Turbomachinery simulation challenges and the future

Tyacke, James; Vadlamani, Nagabhushana Rao; Trojak, Will; Watson, Robert P.; Ma, Yuduan; Tucker, Paul G.

doi:10.1016/j.paerosci.2019.100554

Cited by 55 publications

(19 citation statements)

References 97 publications

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“…Numerical studies on phenomena and mechanisms related to impeller-diffuser and IGVs-impeller interactions in centrifugal compressors have also been performed over past decades. Numerical methods gradually evolve from simulating inviscid steady flow to viscous unsteady flow, and reviews on the numerical methods in turbomachines can be found in (Tucker, 2011a(Tucker, , 2011b(Tucker, , 2012(Tucker, , 2013Tyacke et al, 2019). Some representative numerical studies on the flow in centrifugal compressors are presented below.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of wake and potential interactions in a two-stage centrifugal refrigeration compressor

Fan

Zhang

et al. 2021

Engineering Applications of Computational Fluid Mechanics

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Both potential and wake interactions are usually the primary mechanisms related to the unsteadiness in turbomachines. However, it is usually difficult to distinguish their effects on flow evolution. This paper develops a direct and visual method to investigate the effects of wake and potential interactions on features of the flow velocity in a two-stage centrifugal refrigeration compressor. The centrifugal compressor consists of six cascades of blades/vanes, i.e. inlet guide vanes in the first stage, impeller blades and vaned diffusers in both stages and return channel in the second stage. The detailed features of flow velocity, such as time-averaged flow velocity, instantaneous flow velocity and power density spectrum of the flow velocity, downstream each cascade of blades/vanes are studied in detail to investigate the potential and wake interactions on the flow evolution in the centrifugal compressor.

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Section: Introductionmentioning

confidence: 99%

Numerical study of wake and potential interactions in a two-stage centrifugal refrigeration compressor

Fan

Zhang

et al. 2021

Engineering Applications of Computational Fluid Mechanics

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“…Looking at it from another direction, knowing and quantifying uncertainties of the averaged quantities of interest can also be used to reduce the simulation time by accepting a certain error level. Thus, reliable statistical error analysis can be one key aspect to make SRS of flows with very high Reynolds numbers feasible and to pave the way of SRS into the design process [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Statistical Error Estimation Methods for Engineering-Relevant Quantities From Scale-Resolving Simulations

Bergmann

Morsbach

Ashcroft

et al. 2021

Journal of Turbomachinery

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Scale-resolving simulations, such as large eddy simulations, have become affordable tools to investigate the flow in turbomachinery components. The resulting time-resolved flow field is typically analyzed using first- and second-order statistical moments. However, two sources of uncertainty are present when recording statistical moments from scale-resolving simulations: the influence of initial transients and statistical errors due to the finite number of samples. In this paper, both are systematically analyzed for several quantities of engineering interest using time series from a long-time large eddy simulation of the low-pressure turbine cascade T106C. A set of statistical tools to either remove or quantify these sources of uncertainty is assessed. First, the Marginal Standard Error Rule is used to detect the end of the initial transient. The method is validated for integral and local quantities and guidelines on how to handle spatially varying initial transients are formulated. With the initial transient reliably removed, the statistical error is estimated based on standard error relations considering correlations in the time series. The resulting confidence intervals are carefully verified for quantities of engineering interest utilizing cumulative and simple moving averages. Furthermore, the influence of periodic content from large scale vortex shedding on the error estimation is studied. Based on the confidence intervals, the required averaging interval to reduce the statistical uncertainty to a specific level is indicated for each considered quantity.

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“…The required tip clearance between rotating rows and fixed parts in a turbomachine is responsible for a leakage flow, excessively difficult to measure (Stauter, 1992) or to simulate (Tyacke et al, 2019). This tip-clearance flow generates complex vortical structures (Storer and Cumpsty, 1991) that interact with the main-stream flow yielding substantial losses (Denton, 1993).…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic investigation of a linear cascade with tip gap using large-eddy simulation

Koch

Sanjosé

Moreau

2021

J. Glob. Power Propuls. Soc.

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The flow in a linear compressor cascade with tip gap is simulated using a wall-resolved compressible Large-Eddy Simulation. The cascade is based on the Virginia Tech Low Speed Cascade Wind Tunnel. The Reynolds number based on the chord is 3.88 x 10⁵ and the Mach number is 0.07. The gap considered in this study is 4.0 mm (2.9% of axial chord). An aerodynamic analysis of the tip-leakage flow allow us identifying the main mechanisms responsible for the development and the convection of the tip-leakage vortex downstream of the cascade. A region of high turbulence and vorticity levels is located along an ellipse that borders the top of the tip-leakage vortex. The influence of the airfoil suction side boundary layer development on the tip-leakage vortex is highlighted by tripping the flow. A tripped boundary layer induces a stronger and larger tip-leakage vortex that tends to move further away from the airfoil suction side and from the endwall compared with an untripped flow. The boundary layer turbulent state influences the tip-leakage flow development.

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Turbomachinery simulation challenges and the future

Cited by 55 publications

References 97 publications

Numerical study of wake and potential interactions in a two-stage centrifugal refrigeration compressor

Numerical study of wake and potential interactions in a two-stage centrifugal refrigeration compressor

Statistical Error Estimation Methods for Engineering-Relevant Quantities From Scale-Resolving Simulations

Aerodynamic investigation of a linear cascade with tip gap using large-eddy simulation

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