Effect of the Inlet Velocity Profile in the Three-Dimensional Flow in a Rear Axial Compressor Stage

1988 ◽  
Vol 110 (4) ◽  
pp. 434-440 ◽  
Author(s):  
V. Cyrus
Keyword(s):  
Velocity Profile ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Design Flow ◽  
Flow Coefficient ◽  
Intensity Level ◽  
Compressor Stage ◽  
Three Dimensional Flow ◽  
Inlet Velocity ◽  
Dimensional Flow

A detailed investigation of the three-dimensional flow was carried out in a low-speed rear axial compressor stage with an aspect ratio of 1. Experimental data were obtained for both an inlet velocity profile with thin endwall boundary layer thickness and a distorted inlet velocity profile with a high turbulence intensity level. The distortion was produced by a specially designed screen. The flow mechanism in the rotor and stator blade rows is analyzed for these two velocity profiles at the design flow coefficient.

Experimental Study of Three-Dimensional Flow in an Axial Compressor Stage

1986 ◽  
Author(s):  
Vaclav Cyrus
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Loss Coefficient ◽  
Flow Coefficient ◽  
Compressor Stage ◽  
Three Dimensional Flow ◽  
High Loss ◽  
Dimensional Flow ◽  
Blade Row ◽  
Stator Blade

A detailed investigation of three-dimensional flow was carried out in a low speed axial compressor stage with aspect ratio of 2. Data were obtained over a range of flow coefficient. The origin of large high loss regions in each blade row was found by means of a diffusion factor. The loss coefficient of rotor and stator blade rows was established on the basis of both rotating and stationary pressure probes. The predicted rotor and stator loss coefficient was compared with experiment.

Approximate Three-Dimensional Flow Theory for Axial Turbo-Machines

1963 ◽  
Vol 14 (2) ◽  
pp. 125-142 ◽  
Author(s):  
W. T. Howell
Keyword(s):  
Velocity Profile ◽  
Temperature Rise ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Three Dimensional Flow ◽  
Axial Compressors ◽  
Dimensional Flow ◽  
The Subject ◽  
Work Done

SummaryThe subject of three-dimensional flow in axial compressors and turbomachines has been extensively studied since 1945. This paper gives a means of calculating the approximate three-dimensional flow in an axial compressor by giving expressions for the slope of the velocity profile as a function of the axial co-ordinate. These expressions bring out the rôle of the ratio of stage inlet annulus height to stage length in the three-dimensional flow in these machines. The effect of the three-dimensional flow on the stage temperature rise at mean radius is discussed by introducing a work done factor.

scholarly journals The Turbine Regime of a Rear Axial Compressor Stage

1990 ◽  
Author(s):  
Václav Cyrus
Keyword(s):  
Aspect Ratio ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Compressor Stage ◽  
Flow Mechanism ◽  
Three Dimensional Flow ◽  
Low Speed ◽  
Dimensional Flow ◽  
Blade Row ◽  
Stator Blade

A detailed investigation of three-dimensional flow has been carried out in a low speed rear axial compressor stage with aspect ratio of 1 at the extreme off-design condition-turbine regime. Measurements were performed by means of both stationery and rotating pressure probes. The mechanism of flow in the rotor and stator blade row in the turbine regime is analysed. Comparison is made with flow mechanism at the design condition.

Measurement of the Three-Dimensional Flow Field Behind an Axial Compressor Stage

1977 ◽  
Vol 99 (2) ◽  
pp. 168-179 ◽  
Author(s):  
Ch. Hirsch ◽  
P. Kool
Keyword(s):  
Flow Field ◽  
Measurement Technique ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Turbulence Level ◽  
Compressor Stage ◽  
Hot Wire ◽  
Three Dimensional Flow ◽  
Dimensional Flow

Hot wire instrumentation and a periodic sampling and averaging technique have been used in order to measure the three-dimensional flow field behind a rotor of an axial compressor stage. A single slanted rotating wire allows the determination of the three components of the blade-to-blade velocity distribution together with informations on the turbulence level. A description is given of the measurement technique, and typical experimental results are presented.

Some Experiments With a Supersonic Axial Compressor Stage

1987 ◽  
Vol 109 (3) ◽  
pp. 388-397 ◽  
Author(s):  
A. J. Wennerstrom
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Design Flow ◽  
Vortex Generators ◽  
Boundary Layer Control ◽  
Compressor Stage ◽  
Design Speed ◽  
Isentropic Efficiency ◽  
Layer Control

Between 1970 and 1974, ten variants of a supersonic axial compressor stage were designed and tested. These included two rotor configurations, three rotor tip clearances, addition of boundary-layer control consisting of vortex generators on both the outer casing and the rotor, and the introduction of slots in the stator vanes. Design performance objectives were a stage total pressure ratio of 3.0 with an isentropic efficiency of 0.82 at a tip speed of 1600 ft/s (488 m/s). The first configuration passed only 70 percent of design flow at design speed, achieving a stage pressure ratio of 2.25 at a peak stage isentropic efficiency of 0.61. The rotor was grossly separated. The tenth variant passed 91.4 percent of design flow at design speed, producing a stage pressure ratio of 3.03 with an isentropic efficiency of 0.75. The rotor achieved a pressure ratio of 3.59 at an efficiency of 0.87 under the same conditions. Major conclusions were that design tools available today would undoubtedly permit the original goals to be met or exceeded. However, the application for such a design is currently questionable because efficiency goals considered acceptable for most current programs have risen considerably from the level considered acceptable at the inception of this effort. Splitter vanes placed in the rotor permitted very high diffusion levels to be achieved without stalling. However, viscous effects causing three-dimensional flows violating the assumption of flow confined to concentric stream tubes were so strong that a geometry optimization does not appear practical without a three-dimensional, viscous analysis. Passive boundary-layer control in the form of vortex generators and slots does appear to offer some benefit under certain circumstances.

Three-Dimensional-Flow Theories for Axial Compressors and Turbines

1948 ◽  
Vol 159 (1) ◽  
pp. 255-268 ◽  
Author(s):  
A. D. S. Carter
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Physical Nature ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Three Dimensional Flow ◽  
Axial Compressors ◽  
Dimensional Flow ◽  
Blade Row

It has long been known that the energy losses occurring in an axial compressor or turbine cannot be fully accounted for by the skin-friction losses on the blades and annulus walls. The difference, usually termed secondary loss, is attributed to miscellaneous secondary flows which take place in the blade row. These flows both cause losses in themselves and modify the operating conditions of the individual blade sections, to the detriment of the overall performance. This lecture analyses the three-dimensional flow in axial compressors and turbines, so that, by appreciation of the factors involved, possible methods of improving the performance can readily be investigated. The origin of secondary flow is first examined for the simple case of a straight cascade. The physical nature of the flow, and theories which enable quantitative estimates to be made, are discussed at some length. Following this, the three-dimensional flow in an annulus with a stationary blade row is examined, and, among other things, the influence of radial equilibrium on the flow pattern is noted. All physical restrictions are then removed, and the major factors governing the three-dimensional flow in an actual machine are investigated as far as is possible with existing information, particular attention being paid to the influence of a non-uniform velocity profile, tip clearance, shrouding, and boundary layer displacement. Finally the various empirical factors used in design are discussed, and the relationships between them established.

Aerodynamic Performance of Rear Axial Compressor Stage With Annular Diffuser and Outlet Chamber

1996 ◽  
Author(s):  
Václav Cyrus
Keyword(s):  
Aspect Ratio ◽  
Velocity Profile ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Compressor Stage ◽  
Guide Vanes ◽  
Inlet Velocity ◽  
Aspect Ratios ◽  
Annular Diffuser ◽  
Outlet Chamber

A detailed investigation of aerodynamic performance of three low-speed rear axial compressor stage bladings with the aspect ratios: 0.75, 1.0 and 1.25 was carried out. The bladings of industrial type consist of rotor, stator and outlet guide vanes. The outer and inner diameters of the stage are constant. The hub/tip ratio is 0.871 and the outer diameter is 800 mm. Stage blading is followed by an annular diffuser with outlet chamber. The effect of blade aspect ratio on compressor stage performance was also analysed with the use of straight cascade data. This data supported the test stage experimental results. We found that the effect of aspect ratio on stage performance is not remarkable in the considered range. There are some differences at off-design conditions. The lowest value of blading efficiency was obtained in the case with the lowest aspect ratio value. Three inlet velocity profiles were modelled with the use of lengthened inlet annulus and a screen specially designed. It was found that there is a significant effect of inlet velocity profile distortion on rear compressor stage blading performance for all aspect ratios. Aerodynamic characteristics of compressor stage blading with annular diffuser and outlet chamber were determined. During the investigation we also removed the outlet guide vanes. Therefore the effect of swirl and inlet velocity profile could be investigated.

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