Fluid Field And Thermal Field Calculation For The Rotor Of Large Turbo-Generator

In order to ensure that the turbo-generator work safely, the temperature of everypart in generator must be controlled within safe range. The flow rate and temperaturemust be calculated exactly, because the rotor is the main part in the turbo-generator.According to the theory of CFD and Heat Transfer, the fluid field of rotor’s line partwas calculated, meanwhile, the thermal property was also analyzed.The ventilating structure of turbo-generator was introduced. The3D finite modelsof fluid field and thermal field were established in the paper. The half axial modelincluding the radial ventilating ducts and axial sub-slot was established in one slot,because the ventilating structure of rotor is symmetrical. Based on the characteristics ofthermal field, the3D model of rotor circumference1/4including iron core, windings,slot wedge and slot insulation was established.The fluid field of ventilating ducts in generator rotor was calculated and analyzed,and the fluid field distribution under the rotary and static conditions was obtained.Based on the rotary condition, the absolute velocity and relative velocity weresimulated, meanwhile, the velocity vector diagram, the velocity curve, and the flowwere also obtained. The flow characteristic was analyzed under a speed variationcondition. According to the velocity in ventilating ducts, the heat transfer coefficientwas calculated.According to the result of air-gap flux density, the stray loss on rotor surface wascalculated. The3D thermal fields of generator rotor were also calculated by using alllosses and heat release coefficient calculated above as the solving condition. Theaccurate results of rotor thermal fields were attained under rated load condition, and thetemperature distribution of the rotor was analyzed. At the same time, the influence ofthe stray loss and the slot insulation on thermal fields were analyzed quantitatively.