Numerical analysis of the effects of circumferential groove casing suction in a counter-rotating axial flow compressor

2020 ◽  
pp. 095765092095169
Author(s):  
Tian Liang ◽  
Bo Liu ◽  
Stephen Spence ◽  
Liying Jiao
Keyword(s):  
Axial Flow ◽  
Main Flow ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Stall Margin ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Circumferential Groove ◽  
Flow Compressor ◽  
The Impact

To extend the current understanding of the circumferential groove casing suction applied to a counter-rotating axial flow compressor, the impact of different axial locations of the circumferential suction groove on the characteristics of the tip leakage flow (TLF) and the corresponding physical mechanisms producing the stability enhancement have been studied based on validated numerical simulations. The results show that the optimal location for the suction groove is at around 20% axial chord, which demonstrated a high potential for reducing additional stall mass flow coefficient with about 8.4% increment in the stall margin. After the casing suction groove was applied, the interface between the incoming main flow and TLF was pushed significantly downstream in the second rotor. The blade loading in the region below the groove, the tip leakage flow angle and the reversed axial momentum flux injected into main flow passage through the tip gap were all reduced, which contributed to the stall margin improvement. Detailed analysis of the tip leakage flow structures showed that the TLF originating from different chord locations played different roles in the stall inception process. It was found to be more effective to improve stall margin and adiabatic efficiency by controlling the front part of the TLF, which was most sensitive.

The Effects on Stability, Performance, and Tip Leakage Flow of Recirculating Casing Treatment in a Subsonic Axial Flow Compressor

2016 ◽  
Author(s):  
Wei Wang ◽  
Wuli Chu ◽  
Haoguang Zhang ◽  
Yanhui Wu
Keyword(s):  
Axial Flow ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage Vortex ◽  
Stall Inception ◽  
Casing Treatment ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Overall Performance ◽  
Flow Compressor

Recirculating casing treatment (RCT) was studied in a subsonic axial flow compressor experimentally and numerically. The RCT was parameterized with the injector throat height and circumferential coverage percentage (ccp) to investigate its influence on compressor stability and on the overall performance in the experimentation. The injector throat height varied from 2 to 6 times the height of the rotor tip clearance, and the ccp ranged from 8.3% to 25% of the casing perimeter. Various RCT configurations were achieved with a modular design procedure. The rotor casing was instrumented with fast-response pressure transducers to detect the stall inception, rotational speed of stall cells, and pressure flow fields. Whole-passage unsteady simulations were also implemented for the RCT and solid casing to understand the flow details. Results indicate that both the compressor stability and overall performance can be improved through RCT with appropriate geometrical parameters. The effect of injector throat height on the stability depends on the choice of ccp, i.e., interaction effect exists. In general, the RCT with a moderate injector throat height and a large circumferential coverage is the optimal choice. Phase-locked pattern of the casing wall pressure reveals a weakened tip leakage vortex under the effect of RCT compared with the solid casing. The numerical results show that the RCT has a substantial effect on tip blockage even when the blade passages break away from the domain of RCT. The reduction of tip blockage induced by the tip leakage vortex is the main reason for the extension of stable operation range. The unsteadiness of double-leakage flow is detected both in the experiment and in numerical simulations. The pressure fluctuations caused by double-leakage flow are depressed with RCT. This observation indicates reduced losses related with the double-leakage flow. Although the stall inception is not changed by implementing RCT, the stall pattern is altered. The stall with two cells is detected in RCT compared with the solid casing with only one stall cell.

Effects of tip clearance size on the unsteady flow behaviors and performance in a counter-rotating axial flow compressor

2017 ◽  
Vol 233 (3) ◽  
pp. 1059-1070 ◽  
Author(s):  
Xiaochen Mao ◽  
Bo Liu ◽  
Hang Zhao
Keyword(s):  
Unsteady Flow ◽  
Incidence Angle ◽  
Axial Flow ◽  
Leading Edge ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Flow Compressor

This paper presents the studies performed to better understand the effects of increased tip clearance size on the unsteady flow behaviors and overall performance under the rotor–rotor interaction environment in a counter-rotating axial flow compressor. The investigation method is based on the three-dimensional unsteady Reynolds-averaged Navier–Stokes simulations. The results show that the intensified tip leakage flow in front rotor (R1) caused by the increased tip clearance size will lead to the growth of incoming incidence angle near the tip of the rear rotor (R2). The increasing of double leakage flow range plays a significant role in the sensitivity of the efficiency to tip clearance size and its extent is enlarged gradually with the increase of tip clearance size. As the tip clearance size is increased to 1.5τ (τ represents the designed tip clearance size) from 0.5τ, the results of the fast Fourier transform for the static pressure near blade tip show that two other new fluctuating frequency components appear due to the happening of tip leakage flow self-unsteadiness in R1 and R2, respectively. Additionally, the fluctuating strength near the tip in R2 is significantly increased. However, both the overall fluctuation in R1 caused by the potential effect from downstream and the oscillation in the hub corner on the pressure side of R2 are decreased obviously. The relative inflow angle tends to increase when the incoming wakes and tip leakage flow from R1 encounter the blade leading edge of R2, which leads to the result that the trajectory of tip leakage flow is shifted more upstream.

Influence of Blade Tip Surface Roughness On the Performance of a Single Stage Axial Flow Compressor

2021 ◽  
Author(s):  
Pradyumna Kodancha ◽  
Pramod Salunkhe
Keyword(s):  
Surface Roughness ◽  
Axial Flow ◽  
Single Stage ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Blade Tip ◽  
Flow Compressor

Abstract Numerical investigations are carried out in a single-stage subsonic axial flow compressor to unravel the influence of blade tip surface roughness on the tip leakage flow characteristics and hence the compressor performance. The studies were carried out at different tip clearance of 0.38?, 0.77?, 1.15? and 1.54? and blade tip surface roughness of 0.31? and 0.62?. The tip clearance of 0.38? with blade tip surface roughness of 0.62? resulted in the highest stall margin and pressure rise of 20.3% and 4.3%, respectively. The compressor blade loading was found to be improved by 5.9% after incorporating the blade tip surface roughness. The iso-surfaces of vorticity contour plotted using the Q-criterion showed the reduction in strength of the tip leakage vortex. The tip leakage trajectory was found to be shifted towards the suction surface of the blade for the blade tip with surface roughness. This positive alteration in the tip leakage flow structure led to the improved performance for the blade tip with surface roughness.

The Effects of Stepped Tip Gap on Performance and Flowfield of a Subsonic Axial-Flow Compressor Rotor

2005 ◽  
Author(s):  
Xingen Lu ◽  
Junqiang Zhu ◽  
Wuli Chu ◽  
Rugen Wang
Keyword(s):  
Axial Flow ◽  
Operating Conditions ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Small Clearance ◽  
Clearance Level ◽  
Flow Compressor

This paper investigates the flow field at the tip region of compressor rotor. In particular, the effect of stepped tip gaps on the performance and flowfield of an axial-flow compressor rotor was reviewed using both experimental and computational methods. An axial compressor rotor with no inlet guide vanes was tested under subsonic condition. A parametric study of clearance levels and step profiles was performed using eight different casing geometries. This study was aimed at comparing compressor performance in specified configurations. The experimental results showed that the inclusion of stepped tip gaps with the small clearance level gave increased pressure ratio, efficiency, and stall margin throughout the mass flow range at both speeds. However, when using medium and large clearance level, the benefits of stepped tip gaps were not noticed for all rotor operating conditions if compared with the baseline case. Steady-state Navier-Stokes analyses were performed for cases involving small clearance level and stepped tip gap geometries. They highlighted the mechanisms associated with performance improvement. The numerical procedure correctly predicted the overall effects of stepped tip gaps. Detailed numerical simulation results showed that the interaction between the stepped groove flow and blade passage flow could entrain the blockage produced by upstream tip leakage flow into the tip gap of adjacent blades of the compressor rotor. It is through this process that stepped tip gaps can help dissipating blockage that was caused by upstream tip leakage flow. Thus the path and extent of the blockage in the tip region is altered to increase the passage throughflow area and so, the rotor performance can be improved.

Analysis of Three-Dimensional Viscous Flow in a Supersonic Axial Flow Compressor Rotor With Emphasis on Tip Leakage Flow

1992 ◽  
Author(s):  
G. Perrin ◽  
F. Leboeuf ◽  
W. N. Dawes
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Flow ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Axial Velocity Component ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Flow Compressor

A three-dimensional computation has been performed for a supersonic axial flow compressor rotor by solving the Navier-Stokes equations. The results of the computation are used to analyse the tip leakage flow in more detail. As well as the global behaviour of the tip leakage vortex, the analysis focuses on the origins of this vortex. It is shown that the main source of its vorticity is the shear layer at the tip of the blade associated with the shedding of the blade loading. A separation occurs, with respect to the axial velocity component, as the jet leakage flow, crossing the clearance gap, encounters the upstream incoming flow. Although the entropy increase of this separation is low, it has a strong effect on the mixing around the leakage vortex. Overall, for this compressor and the choosen operating point, the tip leakage effects are localised near the tip wall and suction side of the blade.

Analysis of Rotor-Stator-Interaction and Blade-to-Blade Measurements in a Two Stage Axial Flow Compressor

2009 ◽  
Author(s):  
Marco Ernst ◽  
Armin Michel ◽  
Peter Jeschke
Keyword(s):  
Frequency Analysis ◽  
Axial Flow ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Two Stage ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Flow Phenomena ◽  
Rotor Stator Interaction ◽  
Flow Compressor

In order to improve unsteady CFD analysis for turbomachinery applications there is still the need for high quality experimental data for validation. The first aim of this paper is to represent a unique work in providing unsteady data for the purpose of a CFD test case. Secondly, a detailed analysis of rotor-stator-interaction in a multi-stage compressor is performed by means of accompanying frequency analysis of the blading and the tip leakage flow for different indexing positions. The transonic two stage axial flow compressor is equipped with integrally bladed rotors and vanes with hub and tip shrouds with regard to a modern high pressure jet engine compressor. For detailed flow measurements both intrusive and non-intrusive measurement techniques were used. Beside pressure probes mounted with a semiconductor and micro strain gauges applied to the blades and vanes, a 3 Component Doppler Laser-Two-Focus Velocimeter was used. The results of the time resolved pressure traverse measurements in the axial gaps as well as the analysis of the tip leakage flow show the propagation of the wakes and the potential upstream influence which can be clearly detected by the blade passing frequencies as well. Additionally, the results of the blade-to-blade measurements impart an idea of the intra-rotor-transport of the fluid and the flow phenomena within the rotor. Beside detailed flow analysis, the preferential aim of this paper is to establish a method for the detection of flow phenomena due to blade-row-interaction by means of a frequency analysis.

Linear to Nonlinear Transition During the Spike Stall Process in a Low Speed Axial Flow Compressor Rotor

2016 ◽  
Author(s):  
Yuping Qian ◽  
Yuzhi Jin ◽  
Weilin Zhuge ◽  
Yangjun Zhang ◽  
Yajun Lu
Keyword(s):  
Axial Flow ◽  
Second Order ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Stall Inception ◽  
Compression System ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Flow Compressor

A linear to nonlinear transition during the spike stall process of an axial flow compressor rotor is presented. Recently, some researchers thought that spike stall inception is directly induced by the tip leakage flow. However, the authors utilized unsteady full annular simulations and found that a second-order disturbance appeared two revolutions before the breakdown of the tip leakage flow in an axial rotor, associate with spike stall inception while the tip leakage flow is still stable. This second-order disturbance grew rapidly in the next two revolutions and the process was unlike the low order disturbance development in modal stall inception. The response of the compression system was still linear in this process. The rapidly developing second-order disturbance made the tip leakage flow unstable, leading to the start of spike stall inception. The response of the compression system became nonlinear in this process.

Analysis of Rotor-Stator-Interaction and Blade-to-Blade Measurements in a Two Stage Axial Flow Compressor

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Marco Ernst ◽  
Armin Michel ◽  
Peter Jeschke
Keyword(s):  
Frequency Analysis ◽  
Axial Flow ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Two Stage ◽  
Tip Leakage ◽  
Axial Flow Compressor ◽  
Flow Phenomena ◽  
Rotor Stator Interaction ◽  
Flow Compressor

In order to improve unsteady CFD analysis for turbomachinery applications, there is still the need for high quality experimental data for validation. The first aim of this paper is to represent a unique work in providing unsteady data for the purpose of a CFD test case. Second, a detailed analysis of rotor-stator-interaction in a multistage compressor is performed by means of accompanying frequency analysis of the blading and the tip leakage flow for different indexing positions. The transonic two stage axial flow compressor is equipped with integrally bladed rotors and vanes with hub and tip shrouds with regard to a modern high pressure jet engine compressor. For detailed flow measurements both intrusive and nonintrusive measurement techniques were used. Beside pressure probes mounted with a semiconductor and microstrain gauges applied to the blades and vanes, a three component Doppler laser-two-focus velocimeter was used. The results of the time resolved pressure traverse measurements in the axial gaps as well as the analysis of the tip leakage flow show the propagation of the wakes and the potential upstream influence, which can be clearly detected by the blade passing frequencies as well. Additionally, the results of the blade-to-blade measurements impart an idea of the intrarotor-transport of the fluid and the flow phenomena within the rotor. Beside the detailed flow analysis, the preferential aim of this paper is to establish a method for the detection of flow phenomena due to the blade-row-interaction by means of a frequency analysis. This paper shows that a correlation of the fast Fourier transform results of strain gauges and semiconductor probes in the axial gaps and tip leakage flow region is a very promising starting point, especially for the analysis of forced response operating points.

Sign in / Sign up

Export Citation Format

Share Document