Cut-Cell Method Based Large-Eddy Simulation of a Tip-Leakage Vortex of an Axial Fan

The tip leakage vortex (TLV) has aroused great concern for turbomachine performance, stability and noise generation as well as cavitation erosion. To better understand structures and dynamics of the TLV, large-eddy simulation (LES) is coupled with a homogeneous cavitation model to simulate the cavitation flow around a NACA0009 hydrofoil with a given clearance. The numerical results are validated by comparisons with experimental measurements. The results demonstrate that the present LES can well predict the mean behavior of the TLV. By visualizing the mean streamlines and mean streamwise vorticity, it shows that the TLV dominates the end-wall vortex structures, and that the generation and evolution of the other vortices are found to be closely related to the development of the TLV. In addition, as the TLV moves downstream, it undergoes an interesting progression, i.e., the vortex core radius keeps increasing and the axial velocity of vortex center experiences a conversion from jet-like profile to wake-like profile.

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

Journal of the Global Power and Propulsion Society ◽

10.33737/jgpps/133601 ◽

2021 ◽

Vol 5 ◽

pp. 39-49

Author(s):

Koch Régis ◽

Sanjosé Marlène ◽

Moreau Stéphane

Keyword(s):

Boundary Layer ◽

Large Eddy Simulation ◽

Suction Side ◽

Leakage Flow ◽

Compressor Cascade ◽

Tip Leakage Flow ◽

Tip Leakage Vortex ◽

Tip Leakage ◽

Eddy Simulation ◽

Large Eddy

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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Large eddy simulation of tip leakage cavitating flow focusing on cavitation-vortex interaction with Cartesian cut-cell mesh method

Journal of Hydrodynamics ◽

10.1007/s42241-018-0068-8 ◽

2018 ◽

Vol 30 (4) ◽

pp. 750-753 ◽

Cited By ~ 8

Author(s):

Xiao-rui Bai ◽

Huai-yu Cheng ◽

Bin Ji ◽

Xin-ping Long

Keyword(s):

Large Eddy Simulation ◽

Cavitating Flow ◽

Vortex Interaction ◽

Flow Focusing ◽

Tip Leakage ◽

Eddy Simulation ◽

Cut Cell ◽

Large Eddy ◽

Mesh Method ◽

Cartesian Cut

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Numerical Prediction of the Aerodynamics and Acoustics of a Tip Leakage Flow Using Large-Eddy Simulation

International Journal of Turbomachinery Propulsion and Power ◽

10.3390/ijtpp6030027 ◽

2021 ◽

Vol 6 (3) ◽

pp. 27

Author(s):

David Lamidel ◽

Guillaume Daviller ◽

Michel Roger ◽

Hélène Posson

Keyword(s):

Large Eddy Simulation ◽

Complex Structure ◽

Flow Region ◽

Leakage Flow ◽

Tip Leakage Flow ◽

Tip Leakage Vortex ◽

Tip Leakage ◽

Eddy Simulation ◽

Wall Pressure Fluctuations ◽

Large Eddy

A Large-Eddy Simulation of the tip leakage flow of a single airfoil is carried out. The configuration consists of a non-rotating, isolated airfoil between two horizontal plates with a gap of 10 mm between the tip of the airfoil and the lower plate. The Mach number of the incoming flow is 0.2, and the Reynolds number based on the chord is 9.3 × 105. The objective of the present study is to investigate the best way to compute both the aerodynamics and acoustics of the tip leakage flow. In particular, the importance of the inflow conditions on the prediction of the tip leakage vortex and the airfoil loading is underlined. On the other hand, the complex structure of the tip leakage vortex and its convection along the airfoil was recovered due to the use of a mesh adaptation based on the dissipation of the kinetic energy. Finally, the ability of the wall law to model the flow in the tip leakage flow region was proven in terms of wall pressure fluctuations and acoustics in the far-field.

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