Computation of tip-leakage flow in a linear compressor cascade with a second-moment turbulence closure

Borello, Domenico; Hanjalić, K.; Rispoli, Franco

doi:10.1016/j.ijheatfluidflow.2007.04.008

Cited by 34 publications

(25 citation statements)

References 42 publications

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“…[20] Nevertheless, due to their assumptions, these models fail to predict accurately the turbulence field in the tip clearance area. For this reason, enhanced RANS models as non-linear eddy viscosity models [22] or second-moment closure [23] have been used. These models improve the flow prediction in the blade passage through an accurate capture of the swirling flow compared to the eddy viscosity models.…”

Section: Introductionmentioning

confidence: 99%

RANS and LES computations of the tip-leakage vortex for different gap widths

Decaix

Balarac

Dreyer

et al. 2015

Journal of Turbulence

100

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In hydraulic turbines, the tip-leakage vortex is responsible for flow instabilities and for promoting erosion due to cavitation. To better understand the tip vortex flow, Reynoldsaveraged Navier-Stokes (RANS) and large eddy simulation (LES) computations are carried out to simulate the flow around a NACA0009 blade including the gap between the tip and the wall. The main focus of the study is to understand the influence of the gap width on the development of the tip vortex, as for instance its trajectory. The RANS computations are performed using the open source solver OpenFOAM 2.1.0, two incidences and five gaps are considered. The LESs are achieved using the YALES2 solver for one incidence and two gaps.The validation of the results is performed by comparisons with experimental data available downstream the trailing edge. The position of the vortex core, the mean velocity and the mean axial vorticity fields are compared at three different downstream locations. The results show that the mean behaviour of the tip vortex is well captured by the RANS and LES computations compared to the experiment. The LES results are also analysed to bring out the influence of the gap width on the development of the tip-leakage vortex. Finally, a law that matches the vortex trajectory from the leading edge to the mid-chord is proposed. Such a law can be helpful to determine, in case of cavitation, if the tip vortex will interact with the walls and cause erosion.

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Section: Introductionmentioning

confidence: 99%

RANS and LES computations of the tip-leakage vortex for different gap widths

Decaix

Balarac

Dreyer

et al. 2015

Journal of Turbulence

100

View full text Add to dashboard Cite

show abstract

“…Pioneering work in the area by You et al [7] established a computational framework within which Large Eddy Simulations of the loss mechanisms in rotor tip-clearance flows were investigated [8], including the effect of varying tip-gap size [9]. Based on the findings of this work, further efforts were made to improve turbulence modelling of the flow in turbomachinery [10]. The influence of freestream turbulence on transition on turbine blades has been investigated using LES [11], highlighting the need for reasonably posed inlet conditions.…”

Section: Introductionmentioning

confidence: 93%

Large Eddy Simulation of a Controlled Diffusion Compressor Cascade

McMullan

Page

2010

Flow Turbulence Combust

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In this research a Controlled Diffusion (CD) compressor cascade stator blade is simulated at a Reynolds number of ∼ 700, 000, based on inflow velocity and chord length, using Large Eddy Simulation (LES). A wide range of flow inlet angles are computed, including conditions near the design angle, and at high negative and positive incidence. At all inlet angles the surface pressure distributions are well-predicted by the LES. Near the design angle the computed suction side boundary layer thickness agrees well with experimental data, whilst the pressure side boundary layer is poorly predicted due to the inability of LES to capture natural boundary layer transition on the present grid. A good estimation of the loss is computed near the design angle, whilst at both high positive and negative incidences the loss is less well predicted owing to discrepancies between the computed and experimental boundary layer thickness. At incidences above the design angle a laminar separation bubble forms near the leading edge of the suction surface, which undergoes a transition to turbulence. Similar behaviour is noted on the pressure surface at negative incidence. At high negative incidence contra-rotating vortex pairs are found to form around the leading edge inThe authors would like to thank Rolls-Royce plc and the UK Technology Strategy Board for the funding this work under the CFMS Core Programme (TP/L3001H). The simulations in this study were performed on HECToR, the UK National Supercomputing Facility, under the UKAAC-2 Framework, EPSRC grant number EP/F005954/1. response to an unsteady stagnation line across the span of the blade. Such structures are not apparent in time-averaged statistical data due to their highly-transient nature.

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“…Numerically, the tip vortex was investigated using various models as vortex methods [6], Reynolds Averaged Navier Sokes (RANS) approach coupling with an eddy viscosity model [7] or second moment closure [8], or Large Eddy Simulation [9]. In [10], the author uses the Joseph criterion to determine the regions that can be affected by cavitation.…”

Section: Introductionmentioning

confidence: 99%

Rans Computations of a Cavitating Tip Vortex

Decaix¹,

Balarac

Münch³

2015

Advances in Hydroinformatics

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Nomenclature a L Liquid volume fraction r v Cavitation parameter C Chord length (m) I Angle of incidence (degree) K Turbulent kinetic energy (m 2 /s 2 ) P Pressure field (Pa) p vap Vaporisation pressure (Pa) u i Velocity field (m/s) m Molecular kinematic viscosity (m 2 /s) m t Turbulent eddy viscosity (m 2 /s) x Turbulence frequency (1/s) r ij Viscous stress tensor (kg/(m.s 2 ) s ij Reynolds stress tensor (kg/(m.s 2 ) s Gap width (m) J. Decaix (&) Á C. Münch Route Du

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Computation of tip-leakage flow in a linear compressor cascade with a second-moment turbulence closure

Cited by 34 publications

References 42 publications

RANS and LES computations of the tip-leakage vortex for different gap widths

RANS and LES computations of the tip-leakage vortex for different gap widths

Large Eddy Simulation of a Controlled Diffusion Compressor Cascade

Rans Computations of a Cavitating Tip Vortex

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