A General Calculating Method of Rotor’s Torsional Stiffness Based on Stiffness Influence Coefficient

Danmei Xie, Wangfan Li, Ling Yang, Yong Qian, Xianbo Zhao, Zhigang Gao

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DOI: 10.4236/eng.2010.29090                

Abstract

In order to develop a general calculating rotor’s torsional stiffness based on stiffness influence coefficient for different rotor assembling, the calculation method of the torsional stiffness influence coefficient of equal thickness disc is researched in this paper at first. Then the torsional stiffness influence coefficient λ of equal thickness disc is fit to a binary curved face and a calculation equation is obtained based on a large quantity of calculating data, which lays the foundation for research on a general calculating method of rotor torsional stiffness. Thirdly a simplified calculation method for equivalent stiffness diameter of stepped equal thickness disc and cone disc in the steam turbine generators is suggested. Finally a general calculating program for calculating rotor’s torsional vibration features is developed, and the torsional vibration features of a verity of steam turbine rotors are calculated for verification. The calculating results show that stiffness influence coefficient λ of equal-thickness disc depends on parameters of B and H, as well as the stiffness influence coefficient λ; and discs with complex structure can be simplified to equal-thickness discs with little error by using the method suggested in this paper; error can be controlled within 1% when equivalent diameter of stiffness is calculated by this method.

Keywords

Rotor, Disc, General Calculating Method, Torsional Stiffness, Stiffness Influence Coefficient

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	W. F. Li, D. M. Xie, et al., “Calculation of Rotor’s Torsional Vibration Characteristics Based on Equivalent Diameter of Stiffness,” Asia-Pacific Power and Energy Engineering Confe-rence (APPEEC2010), Chengdu, 2010.
[2]	W. X. Shi, “Tur-bine Vibration,” Water Conservancy and Electric Power Press, Beijing, 1991.
[3]	H. T. Sun, “Approach to Torsional Vibra-tion of Shaft System for High-Capacity Turbo-Generations,” Thermal Power Generation, Vol. 33, No. 1, 2004, pp. 42-44.
[4]	D. N. Walker, S. L. Adams and R. J. Placek, “Torsional Vibration and Fatigue of Turbine Generator Shafts,” IEEE Transactions on Power Apparatus and Systems, Vol. 100, No. 11, 1981, pp. 4373-4380.
[5]	Y. L. Li, “Study on Tor-sional Vibration Characteristics of Turbine Rotor with Cracks Based on ANSYS,” Wuhan University, Wuhan, 2008.
[6]	L. L. Dang, Z. Y. Weng and G. L. Xu, “Research in Equivalent Rigidity of Rotor Vibration,” Mechanical Engineer, No. 4, 2009, pp. 89-91.
[7]	D. M. Xie, C. Dong and Z. H. Liu, “The Torsional Rigidity of a Shafting Specific Structure and its Effect on the Torsional Vibration Characteristics,” Thermal Power Engineering, Vol. 22, No. 2, 2007, pp. 146-148.
[8]	H. Y. Wu, “Structure and Strength Calculation of Turbine Parts,” Machinery Industry Press, Beijing, 1982.