Research On Dynamic Characteristic And Structural Optimization Design Of Turbine Blade With Zigzag-shroud

The main purpose of this paper is to analyze the vibration characteristic of the zigzag-shroud blade and the factors that influence the vibration characteristic and how to influence; to find the optimization design method and the optimal structure parameters of the zigzag shroud. The result of the research in this paper can provide guide in some extent in the design of zigzag shroud.To analyze the vibration characteristic of the zigzag-shroud blade, cantilever beam model with mass and spring is set up to simulate the zigzag-shroud turbine blade. From the result of the analysis, we found that, while the mass increase, the prior-five frequencies reduce; as the stiffness of the spring increase, the prior-five frequencies raise as well, however, the each frequency raise magnitude is different. The FEM models of one, two and three blades were set up and the mode analysis, harmonic analysis and transient dynamic analysis was finished. It was indicted that the each frequency will go up, but the raise magnitude of each frequency is different when the rotation velocity go up; with the increase of the stiffness, the activated response caused by the harmonic force will change as well and the frequency correspond to the biggest response will change,there is a stiffness that make the response be minimum; the attenuation curve of the kinetic energy in each model was researched. In the end, the experiment of one and three blades model was completed based on the analysis of the numerical model, to indicate the function of the zigzag-shroud which could adjust the vibration mode of the blade and whittle the vibration response of the model.In the optimization design part, the following works were finished: the parameterized model was set up based on the analysis of the design parameters of the zigzag-shroud; two major geometry parameter: pre-twist degree and the variety deflexion degree, that influence the stress distribution on the work face of the zigzag shroud were pointed out and the optimizing model was set up using these two parameter as the variables; the function of the parametric modeling and the FEM analysis was concealed together with the VC, UG/OPEN API and ANSYS APDL, the optimization design was finished with the multidisciplinary design optimization tool iSIGHT. The stress distribution on the work face of the zigzag shroud improved a lot compared to that without optimized.