Unsteady Pressure Investigations of Corner Separated Flow in a Linear Compressor Cascade

2015 ◽  
Author(s):  
Gherardo Zambonini ◽  
Xavier Ottavy
Keyword(s):  
Transfer Functions ◽  
Leading Edge ◽  
Positive Pressure ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Linear Compressor ◽  
Corner Separation ◽  
Unsteady Pressure ◽  
Linear Compressor Cascade ◽  
End Wall

The aim of this work is to present detailed unsteady pressure measurements of three-dimensional flow field in a NACA 65 linear compressor cascade. Chord-based Reynolds number of 382000 and incidence angle of 4 degrees were chosen as target configuration of the rig, which clearly presents the corner separation phenomenon at the juncture of the blade suction side and the end-wall. Concerning the experiments, a characterization of the mean and fluctuating component of wall static pressure on the surface of a specially developed blade is achieved at first. This fluctuating component is investigated utilizing nineteen high sensitivity condenser microphones plugged into blade cavities which have been carefully calibrated. Transfer functions obtained by calibration are exploited to reconstruct the time-dependent pressure signal and finally statistics, conditional ensemble averages, coherence and spectra analyses of fluctuations are presented in order to investigate the unsteady characteristics of the corner separation. High values of root mean square are individuated near the leading edge and in the separation region on the suction surface of the blade. Skewness and kurtosis show an intermittent behavior of the separation onset, which moves upstream and downstream on the suction surface. This intermittency of the separation line is probably linked with the existence of a bimodal behavior of the size of the corner separation. The analyses of coherence and conditional ensemble average between the signals at the leading edge and at the onset of the separation suggest a critical influence of angle and velocity of the incoming end-wall boundary layer on the positive pressure signatures of the shear layer, which characterize the inception of the separation.

Numerical Investigation of Intermittent Corner Separation in a Linear Compressor Cascade

2016 ◽  
Author(s):  
Wei Ma ◽  
Feng Gao ◽  
Xavier Ottavy ◽  
Lipeng Lu ◽  
A. J. Wang
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Leading Edge ◽  
Suction Side ◽  
Detached Eddy Simulation ◽  
Compressor Cascade ◽  
Linear Compressor ◽  
Corner Separation ◽  
Eddy Simulation ◽  
Linear Compressor Cascade

Recently bimodal phenomenon in corner separation has been found by Ma et al. (Experiments in Fluids, 2013, doi:10.1007/s00348-013-1546-y). Through detailed and accurate experimental results of the velocity flow field in a linear compressor cascade, they discovered two aperiodic modes exist in the corner separation of the compressor cascade. This phenomenon reflects the flow in corner separation is high intermittent, and large-scale coherent structures corresponding to two modes exist in the flow field of corner separation. However the generation mechanism of the bimodal phenomenon in corner separation is still unclear and thus needs to be studied further. In order to obtain instantaneous flow field with different unsteadiness and thus to analyse the mechanisms of bimodal phenomenon in corner separation, in this paper detached-eddy simulation (DES) is used to simulate the flow field in the linear compressor cascade where bimodal phenomenon has been found in previous experiment. DES in this paper successfully captures the bimodal phenomenon in the linear compressor cascade found in experiment, including the locations of bimodal points and the development of bimodal points along a line that normal to the blade suction side. We infer that the bimodal phenomenon in the corner separation is induced by the strong interaction between the following two facts. The first is the unsteady upstream flow nearby the leading edge whose angle and magnitude fluctuate simultaneously and significantly. The second is the high unsteady separation in the corner region.

Experimental Study and Vortex Analysis in a Linear Compressor Cascade With Active Flow Control

2016 ◽  
Author(s):  
Simeng Tian ◽  
Yangyang Wu ◽  
Zhibo Zhang ◽  
Bangqin Cheng ◽  
Yinghong Li ◽  
...  
Keyword(s):  
Flow Control ◽  
Active Flow Control ◽  
Test System ◽  
Experimental Investigations ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Linear Compressor ◽  
Corner Separation ◽  
Suction Control ◽  
Linear Compressor Cascade

In this paper, experimental investigations of a linear compressor cascade have been performed with Reynolds number of 2.4×105 to analyze the flow mechanism of hub-corner separation with end-wall jet and suction control. The vortices are measured with a quasi-three dimensional test system in different axial planes consisting of vorticity distribution and secondary flow structure. The experimental results give detailed insight into the performance of the principle vortices with different flow control methods. Corner separation losses could remarkably decrease with the jets and suction position near the asymptotic line of separation lines on suction surface. The flow control position plays a great role in affecting the corner separation losses while it is a more sensitive factor in the case of jets rather than the suction. It is evidenced that the combined flow control would get a higher decrease in the total pressure loss coefficient while an additional benefit in the reduction of losses has been gained in the case of a combined actuator layout.

Three Dimensional Flow in a Linear Compressor Cascade at Design Conditions

1991 ◽  
Author(s):  
Shun Kang ◽  
Ch. Hirsch
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Leading Edge ◽  
Vortex Sheet ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Three Dimensional Flow ◽  
Linear Compressor ◽  
Dimensional Flow ◽  
Linear Compressor Cascade

Experimental data measured upstream, inside and downstream of a large scale linear compressor cascade with NACA 65-1810 blade profile are presented. The flow is surveyed at 15 traverse planes with 14 (in half span) × 24 (in pitch) points inside a passage, and 14 × 33 points downstream exit plane. The measurements are obtained with a small size five hole probe, and wall static pressure taps. It is observed that the three dimensional flow inside and behind the cascade is characterized, not only by the conventional aspects, such as leading edge horseshoe vortices, passage vortices, trailing edge vortex sheet and corner vortices, but also by two spiral node points, formed from the three dimensional separation lines, on suction surface, and the resulting concentrated vortices.

Experimental Investigation of Vortex Structure in Corner Region of a Linear Compressor Cascade

1991 ◽  
Author(s):  
Y. P. Tang ◽  
F. Chen ◽  
M. Z. Chen
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Vortex Structure ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Linear Compressor ◽  
Corner Flow ◽  
Linear Compressor Cascade ◽  
End Wall ◽  
Corner Vortex

A detailed experimental investigation was carried out to examine the vortex structure in the corner region (between the end wall and the suction surface of blades) of a linear compressor cascade. A corner vortex was identified in the corner flow in the experiment. The corner vortex sheds from the pressure-driven boundary layer on the end wall in a process of three-dimensional separation. It dominates the corner flow by the strong interaction with the main flow and the boundary layer on the suction surface of blade. The difference between the corner vortex and the well-known passage vortex is discussed. A topology of the vortex structure is proposed. Furthermore, the dynamic effects of the vortex structure has been investigated, which leads to a explanation for the mechanism of corner stall in compressor cascades.

scholarly journals Numerical Simulation of 3D Viscous Flow in a Linear Compressor Cascade With Tip Clearance

1994 ◽  
Author(s):  
Shun Kang ◽  
Charles Hirsch
Keyword(s):  
Viscous Flow ◽  
Flow Structure ◽  
Leading Edge ◽  
Secondary Flows ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Compressor Cascade ◽  
Tip Leakage Flow ◽  
Linear Compressor ◽  
Linear Compressor Cascade

A Navier-Stokes solver is applied to investigate the 3D viscous flow in a low speed linear compressor cascade with tip clearance at design and off-design conditions with two different meshes. The algebraic turbulence model of Baldwin-Lomax is used for closure. Relative motion between the blades and wall is simulated for one flow coefficient. Comparisons with experimental data, including flow structure, static and total pressures, velocity profiles, secondary flows and vorticity, are presented for the stationary wall case. It is shown that the code predicts well the flow structure observed in experiments and shows the details of the tip leakage flow and the leading edge horseshoe vortex.

scholarly journals Large-eddy simulation of 3-D corner separation in a linear compressor cascade

2015 ◽  
Vol 27 (8) ◽  
pp. 085105 ◽  
Author(s):  
Feng Gao ◽  
Wei Ma ◽  
Gherardo Zambonini ◽  
Jérôme Boudet ◽  
Xavier Ottavy ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Compressor Cascade ◽  
Linear Compressor ◽  
Corner Separation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Linear Compressor Cascade

Adaptive Detached Eddy Simulation of End-Wall Flow in a Linear Compressor Cascade

2020 ◽  
Author(s):  
Zifei Yin
Keyword(s):  
Pressure Coefficient ◽  
Detached Eddy Simulation ◽  
Compressor Cascade ◽  
Local Flow ◽  
Linear Compressor ◽  
Eddy Simulation ◽  
Wall Flow ◽  
Linear Compressor Cascade ◽  
End Wall ◽  
Des Model

Abstract Delayed detached eddy simulations and wall-modeled eddy simulations using the adaptive DES model were performed to simulate corner separation in the Ecole Centrale de Lyon linear compressor cascade. The adaptive DES model directly uses length scale to define eddy viscosity, which makes it nature to compute the model constant CDES dynamically. The dynamic procedure adapts viscosity to local flow and grid. Delayed detached eddy simulations, with and without the dynamic procedure, were performed to demonstrate the benefit of adapting viscosity to local flow. Recycling method was adopted to generate inflow unsteady turbulent boundary layer for wall-modeled eddy simulations. The wall-modeled eddy simulation showed improvement over delayed-DES, in terms of static pressure coefficient around the blade and total pressure loss at downstream locations.

scholarly journals Parameter study on numerical simulation of corner separation in LMFA-NACA65 linear compressor cascade

2017 ◽  
Vol 30 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Feng Gao ◽  
Wei Ma ◽  
Jinjing Sun ◽  
Jérôme Boudet ◽  
Xavier Ottavy ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Parameter Study ◽  
Compressor Cascade ◽  
Linear Compressor ◽  
Corner Separation ◽  
Linear Compressor Cascade
Sign in / Sign up

Export Citation Format

Share Document