Strength Research And Structure Optimization Of The Main Helium Ventilator Drive Motor Rotor

The nuclear power is increasingly demanded in China, for sakes of the decrease of nonrenewable resource and the rapid development of economy. The large main helium ventilator drive motor is a driving equipment of nuclear reactor's primary coolant(helium), providing the cooling medium to the nuclear reactor by driving coolant. A large centrifugal force is to be beared by the rotor during its high speed operation. The accurate calculation of the strength of the rotor is particularly important for the stable operation of motor.The circumferential stress of rotor punching sheet is analyzed in this dissertation.The circumferential stress values on the inner circle of rotor punching sheet are calculated by the analytical method. The three-dimensional model of the rotor is established. The circumferential stress nephograms of rotor core are simulated by the finite element method. The results of circumference stress values on the inner circle of rotor punching sheet obtainted by finite element method are compared with the results of the analytic method. And the correctness of the method used in this dissertation is verified.The Mises equivalent stress values of the rotor core on different working conditions are simulated by using the finite element method. And the strength of the rotor punching sheet is checked. According to control variable method, the effect of the speed of rotor, the temperature of the rotor and the assembly interference of the rotor core and the shaft on the Mises equivalent stress of the rotor punching sheet and the contact pressure between the rotor punching sheet and the shaft's interference surfaces is analyzed.The structure of the rotor punching sheet is optimized in this dissertation, on the premise that the stress of the rotor punching sheet meets the strength requirement.The structure of rotor punching sheet is improved by changing the shape of rotor slot,the position of axial vent of rotor punching sheet or the diameter of axial vent ofrotor punching sheet. The Mises equivalent stress values of the rotor core under different structure are simulated. The ability of resisting destruction of the rotor punching sheet under different structure is analyzed. A higher strength rotor punching sheet structure, without the axial vent, is designed, whose maximum Mises equivalent stress value is reduced.The strength of the rotor end is studied. The three-dimensional model of the rotor end is established. The stress values of the rotor end are simulated by using the finite element method under the high speed operation. And the strength of the rotor end is checked. A rotor end with higher strength is designed in this dissertation. The clearance fit adapted between the end ring and the retaining ring is changed to the interference fit, which makes the radial deformations of the end ring and the copper bar under high speed can be limited effectively by retaining ring. The strengths of the rotor end before and after optimization are compared. And the rationality and necessity of the optimization are elaborated.Investigation contents of this dissertation are able to provide some theory reference for improving the ability of resisting permanent deformation and fracture of rotor when the external force is beared by the rotor and structure design of rotor,and there is important significance to the main helium ventilator drive motor safety and stable operation.