scholarly journals Experimental Investigations of Airfoil- and Endwall Boundary Layers in a Subsonic Compressor Stage

1986 ◽  
Author(s):  
H. E. Gallus ◽  
H. Hoenen
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Boundary Layers ◽  
Three Dimensional ◽  
Axial Flow ◽  
Experimental Investigations ◽  
Turbulence Energy ◽  
Compressor Stage ◽  
Stator Blade ◽  
Flow Compressor

Criteria for the maximum diffusion allowable in a blade row without reaching stall play an important part in the design of highly loaded axial-flow compressors. Most of these criteria for maximum blade loading were derived from wind tunnel measurements of 2-d-steady cascade flow. As the flow field in turbomachines is extremely unsteady and of three-dimensional nature the boundary layers are influenced by these effects. The paper deals with the results of boundary layer measurements in a stator blade channel of a subsonic axial-flow compressor stage at various operating points between unthrottled and highly throttled flow (near stall). In front of the stator, the time-averaged velocity profiles as well as the fluctuations due to the unsteady flow field downstream of the rotor were measured. The growing of the separation zones inside the channel with increased blade load is studied in detail. Photos of flow visualization in the boundary layers by dye-injection and flow patterns derived from hot-wire measurements illustrate the physics of boundary layer behavior and separation due to increasing stator blade load. The investigations include measurements of the turbulence energy and a frequency analysis of the velocity fluctuations in the boundary layers.

Separated Flows in Axial Flow Compressor With Variable Stator Vanes at Positive Incidence Angles

1994 ◽  
Author(s):  
Vaclav Cyrus
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Flow ◽  
Separated Flow ◽  
Rotating Stall ◽  
Compressor Stage ◽  
Diffusion Factor ◽  
Stator Blade ◽  
Flow Compressor ◽  
End Wall

A detailed investigation of three-dimensional flow was carried out in a low speed rear axial compressor stage with the change of the stator blade row setting. The stator blade stagger change was in the range of (−14) – (23) degree. Measurements were performed by means of both stationary and rotating pressure probes at seven working points. The origin of large regions of separated flow in blade rows at positive incidence angles was analysed with the use of the spanwise diffusion factor distribution. These areas in the rotor and stator rows originated as the diffusion factor exceeded the critial value D = 0.6 within (1/4 – 1/3) of the blade height near one end-wall. The rotating stall in compressor stage arised when large regions of separated flow occured simultaneously in both rotor and stator blade rows.

Three-Dimensional Flow Phenomena in a Transonic, High-Throughflow, Axial-Flow Compressor Stage

1993 ◽  
Vol 115 (2) ◽  
pp. 240-248 ◽  
Author(s):  
W. W. Copenhaver ◽  
C. Hah ◽  
S. L. Puterbaugh
Keyword(s):  
Flow Field ◽  
Viscous Flow ◽  
Numerical Technique ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Flow ◽  
Compressor Stage ◽  
Complex Flow ◽  
Pressure Transducers ◽  
Flow Compressor

A detailed aerodynamic study of a transonic, high-throughflow, single-stage compressor is presented. The compressor stage was comprised of a low-aspect-ratio rotor combined alternately with two different stator designs. Both experimental and numerical studies are conducted to understand the details of the complex flow field present in this stage. Aerodynamic measurements using high-frequency, Kulite pressure transducers and conventional probes are compared with results from a three-dimensional viscous flow analysis. A steady multiple blade row approach is used in the numerical technique to examine the detailed flow structure inside the rotor and the stator passages. The comparisons indicate that many flow field features are correctly captured by viscous flow analysis, and therefore unmeasured phenomena can be studied with some level of confidence.

Stall Margin Improvement of a Single Stage Transonic Axial Flow Compressor Using Naturally Aspirated Slots

2015 ◽  
Author(s):  
Hari Krishna Borra ◽  
Dilipkumar Bhanudasji Alone
Keyword(s):  
Boundary Layer ◽  
Steady State ◽  
Rotor Blade ◽  
Three Dimensional ◽  
Axial Flow ◽  
Compressor Stage ◽  
Suction Surface ◽  
Stall Margin ◽  
Blade Tip ◽  
Flow Compressor

This paper describes the method to improve the stall margin of transonic axial flow compressor by controlling the boundary layer on the suction surface of the rotor blade tip through natural aspiration. Aspiration slots in the compressor blade are intended to energize the flow by increasing its momentum on the suction surface. This phenomenon of boundary layer control can delay the flow separation and hence results in enhancement of the stall margin of the compressor stage. Flow behavior with aspiration slots and its performance are evaluated using commercially available numerical software. Steady state RANS simulations with three dimensional implicit pressure-based coupled solver and turbulence model SST k-ω are used. The effect of natural aspiration slot on the rotor blade performance is computed numerically. The main objective of the study was to identify the optimum location of the aspiration slot along the chord of the compressor on the rotor blade. The axial location chosen for the performance evaluations were 20%,40%,50%,60% and 70% of the rotor blade axial tip chord. By comparing the numerical simulation results with the steady state behavior in the absence of the aspirated slots, the optimized location of the aspiration slot that results in maximum stall improvement is identified. At the optimized location, natural aspiration slots on the rotor blade tip improved the stall margin with the minimum reduction in efficiency and stage pressure ratio when compared to base model. After critically understanding the performance with straight aspiration slots the compressor stage performance has enhanced further by orienting the aspiration slots. The numerical three dimensional results conclude an optimal improvement in the stall margin for the slots near the trailing edge of the rotor. The prediction shows that with the inclined aspiration slots at proper location it is possible to improve the stall margin of the compressor stage and also to restore the stage efficiency.

Three-Dimensional Flows and Loss Reduction in Axial Compressors

1987 ◽  
Vol 109 (3) ◽  
pp. 354-361 ◽  
Author(s):  
Y. Dong ◽  
S. J. Gallimore ◽  
H. P. Hodson
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Flow ◽  
Tracer Gas ◽  
Suction Surface ◽  
Axial Compressors ◽  
Small Clearance ◽  
Oil Flow ◽  
Stator Blade ◽  
Flow Compressor

Measurements have been performed in a low-speed high-reaction single-stage axial compressor. Data obtained within and downstream of the rotor, when correlated with the results of other investigations, provide a link between the existence of suction surface–hub corner separations, their associated loss mechanisms, and blade loading. Within the stator, it has been shown that introducing a small clearance between the stator blade and the stationary hub increases the efficiency of the stator compared to the case with no clearance. Oil flow visualizaton indicated that the leakage reduced the extensive suction surface–hub corner separation that would otherwise exist. A tracer gas experiment showed that the large radial shifts of the surface streamlines indicated by the oil flow technique were only present close to the blade. The investigation demonstrates the possible advantages of including hub clearance in axial flow compressor stator blade rows.

scholarly journals Boundary Layers on Rough Compressor Blades

1972 ◽  
Author(s):  
K. Bammert ◽  
R. Milsch
Keyword(s):  
Boundary Layer ◽  
Friction Coefficient ◽  
Boundary Layers ◽  
Axial Flow ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Compressor Blades ◽  
Turbulent Transition ◽  
Good Reproduction ◽  
Compressor Efficiency

Blades of axial flow compressors are often roughened by corrosion or erosion. There is only scant information about the influence of this roughening on the boundary layers of the blades and thereby on the compressor efficiency. To obtain detailed information for calculating the efficiency drop due to the roughness, experimental investigations with an enlarged cascade have been executed. The results enabled to develop new formulas for a modified friction coefficient in the laminar region and for the laminar-turbulent transition and the separation points of the boundary layer. Thus, together with the Truckenbrodt theory, it was possible, to get a good reproduction of the experimental results.

Effects of Endwall Profiling on Axial Flow Compressor Stage

2009 ◽  
Author(s):  
Jialing Lu ◽  
Wuli Chu ◽  
Yanhui Wu
Keyword(s):  
Flow Field ◽  
Engineering Design ◽  
Axial Flow ◽  
Design Tool ◽  
Operating Conditions ◽  
Compressor Stage ◽  
Corner Separation ◽  
Axial Flow Compressor ◽  
Flow Compressor ◽  
Stage Efficiency

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.

Wall Boundary Layer Development Near the Tip Region of an IGV of an Axial Flow Compressor

1984 ◽  
Vol 106 (2) ◽  
pp. 337-345
Author(s):  
B. Lakshminarayana ◽  
N. Sitaram
Keyword(s):  
Boundary Layer ◽  
Guide Vane ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Flow ◽  
Inlet Guide Vane ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
Boundary Layer Development ◽  
Flow Compressor

The annulus wall boundary layer inside the blade passage of the inlet guide vane (IGV) passage of a low-speed axial compressor stage was measured with a miniature five-hole probe. The three-dimensional velocity and pressure fields were measured at various axial and tangential locations. Limiting streamline angles and static pressures were also measured on the casing of the IGV passage. Strong secondary vorticity was developed. The data were analyzed and correlated with the existing velocity profile correlations. The end wall losses were also derived from these data.

Three-Dimensional Flows and Loss Reduction in Axial Compressors

1986 ◽  
Author(s):  
Y. Dong ◽  
S. J. Gallimore ◽  
H. P. Hodson
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Flow ◽  
Flow Visualisation ◽  
Tracer Gas ◽  
Suction Surface ◽  
Axial Compressors ◽  
Oil Flow ◽  
Stator Blade ◽  
Flow Compressor

Measurements have been performed in a low speed high reaction single stage axial compressor. Data obtained within and downstream of the rotor, when correlated with the results of other investigations, provide a link between the existence of suction surface-hub corner separations, their associated loss mechanisms and blade loading. Within the stator, it has been shown that introducing a small clearance between the stator blade and the stationary hub increases the efficiency of the stator compared to the case with no clearance. Oil flow visualisation indicated that the leakage reduced the extensive suction surface-hub corner separation that would otherwise exist. A tracer gas experiment showed that the large radial shifts of the surface streamlines indicated by the oil flow technique were only present close to the blade. The investigation demonstrates the possible advantages of including hub clearance in axial flow compressor stator blade rows.

Three-Dimensional Flow Phenomena in a Transonic, High-Through-Flow, Axial-Flow Compressor Stage

1992 ◽  
Author(s):  
William W. Copenhaver ◽  
Chunill Hah ◽  
Steven L. Puterbaugh
Keyword(s):  
Flow Field ◽  
Viscous Flow ◽  
Numerical Technique ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Flow ◽  
Compressor Stage ◽  
Complex Flow ◽  
Pressure Transducers ◽  
Through Flow

A detailed aerodynamic study of a transonic, high-through-flow, single stage compressor is presented. The compressor stage was comprised of a low-aspect-ratio rotor combined alternately with two different stator designs. Both experimental and numerical studies are conducted to understand the details of the complex flow field present in this stage. Aerodynamic measurements using high-frequency, Kulite pressure transducers and conventional probes are compared with results from a three-dimensional viscous flow analysis. A steady multiple blade row approach is used in the numerical technique to examine the detailed flow structure inside the rotor and the stator passages. The comparisons indicate that many flow field features are correctly captured by viscous flow analysis, and therefore unmeasured phenomena can be studied with some level of confidence.

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