optimal trade between efficiency and weight to achieve the lowest engine fuel burn. This paper summarizes work done recently and in the past to address the main influences and mechanisms of the airfoil lift level, with respect to losses and efficiency as a basis for determination of optimal airfoil lift selection.