Study of the Tip Leakage Flow in a Compressor Cascade With Incidence Exceeding the Stability Limit

2019 ◽  
Author(s):  
Markus W. Leitner ◽  
Stephan Staudacher ◽  
Martin G. Rose
Keyword(s):  
Water Table ◽  
Vortex Breakdown ◽  
Stability Limit ◽  
Leakage Flow ◽  
Angle Of Incidence ◽  
Compressor Cascade ◽  
Tip Leakage Flow ◽  
Unstable Flow ◽  
Tip Leakage ◽  
The Stability

Abstract In axial compressors, tip leakage flow is disadvantageous to efficiency and mass flow stability. We analyzed the tip leakage flow in a compressor cascade on a water table at various angles of incidence. When the angle of incidence is systematically increased, the flow rate is decreased and, finally, the stability limit is exceeded. To study the flow structures and vortex behavior, we installed Particle Tracking Velocimetry (PTV) on the water table. 3D-trajectories of the stable and unstable flow reveal significant effects. Increasing incidence generates a significant change in the nature of the flow. The tip leakage flow fluctuates and features unstable flow phenomena. A large blockage of the flow passage occurs, probably due vortex breakdown. Such a serious disturbance of the incoming flow may induce stall.

Effect of Sloped Trench Casing Treatment on Performance and Stability of Axial Compressors

2020 ◽  
Author(s):  
Hou Jiexuan ◽  
Liu Yangwei
Keyword(s):  
Working Environment ◽  
Leakage Flow ◽  
Compressor Cascade ◽  
Tip Leakage Flow ◽  
Tip Leakage Vortex ◽  
Casing Treatment ◽  
Axial Compressors ◽  
Tip Leakage ◽  
Inflow Condition ◽  
The Stability

Abstract Numerical simulations are carried out to investigate the effect of the sloped trench casing treatment on the performance and stability of a compressor cascade, an isolated rotor, and a single compressor stage. The research objects alter from a simplified flow model to an actual compressor working environment. Firstly, a detailed study of how the sloped trench casing treatment effects the tip leakage flow structure, especially the tip leakage vortex of a compressor cascade, is presented. Results show that the strength of the tip leakage vortex is weakened as the sloped trench casing treatment transforms the structure of the tip leakage vortex. Then the simulation results of the isolated rotor and the single stage are studied. For both cases, the effect of the sloped trench casing treatment on the tip leakage flow is analogous to that of the cascade case. For the isolated rotor, the improvement on the performance is not obvious. While under the stage environment, different from the traditional casing treatment, both the performance and the stability of the compressor are advanced, by getting the tip leakage vortex under control and letting the downstream stator working under a better inflow condition.

Tip Leakage Flow Instability in a Centrifugal Compressor

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Teng Cao ◽  
Tadashi Kanzaka ◽  
Liping Xu ◽  
Tobias Brandvik
Keyword(s):  
Shear Layer ◽  
Centrifugal Compressor ◽  
Large Scale ◽  
Flow Instability ◽  
Leading Edge ◽  
Main Stream ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Unstable Flow ◽  
Tip Leakage

Abstract In this paper, an unsteady tip leakage flow phenomenon is identified and investigated in a centrifugal compressor with a vaneless diffuser at near-stall conditions. This phenomenon is associated with the inception of a rotating instability in the compressor. The study is based on numerical simulations that are supported by experimental measurements. The study confirms that the unstable flow is governed by a Kelvin–Helmholtz type instability of the shear layer formed between the main-stream flow and the tip leakage flow. The shear layer instability induces large-scale vortex roll-up and forms vortex tubes, which propagate circumferentially, resulting in measured pressure fluctuations with short wavelength and high amplitude which rotate at about half of the blade speed. The 3D vortex tube is also found to interact with the main blade leading edge, causing the reduction of the blade loading identified in the experiment. The paper also reveals that the downstream volute imposes a once-per-rev circumferential nonuniform back pressure at the impeller exit, inducing circumferential loading variation at the impeller inducer, and causing circumferential variation in the unsteady tip leakage flow.

scholarly journals Tip Leakage Flow in Linear Compressor Cascade

1993 ◽  
Author(s):  
S. Kang ◽  
C. Hirsch
Keyword(s):  
Design Flow ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Compressor Cascade ◽  
Tip Leakage Flow ◽  
Linear Compressor ◽  
Tip Leakage ◽  
Flow Mixing ◽  
Internal Loss ◽  
Linear Compressor Cascade

Tip leakage flow in a linear compressor cascade of NACA 65-1810 profiles is investigated, for tip clearance levels of 1.0, 2.0 and 3.25 percent of chord at design and off-design flow conditions. Data, velocity and pressures, are collected from three transverse sections inside tip clearance and sixteen sections within flow passage. Tip separation vortex influence is identified from the data. Leakage flow mixing is clearly present inside the clearance and has a significant influence on the internal loss.

Performance Assessment of Turbulence Models for the Quantitative Prediction of Tip Leakage Flow in Turbomachines

2004 ◽  
Author(s):  
Gong Hee Lee ◽  
Jong Il Park ◽  
Je Hyun Baek
Keyword(s):  
Measurement Data ◽  
Axial Flow ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Quantitative Prediction ◽  
Leakage Flow ◽  
Compressor Cascade ◽  
Tip Leakage Flow ◽  
Production Term ◽  
Tip Leakage

It is experimentally well-known that high anisotropy of turbulent flow field, which results from the complex shear and rotation effect, is dominant inside tip leakage vortex (TLV). With all this fact, the greater part of the numerical studies to deal with TLV have used an isotropic eddy viscosity model (EVM), and their predictions showed some disagreement with the measurement data. The main objective of the present study is to show the superior ability of the Reynolds stress model (RSM), which can naturally consider the effect of system rotation on turbulence via the rotational production term, over the isotropic EVM for predicting appropriately the complex tip leakage flow in axial type of turbomachines. To achieve this aim, the results obtained from steady-state Reynolds averaged Navier-Stokes simulations based on the Spalart-Allmaras model, Renormalization Group (RNG) k-ε model and RSM are compared with the experimental data for two test configurations: a linear compressor cascade and a forward-swept axial-flow fan. This comparative study of turbulence models suggests that the RSM should be used to predict reasonably the complex tip leakage flow, especially in a rotating environment.

Behavior of Tip Leakage Flow in an Axial Flow Compressor Rotor

2006 ◽  
Author(s):  
Yanhui Wu ◽  
Wuli Chu ◽  
Xingen Lu ◽  
Junqiang Zhu
Keyword(s):  
Boundary Layer ◽  
Vortex Breakdown ◽  
Axial Flow ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Pressure Side ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Compressor Rotor ◽  
Flow Compressor

The current paper reports on investigations with an aim to advance the understanding of the flow field near the casing of a small-scale high-speed axial flow compressor rotor. Steady three dimensional viscous flow calculations are applied to obtain flow fields at various operating conditions. To demonstrate the validity of the computation, the numerical results are first compared with available measured data. Then, the numerically obtained flow fields are analyzed to identify the behavior of tip leakage flow, and the mechanism of blockage generation arising from flow interactions between the tip clearance flow, the blade/casing wall boundary layers, and non-uniform main flow. The current investigation indicates that the “breakdown” of the tip leakage vortex occurs inside the rotor passage at the near stall condition. The vortex “breakdown” results in the low-energy fluid accumulating on the casing wall spreads out remarkably, which causes a sudden growth of the casing wall boundary layer having a large blockage effect. A low-velocity region develops along the tip clearance vortex at the near stall condition due to the vortex “breakdown”. As the mass flow rate is further decreased, this area builds up rapidly and moves upstream. This area prevents incoming flow from passing through the pressure side of the passage and forces the tip leakage flow to spill into the adjacent blade passage from the pressure side at the leading edge. It is found that the tip leakage flow exerts little influence on the development of the blade suction surface boundary layer even at the near stall condition.

Suppression of Unstable Flow at Small Flow Rates in a Centrifugal Blower by Controlling Tip Leakage Flow and Reverse Flow

2005 ◽  
Vol 127 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Mashiro Ishida ◽  
Taufan Surana ◽  
Hironobu Ueki ◽  
Daisaku Sakaguchi
Keyword(s):  
Reverse Flow ◽  
Centrifugal Impeller ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Centrifugal Blower ◽  
Unstable Flow ◽  
Ring Groove ◽  
Recirculation Flow ◽  
Tip Leakage ◽  
Small Flow

The effects of the inlet recirculation arrangement on inducer stall and the diffuser width on diffuser stall in a high-specific-speed-type centrifugal impeller with inducer were analyzed by numerical simulation and also verified experimentally. It was found that the incipient unstable flow occurs due to a rolling-up vortex flow, resulting from an interaction between the tip leakage flow and the reverse flow accumulated at the pressure side immediately downstream of the inducer tip throat, in which a strong streamwise component of vorticity is included. By forming the inlet recirculation flow, the tip leakage vortex is effectively sucked into the suction ring groove, and the flow incidence is decreased simultaneously. The unstable flow range of the test blower was reduced significantly by about 45% without deteriorating the impeller characteristics by implementing optimally both the ring groove arrangement and the narrowed diffuser width.

Breakdown of Tip Leakage Vortices in Compressors at Flow Conditions Close to Stall

1997 ◽  
Author(s):  
Stefan Schlechtriem ◽  
Michael Lötzerich
Keyword(s):  
Vortex Breakdown ◽  
Stability Limit ◽  
Flow Conditions ◽  
Mixed Flow ◽  
Stall Inception ◽  
Tip Leakage ◽  
Transonic Compressor ◽  
Flow Compressor ◽  
The Stability ◽  
Operating Points

The breakdown of tip leakage vortices at operating points close to the stability limit of transonic compressor rotors has been detected. The aerodynamic phenomenon is considered to have a major impact on stall inception. Computations have been carried out and a detailed visualization of the phenomenon is given. In addition the connection of vortex breakdown to rotating instabilities and stall is discussed. Furthermore the tip flow field of the axial rotor is compared to the results for a centrifugal and a mixed flow compressor operating at similar tip speeds.

Numerical Investigation of Tip Clearance Flow in an Axial Compressor Cascade

2014 ◽  
Vol 599-601 ◽  
pp. 368-371
Author(s):  
Zhi Hui Xu ◽  
He Bin Lv ◽  
Ru Bin Zhao
Keyword(s):  
Computational Simulation ◽  
Suction Side ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Compressor Cascade ◽  
Tip Leakage Flow ◽  
Tip Clearance Flow ◽  
Tip Leakage ◽  
Clearance Flow ◽  
Blade Tip

Using blade tip winglet to control the tip leakage flow has been concerned in the field of turbomachinery. Computational simulation was conducted to investigate the phenomenological features of tip clearance flow. The simulation results show that suction-side winglet can reduce leakage flow intensity. The tip winglet can also decrease tip leakage mass flow and weaken tip leakage flow mixing with the mainstream and therefore reduce the total pressure loss at the blade tip.

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