Towards a High Order Throughflow: Part I—Investigating the Effectiveness of a Harmonic Reconstruction for 3D Flows

Thomas, Jean-Philippe; ́onard, O. Le

doi:10.1115/gt2010-22841

Cited by 2 publications

(1 citation statement)

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“…In the special case of no further simplifications, the estimation of the right-hand side can be tedious since it implies the precise estimation of all the stresses and blade terms obtained in the average process. Such a task has been partly addressed by Thomas et al [14] with the use of the circumferential stresses from 3D Navier-Stokes simulations, showing gain in results precision compared to the case without the extracted terms. This is relevant to high order throughflow modeling topic.…”

Section: General Governing Equationsmentioning

confidence: 99%

A CFD-Based Throughflow Solver Using Cascade Potential Theory for Axial Compressor Flow Modeling

Kravtsoff,

Schvallinger,

Ottavy

2023

Volume 13C: Turbomachinery — Deposition, Erosion, Fouling, and Icing; Design Methods and CFD Modeling for Turbomachinery; Ducts

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This paper describes the use of the Hess & Smith cascade potential method as an additional feature for throughflow modeling. This method is incorporated inside ASTEC, a CFD-based throughflow solver developed by Safran Tech providing local blade loading information for blade force and loss modeling. The test cases are all subsonic, composed of two compressors cascades and a low speed compressor. The two profile families for the cascades are a classical NACA 65 009 and a controlled diffusion cascade designed by the Whittle Laboratory. The compressor is the well studied CME2, a research single stage designed by Safran Aircraft Engines. From the potential calculation, boundary layers and wakes are calculated on the blades providing deviation angles and profile losses. The tip leakage losses are also estimated from blade loading at the tip of a rotor. The results are compared to MISES code predictions, RANS simulations, experimental data and classic Lieblein empirical correlations. This work aims to model compressors flow with geometry-based classic analytical methodologies for a minimal use of empiricism. The predictions are good on bi-dimensional cascades cases compared to several other methodologies and at mid-span for the multiple incidences considered compared to experimental cascade results. For the compressor case, the blade loading near mid-span of the rotor blades show good agreement compared to RANS results leading to an overall good capture of the performance characteristic trends near design point. There is still room for improvements near the end-walls, mostly due to the lack of hub boundary layer model in the actual methodology. These results still build a step on which the enrichment of the flow model can be pursued.

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Section: General Governing Equationsmentioning

confidence: 99%

A CFD-Based Throughflow Solver Using Cascade Potential Theory for Axial Compressor Flow Modeling

Kravtsoff,

Schvallinger,

Ottavy

2023

Volume 13C: Turbomachinery — Deposition, Erosion, Fouling, and Icing; Design Methods and CFD Modeling for Turbomachinery; Ducts

View full text Add to dashboard Cite

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Toward a High Order Throughflow––Investigation of the Nonlinear Harmonic Method Coupled With an Immersed Boundary Method for the Modeling of the Circumferential Stresses

Thomas

Léonard

2011

Journal of Turbomachinery

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Capturing a level of modeling of the flow inside a multistage turbomachine, such as unsteadiness for example, can be done at different levels of detail, either by capturing all deterministic features of the flow with a pure unsteady method or by settling for an approximated solution at a lower computational cost. The harmonic methods stand in this second category. Among them, the “nonlinear harmonic method” (NLHM) from He and Ning [1998, “Efficient Approach for Analysis of Unsteady Viscous Flows in Turbomachines,” AIAA J., 36, pp. 2005–2012] revealed the most efficient. This method consists of solving the fully nonlinear 3D steady problem and a linearized perturbation system in the frequency domain. As it has been shown by the authors that the circumferential variations exhibit a harmonic behavior, it is proposed here to adapt the NLHM to the throughflow model, where the main nonlinear system would be the common throughflow equations and the auxiliary system would give access to the circumferential stresses. As the numerical local explicit impermeability conditions are unsupported by Fourier series, the adaptation of this technique to the throughflow model relies on a reformulation of the blade effect by a smooth force field as in the “immersed boundary method” from Peskin [2002, “The Immersed Boundary Method,” Acta Numerica, 11, pp. 1–39]. A simple example of an inviscid flow around a cylinder will illustrate the preceding developments, bringing back the mean effect of the circumferential nonuniformities into the meridional flow.

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Towards a High Order Throughflow: Part I—Investigating the Effectiveness of a Harmonic Reconstruction for 3D Flows

Cited by 2 publications

References 0 publications

A CFD-Based Throughflow Solver Using Cascade Potential Theory for Axial Compressor Flow Modeling

A CFD-Based Throughflow Solver Using Cascade Potential Theory for Axial Compressor Flow Modeling

Toward a High Order Throughflow––Investigation of the Nonlinear Harmonic Method Coupled With an Immersed Boundary Method for the Modeling of the Circumferential Stresses

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