Calculation And Analysis Of Magnetic Field And Temperature Field Of The Main Helium Ventilator Driving Motor End

The main helium ventilator driving motor is the main power equipment ofhelium loop in China’s fourth nuclear power plant generation high-temperature gascooled reactor, it drives helium to flow through the reactor core in the helium loop, toensure it can provide enough helium flows through the helium circulating system,taking away the heat generated by the reactor core to realize the energy exchange,when the reactor is in starting, operation and shutting-down conditions. The motoradopts a large vertical frequency conversion motor, with long service life, high safetyand reliability. Because the motor is totally immersed in helium environment, to becooled and ventilated by the helium, there are not many corresponding empiricalformulas and experimental data as the reference basis when the research ofthe helium as the motor coolant is not enough. Therefore it is necessary to conduct adeep study of helium cooling performance, so as to calculate and analyze accuratelythe temperature distribution of the each part in the motor, which plays an importantrole in motor operation, prolonging the service life and high-temperature gas cooledreactor safety.In the dissertation, the motor end was selected as the relevant research andanalysis object. Firstly the3D physical motor end model was established accordingto the motor end size data, one hand the3D transient magnetic field distribution ofthe stator winding end was calculated by means of the three dimensional finiteelement method, on the basis of it, the electromagnetic force of the stator windingend was calculated, and then taking the electromagnetic force as the motivation, thestator winding end’s electromagnetic force strain was analyzed and calculated. Onthe other hand, based on the physical properties of helium and according to theventilation structure and the cooling mode of the motor end, ventilation loss of motor end was calculated, a mathematical model to solve the motor end temperaturewas established and the boundary conditions were given, with the method of fluidsolid coupling,the motor end temperature distribution was calculated when themotor works in13Hz,67Hz,71Hz.In order to strengthen further the research ofhelium cooling performance, the motor end temperature distribution under differenthelium pressures0.2MPa,0.4MPa,0.8MPa,1.6MPa,3.2MPa were calculated and theinfluence of pressure on the cooling performance of helium was analyzed, too. In theend the dissertation compared the cooling effect about air, hydrogen which arecommonly used as the gas cooling medium in motor with the cooling effect ofhelium, mastering helium cooling effect preliminary. Results of the study forcalculating the temperature rise of the motor and insulation treatment of the endprovides an important reference.