Title: Modal analysis of Francis turbine blade based on fluid-structure interaction theorem

Authors: Zhang Lixia, Zhang Wei, Yang Zhaohong

Addresses: Key Laboratory for Advanced Material Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, 100084, Beijing, China; Department of Mechanical Engineering, Academy of Armored Force Engineering, 100072, Beijing, China. ' Key Laboratory for Advanced Material Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, 100084, Beijing, China. ' Department of Information Engineering, Academy of Armored Force Engineering, 100072, Beijing, China

Abstract: The paper deals with the modal analysis of Francis turbine blade with fluid-structure interaction (FSI). The dynamic equation of Francis turbine blade in air and operating flow path is studied, and two different governing equations are solved together. Then the mathematic model for vibration and stress analysis was built to calculate the natural frequency in air by using finite element analysis (FEA). In addition, the blade|s coupled modelling in operating flow path lies on a classical finite element discretisation of the coupled fluid-structure equation. According to the analysis of results, the influential coefficients by the FEA adopted in the present study are in fairly good agreement with the experienced data listed in some documents. The modal analysis of the blade highlights that the natural frequencies decrease dramatically and the mode shapes in operating flow path are close to those in air. So the method presented herein can be used efficiently as a reliable tool for the fatigue reliability design and performance analysis of Francis turbine blade.

Keywords: fluid-structure interaction; FSI; modal analysis; Francis turbine blades; fatigue design; mathematic modelling; vibration; stress analysis; finite element analysis; FEA.

DOI: 10.1504/IJMIC.2010.033851

International Journal of Modelling, Identification and Control, 2010 Vol.10 No.1/2, pp.101 - 105

Available online: 02 Jul 2010 *

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