A Reduced Model for Prediction of Thermal and Rotational Effects on Turbine Tip Clearance

This paper describes a dynamic model that was developed to predict changes in turbine tip clearance the radial distance between the end of a turbine blade and the abradable tip seal. The clearance is estimated by using a first principles approach to model the thermal and mechanical effects of engine operating conditions on the turbine sub-components. These effects are summed to determine the resulting clearance. The model is demonstrated via a ground idle to maximum power transient and a lapse-rate takeoff transient. Results show the model demonstrates the expected pinch point behavior. The paper concludes by identifying knowledge gaps and suggesting additional research to improve the model.

[1]  D. E. Metzger,et al.  Heat Transfer and Effectiveness on Film Cooled Turbine Blade Tip Models , 1993 .

[2]  Paul A. Durbin,et al.  Toward improved film cooling prediction , 2002 .

[3]  Osamu Watanabe,et al.  Tip Clearance Effect on Heat Transfer and Leakage Flows on the Shroud-Wall Surface in an Axial Flow Turbine , 1992 .

[4]  Paul A. Durbin,et al.  Toward Improved Prediction of Heat Transfer on Turbine Blades , 2002 .

[5]  Je-Chin Han,et al.  Heat Transfer and Pressure Distributions on a Gas Turbine Blade Tip , 2000 .

[6]  J. M. Owen,et al.  Flow and Heat Transfer in Rotating Disc Systems, Vol.1: Rotor-Stator Systems , 1989 .

[7]  S. Timoshenko,et al.  Theory of elasticity , 1975 .

[8]  Bruce M. Steinetz,et al.  Turbine Engine Clearance Control Systems: Current Practices and Future Directions , 2002 .

[9]  D. G. Cherry,et al.  Energy efficient engine. Low pressure turbine test hardware detailed design report , 1982 .

[10]  W. A. Fasching,et al.  CF6 jet engine diagnostics program. High pressure turbine roundness/clearance investigation , 1982 .

[11]  Y. W. Kim,et al.  Darryl E. Metzger Memorial Session Paper: A Summary of the Cooled Turbine Blade Tip Heat Transfer and Film Effectiveness Investigations Performed by Dr. D. E. Metzger , 1995 .

[12]  R. L. Martin,et al.  B747/JT9D flight loads and their effect on engine running clearances and performance deterioration; BCAC NAIL/P and WA JT9D engine diagnostics programs , 1982 .

[13]  Je-Chin Han,et al.  Heat Transfer and Flow on the Squealer Tip of a Gas Turbine Blade , 2000 .