Advanced Endwall Contouring for Loss Reduction and Outflow Homogenization for an Optimized Compressor Cascade

Reutter, Oliver; Rozanski, Magdalena; Hergt, Alexander; Nicke, Eberhard

doi:10.3390/ijtpp2010001

Cited by 6 publications

(4 citation statements)

References 18 publications

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“…The baseline blade geometry is generated starting from the DLR SC14-067 [20,21] airfoil coordinates provided by the Institute of Propulsion Technology -Department of Fan and Compressor of the German Aerospace Center (DLR). The blade is straight with no twist (Fig.…”

Section: Geometry Generationmentioning

confidence: 99%

Aero-Structural Coupling Strategy for a Morphing Blade Cascade Study

Abate

Riemenschneider

Hergt

2022

Journal of Turbomachinery

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The coupling of aerodynamics and structural mechanics is an important step in the design process of aeronautical devices with morphing parts. In this paper, a 2D-3D coupling approach is developed to study a morphing blade cascade. Two shape memory alloy actuators are placed on the upper and lower sides of the blade to make possible the change in shape of the leading-edge. In the present work, a preliminary design study is conducted by considering a two-dimensional CFD analysis of an airfoil cascade coupled with a three-dimensional structural analysis of the whole 3D blade. A methodology is developed to match 2D and 3D meshes such that the aerodynamic loads can be easily transferred to the structural analysis. From there, the deformed blade geometry due to both aerodynamic loads and actuator work can be transferred back to the CFD solver, and the iterative aero-structural coupling loop can be repeated until convergence. The aero-structural coupling strategy developed in this work is also applied to a blade cascade study aiming to improve its performance by morphing the leading-edge of the blade. The results of this application show that by morphing the leading-edge blade of only few millimeters (less than 2 mm), it is possible to achieve a relevant performance improvement in terms of total pressure loss coefficient decrease of about 53%.

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Section: Geometry Generationmentioning

confidence: 99%

Aero-Structural Coupling Strategy for a Morphing Blade Cascade Study

Abate

Riemenschneider

Hergt

2022

Journal of Turbomachinery

Self Cite

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“…Axisymmetric deformations of the endwall were studied with the objective of energizing the endwall boundary layer [9]. Non-axisymmetric endwall deformations were also used to smoothly deflect the passage flow [10] or generate a local aerodynamic barrier [11]. However, in these examples, the non-axisymmetric deformation relies on negative height values, which might yield practical issues in real compressor stages.…”

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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“…The presence and type of fillets and hub clearance can indeed significantly impact the corner separation (Goodhand and Miller, 2012;Sun et al, 2021). Non-axisymmetric endwall deformation can also be used to smoothly deflect the flow (Reutter et al, 2017) or act as an aerodynamic separator (Hergt et al, 2009). On top of these geometrical modifications, technological devices such as vortex generators or fences can be added (Hergt et al, 2011(Hergt et al, , 2013.…”

Section: Introductionmentioning

confidence: 99%

Experimental validation of a corner stall control methodology using parametrised guide fins

Mondin

Duquesne

Ottavy

et al. 2022

J. Glob. Power Propuls. Soc.

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Corner separation is known to limit the operability of aeronautical compressors. Dedicated control devices such as guide fins are envisioned to reduce its negative effects. This paper presents a methodology based on RANS (Reynolds-Averaged Navier-Stokes) computations enabling to select guide fins efficient for that purpose. This methodology is applied to a reference case of linear compressor cascade operating at low Mach number (∼0.11). A set of 17 parameters is used to define two design spaces of interest, from which guide fins are generated. From then, an automated process generates and merges an unstructured mesh built around each guide fin with a fixed, structured mesh of reference representing a single channel of the cascade. Finally, RANS results on the resulting hybrid mesh are obtained using the Computational Fluid Dynamics solver elsA. This set up has proven successful in evaluating automatically hundreds of guide fins of various shapes. Several geometries illustrate the diversity of the design space. A selection of guide fins is then evaluated experimentally. Evolutions of the losses downstream of the cascade are compared to their respective RANS predictions, and to the reference case without guide fin. These experimental results validate the implemented methodology and show encouraging results in terms of loss redistribution brought by the control device.

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Advanced Endwall Contouring for Loss Reduction and Outflow Homogenization for an Optimized Compressor Cascade

Cited by 6 publications

References 18 publications

Aero-Structural Coupling Strategy for a Morphing Blade Cascade Study

Aero-Structural Coupling Strategy for a Morphing Blade Cascade Study

Beneficial Effects of Guide Fins on Corner Separation

Experimental validation of a corner stall control methodology using parametrised guide fins

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