Criteria for Spike Initiated Rotating Stall

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Huu Duc Vo ◽  
Choon S. Tan ◽  
Edward M. Greitzer
Keyword(s):  
Computational Study ◽  
Axial Compressor ◽  
Leading Edge ◽  
Rotating Stall ◽  
Short Length ◽  
Tip Clearance ◽  
Length Scale ◽  
Stall Inception ◽  
Tip Clearance Flow ◽  
Clearance Flow

A computational study to define the phenomena that lead to the onset of short length-scale (spike) rotating stall disturbances has been carried out. Based on unsteady simulations, we hypothesize there are two conditions necessary for the formation of spike disturbances, both of which are linked to the tip clearance flow. One is that the interface between the tip clearance and oncoming flows becomes parallel to the leading-edge plane. The second is the initiation of backflow, stemming from the fluid in adjacent passages, at the trailing-edge plane. The two criteria also imply a circumferential length scale for spike disturbances. The hypothesis and scenario developed are consistent with numerical simulations and experimental observations of axial compressor stall inception. A comparison of calculations for multiple blades with those for single passages also allows statements to be made about the utility of single passage computations as a descriptor of compressor stall.

Criteria for Spike Initiated Rotating Stall

2005 ◽  
Author(s):  
Huu Duc Vo ◽  
Choon S. Tan ◽  
Edward M. Greitzer
Keyword(s):  
Computational Study ◽  
Axial Compressor ◽  
Leading Edge ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Length Scale ◽  
Stall Inception ◽  
Tip Clearance Flow ◽  
Clearance Flow ◽  
Circumferential Extent

A computational study to define the phenomena that lead to the onset of short length-scale (spike) rotating stall disturbances has been carried out. Unsteady simulations show there are two conditions necessary for the formation of spike disturbances, both of which are linked to the tip clearance flow. One is that the interface between the tip clearance and oncoming flows becomes parallel to the leading edge plane. The second is the initiation of backflow, stemming from the fluid in adjacent passages, at the trailing edge plane. The two criteria also imply a length scale circumferential extent of spike disturbances. The scenario developed is consistent with numerical simulations as well as with experimental observations of axial compressor stall inception. A comparison of calculations for multiple blades with those for single passages also allows statements to be made about the utility of single passage computations as a descriptor of compressor stall.

Short and Long Length-Scale Disturbances Leading to Rotating Stall in an Axial Compressor Stage With Different Stator/Rotor Gaps

2001 ◽  
Author(s):  
M. Inoue ◽  
M. Kuroumaru ◽  
S. Yoshida ◽  
M. Furukawa
Keyword(s):  
High Frequency ◽  
Wavelet Transforms ◽  
Wave Length ◽  
Axial Compressor ◽  
Leading Edge ◽  
Rotating Stall ◽  
Short Length ◽  
Length Scale ◽  
Compressor Stage ◽  
Stall Inception

The transient processes of rotating stall evolution have been investigated experimentally in a low-speed axial compressor stage with three stator-rotor gaps. The pressure traces at 8 circumferential locations on the casing wall near the rotor leading edge have been analyzed by the wavelet transforms. With the appropriate mother wavelets, the evolution of short and long length-scale disturbances leading to the stall can be captured clearly. Behavior of these disturbances is different depending on the stator-rotor gap. For the large and middle gap, the stall inception is detected by a spiky short length-scale disturbance, and the number of spiky waves increases to generate the high frequency waves. They becomes the short length-scale part-span stall cells at the mild stall for the large gap, while they turn into a big stall cell with growth of a long length-scale disturbance for the middle gap. In the latter case, therefore, the stalling process was identified with ‘high frequency stall inception’. For the small stator-rotor gap, the stalling process is identified with ‘long wave-length stall inception’, and supported the recent computational model for the short wave-length stall inception by showing that closing the rotor-stator gaps suppressed the growth of short length-scale disturbances. From the measurement of the pressure field traces on the casing wall, a hypothesis has been built up that the short length-scale disturbance should result from a separation vortex from a blade surface to reduce circulation. The processes of the stall evolution are discussed on this hypothesis.

An Experimental and Computational Investigation of Tip Clearance Flow and Its Impact on Stall Inception

2010 ◽  
Author(s):  
Matthew A. Bennington ◽  
Mark H. Ross ◽  
Joshua D. Cameron ◽  
Scott C. Morris ◽  
Juan Du ◽  
...  
Keyword(s):  
Axial Compressor ◽  
Axial Flow ◽  
Leading Edge ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Momentum Balance ◽  
Tip Leakage Flow ◽  
Stall Inception ◽  
Tip Clearance Flow ◽  
Clearance Flow

A numerical and experimental study was conducted to investigate the tip clearance flow and its relationship to stall in a transonic axial compressor. The CFD results were used to identify the existence of an interface between incoming axial flow and the reverse tip clearance flow. A surface streaking method was used to experimentally identify this interface as a line of zero axial shear stress at the casing. The position of this line, denoted xzs, moved upstream with decreasing flow coefficient in both the experiments and computations. The line was found to be at the rotor leading edge plane when the compressor stalled. Further measurements using rotor offset and inlet distortion further corroborated these results, and demonstrated that the movement of the interface upstream of the leading edge leads to the generation of rotating (“spike”) disturbances. Stall was therefore interpreted to occur as a result of a critical momentum balance between the approach fluid and the tip-leakage flow.

Short and Long Length-Scale Disturbances Leading to Rotating Stall in an Axial Compressor Stage With Different Stator/Rotor Gaps

2002 ◽  
Vol 124 (3) ◽  
pp. 376-384 ◽  
Author(s):  
M. Inoue ◽  
M. Kuroumaru ◽  
S. Yoshida ◽  
M. Furukawa
Keyword(s):  
High Frequency ◽  
Wavelet Transforms ◽  
Axial Compressor ◽  
Leading Edge ◽  
Rotating Stall ◽  
Short Length ◽  
Length Scale ◽  
Compressor Stage ◽  
Stall Inception ◽  
High Frequency Waves

The transient processes of rotating stall evolution have been investigated experimentally in a low-speed axial compressor stage with three stator-rotor gaps. The pressure traces at eight circumferential locations on the casing wall near the rotor leading edge have been analyzed by the wavelet transforms. With the appropriate mother wavelets, the evolution of short and long length-scale disturbances leading to the stall can be captured clearly. Behavior of these disturbances is different depending on the stator-rotor gap. For the large and middle gap, the stall inception is detected by a spiky short length-scale disturbance, and the number of spiky waves increases to generate the high frequency waves. They become the short length-scale part-span stall cells at the mild stall for the large gap, while they turn into a big stall cell with growth of a long length-scale disturbance for the middle gap. In the latter case, therefore, the stalling process was identified with “high-frequency stall inception.” For the small stator-rotor gap, the stalling process is identified with “long wavelength stall inception” and supported the recent computational model for the short wavelength stall inception by showing that closing the rotor-stator gaps suppressed the growth of short length-scale disturbances. From the measurement of the pressure field traces on the casing wall, a hypothesis has been developed that the short length-scale disturbance should result from a separation vortex from a blade surface to reduce circulation. The processes of the stall evolution are discussed on this hypothesis.

Short Length-Scale Rotating Stall Inception in a Transonic Axial Compressor: Criteria and Mechanisms

2006 ◽  
Author(s):  
Chunill Hah ◽  
Jo¨rg Bergner ◽  
Heinz-Peter Schiffer
Keyword(s):  
Axial Compressor ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Stall Inception ◽  
Tip Clearance Flow ◽  
Transonic Compressor ◽  
Eddy Simulation ◽  
Clearance Flow ◽  
Flow Mechanisms ◽  
Tip Clearance Vortex

The current paper reports on investigations aimed at advancing the understanding of the flow mechanism that leads to the onset of short-length scale rotating stall in a transonic axial compressor. Experimental data show large oscillation of the tip clearance vortex as the rotor operates near the stall condition. Inception of spike-type rotating stall is also measured in the current transonic compressor with high response pressure transducers. Computational studies of a single passage and the full annulus were carried out to identify flow mechanisms behind the spike-type stall inception in the current transonic compressor rotor. Steady and unsteady single passage flow simulations were performed, first to get insight into the interaction between the tip clearance vortex and the passage shock. The conventional Reynolds-averaged Navier-Stokes method with a standard turbulence closure scheme does not accurately reproduce tip clearance vortex oscillation and the measured unsteady pressure field. Consequently, a Large Eddy Simulation (LES) was carried out to capture more relevant physics in the computational simulation of the rotating stall inception. The unsteady random behavior of the tip clearance vortex and it’s interaction with the passage shock seem to be critical ingredients in the development of spike-type rotating stall in a transonic compressor. The Large Eddy Simulation was further extended to the full annulus to identify flow mechanisms behind the measured spike-type rotating stall inception. The current study shows that the spike-type rotating stall develops after the passage shock is fully detached from the blade passages. Interaction between the tip clearance vortex and the passage shock creates a low momentum area near the pressure side of the blade. As the mass flow rate decreases, this low momentum area moves further upstream and reversed tip clearance flow is initiated at the trailing edge plane. Eventually, the low momentum area near the pressure side reaches the leading edge and forward spillage of the tip clearance flow occurs. The flows in the affected blade passage or passages then stall. As the stalled blade passages are formed behind the passage shock, the stalled area rotates counter to the blade rotation just like the classical Emmon’s type rotating stall. Both the measurements and the computations show that the rotating stall cell covers one to two blade passage lengths and rotates at roughly 50% of the rotor speed.

Short Length-Scale Rotating Stall Inception in a Transonic Axial Compressor: Experimental Investigation

2006 ◽  
Author(s):  
Jo¨rg Bergner ◽  
Matthias Kinzel ◽  
Heinz-Peter Schiffer ◽  
Chunill Hah
Keyword(s):  
Experimental Investigation ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Wall Pressure ◽  
Tip Clearance ◽  
Stall Inception ◽  
Tip Clearance Flow ◽  
Clearance Flow ◽  
Contour Plots ◽  
Transonic Axial Compressor

To improve the understanding of spike-type stall inception of a transonic axial compressor, measurements of the unsteady static pressure in the rotor endwall region are analyzed. At design speed, a detailed experimental investigation of the unsteadiness of the pressure field at the rotor endwall at near stall condition shows a strong fluctuation of the tip clearance flow. Both vortex strength and -trajectory oscillate randomly. Analysis of the wall pressure time histories during stall inception suggests that spike-type disturbances of the flow field correlate with an upstream motion of one blade passages shock front. In addition, the evolution of a stall cell could be visualized by means of static wall-pressure contour plots.

Experimental Study of Modal Disturbance and Rotating Stall Distribution

2013 ◽  
Vol 718-720 ◽  
pp. 1804-1810
Author(s):  
An Qing Lai ◽  
Jun Hu ◽  
Liang Li ◽  
Ju Luo
Keyword(s):  
Axial Compressor ◽  
Leading Edge ◽  
Propagation Speed ◽  
Axial Direction ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Rotor Speed ◽  
Stall Inception ◽  
Tip Clearance Flow ◽  
Modal Type

To execute stall active control technology effectively and make clear of stall inception induced by modal disturbance, this paper carries out the correlative research on modal disturbance and rotating stall on the two-stage low-speed axial compressor. The results indicate that the stall inception of the compressor is modal style and the modal oscillation propagates at 38% rotor speed while the stall cell propagation speed is 42% rotor speed. The phase angles of modal oscillation and rotating stall along the axial direction are different, but their trajectories are both similar to the blade passage shape. The stall mechanisms of modal-type and spike-type inceptions are different. It doesnt appear that leading-edge tip clearance flow spillage blow the blade tip while the modal-type stall formation.

Role of Blade Passage Flow Structurs in Axial Compressor Rotating Stall Inception

1999 ◽  
Vol 121 (4) ◽  
pp. 735-742 ◽  
Author(s):  
D. A. Hoying ◽  
C. S. Tan ◽  
Huu Duc Vo ◽  
E. M. Greitzer
Keyword(s):  
Leading Edge ◽  
Rotating Stall ◽  
Short Length ◽  
Tip Clearance ◽  
Length Scale ◽  
Central Feature ◽  
Local Flow ◽  
Stall Inception ◽  
Blade Passage ◽  
Tip Clearance Vortex

The influence of three-dimensional flow structures within a compressor blade passage has been examined computationally to determine their role in rotating stall inception. The computations displayed a short length-scale (or spike) type of stall inception similar to that seen in experiments; to the authors’ knowledge this is the first time such a feature has been simulated. A central feature observed during the rotating stall inception was the tip clearance vortex moving forward of the blade row leading edge. Vortex kinematic arguments are used to provide a physical explanation of this motion as well as to motivate the conditions for its occurrence. The resulting criterion for this type of stall inception (the movement of the tip clearance vortex forward of the leading edge) depends upon local flow phenomena related to the tip clearance with the implication that for this and possibly other stall mechanisms the flow structure within the blade passages must be addressed to explain the stability of an axial compression system that exhibits such short length-scale disturbances.

Performance and Short Length-Scale Disturbance Generation in an Axial Compressor With Non-Uniform Tip Clearance

2008 ◽  
Author(s):  
Scott C. Morris ◽  
Joshua D. Cameron ◽  
Matthew A. Bennington ◽  
G. Scott McNulty ◽  
Aspi Wadia
Keyword(s):  
Flow Field ◽  
Mass Flow ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Short Length ◽  
Tip Clearance ◽  
Length Scale ◽  
Stagnation Temperature ◽  
Local Flow ◽  
Stall Inception

The performance, efficiency, and stall inception of an axial compressor was investigated experimentally with small levels of rotor centerline offset. The measurements were acquired using a high-speed, single-stage compressor. The rotor was levitated magnetically during operation which allowed precise positioning of the rotor centerline within the circular casing. The offset magnitude used in this study was 0.23% of the rotor tip chord, equivalent to approximately 24% of the nominal gap value. The resulting asymmetry in the tip gap resulted in circumferential and radial variations in the measured stagnation pressure and stagnation temperature downstream of the stage. However, the spatially averaged performance of the compressor was not measurably different from that obtained with a concentric rotor. An array of unsteady (Kulite) pressure transducers was used to investigate the flow field during stall inception. These measurements were recorded during transient throttle movements which quickly decreased the mass flow in the compressor until the onset of rotating stall. A second set of measurements was acquired during quasi-transient throttling starting from a mass flow about 1% larger than the stalling mass flow. In both the symmetric and offset cases the flow breakdown was consistent with spike type inception. The measurements with offset indicated that the asymmetries in the local compressor flow field produced significant changes in the number of short-length scale rotating disturbances observed during throttling to stall. These disturbances appeared in the region of the annulus where the local flow coefficient was lowest and usually decayed upon rotating to the higher flow region. In this way, the addition of very small amounts of rotor offset tended to fix the disturbance generation location in the stationary reference frame. This was in contrast to the symmetric tip clearance case where the location of spike generation appeared stochastic.

scholarly journals Role of Blade Passage Flow Structures in Axial Compressor Rotating Stall Inception

1998 ◽  
Author(s):  
Donald A. Hoying ◽  
Choon S. Tan ◽  
Huu Duc Vo ◽  
Edward M. Greitzer
Keyword(s):  
Leading Edge ◽  
Rotating Stall ◽  
Short Length ◽  
Tip Clearance ◽  
Flow Structures ◽  
Length Scale ◽  
Central Feature ◽  
Local Flow ◽  
Stall Inception ◽  
Blade Passage

The influence of three-dimensional flow structures within a compressor blade passage has been examined computationally to determine their role in rotating stall inception. The computations displayed a short length-scale (or spike) type of stall inception similar to that seen in experiments; to the authors’ knowledge this is the first time such a feature has been simulated. A central feature observed during the rotating stall inception was the tip clearance vortex moving forward of the blade row leading edge. Vortex kinematic arguments are used to provide a physical explanation of this motion as well as to motivate the conditions for its occurrence. The resulting criterion for this type of stall inception (which appears generic for axial compressors with tip-critical flow fields) depends upon local flow phenomena related to the tip clearance and it is thus concluded that the flow structure within the blade passages must be addressed to explain the stability of an axial compression system which exhibits such short length-scale disturbances.

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