Rotor Dynamic Analysis And Impeller Strength Analysis In A Big-Sized Turbo-Expander

This dissertation is one part of "Designs Optimization and Manufacture of the Big-Sized Turbo-Expander ", which is the subject of the institute of hangzhou science and technology. The turbo-expander with a capacity of 50000m~3/h (oxygen) will be the largest one designed by ourselves at home. The rotor dynamic characters and the strength analysis of the impellers are discussed in this paper. Then, a suitable analysis guide during the design process of the big-sized turbo-expander is expected in this paper, which could mostly improve the design efficiency and reliability, and also could be convenient and useful for much larger capacity equipments in the future.It is the first that three ridge shaft is taken into account. A rotor dynamics calculation software is designed by MATLAB using the finite element method, which is specially for the big-sized turbo-expander. The software includes the effects moment of inertia, gyroscopic moment, equivalent damping and stiffness of bearing. And all the parameters required are discussed outside the program, which is much convenient to the users. The calculation samples show that the software has high accuracy with an extremely smaller error. The software was ideal in the dynamic calculation of the rotor in a big-sized turbo-expander. Then comes this conclusion: the program could fully satisfy the project desire and also has an active effect on the study of rotor dynamics.A strength analysis has been conducted using the three-dimensional finite element method, which is the first on considering the interference fit, temperature load and centrifugal load. Due to the temperature between the inlet and the outlet is significant different, the temperature load has been discussed in this paper. Then, an equivalent temperature is adopted to treat the interference fit. By the way, a suitable interference allowance between the impeller and the shaft is suggested based on the FEA analysis results. It is indicated that this method of treating interference fit and temperature load has a positive effect on the similar structural strength analysis.