Performance of a Splittered Transonic Rotor With Several Tip Clearances

The effect of increasing the tip-gap size on the performance of a splittered transonic rotor is presented. Tip clearance has a large influence on the performance and efficiency of compressors and fans during operation. In a gas turbine engine the ratio of tip-gap to blade height or span usually increases in the direction of flow. The front stages usually have a smaller ratio of tip-gap to blade height than the aft core stages. In addition the front stages are usually operating in the transonic regime while the rear stages operate sub-sonically.In order to be representative of these differing flow regimes the results of a range of tests at varying tip-gaps and speeds from subsonic to transonic are presented. A highly loaded transonic axial splittered rotor is used as the test article in this study. Three experiments with cold tip gaps of 0.53 [mm], 0.76 [mm] and 0.99 [mm] are presented. Each experiment was run at six tip-Mach numbers ranging from Mach 0.72 to Mach 1.2 each over a full speed-line from choked to stalling conditions. Exit temperature and pressure profiles at the rotor exit are presented along with performance maps of pressure ratio and efficiency. Significant differences in performance in terms of pressure ratio, efficiency and operating range due to the tip-gap increase were observed and are presented.The full mechanical geometry is available upon request to provide an open test case to evaluate simulation codes. This includes the cold-shape, the cavity between the rotor and stationary exit and the mounting bolts and geometry. The manufacturing steps in the preparation of the material and methods used to form the abradable material used over the rotor are presented. In addition the inlet conditions taking into account the effect of relative humidity on gas properties are presented. The complete data set of experimental results is also available electronically.Copyright © 2015 by ASME

[1]  C. C. Koch,et al.  Stalling Pressure Rise Capability of Axial Flow Compressor Stages , 1981 .

[2]  David C. Wisler.  Advanced compressor and fan systems , 1985 .

[3]  I. Moyle.  An experimental and analytical study of tip clearance effects in axial flow compressors , 1991 .

[4]  John D. Denton,et al.  The 1993 IGTI Scholar Lecture: Loss Mechanisms in Turbomachines , 1993 .

[5]  M. Furukawa,et al.  Effects of Stream Surface Inclination on Tip Leakage Flow Fields in Compressor Rotors , 1997 .

[6]  Richard Edwin Sonntag,et al.  Fundamentals of Thermodynamics , 1998 .

[7]  B. T. Sirakov,et al.  Effect of Unsteady Stator Wake—Rotor Double-Leakage Tip Clearance Flow Interaction on Time-Average Compressor Performance , 2003 .

[8]  Paul C. Ivey,et al.  Parametric Study of Tip Clearance—Casing Treatment on Performance and Stability of a Transonic Axial Compressor , 2004 .

[9]  Thomas A. Payne.  Inlet Flow-Field Measurements of a Transonic Compressor Rotor Prior to and During Steam-Induced Rotating Stall , 2005 .

[10]  Aamir Shabbir,et al.  Flow Mechanism for Stall Margin Improvement due to Circumferential Casing Grooves on Axial Compressors , 2005 .

[11]  T. V. Backström.  The Effect of Specific Heat Ratio on the Performance of Compressible Flow Turbo-Machines , 2008 .

[12]  Christian Cornelius,et al.  Compressor Efficiency Variation With Rotor Tip Gap From Vanishing to Large Clearance , 2012 .

[13]  Mark G. Turner,et al.  Isothermal Boundary Condition at Casing Applied to the Rotor 37 Transonic Axial Flow Compressor , 2013 .

[14]  Scott Drayton.  Design, test, and evaluation of a transonic axial compressor rotor with splitter blades , 2013 .

[15]  Vincent R. Capece,et al.  Experimental and Numerical Performance Characterization of a Transonic Compressor Rotor Operating Behind an Inlet-Guide Vane With Variable Flap Angles , 2014 .

[16]  Anthony J. Gannon,et al.  Design and Test of a Transonic Axial Splittered Rotor , 2015 .