Experimental investigation of effects of suction side squealer tip on the aeroelastic stability of a linear oscillating compressor cascade

2016 ◽  
Vol 231 (11) ◽  
pp. 2120-2131 ◽  
Author(s):  
Hongwei Ma ◽  
Chao Jin ◽  
Wei Wei
Keyword(s):  
Dominant Role ◽  
Flow Characteristics ◽  
Suction Side ◽  
Tip Clearance ◽  
Test Case ◽  
Compressor Cascade ◽  
Aeroelastic Stability ◽  
Blade Vibration ◽  
Baseline Test ◽  
The Impact

This paper investigates the unsteady tip flow characteristics and their effects on the aeroelastic stability of a linear oscillating compressor cascade experimentally. Two test cases with different tip clearance configurations were tested, including a suction side squealer configuration and a control test. The unsteady pressure on the blade surface was measured at three blade vibration frequencies, and then was utilized to establish the aero-damping of the cascade. The results show that the impact of suction side squealer tip clearance on the tip clearance flow mainly exists at the region where it rolls up, and the unsteady flow induced by the vibration blade has no effect on the time-averaged result. In tip area of the blade, the leakage vortex plays a dominant role in determining the distribution of the first harmonic of unsteady static pressure. Compared with the baseline test case, the suction side squealer tip geometry exhibits better aerodynamic stability at high oscillating frequency. The aerodynamic response (phase angle) of the leakage flow lags behind the vibration of blade, and its streamwise variation implies strongly associated with the development of the tip leakage vortex. The spanwise three-dimensional unsteady characteristic of suction side squealer tip geometry is more obvious than that of the baseline test case.

Experimental Investigation Into the Effects of the Steady Wake-Tip Clearance Vortex Interaction in a Compressor Cascade

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Andreas Krug ◽  
Peter Busse ◽  
Konrad Vogeler
Keyword(s):  
Flow Field ◽  
Experimental Studies ◽  
Axial Compressor ◽  
Field Measurements ◽  
Tip Clearance ◽  
Compressor Cascade ◽  
Unsteady Interaction ◽  
Linear Compressor Cascade ◽  
Tip Clearance Vortex ◽  
The Impact

An important aspect of the aerodynamic flow field in the tip region of axial compressor rotors is the unsteady interaction between the tip clearance vortex (TCV) and the incoming stator wakes. In order to gain an improved understanding of the mechanics involved, systematic studies need to be performed. As a first step toward the characterization of the dynamic effects caused by the relative movement of the blade rows, the impact of a stationary wake-induced inlet disturbance on a linear compressor cascade with tip clearance will be analyzed. The wakes were generated by a fixed grid of cylindrical bars with variable pitch being placed at discrete pitchwise positions. This paper focuses on experimental studies conducted at the newly designed low-speed cascade wind tunnel in Dresden. The general tunnel configuration and details on the specific cascade setup will be presented. Steady state flow field measurements were carried out using five-hole probe traverses up- and downstream of the cascade and accompanied by static wall pressure readings. 2D-particle image velocimetry (PIV) measurements complemented these results by visualizing the blade-to-blade flow field. Hence, the structure of the evolving secondary flow system is evaluated and compared for all tested configurations.

Experimental Study of Effects of Grooved Tip Clearances on the Flow Field in a Compressor Cascade Passage

2010 ◽  
Author(s):  
Hongwei Ma ◽  
Jun Zhang ◽  
Jinghui Zhang ◽  
Zhou Yuan
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Suction Side ◽  
Tip Clearance ◽  
Pressure Probe ◽  
Leakage Flow ◽  
Compressor Cascade ◽  
High Loss ◽  
Static Pressure Distribution ◽  
Blade Tip

This paper presents an experimental investigation of effects of grooved tip clearances on the flow field of a compressor cascade. The tests were performed in a low-speed large-scale cascade respectively with two tip clearance configurations, including flat tip and grooved tip with a chordwise channel on the blade top. The flow field at 10% chord downstream from the cascade trailing edge was measured at four incidence angles using a mini five-hole pressure probe. The static pressure distribution was measured on the tip endwall. The results show that the pressure gradient from the pressure side to the suction side on the blade tip is reduced due to the existence of the channel. As a result, the leakage flow is weakened. The high-blockage and high-loss region caused by the leakage flow is narrower with the grooved tip. In the meantime, the leakage flow migrates to lower spanwise position. The combined result is that the flow capacity in the tip region is improved at the incidence angles of 0° and 5° with the grooved tip. However, the loss is slightly greater than that with the flat tip at all the incidence angles.

Effects of the Steady Wake-Tip Clearance Vortex Interaction in a Compressor Cascade: Part II — Numerical Investigations

2014 ◽  
Author(s):  
Peter Busse ◽  
Andreas Krug ◽  
Konrad Vogeler
Keyword(s):  
Steady State ◽  
Flow Field ◽  
Initial Conditions ◽  
Axial Compressor ◽  
Tip Clearance ◽  
Vortex Interaction ◽  
Compressor Cascade ◽  
Flow Phenomena ◽  
Tip Clearance Vortex ◽  
The Impact

An important aspect of the aerodynamic flow field in the tip region of axial compressor rotors is the unsteady interaction between the tip clearance vortex and the incoming stator wakes. In order to gain an improved understanding of the mechanics involved, systematic studies need to be performed. As a first step towards the characterisation of the dynamic effects caused by the relative movement of the blade rows, the impact of a stationary wake-induced inlet disturbance on a linear compressor cascade with tip clearance will be analyzed. The wakes were generated by a fixed grid of cylindrical bars with variable pitch being placed at discrete pitchwise positions. Part II of this two-part paper focuses on the numerical studies conducted with the scientific flow solver TRACE. Selected measurements, which are discussed in detail in the first part of this paper, are compared with steady state RANS simulation data to determine the validity of the computational model. For this purpose, the flow field obtained in the passage (PIV), at the cascade exit (five-hole probes) and the endwall pressure distributions were used. The presented numerical results show potentials and limitations of the steady state CFD for the prediction of the investigated flow phenomena. The computations provide the initial conditions for future unsteady calculations, and enable a separate depiction of potential effects of steady and unsteady wake-tip clearance vortex interaction.

The Influence of Suction-Side Winglet on Tip Leakage Flow in Compressor Cascade

2011 ◽  
Author(s):  
Jingjun Zhong ◽  
Shaobing Han ◽  
Peng Sun
Keyword(s):  
Numerical Study ◽  
Flow Behavior ◽  
Velocity Ratio ◽  
Suction Side ◽  
Tip Clearance ◽  
Compressor Cascade ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Cascade Flow ◽  
Highly Loaded

The effect of tip winglet on the aerodynamic performance of compressor cascade are mainly determined by the location of the tip winglet, the tip winglet geometry, the size of tip clearance, and the aerodynamic parameters of the cascade. In this paper, an extensive numerical study which includes three aspects has been carried out to investigate the effects of these influencing factors in a highly-loaded compressor cascade in order to give the guidance for the application of tip winglet to control the tip leakage in modern highly-loaded compressor. Firstly, the numerical method is validated by comparing the numerical results with available measured data. Results show that the numerical procedure is valid and accurate. Then, the cascade flow fields are interrogate to identify the physical mechanism of how suction-side winglet improve the cascade flow behavior. It is found that a significant tip leakage mass flow rate and aerodynamic loss reduction is possible by using proper tip winglet located near the suction side corner of the blade tip. Finally, an optimum width of the suction-side tip winglet is obtained by comparing the compressor performance with different clearances and incidences. The use of the suction-side winglet can reduce the pressure difference between the pressure and the suction sides of the blade and tip leakage velocity ratio. And the winglet also can compact the tip leakage vortex structure, which is benefit to decrease the loss of the tip secondary flow mixing with the primary flow.

Study of Three-Dimensional Viscous Flows in an Axial Compressor Cascade Including Tip Leakage Effects Using a SIMPLE-Based Algorithm

1986 ◽  
Vol 108 (1) ◽  
pp. 51-58 ◽  
Author(s):  
M. Pouagare ◽  
R. A. Delaney
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Simple Algorithm ◽  
Suction Side ◽  
Tip Clearance ◽  
High Loading ◽  
Leakage Flow ◽  
Compressor Cascade ◽  
Flow Phenomena

A multisweep space-marching solver based on a modified version of the SIMPLE algorithm was employed to study the three-dimensional flow field through a linear cascade. Three cases were tested: one with moderate loading, one with high loading, and one with high loading and tip clearance. The results of the numerical simulation were compared with available experimental measurements, and the agreement between the two was found satisfactory. The numerical simulation provided insight into several important endwall flow phenomena such as the interaction between the leakage and passage vortices, the interaction between the leakage vortex and the wake, the effect of leakage flow and loading on losses and secondary kinetic energy, the suction side corner separation, and the blowing of this separation by the leakage flow.

The Impact of Leakage Flow Tangential Velocity on Secondary Losses in a Shrouded Compressor Cascade

2012 ◽  
Author(s):  
J. W. Kim ◽  
J. S. Lee ◽  
S. J. Song ◽  
T. Kim ◽  
H-. W. Shin
Keyword(s):  
Secondary Flow ◽  
Tangential Velocity ◽  
Leading Edge ◽  
Suction Side ◽  
Leakage Flow ◽  
Compressor Cascade ◽  
Trailing Edge ◽  
Leading Edge Vortex ◽  
Edge Vortex ◽  
The Impact

Experimental and numerical studies have been performed to investigate the effects of the leakage flow tangential velocity on the secondary flow and aerodynamic loss in an axial compressor cascade with a labyrinth seal. Six selected leakage flow tangential (vy/Uhub = 0.15, 0.25, 0.35, 0.45, 0.55 and 0.65) have been tested. In addition to the classical “secondary” flow, shroud trailing edge vortex and shroud leading edge vortex are examined. The overall loss decreases with increasing leakage flow tangential velocity. Increased leakage flow tangential velocity underturns the hub endwall flows through the blade passage, weakening the suction side hub corner separation. Due to the suction effect of the downstream cavity, increasing leakage flow tangential velocity weakens the shroud trailing edge vortex. Also, increasing leakage flow tangential velocity strengthens the shroud leading edge vortex, weakening the pressure side leg of the horseshoe vortex, and, in turn, the passage vortex. Thus, the overall loss is reduced with increasing leakage flow tangential velocity.

Effect of Various Trench Designs on Axial Compressor Blade Tip Aerodynamics

2019 ◽  
Author(s):  
Ashwin Ashok ◽  
Patur Ananth Vijay Sidhartha ◽  
Shine Sivadasan
Keyword(s):  
Axial Compressor ◽  
Leading Edge ◽  
Suction Side ◽  
Horseshoe Vortex ◽  
Tip Clearance ◽  
Compressor Cascade ◽  
Tip Leakage Vortex ◽  
Stall Margin ◽  
Casing Treatment ◽  
Tip Leakage

Abstract Tip clearance of axial compressor blades allows leakage of the flow, generates significant losses and reduces the compressor efficiency. The present paper aims to discuss the axial compressor tip aerodynamics for various configurations of tip gap with trench. The various configurations are obtained by varying the clearance, trench depth, step geometry and casing contouring. In this paper the axial compressor aerodynamics for various configurations of tip gap with trench have been studied. The leakage flow structure, vorticity features and entropy generations are analyzed using RANS based CFD. The linear compressor cascade comprises of NACA 651810 blade with clearance height varied from 0.5% to 2% blade span. Trail of the tip leakage vortex and the horseshoe vortex on the blade suction side are clearly seen for the geometries with and without casing treatments near the stalling point. Since the trench side walls are similar to forward/backing steps, a step vortex is observed near the leading edge as well as trailing edge of the blade and is not seen for the geometry without the casing treatment. Even though the size of the tip leakage vortex seams to be reduces by providing a trench to the casing wall over the blade, the presence of additional vortices like the step vortex leads to comparatively higher flow losses. An increase in overall total pressure loss due to the application of casing treatment is observed. However an increase in stall margin for the geometries with casing is noted.

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.

Experimental Investigation on Tip Clearance Flow of Compressor Cascade With Blade Tip Winglet

2012 ◽  
Author(s):  
Shaobing Han ◽  
Jingjun Zhong ◽  
Huawei Lu ◽  
Xiaoxu Kan ◽  
Haiyang Gao
Keyword(s):  
Flow Field ◽  
Passive Control ◽  
Control Strategies ◽  
Suction Side ◽  
Tip Clearance ◽  
Compressor Cascade ◽  
Tip Leakage Flow ◽  
Tip Clearance Flow ◽  
Clearance Flow ◽  
Blade Tip

This paper presents the results of experimental research of flow in an axial compressor cascade with different types of winglet on the blade tip, which consists of a suction-side winglet, pressure-side winglet and the combined winglet. The detailed tip leakage flow field with different winglet was described with total pressure loss coefficient, secondary streamline and axial vorticity on the cascade exit flow field. The mechanisms of the three passive control methods were illuminated. The result indicated that the tip clearance flow strengths could be reduced in all the three control strategies. The compressor aerodynamic performance could be improved via the addition of tip winglets. The suction-side winglet had the best effect on the cascade flow field, and the strength of leakage vortex and the associated mixture losses were reduced.

Sign in / Sign up

Export Citation Format

Share Document