A Technological Effect Modeling on Complex Turbomachinery Applications With an Overset Grid Numerical Method

Castillon, Lionel; Billonnet, Gilles; Riou, Jacques; Péron, Stephanie; Benoît, Christophe

doi:10.1115/1.4027997

Cited by 11 publications

(4 citation statements)

References 13 publications

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“…Moreover, compared to a full unstructured grid approach, the hybrid grid approach has the advantage of keeping the "O-nH" type grid topology (well adapted to turbomachinery flows) in most of the part of the blade channel. One last advantage of this approach is that the conformal matching between the structured and nonstructured zones avoids any conservation loss issue, which can be encountered with the Chimera technique [23], or flow filtering issues, which can appear with mismatched abutting interface techniques.…”

Section: Figure 5: Mesh Of the Cme2 Compressor (1/10 Th Of The Circum...mentioning

confidence: 99%

Numerical Investigations on the Rotating Stall in an Axial Compressor and Its Control by Flow Injection at Casing

Marty

Castillon

Joseph

2022

Journal of Turbomachinery

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The operating range of a compressor is limited by surge or rotating stall line, among others. Numerical simulations must accurately predict these phenomena. This study is based on the experimental compressor CME2, which is a low-subsonic axial compressor. This compressor is tip-critical as the rotor tip is responsible for the rotating stall. This paper shows that the rotating stall onset flow rate is well captured by CFD, compared to experiments. After ten revolutions, all cells are merged and only one cell remains, as in experiments. Active flow control improves compressor performance and extends the stable operating range. In the present configuration, flow injection is performed at the casing. In the simulation, the insertion of the actuators is carried out through hybrid meshes: structured mesh for blade passages and unstructured mesh for each actuator. For the some stalled operating points of baseline configuration, there is no rotating cells in the controlled configuration. Thus, the rotating stall is delayed at lower flow rate, as expected by the use of active flow control and is in agreement with the experiments.

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Section: Figure 5: Mesh Of the Cme2 Compressor (1/10 Th Of The Circum...mentioning

confidence: 99%

Numerical Investigations on the Rotating Stall in an Axial Compressor and Its Control by Flow Injection at Casing

Marty

Castillon

Joseph

2022

Journal of Turbomachinery

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“…Regarding the hub cavity, extensive studies have been conducted on the loss mechanism of hub leakage flows. For the commonly used open test case NASA Rotor 37, the discrepancy between the measured data and early CFD simulations near 40% span was believed to be caused by neglecting a 0.75 mm gap between the rotor disk and the stationary center body (Moore and Reid, 1980;Denton, 1997;Chima, 2009); more recent CFD simulations confirmed that the axial gap can generate such a deficit even when there is zero net leakage (Shabbir et al, 1997;Castillon et al, 2014;Seshadri et al, 2014). For stators with a hub cavity, detrimental effects of the leakage flow were usually reported: Wellborn and Okiishi (1999) performed a comprehensive investigation of the effect of stator hub leakage flow on the primary passage flow in a four-stage low-speed compressor, and the leakage flow was found to increase blockage, deviation, and thus total pressure loss near the stator hub; Demargne and Longley (2000) experimentally investigated the cavity effect on a linear compressor cascade, and the total pressure loss was found to increase with the leakage mass flow rate.…”

Section: Introductionmentioning

confidence: 99%

Endwall geometric uncertainty and error on the performance of TUDA-GLR-OpenStage transonic axial compressor

Xia

Zhu

et al. 2023

J. Glob. Power Propuls. Soc.

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The hub and casing walls of axial compressors are often modeled as smooth continuous surfaces in CFD simulations, but in real geometries, non-smooth pinches, steps and leakage cavities may exist. In the GPPS first Turbomachinery CFD Workshop, a comprehensive validation and verification campaign of RANS flow solvers was conducted, and all the simulation results consistently over-predicted the total pressure ratio at the rotor exit near the casing and the stator exit near the hub. From a recent examination of the test rig geometry, a pinched casing wall over the rotor and a leakage cavity below the stator were found, which were not considered in the workshop. In this paper, the effects of these endwall geometric uncertainties and errors are analyzed via numerical simulation. When considering the rotor casing pinch of the test geometry, the predicted total pressure ratio and choke mass flow of the compressor stage are smaller than that without the pinch, leading to better agreement with the measured data. When considering a stator hub cavity with a leakage flow rate of about 0.2% of the compressor inlet mass flow, the near-hub total pressure ratio distribution matches slightly better with the experimental data, but the effects on the global compressor stage characteristics are not visible. The relevant mechanisms of these changes in performances are analyzed in detail. The updated geometries and grids will be released to the public as a benchmark test case for turbomachinery CFD validation and verification.

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“…in computational aeroacoustics [25,26], conjugate heat transfer [27], simulation of moving bodies for aeronautical [28] and marine purposes [29]. For turbomachinery simulations with a structured solver, the overset grid approach is a way to account for complex technological e↵ects such as cavities and casing treatments [30,31]. With respect to other methods, the overset grid method is known to be more flexible since the size of the overlapping zone can vary and the mesh generation of complex geometries is eased [23].…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of a high-order unstructured overset grid method for compressible LES of turbomachinery

Laborderie

Duchaine

Gicquel

et al. 2018

Journal of Computational Physics

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Large-Eddy Simulation (LES) is recognized as a promising method for highfidelity flow predictions in turbomachinery applications. The presented approach consists of the coupling of several instances of the same LES unstructured solver through an overset grid method. A high-order interpolation, implemented within this coupling method, is introduced and evaluated on several test cases. It is shown to be third order accurate, to preserve the accuracy of various second and third order convective schemes and to ensure the continuity of di↵usive fluxes and subgrid scale tensors even in detrimental interface configurations. In this analysis, three types of spurious waves generated at the interface are identified. They are significantly reduced by the high-order interpolation at the interface. The latter having the same cost as the original lower order method, the high-order overset grid method appears as a promising alternative to be used in all the applications.

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A Technological Effect Modeling on Complex Turbomachinery Applications With an Overset Grid Numerical Method

Cited by 11 publications

References 13 publications

Numerical Investigations on the Rotating Stall in an Axial Compressor and Its Control by Flow Injection at Casing

Numerical Investigations on the Rotating Stall in an Axial Compressor and Its Control by Flow Injection at Casing

Endwall geometric uncertainty and error on the performance of TUDA-GLR-OpenStage transonic axial compressor

Numerical analysis of a high-order unstructured overset grid method for compressible LES of turbomachinery

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