Wang Hejian, Liu Bo, Mao Xiaochen, Zhang Botao, Yang Zonghao
School of Power and Energy, Northwestern Polytechnical University, Xi'an 710129, China.
The National Key Laboratory of Science and Technology on Aerodynamic Design and Research, Xi'an 710129, China.
Entropy (Basel). 2022 Apr 19;24(5):570. doi: 10.3390/e24050570.
To comprehensively control the corner separation and mid-span boundary layer (BL) separation, this study proposed and evaluated two new flow control configurations. One is a slotted configuration composed of blade-end and whole-span slots, and the other is a combined configuration with end-wall BL suction and whole-span slot. Additionally, the adaptability of the combined configuration to the lower blade solidity (c/t) condition was verified. The results indicate that both the slotted configuration and combined configuration can eliminate the mid-span BL separation, but a better reduction in the corner separation can be observed in the combined configuration. The two configurations can remove the concentrated shedding vortex and reduce the passage vortex (PV) for the datum cascade, but the wall vortex (WV) will be generated. By contrast, the combined configuration has weaker WV and PV than the slotted configuration, which contributes to further reducing the corner separation. In the combined configuration with a c/t of 1.66 and 1.36, the total pressure loss is reduced by 38.4% and 42.1%, respectively, on average, while the averaged static pressure rise coefficient is increased by 16.2% and 17.6%, respectively. This is advantageous for enhancing the working stability and pressure diffusion capacity for compressors. Besides this, the combined configuration with lower c/t can achieve a stronger pressure diffusion capacity and smaller loss than the higher c/t datum cascade. Therefore, the combined configuration is advantageous to the improvement of the aero-engine thrust-to-weight ratio through decreasing the compressor single-stage blade number.
为了全面控制角区分离和叶展中部边界层（BL）分离，本研究提出并评估了两种新的流动控制构型。一种是由叶尖缝隙和全叶展缝隙组成的开槽构型，另一种是端壁边界层抽吸与全叶展缝隙相结合的组合构型。此外，还验证了组合构型对较低叶片稠度（c/t）工况的适应性。结果表明，开槽构型和组合构型都能消除叶展中部边界层分离，但组合构型对角区分离的抑制效果更好。这两种构型都能消除基准叶栅的集中脱落涡并减少通道涡（PV），但会产生壁面涡（WV）。相比之下，组合构型的壁面涡和通道涡比开槽构型弱，这有助于进一步减少角区分离。在叶片稠度c/t为1.66和1.36的组合构型中，总压损失平均分别降低了38.4%和42.1%，而平均静压升系数分别提高了16.2%和17.6%。这有利于提高压气机的工作稳定性和压力扩散能力。除此之外，叶片稠度较低的组合构型比叶片稠度较高的基准叶栅具有更强的压力扩散能力和更小的损失。因此，组合构型有利于通过减少压气机单级叶片数来提高航空发动机的推重比。
