Numerical investigation of vortex generators to reduce cross-passage flow phenomena in compressor stator end-walls

Ortmanns, Jens; Pixberg, Christian T.; Gümmer, Volker

doi:10.1177/0957650911414323

Cited by 8 publications

(4 citation statements)

References 8 publications

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“…The generated vortex should be located near the SS and has the same rotational direction as the SS branch of the HSV. For example, the backwards wedge-type VG scheme proposed by Hergt et al 43 and the vane-type VG scheme studied by Ortmanns et al 44 and Hu et al 23 can produce a streamwise vortex that meets the above requirement.…”

Section: Discussionmentioning

confidence: 99%

Vortical characteristics of the corner separation flow in a high-speed compressor cascade

Wang

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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In aero-engine compressors, corner separations cause blockage, loss generation, and flow instabilities. The aim of the current study is to gain better knowledge of the vortical structures in corner separation flows and their resultant blockage and loss. Numerical simulations at different incidences have been performed for a high-speed linear compressor cascade. First, vortical structures have been visualized with the help of the Q-criterion and eigenvector method, and those associated with the corner separation have been focused on. It was found that the corner separation occurring on either the pressure surface or suction surface corner region was characterized by a large-scale streamwise vortex, named as the corner separation vortex in this paper. The pressure-side corner separation vortex is observed at a great negative incidence initiated from a focus point on the pressure surface, while the suction-side corner separation vortex observed at all concerned incidences originated from a focus on the endwall near the suction surface. Then, the mechanism by which corner separation vortices resulted in blockage and loss has been uncovered. The results showed that low-momentum fluids inside the core region of corner separation vortices led to the flow blockage and the viscous friction between them, and mainstream was responsible for the entropy generation. One major contributor of low-momentum fluids in the suction-side corner region was an off-wall reversed-flow region which was attributed to the breakdown of the suction-side corner separation vortex. Finally, multi-vortex structures in the leading region of the suction-side corner separation at two high positive incidences have been analyzed. It was found that the horseshoe vortex influenced the formation of the suction-side corner separation vortex, which induced a multi-vortex structure, and prevented the onset location of suction-side corner separation vortex from moving upstream with the increased incidence.

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Section: Discussionmentioning

confidence: 99%

Vortical characteristics of the corner separation flow in a high-speed compressor cascade

Wang

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…However, in these examples, the non-axisymmetric deformation relies on negative height values, which might yield practical issues in real compressor stages. Numerous investigations on the use of vortex generators were also carried out, to energize the near-hub flow ( [12], [13], [14]) or the stator boundary layer [15]. With vortex generators, the main challenge is to compensate the extra losses added by the tip vortex with an efficient reduction of the corner separation losses.…”

Section: Introductionmentioning

confidence: 99%

Beneficial Effects of Guide Fins on Corner Separation

Mondin,

Riéra,

Duquesne

et al. 2023

Volume 13A: Turbomachinery — Axial Flow Fan and Compressor Aerodynamics

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Corner separation is a major phenomenon limiting the operability of aeronautical compressors. Passive control devices such as guide fins are envisioned to reduce its deleterious effects. In this paper, guide fins are optimized to reduce the total pressure losses downstream of a subsonic compressor cascade (M = 0.11, Re = 3.2 105, modern stator blades) at design and near-stall incidences. Guide fins shapes are defined using 15 parameters. An optimization strategy relying on the iterative refinement of surrogate model with Reynolds-Averaged Navier-Stokes (RANS) computations is carried out. A database of 1033 guide fins is obtained, a large number of which strongly reduces the near-stall losses. Three guide fins are thoroughly investigated and referred to as Short Fence (short and straight guide fin), Long Fence (long and straight guide fin) and 3D (long guide fin with a strong pyramidal aspect). Their effect on the downstream measurement plane is validated experimentally, as well as their integrated performances. Large reductions of total pressure losses at near-stall incidence are obtained (−2.4 pt to −2.9 pt, or a relative reduction of −50% to −60%) without degrading neither the nominal losses nor the stator deflection. These guide fins are used to highlight three beneficial mechanisms that alter the corner separation development within the blade passage a) Tip Vortex (energizes the passage flow) b) Fence (induces 2 passage vortices) c) Guide (induces a local favourable pressure gradient). The role of these mechanisms in the generation of total pressure losses are analyzed in depth with streamlines visualisations and with a topological analysis. Kriging surrogate models reveal that three parameters drive the guide fins performances : the axial position, height, and thickness value at hub. The performances of the investigated guide fins are robust to significant variations of these parameters, as well as small variation of the inlet boundary layer thickness.

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“…Nowadays, in addition to adopting a full three-dimensional (3D) blade method to regenerate the internal flow, the local flow control methods have also become an important means to improve the flow situation in the compressor. 1–7…”

Section: Introductionmentioning

confidence: 99%

Effect of the end-wall vortex generator jets on the performance of a high subsonic compressor cascade

Chen

Liu

Chen

2018

Proceedings of the Institution of Mechanical Engineers, Part A:

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This paper presents a numerical and experimental result of the end-wall vortex generator jets for controlling corner separation and enhancing the aerodynamic performance in a high subsonic (Ma = 0.7) compressor cascade. The experiments were carried out on a compressor cascade at design point ( i = 0°) and off-design points ( i = −2°, 2°, and 4°). At design point, the total pressure loss coefficient could be reduced up to 12.1%.With the increase in the incidence, the control effect is enhanced first and then reduced. The maximum total pressure loss reduction is up to 14.6% when the incidence is 2°. The numerical study is further conducted to analyze the flow pattern and the vortex structure. The jet vortex is formed downstream of the jet hole using the vortex generator jets, the cross flow on the end wall is also suppressed.

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Numerical investigation of vortex generators to reduce cross-passage flow phenomena in compressor stator end-walls

Cited by 8 publications

References 8 publications

Vortical characteristics of the corner separation flow in a high-speed compressor cascade

Vortical characteristics of the corner separation flow in a high-speed compressor cascade

Beneficial Effects of Guide Fins on Corner Separation

Effect of the end-wall vortex generator jets on the performance of a high subsonic compressor cascade

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