Nonuniform Flow in a Compressor Due to Asymmetric Tip Clearance

This paper presents an analytical study of flow redistribution in a compressor stage due to asymmetric tip clearance distribution. The entire stage is modeled as an actuator disk and it is assumed that upstream and downstream flow fields are determined by the local tip clearance. The flow is assumed to be inviscid and incompressible. First, an axisymmetric flow model is used to connect upstream and downstream flows. Second, a linear perturbation approximation is used for nonaxisymmetric analysis in which each flow variable is assumed to consist of a mean (axisymmetric value) plus a small perturbation (asymmetric value). Thus, the perturbations in velocity and pressure induced by the tip clearance asymmetry are predicted. Furthermore, rotordynamic effects of such flow nonuniformity are examined as well.

[1]  R. Wohlrab.  Experimental determination of gap flow-conditioned forces at turbine stages and their effect on the running stability of simple rotors. Ph.D. Thesis , 1983 .

[2]  Seung Jin Song,et al.  Rotordynamic Forces Due to Turbine Tip Leakage: Part II—Radius Scale Effects and Experimental Verification , 1997 .

[3]  Gwo-Tung Chen,et al.  Vortical structures in turbomachinery tip clearance flows , 1991 .

[4]  J. Colding-Jorgensen.  Prediction of Rotor Dynamic Destabilizing Forces in Axial Flow Compressors , 1992 .

[5]  A. F. Storace,et al.  Unsteady Flow and Whirl-Inducing Forces in Axial-Flow Compressors: Part I—Experiment , 2001 .

[6]  Seung Jin Song,et al.  Measurement of Turbine Blade-Tip Rotordynamic Excitation Forces , 1995 .

[7]  K. Urlichs.  Clearance flow-generated transverse forces at the rotors of thermal turbomachines. Ph.D. Thesis - Technische Univ., 1975 , 1983 .

[8]  Seung Jin Song,et al.  Rotordynamic Forces due to Turbine Tip Leakage: Part I — Blade Scale Effects , 1996 .

[9]  Manuel Martinez-Sanchez,et al.  Blade scale effects of tip leakage , 1990 .

[10]  J. S. Alford,et al.  Protecting Turbomachinery From Self-Excited Rotor Whirl , 1965 .

[11]  Nicholas A. Cumpsty,et al.  Casing Wall Boundary-Layer Development Through an Isolated Compressor Rotor , 1982 .

[12]  F. E. Marble,et al.  Effects of Nonaxisymmetric Tip Clearance on Axial Compressor Performance and Stability , 1998 .

[13]  Seung Jin Song,et al.  Rotordynamic Forces Due to Turbine Tip Leakage: Part I—Blade Scale Effects , 1997 .

[14]  J H Horlock,et al.  Non-Uniform Flows in Axial Compressors Due to Tip Clearance Variation , 1983 .

[15]  F. F. Ehrich,et al.  Rotor whirl forces induced by the tip clearance effect in axial flow compressors , 1993 .

[16]  A. F. Storace,et al.  Unsteady Flow and Whirl-Inducing Forces in Axial-Flow Compressors: Part II—Analysis , 2001 .

[17]  D. C. Wisler,et al.  Unsteady Flow and Whirl-Inducing Forces in Axial-Flow Compressors: Part II — Analysis , 2000 .