Use of swirl for flow control in propulsion nozzles
Use of swirl for flow control in propulsion nozzles
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DOI：
10.2514/3.23238
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发表时间：
1990-03
影响因子：
1.9
通讯作者：
K. Knowles;P. Carpenter
中科院分区：
文献类型：
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作者：
K. Knowles;P. Carpenter
在某些非设计条件下，需要改变涡轮风扇推进喷嘴的有效面积，例如，以帮助部件匹配或减少接近时的风扇噪音。有人建议，与涡流相关的质量通量减少可用于实现这种变化。本文解决了旋流是否可以实现所需的质量通量减少以及是否可以以最小的推力损失来实现这一问题。采用准圆柱理论对旋流流进行了分析，并与变面积喷嘴进行了具体案例的比较。对于高涵道比 (BPR = 12) 的低比推力发动机，使用涡流无法实现所需的风扇喷嘴质量通量降低，并且在任何情况下，涡流都会比可变面积喷嘴提供更快的风扇喷嘴质量通量推力衰减率。对于 BPR -4 的涵道风扇，通过旋流可实现核心喷嘴质量通量减少 10%，推力损失比使用可变面积喷嘴略小。然而，旋流轮廓需要仔细优化。
In certain off-design conditions it is desirable to vary the effective area of turbofan propulsion nozzles, e.g., to aid component matching or to reduce fan noise on approach. It has been suggested that the mass flux reductions associated with swirl could be used to achieve such variations. This paper addresses the questions of whether swirl can achieve the required mass flux reductions and whether this can be done with minimal thrust losses. A quasicylindrical theory is used to analyze the swirling flow, and comparisons are made with variablearea nozzles for specific case studies. For a low-specific thrust engine of high bypass ratio (BPR = 12) the required fan nozzle mass flux reduction cannot be achieved using swirl, and in any case, swirl gives a far faster rate of decay of thrust with fan nozzle mass flux than does a variable-area nozzle. For a ducted fan of BPR -4, a 10% reduction in core nozzle mass flux can be achieved with swirl for slightly less thrust loss than with a variable-area nozzle. The swirl profile, however, needs to be carefully optimized.