Non-axisymmetric endwall profiling in a highly loaded compressor cascade

Cao, Zeyuan; Liu, Bo; Zhang, Ting; Xu, Yibing; Zhao, Hao

doi:10.1177/0957650918786148

Cited by 9 publications

(5 citation statements)

References 22 publications

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“…Liu 14 and Li 15 found that the groove near the leading edge mostly influenced the adverse pressure gradient and improved the compressor performance. Cao 16 proposed that the CEW introduced an increased spanwise inward pressure gradient, which was beneficial to the performance. Besides, Dorfner 17 optimized the endwall of a linear compressor and found that the groove structure upstream of the leading edge of the blade acted as an aerodynamic separator.…”

Section: Introductionmentioning

confidence: 99%

Influence of the inlet boundary layer on non-axisymmetric endwall contouring effects in a linear compressor cascade

Teng

Zhu

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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The modern aero-engine compressors are commonly designed to be highly loaded which can introduce strong three-dimensional flow separation, and effective flow control is of vital importance in improving compressor performance. Non-axisymmetric endwall contouring nowadays is conducted on axial compressors to control the flow separation. In this paper, contoured endwall is designed based on a linear CDA compressor cascade. The Genetic Algorithm and ANN surrogate model are used in the optimization process of the hub contouring, based on RANS simulations. Three inlet boundary layers which follow the fully turbulent boundary layer assumption are generated with different thickness and the influence mechanism are numerically investigated. The optimal endwall with streamwise concave near suction side provides great performance improvement at all inlet boundary layers at the aerodynamic design point. The endwall flow near the suction side is accelerated by the contoured endwall with cross-flow pressure gradient altered, suppressing the corner separation. The main pressure loss is closely related to one streamwise vortex that blocks the endwall flow. Thicker inlet boundary layer can induce early forming and increased strength of the streamwise vortex, enhancing the cross-flow movement and its interaction with the blade surface flow. In addition, the pressure loss near endwall in the inlet boundary layer is found more dominant on endwall contouring effect than the boundary layer thickness.

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Section: Introductionmentioning

confidence: 99%

Influence of the inlet boundary layer on non-axisymmetric endwall contouring effects in a linear compressor cascade

Teng

Zhu

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…The diffuser with leaned vanes accelerated the flow in the diffuser inlet region and reduced the losses of incidence angle, which weakened flow separation and delayed the onset of rotating stall. Recently, nonaxisymmetric endwall contouring technology proved its effectiveness in turbines 16,17 and axil compressors [18][19][20] to suppress the secondary flow and flow separation. Zhou et al 21 performed a numerical optimization on non-axisymmetric contouring endwall for a vaned diffuser hub-side wall of a centrifugal compressor, which showed the total pressure loss of the diffuser decreased under design condition, but the stable operating range of compressor stage decreased as well.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of centrifugal compressor stability enhancement using vaned diffuser endwall contouring technology

Cui

Qin

Jia

et al. 2022

Energy Science & Engineering

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To improve the stable operating range of centrifugal compressor stage, endwall contouring technology is introduced on the hub-side wall of the vaned diffuser for NASA CC3 centrifugal compressor as a promising technique to redistribute the flow field near the endwall in this paper. The main contents of this paper are listed as follows. First, a specific parameterized endwall contouring guideline is developed based on sinusoidal function and Bézier curve, and three factors are considered, namely, peak height, peak radial position, and frequency coefficient. Then, centrifugal compressor stages with baseline diffuser and contoured endwall diffusers are numerically investigated to reveal the influence of endwall contouring on the stable operating range. Results show that endwall contouring is an effective method to achieve stability enhancement with no evident reduction in stage performance on the design point. CEW13-12 has the most successful combination of endwall contouring parameters, and stall margin is increased by up to 40% for CEW13-12. Finally, the influence mechanism of endwall contouring on the stable operating range is discussed. At the near stall condition, the contouring endwall forces the fluid within the semi vaneless space to deflect toward the suction side to increase the momentum of low-energy fluid in the suction surface boundary layer and reduce the adverse pressure gradient on the suction side, which delay the development of flow separation on the vane leading edge near the shroud side to suppress the onset of rotating stall. At the near choke condition, the contouring endwall has more potential to increase the throat area, resulting in a decrease of throat blockage to improve choke margin. The results show that the endwall contouring technology is a reliable method to achieve stability enhancement of centrifugal compressor stage.

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“…Wang 25 studied endwall contouring and tested it in a large size research compressor with embedded stators and showed that the strategy to minimize the pressure above 90% span was best to decrease stator loss. Cao 26 studied control mechanism of CEW and found that the increased spanwise inward pressure gradient also contributed to the performance improvement. Zhang 27 studied the co-work of endwall contouring with tandem compressor and revealed that the positive of the optimum profiled endwall was to limit the extension of recirculation region in the front passage and suppress the suction corner separation in the rear passage.…”

Section: Introductionmentioning

confidence: 99%

Effective strategy of non-axisymmetric endwall contouring in a linear compressor cascade

Teng

Zhu

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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The corner separation and the related secondary flow have great impact on the compressor performance, and non-axisymmetric endwall contouring is proved effective in improving compressor efficiency. The aim of the study is to improve the compressor performance by two local endwall contouring strategies at the design and off-design conditions. The endwall is parameterized and the Bezier curve is used to loft the endwall surface. The design of the contoured endwall is based on a multi-point optimization method to minimize the aerodynamic pressure loss. In order to identify the influence of the contoured endwall, a detailed flow analysis is conducted on four effective contoured endwall designs. The selected endwall geometries exhibit great control ability on the corner separation and significantly reduce the pressure loss at the two operating conditions. The directional concave near the leading edge can induce strong streamwise pressure gradient and accelerate the endwall flow, greatly reducing the cross-passage pressure gradient. The convex structures near the concave edge and at the outlet can block the cross-flow and prevent the interaction between the cross-flow and the suction corner flow. The benefit of the contoured endwall is mainly due to the re-distributed endwall static pressure and blocking of the cross-flow movement. In terms of the control effect, the shape of the concave also matters and better control effect is observed on the deep and wide concave. The flow will be guided by the concave, and the best suppression on corner separation is observed on the concave which follows the suction side. The results also indicate that the relief of the hub corner separation slightly increases the shroud pressure loss.

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Non-axisymmetric endwall profiling in a highly loaded compressor cascade

Cited by 9 publications

References 22 publications

Influence of the inlet boundary layer on non-axisymmetric endwall contouring effects in a linear compressor cascade

Influence of the inlet boundary layer on non-axisymmetric endwall contouring effects in a linear compressor cascade

Numerical investigation of centrifugal compressor stability enhancement using vaned diffuser endwall contouring technology

Effective strategy of non-axisymmetric endwall contouring in a linear compressor cascade

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