Effect of Stator Design on Stator Boundary Layer Flow in a Highly Loaded Single-Stage Axial-Flow Low-Speed Compressor

2000 ◽  
Vol 123 (3) ◽  
pp. 483-489 ◽  
Author(s):  
Jens Friedrichs ◽  
Sven Baumgarten ◽  
Gu¨nter Kosyna ◽  
Udo Stark
Keyword(s):  
Axial Flow ◽  
Leading Edge ◽  
Single Stage ◽  
Swept Wing ◽  
Sweep Angle ◽  
Low Speed ◽  
Overall Performance ◽  
Layer Flow ◽  
Stator Design ◽  
Highly Loaded

The paper describes an experimental investigation of the stator hub and blade flow in two different stators of a highly loaded single-stage axial-flow low-speed compressor. The first stator (A) is a conventional design with blades of rectangular planform. The second stator (K) is an unconventional, more advanced design with blades of a special planform, characterized by an aft-swept leading edge with increasing sweep angle toward hub and casing. The experimental results show that stator K exhibits a much better hub performance than stator A, finally leading to a better overall performance of stage K compared to stage A. The better hub performance of stator K is, primarily, the result of a planform effect of the newly introduced blades with an aft-swept leading edge and the aerodynamics of an aft-swept wing.

Effect of Stator Design on Stator Boundary Layer Flow in a Highly Loaded Single-Stage Axial-Flow Low-Speed Compressor

2000 ◽  
Author(s):  
Jens Friedrichs ◽  
Sven Baumgarten ◽  
Günter Kosyna ◽  
Udo Stark
Keyword(s):  
Axial Flow ◽  
Leading Edge ◽  
Single Stage ◽  
Swept Wing ◽  
Sweep Angle ◽  
Low Speed ◽  
Overall Performance ◽  
Layer Flow ◽  
Stator Design ◽  
Highly Loaded

The paper describes an experimental investigation of the stator hub and blade flow in two different stators of a highly loaded single-stage axial-flow low-speed compressor. The first stator (A) is a conventional design with blades of rectangular planform. The second stator (K) is an unconventional, more advanced design with blades of a special planform, characterized by an aft-swept leading edge with increasing sweep angle towards hub and casing. The experimental results show that stator K exhibits a much better hub performance than stator A, finally leading to a better overall performance of stage K compared to stage A. The better hub performance of stator K is, primarily, the result of a planform effect of the newly introduced blades with an aft-swept leading edge and the aerodynamics of an aft-swept wing.

Aerodynamic and Acoustic Performance of a Single Stage Axial Fan With Extensive Blade Sweep Designed to Limit Noise Emissions

2016 ◽  
Author(s):  
Daniel Giesecke ◽  
Jens Friedrichs ◽  
Udo Stark ◽  
Maik Dierks
Keyword(s):  
Axial Flow ◽  
Leading Edge ◽  
Vital Role ◽  
Single Stage ◽  
Numerical Verification ◽  
Axial Fan ◽  
Trailing Edge ◽  
Sweep Angle ◽  
Acoustic Performance ◽  
Versatile Tool

Not only the aerodynamic performance of axial flow fans is important but also the acoustic behaviour plays a vital role. It is to be expected that in the future noise limits will be more regulated by legislation. The aim of this project is to develop a very versatile tool for efficient and noise reduced axial flow fans in rotor / stator configuration. This paper describes the design, numerical verification and tests of a highly loaded single stage axial flow fan making use of extensive blade sweep in rotor and stator for acoustic reasons. The tests include aerodynamic and acoustic investigations. The stage is a conventional free vortex design with unconventional blades of a special planform. The blade sections of both rotor and stator are NACA 65-sections on circular arc mean lines. Sectional diffusion factors and de Haller numbers are close to their respective limits, especially for the sections next to the rotor and stator hubs. The rotor is characterised by a forward-swept leading edge with increasing sweep angle towards hub and tip and an unswept trailing edge. The leading edge of the stator blades is forward-swept as before but this time at an almost constant sweep angle between the hub and the two-thirds position of the blade span. The trailing edge is straightened for reducing the previously mentioned aerodynamic loadings. The study shows that the numerical results are consistent with the experimental outcome. It concludes that the advanced design features show potential aerodynamic and acoustic benefits by sweeping the blade in the described manner. This is particularly the case when comparing to single row designs.

Keel Design for Low Viscous Drag

1987 ◽  
Author(s):  
Clifford J. Obara ◽  
C. P. van Dam
Keyword(s):  
Boundary Layer ◽  
Laminar Flow ◽  
Laminar Boundary Layer ◽  
Leading Edge ◽  
Boundary Layer Transition ◽  
Viscous Drag ◽  
Hydrodynamic Characteristics ◽  
Sweep Angle ◽  
Layer Transition ◽  
Layer Flow

In this paper, foil and planform parameters which govern the level of viscous drag produced by the keel of a sailing yacht are discussed. It is shown that the application of laminar boundary-Layer flow offers great potential for increased boat speed resulting from the reduction in viscous drag. Three foil shapes have been designed and it is shown that their hydro­dynamic characteristics are very much dependent on location and mode of boundary-Layer transition. The planform parameter which strongly affects the capabilities of the keel to achieve laminar flow is lea ding-edge sweep angle. The two significant phenomena related to keel sweep angle which can cause premature transition of the laminar boundary layer are crossflow instability and turbulent contamination of the leading-edge attachment line. These flow phenomena and methods to control them are discussed in detail. The remaining factors that affect the maintainability of laminar flow include surface roughness, surface waviness, and freestream turbulence. Recommended limits for these factors are given to insure achievability of laminar flow on the keel. In addition, the application of a simple trailing-edge flap to improve the hydrodynamic characteristics of a foil at moderate-to-high leeway angles is studied.

Tip Clearance Flow Induced Endwall Boundary Layer Separation in a Single–Stage Axial–Flow Low–Speed Compressor

2000 ◽  
Author(s):  
Horst Saathoff ◽  
Udo Stark
Keyword(s):  
Axial Flow ◽  
Boundary Layer Separation ◽  
Single Stage ◽  
Tip Clearance ◽  
Compressor Cascade ◽  
Tip Clearance Flow ◽  
Low Speed ◽  
Pressure Distributions ◽  
Oil Flow ◽  
Clearance Flow

The paper describes an investigation of the overtip end-wall flow in a single–stage axial–flow low–speed compressor utilizing an oil flow technique and a periodic multisampling pressure measurement technique. Representative oil flow pictures and ensemble averaged casingwall pressure distributions with standard deviations — supplemented by selected endwall oil flow pictures from a corresponding 2D compressor cascade — are shown and carefully analysed. The results enable the key features of the overtip endwall flow to be identified and changes with flow rate — or inlet angle — to be determined.

Mixing in Axial Flow Compressors: Part I — Test Facilities and Measurements in a Four-Stage Compressor

1990 ◽  
Author(s):  
Y. S. Li ◽  
N. A. Cumpsty
Keyword(s):  
Axial Flow ◽  
Single Stage ◽  
Two Dimensional ◽  
Similar Magnitude ◽  
Low Speed ◽  
The Third ◽  
Mixing Coefficients ◽  
Experimental Facilities ◽  
Axial Flow Compressors

The mechanism of mixing in axial flow compressors has been investigated in two low speed machines. For reasons of length this is described in two parts. Results in a 4-stage compressor are described here in Part I and show that the mixing coefficients across the first and the third stators are of similar magnitude. Part I also describes the background and experimental facilities and techniques used in both parts together with the nomenclature and all the references. Part II describes the results from a large single stage compressor. It also presents measurements of mixing in a simple two-dimensional duct, and presents conclusions for the whole investigation.

Excitation Of Localized Wave Packet In 3d Supersonic Boundary Layer

2017 ◽  
Vol 12 (1) ◽  
pp. 57-65
Author(s):  
Alex Yatskih ◽  
Marina Rumenskikh ◽  
Yuri Yermolaev ◽  
Aleksandr Kosinov ◽  
Nikolay Semionov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wave Packet ◽  
Wave Packets ◽  
Leading Edge ◽  
Supersonic Boundary Layer ◽  
Swept Wing ◽  
Sweep Angle ◽  
Asymmetric Shape ◽  
Pulse Electric ◽  
Pulse Electric Discharge

The results of experimental study of excitation of localized in time and space controlled disturbances (wave packets) in a supersonic swept-wing boundary layer are presented. The experiments were performed at Mach number M = 2 on the model of wing with a lenticular profile and a 40 degrees sweep angle of the leading edge at zero angle of attack. Wave packets were generated by a pulse electric discharge on the surface of the model. A structure of controlled wave packet was studied. It was found that the wave packet has an asymmetric shape. Comparison with the case of twodimensional boundary layer was done.

Controllability Analysis of Flexible Variable Sweep Control Wing

2012 ◽  
Vol 542-543 ◽  
pp. 873-877
Author(s):  
Lai Bin Xu ◽  
Shu Xing Yang ◽  
Bo Mo
Keyword(s):  
Control Surface ◽  
Control Performance ◽  
Swept Wing ◽  
Sweep Angle ◽  
Low Speed ◽  
Control Effectiveness ◽  
Control Moment ◽  
Speed Range ◽  
Effective Angle ◽  
The Right

Variable Sweep Control Wing (VSCW) was introduced to generate the rolling control moment with the sweep angle differences between the left and the right wings. Influence flexible matrixes were generated to obtain the deflection of the effective angle of attack (AOA) of the flexible swept wing. Comparison between aileron control surface and VSCW shows that VSCW can get benefit from wing flexibility, which degrades the control effectiveness of the traditional aileron. The main advantage and difference from the traditional aircraft is that VSCW has higher control effectiveness and can prevent control reversal especially at high flight speed range; and at low speed, with an AOA variation device VSCW can get similar rolling control performance compared with traditional aileron control surface.

Kinematic Analysis of 3-D Swept Shock Surfaces in Axial Flow Compressors

2000 ◽  
Vol 123 (3) ◽  
pp. 490-500 ◽  
Author(s):  
Peng Shan
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Leading Edge ◽  
Research Field ◽  
High Loading ◽  
Kinematic Characteristic ◽  
Sweep Angle ◽  
Quantitative Classification ◽  
Axial Flow Compressors ◽  
Blade Leading Edge

This paper is part II of a comprehensive study on the blade leading edge sweep/bend of supersonic and transonic axial compressors. The paper explores and analyzes the kinematic characteristic variables of three-dimensional (3-D) swept shock surfaces. In the research field studying the sweep aerodynamics of axial flow compressors and fans, many types of high loading swept blades are under intensive study. So, in both direct and inverse design methods and experimental validations, an accurate grasp of the sweep characteristic of the blade’s 3-D swept shock surface becomes of more concern than before. Associated with relevant blading variables, this paper studies the forward and zero and backward sweeps of shock surfaces, defines and resolves every kind of useful sweep angle, obtains dimensionless sweep similarity factors, suggests a kind of method for the quantitative classification of 3-D shock structures, and proposes the principle of 3-D shock structure measurements. Two rotor blade leading edge shock surfaces from two high loading single stage fans are analyzed and contrasted. This study is the foundation of the kinematic design of swept shock surfaces.

Mixing in Axial Flow Compressors: Part I—Test Facilities and Measurements in a Four-Stage Compressor

1991 ◽  
Vol 113 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Y. S. Li ◽  
N. A. Cumpsty
Keyword(s):  
Axial Flow ◽  
Single Stage ◽  
Two Dimensional ◽  
Similar Magnitude ◽  
Low Speed ◽  
The Third ◽  
Mixing Coefficients ◽  
Experimental Facilities ◽  
Axial Flow Compressors

The mechanism of mixing in axial flow compressors has been investigated in two low-speed machines. For reasons of length this is described in two parts. Results in a four-stage compressor are described here in Part I and show that the mixing coefficients across the first and the third stators are of similar magnitude. Part I also describes the background and experimental facilities and techniques used in both parts together with the nomenclature and all the references. Part II describes the results from a large single-stage compressor. It also presents measurements of mixing in a simple two-dimensional duct, and presents conclusions for the whole investigation.

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