scholarly journals 3D Flow Field Measurement Around a Rotating Stall Cell

Author(s):  
C. Palomba ◽  
P. Puddu ◽  
F. Nurzia

Rotating stall is an unsteady phenomenon that arises in axial and radial flow compressors. Under certain operating conditions a more or less regular cell of turbulent flow develops and propagates around the annulus at a speed lower than rotor speed. Recently little work has been devoted to the understanding of the flow field pattern inside a rotating cell. However, this knowledge could be of help in the understanding of the interaction between the cell and the surrounding flow. Such information could be extremely important during the modelling process when some hypothesis have to be made about the cell behaviour. A detailed experimental investigation has been conducted during one cell operation of an isolated low-speed axial flow compressor rotor using a slanted hot wire and an ensemble average technique based on the cell revolution time. The three flow field components have been measured on 9 axial section for 800 circumferential points and on 21 radial stations to give a complete description of the flow field upstream and downstream of the rotor. Interpretation of data can give a description of the mean flow field patterns inside and around the rotating cell.

1959 ◽  
Vol 81 (1) ◽  
pp. 24-34 ◽  
Author(s):  
Gino Sovran

The technique of smoke-flow visualization has been used to show clearly the action of the flow field upstream of a single rotor during rotating stall. The flow processes on the blades and in the blade passages of a stationary compressor cascade also have been observed using the same technique. An audio method of detecting rotating-stall patterns has been developed and has indicated that some compressor operating conditions at which no periodic flow disturbance was previously thought to occur actually contained rotating-stall patterns whose number of stalled regions changed very quickly from one value to another. The absolute speed of rotation of a stall zone was reduced to zero and its over-all shape clearly outlined by means of smoke visualization. The qualitative results of all these investigations have given a good physical picture of the rotating-stall phenomenon. Severe reverse flows were found to exist during rotating stall and these caused the formation of reversed flow regions extending upstream of a blade row. Furthermore, the distortions of the flow field in the vicinity of a blade row were found to be of such large magnitude that it does not seem likely that they can be described adequately by any linearized theory. Quantitative investigations were made into the effects of guide-vane turning and axial position on the rotating-stall characteristics of an axial-flow-compressor rotor. The absolute direction of the fluid entering such a configuration was found to affect nearly all facets of rotating-stall behavior.


Author(s):  
Jialing Lu ◽  
Wuli Chu ◽  
Yanhui Wu

In recent years endwall profiling has been well validated as a major new engineering design tool for the reduction of secondary loss in turbines. However, its application on compressors have been rarely performed and reported. This paper documents the findings of the analysis for diminishing compressor stator corner separation using endwall profiling; In the study, novel profiled endwalls were designed and numerically studied on a subsonic axial-flow compressor stage. The compressor stator endwalls were profiled on both axial and azimuthal directions. The results showed, the stator corner separation was significantly suppressed under all the operating conditions by implementing this profiled endwall. Significant improvements on stage pressure ratios and stage efficiency were observed. Detailed flow field changes, as well as endwall profiling methods are provided in the paper, so that the results of this research can be referenced to other compressor designs.


1977 ◽  
Vol 99 (1) ◽  
pp. 97-105 ◽  
Author(s):  
J. P. Gostelow

Measurements of the unsteady flow field over a rotor and within its wake are needed in the development of most turbomachines. The technique advocated is that of data acquisition by on-line computer, using the periodic passing of a blade as a phase reference. The phase-lock averaging process is described as is its use in reducing the noise of raw data traces. Measurements of the unsteady flow over a cascade and of the resulting boundary layer behavior are presented. The approach was used in interpreting the unsteady flow field of an axial-flow compressor rotor and the static pressure distribution over the rotor tip. Finally the application to centrifugal pumps is discussed, enabling the designer to obtain information on the suction pressures and the extent of any separated region.


2009 ◽  
Vol 2009 (0) ◽  
pp. 377-378 ◽  
Author(s):  
Hiroaki KIKUTA ◽  
Masato FURUKAWA ◽  
Satoshi GUNJISHIMA ◽  
Kenichiro IWAKIRI ◽  
Takuro KAMEDA

2006 ◽  
Vol 2006.2 (0) ◽  
pp. 149-150
Author(s):  
Sho BONKOHARA ◽  
Ken-ichiro IWAKIRI ◽  
Ryusuke OHTAGURO ◽  
Yasuhiro SHIBAMOTO ◽  
Masato FURUKAWA

Author(s):  
Qiushi Li ◽  
Tianyu Pan ◽  
Tailu Sun ◽  
Zhiping Li ◽  
Yifang Gong

Experimental investigations are conducted to study the instability evolution in a transonic axial flow compressor at four specific rotor speeds covering both subsonic and transonic operating conditions. Two routes of evolution to final instability are observed in the test compressor: at low rotor speeds, a disturbance in the rotor tip region occurs and then leads to rotating stall, while at high rotor speeds, a low-frequency disturbance in the hub region leads the compressor into instability. Different from stall and surge, this new type of compressor instability at high rotor speed is initiated through the development of a low-frequency axisymmetric disturbance at the hub, and we name it “partial surge”. The frequency of this low-frequency disturbance is approximately the Helmholtz frequency of the system and remains constant during instability inception. Finally, a possible mechanism for the occurrence of different instability evolutions and the formation of partial surge are also discussed.


Author(s):  
Daisuke Morita ◽  
Yutaka Fujita ◽  
Yutaka Ohta ◽  
Eisuke Outa

Transient characteristics as well as unsteady cascade flow fields of a three-stage axial flow compressor with compression plane wave injection from the compressor downstream were experimentally investigated by detail measurements of casing wall pressure fluctuations and unsteady velocity. The main feature of tested compressor is a shock tube facility connected in series to the compressor outlet duct in order to supply a compression plane wave which simulates the sudden rise of the compressor back pressure in a gas turbine system. Research attention is mainly focused on the unsteady behavior of surge and rotating stall coexistence phenomenon, and influence of the compression plane wave injection on the compressor operating conditions. When the compressor is connected to the capacity tank, surge and rotating stall occur simultaneously according to the capacitance increment of the whole compression system. The surge cycle changes irregularly with a throttling of the valve installed just behind the compressor and several different types of surge behaviors are observed. Furthermore, even though the compressor is operating under the stable condition, it goes into surge by injecting the compression plane wave.


2011 ◽  
Vol 20 (1) ◽  
pp. 6-12 ◽  
Author(s):  
Takayuki Hara ◽  
Daisuke Morita ◽  
Yutaka Ohta ◽  
Eisuke Outa

1998 ◽  
Vol 120 (3) ◽  
pp. 477-486 ◽  
Author(s):  
D. W. Thompson ◽  
P. I. King ◽  
D. C. Rabe

The effects of stepped-tip gaps and clearance levels on the performance of a transonic axial-flow compressor rotor were experimentally determined. A two-stage compressor with no inlet guide vanes was tested in a modern transonic compressor research facility. The first-stage rotor was unswept and was tested for an optimum tip clearance with variations in stepped gaps machined into the casing near the aft tip region of the rotor. Nine causing geometries were investigated consisting of three step profiles at each of three clearance levels. For small and intermediate clearances, stepped tip gaps were found to improve pressure ratio, efficiency, and flow range for most operating conditions. At 100 percent design rotor speed, stepped tip gaps produced a doubling of mass flow range with as much as a 2.0 percent increase in mass flow and a 1.5 percent improvement in efficiency. This study provides guidelines for engineers to improve compressor performance for an existing design by applying an optimum casing profile.


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