Numerical investigation of inlet boundary layer skew in axial-flow compressor cascade and the corresponding non-axisymmetric end wall profiling

This paper investigates the influence of boundary layer skew on flow structure, total pressure loss, and flow control technique numerically on a high-loaded axial-flow compressor cascade. We have developed two new models respectively about loss evaluation and end wall flow control mechanism for more specific analysis. The result shows that boundary layer skew weakens the secondary flow and delays the generation of passage vortex when incidence approaches 0°. This results in a reduction of total pressure loss mainly (89.4%) due to relieved corner separation. However, as incidence exceeds a certain value (+7°), severe corner separation or even earlier corner stall can be induced by inlet boundary layer skew. Optimization procedure for profiled end wall at inflow condition of +7° incidence is further carried out to investigate the impact of boundary layer skew on flow control technique. The result shows that boundary layer skew should be counted in the optimization design of profiled end wall because of its significant influence on the development of end wall flow. The optimum profiled end walls for cases with and without boundary layer skew show great difference in the manner of end wall flow control. According to the improvement of cascades’ performance, end wall profiling seems more efficient in reducing loss when influenced by the boundary layer skew.

[1]  Jinhee Jeong,et al.  On the identification of a vortex , 1995, Journal of Fluid Mechanics.

[2]  N. W. Harvey.  Some Effects of Non-Axisymmetric End Wall Profiling on Axial Flow Compressor Aerodynamics: Part I—Linear Cascade Investigation , 2008 .

[3]  Heinz-Peter Schiffer,et al.  Non-Axisymmetric End Wall Profiling in Transonic Compressors—Part II: Design Study of a Transonic Compressor Rotor Using Non-Axisymmetric End Walls—Optimization Strategies and Performance , 2009 .

[4]  S. Hiernaux,et al.  Highly Loaded LPC Blade and Non Axisymmetric Hub Profiling Optimization for Enhanced Efficiency and Stability , 2011 .

[5]  Heinz-Peter Schiffer,et al.  Non-Axisymmetric End Wall Profiling in Transonic Compressors—Part I: Improving the Static Pressure Recovery at Off-Design Conditions by Sequential Hub and Shroud End Wall Profiling , 2009 .

[6]  Eberhard Nicke,et al.  Advanced Nonaxisymmetric Endwall Contouring for Axial Compressors by Generating an Aerodynamic Separator—Part I: Principal Cascade Design and Compressor Application , 2011 .

[7]  Tom Hynes,et al.  Three-Dimensional Separations in Axial Compressors , 2005 .

[8]  Zhu Junqiang.  Secondary flow analysis for non-axisymmetric endwall on the high-load compressor cascade , 2011 .

[9]  Dragan Kozulovic,et al.  Experimental and Numerical Analysis of Hub-Corner Stall in Compressor Cascades , 2010 .

[10]  N. W. Harvey,et al.  Some Effects of Non-Axisymmetric End Wall Profiling on Axial Flow Compressor Aerodynamics: Part II—Multi-Stage HPC CFD Study , 2008 .

[11]  Eberhard Nicke,et al.  Advanced Nonaxisymmetric Endwall Contouring for Axial Compressors by Generating an Aerodynamic Separator—Part II: Experimental and Numerical Cascade Investigation , 2011 .

[12]  J. P. Longley,et al.  The Aerodynamic Interaction of Stator Shroud Leakage and Mainstream Flows in Compressors , 2000 .

[13]  Martin Böhle,et al.  A CFD-Based Investigation of Boundary Layer Skew in the Hub Region of a Low Speed Axial Compressor and its Influence on Performance and Losses , 2009 .

[14]  Z. S. Spakovszky,et al.  A Criterion for Axial Compressor Hub-Corner Stall , 2008 .

[15]  Martin Böhle,et al.  A Numerical Investigation of the Effect of End-Wall Boundary Layer Skew on the Aerodynamic Performance of a Low Aspect Ratio, High Turning Compressor Cascade , 2007 .