Advanced Nonaxisymmetric Endwall Contouring for Axial Compressors by Generating an Aerodynamic Separator—Part I: Principal Cascade Design and Compressor Application

2010 ◽  
Vol 133 (2) ◽  
Author(s):  
Christian Dorfner ◽  
Alexander Hergt ◽  
Eberhard Nicke ◽  
Reinhard Moenig
Keyword(s):  
Flow Behavior ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Significant Loss ◽  
Optimization Techniques ◽  
Tip Vortex ◽  
Compressor Cascade ◽  
Axial Compressors ◽  
Endwall Contouring ◽  
Automated Optimization

Modern methods for axial compressor design are capable of shaping the blade surfaces in a three-dimensional way. Linking these methods with automated optimization techniques provides a major benefit to the design process. The application of nonaxisymmetric contoured endwalls is considered to be very successful in turbine rotors and vanes. Concerning axial compressors, nonaxisymmetric endwalls are still a field of research. This two-part paper presents the recent development of a novel endwall design. An aerodynamic separator, generated by a nonaxisymmetric endwall groove, interacts with the passage vortex. This major impact on the secondary flow results in a significant loss reduction because of load redistribution, reduction in recirculation areas, and suppressed corner separation. The first paper deals with the development of the initial endwall design using a linear compressor cascade application. A brief introduction of the design methods is provided, including the automated optimization and the 3D process chain with a focus on the endwall contouring tool. Hereafter, the resulting flow phenomena and physics due to the modified endwall surface are described and analyzed in detail. Additionally, the endwall design principal is transferred to an axial compressor stage. The endwall groove is applied to the hub and casing endwalls of the stator, and the initial numerical investigation is presented. For highly loaded operating points, the flow behavior at the hub region can be improved in accord with the cascade results. Obviously, the casing region is dominated by the incoming tip vortex generated by the rotor and still remains an area for further investigations concerning nonaxisymmetric endwall contouring.

Advanced Non-Axisymmetric Endwall Contouring for Axial Compressors by Generating an Aerodynamic Separator—Part I: Principal Cascade Design and Compressor Application

2009 ◽  
Author(s):  
Christian Dorfner ◽  
Alexander Hergt ◽  
Eberhard Nicke ◽  
Reinhard Moenig
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Significant Loss ◽  
Optimization Techniques ◽  
Tip Vortex ◽  
Compressor Cascade ◽  
Axial Compressors ◽  
Flow Phenomena ◽  
Endwall Contouring ◽  
Automated Optimization

Modern methods for axial compressor design are capable of shaping the blade surfaces in a three dimensional way. Linking these methods with automated optimization techniques provides a major benefit to the design process. The application of non-axisymmetric contoured endwalls is considered to be very successful in turbine rotors and vanes. Concerning axial compressors non-axisymmetric endwalls are still a field of research. This two-part paper presents the recent development of a novel endwall design. An aerodynamic separator, generated by a non-axisymmetric endwall groove, interacts with the passage vortex. This major impact on the secondary flow results in a significant loss reduction because of load redistribution, reduction of recirculation areas and suppressed corner separation. The first paper deals with the development of the initial endwall design using a linear compressor cascade application. A brief introduction of the design methods is provided, including the automated optimization, the 3D process chain with a focus on the endwall contouring tool. Hereafter the resulting flow phenomena and physics due to the modified endwall surface are described and analyzed in detail. Additionally, the endwall design principal is transferred to an axial compressor stage. The endwall groove is applied to the hub and casing endwalls of the stator and the initial numerical investigation is presented. For highly loaded operating points the flow behaviour at the hub region can be improved in accord with the cascade results. Obviously, the casing region is dominated by the incoming tip vortex generated by the rotor and still remains an area for further investigations concerning non-axisymmetric endwall contouring.

Advanced Nonaxisymmetric Endwall Contouring for Axial Compressors by Generating an Aerodynamic Separator—Part II: Experimental and Numerical Cascade Investigation

2010 ◽  
Vol 133 (2) ◽  
Author(s):  
Alexander Hergt ◽  
Christian Dorfner ◽  
Wolfgang Steinert ◽  
Eberhard Nicke ◽  
Heinz-Adolf Schreiber
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Suction Side ◽  
Significant Loss ◽  
Optimization Techniques ◽  
Navier Stokes ◽  
Loss Reduction ◽  
Axial Compressors ◽  
Flow Phenomena

Modern methods for axial compressor design are capable of shaping the blade surfaces in a three-dimensional way. Linking these methods with automated optimization techniques provides a major benefit to the design process. The application of nonaxisymmetric contoured endwalls is considered to be very successful in turbine rotors and vanes. Concerning axial compressors, nonaxisymmetric endwalls are still a field of research. This two-part paper presents the recent development of a novel endwall design. A vortex created by a nonaxisymmetric endwall groove acts as an aerodynamic separator, preventing the passage vortex from interacting with the suction side boundary layer. This major impact on the secondary flow results in a significant loss reduction by means of load redistribution, reduction in recirculation areas, and suppressed corner separation. Part I of this paper deals with the endwall design and its compressor application. The resulting flow phenomena and physics are described and analyzed in detail. The second paper presents the detailed experimental and numerical investigation of the developed endwall groove. The measurements carried out at the transonic cascade wind tunnel of DLR in Cologne, demonstrated a considerable influence on the cascade performance. A loss reduction and redistribution of the cascade loading were achieved at the aerodynamic design point, as well as near the stall condition of the cascade. This behavior is well predicted by the numerical simulation. The combined analysis of experimental and numerical flow patterns allows a detailed interpretation and description of the resulting flow phenomena. In this context, high fidelity 3D-Reynolds-averaged Navier–Stokes flow simulations are required to analyze the complex blade and endwall boundary layer interaction.

Advanced Non-Axisymmetric Endwall Contouring for Axial Compressors by Generating an Aerodynamic Separator—Part II: Experimental and Numerical Cascade Investigation

2009 ◽  
Author(s):  
Alexander Hergt ◽  
Christian Dorfner ◽  
Wolfgang Steinert ◽  
Eberhard Nicke ◽  
Heinz-Adolf Schreiber
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Suction Side ◽  
Significant Loss ◽  
Optimization Techniques ◽  
Loss Reduction ◽  
Axial Compressors ◽  
Boundary Layer Interaction ◽  
Flow Phenomena

Modern methods for axial compressor design are capable of shaping the blade surfaces in a three dimensional way. Linking these methods with automated optimization techniques provides a major benefit to the design process. The application of non-axisymmetric contoured endwalls is considered to be very successful in turbine rotors and vanes. Concerning axial compressors non-axisymmetric endwalls are still a field of research. This two-part paper presents the recent development of a novel endwall design. A vortex created by a nonaxisymmetric endwall groove acts as an aerodynamic separator, preventing the passage vortex from interacting with the suction side boundary layer. This major impact on the secondary flow results in a significant loss reduction by means of load redistribution, reduction of recirculation areas and suppressed corner separation. Part I of this paper deals with the endwall design and its compressor application. The resulting flow phenomena and physics are described and analysed in detail. The second paper presents the detailed experimental and numerical investigation of the developed endwall groove. The measurements carried out at the transonic cascade wind tunnel of DLR in Cologne, demonstrated a considerable influence on the cascade performance. A loss reduction and redistribution of the cascade loading were achieved at the aerodynamic design point as well as near the stall condition of the cascade. This behaviour is well predicted by the numerical simulation. The combined analysis of experimental and numerical flow patterns allows a detailed interpretation and description of the resulting flow phenomena. In this context high fidelity 3D-RANS flow simulations are required to analyse the complex blade and endwall boundary layer interaction.

A Three-Dimensional Unsteady Through-Flow Model for Rotating Stall in Axial Compressors

2020 ◽  
Author(s):  
Jin Guo ◽  
Jun Hu ◽  
Xuegao Wang ◽  
Rong Xu
Keyword(s):  
Flow Model ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Design Stage ◽  
Preliminary Evaluation ◽  
Source Terms ◽  
Axial Compressors ◽  
Through Flow

Abstract Rotating stall is a natural limit to the stable operating range of compressors due to the inverse pressure gradient of viscous gas. Effective prediction of compressor stall boundary is an important guarantee for the successful development of aeroengine. In this paper, a three-dimensional unsteady through-flow model based on body force theory is developed to reflect the dynamic stall process of multistage axial compressors with acceptable computational costs. The influence of blade geometric parameters is fully considered in blade force source terms. The source terms are related to the attack angle and Mach number of the blade inlet using the deviation angle and loss model in the through-flow theory. Meanwhile, the temporal lag response of the source terms to the upstream flow conditions is taken into account. Therefore, it can be utilized for predicting the off-design performance and rotating stall characteristics of multistage axial compressors. The developed model is validated on a two-stage low-speed axial compressor. The calculated performance line and stall cell speed are in agreement with the experimental results. The unsteady flow behavior of the compressor during stall is presented by the model. The results indicate that the developed model has the potential to be applied to the preliminary evaluation of compressor stability in design stage.

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.

Improving a one-dimensional centrifugal compressor performance prediction method

2005 ◽  
Vol 219 (8) ◽  
pp. 653-659 ◽  
Author(s):  
E Swain
Keyword(s):  
Centrifugal Compressor ◽  
Performance Prediction ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Prediction Method ◽  
Compressor Cascade ◽  
One Dimensional ◽  
Compressor Performance ◽  
Cfd Analyses

A one-dimensional centrifugal compressor performance prediction technique that has been available for some time is updated as a result of extracting the component performance from three-dimensional computational fluid dynamic (CFD) analyses. Confidence in the CFD results is provided by comparison of overall performance for one of the compressor examples. The extracted impeller characteristic is compared with the original impeller loss model, and this indicated that some improvement was desirable. The position of least impeller loss was determined using a traditional axial compressor cascade method, and suitable algebraic expressions were derived to match the CFD data. The merit of the approach lies with the relative ease that CFD component performance currently can be achieved and adjusting one-dimensional methods to agree with the CFD-derived models.

Development of an Improved Streamline Curvature Approach for Transonic Axial Compressor

2016 ◽  
Author(s):  
Wu Xiaoxiong ◽  
Bo Liu ◽  
Shi Lei ◽  
Zhang Guochen ◽  
Mao Xiaochen
Keyword(s):  
Incidence Angle ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Internal Flow ◽  
Field Analysis ◽  
Design Stage ◽  
Axial Compressors ◽  
Transonic Compressor ◽  
Streamline Curvature

In this paper, an improved streamline curvature (SLC) approach is presented to obtain the internal flow fields and evaluate the performance of transonic axial compressors. The approach includes some semi-empirical correlations established based on previous literatures, such as minimum loss incidence angle model, deviation model and total pressure loss model. Several developments have been made in this paper for the purpose of considering the influences of three-dimensional (3D) flow in high-loaded multistage compressors with high accuracy. A revised deviation model is applied to predict the cascade with large deflection range. The method for predicting the shock loss is also discussed in detail. In order to validate the reliability of the approach, two test cases including a two-stage transonic fan and a three-stage transonic compressor are conducted. The overall performance and distribution of spanwise aerodynamic parameters are illustrated in this paper. Compared with both the experimental and computational fluid dynamic (CFD) data at design and a number of different off-design condition, the SLC results give reasonable characteristic curves. The validation demonstrates that this improved approach can serve as a fast and reliable tool for flow field analysis and performance prediction in preliminary design stage of axial compressors.

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 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.

Considerations for Using 3D Pneumatic Probes in High Speed Axial Compressors

2002 ◽  
Author(s):  
Simon Coldrick ◽  
Paul Ivey ◽  
Roger Wells
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Pressure Probe ◽  
Probe Type ◽  
Calibration Data ◽  
Axial Compressors ◽  
Close Proximity ◽  
Multistage Axial Compressor ◽  
Preparatory Work

This paper describes preparatory work towards three dimensional flowfield measurements downstream of the rotor in an industrial, multistage, axial compressor, using a pneumatic pressure probe. The probe is of the steady state four hole cobra probe type. The design manufacture and calibration of the probe is described. CFD calculations have been undertaken in order to assess the feasability of using such a probe in the high speed compressor environment where space is limited. This includes effects of mounting the probe in close proximity to the downstream stator blades and whether it is necessary to adjust the calibration data to compensate for these effects.

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