The Critical Speed Research Of High Speed Rotating Machinery

With the rapid development of electricity, aviation, machinery, petrifaction, the power and rotational speed of various kinds of rotating machinery have become higher and higher, working speed even reaches over third or fourth critical speed, which set much higher demands on research and analysis of rotor dynamics. So how to reasonably analyze rotor model and accurately solve critical speed are becoming great significant issues in engineering practice, which can increase efficiency, ensure security, reduce malfunction and prolong operating life of rotating machinery.Aimed at the characteristics of rotating machinery, based on the analytical study of lumped parameter method and distribution quality method, combined the principles of rotor dynamics mathematical model, rotor-bearing system was reasonably simplified in this paper, and a mixed mathematical model of multi-supported, poly disc rotor-bearing system was established. Such mixed model has the advantages of more practicable and faster calculating speed; in addition, the effect factors of gyroscopic moment, supporting stiffness, shear deformation were taken into account, and then based on Riccati transfer matrix method, the critical speed of mixed model rotor-bearing system was calculated.Then, requirements analysis were carries on, the scientific and rational algorithm was designed as well. And a user-friendly, simple operation, strong expansion common rotor-bearing system critical speed calculation program was developed with VB in this paper. In the programming, modularization program frame was adopted, it makes the function module mutually independent as well as related and is convenient for system upgrading and combining of other algorithms. Finally, the correctness and practicability of the program were verified with some examples.Results shows that the critical speed calculation method of mixed model combining with Riccati transfer matrix makes the calculation result more accurate and stable; the general rotor critical speed software is reliable with correct algorithm, and can satisfy the requirement of the engineering application, it has a very high value in overall design and safety reliability analysis of machines.