Multi-physical fields of rotor windings with axial-radial ventilation system for 1100 MW nuclear half-speed turbine generator

Due to super capacity, nuclear turbine generator is designed with high electromagnetic and thermal load, it easily leads to overheat of rotor windings. Thus, rotor is cooled by hydrogen in complicated ventilation system to protect generator from overheat. It is very difficult to determine the rotor temperature distribution by accounting the influence of complicated ventilation system and rotor rotating. In light of this situation, taking a 1100 MW nuclear turbine generator as an example, the synergistic coupling method is proposed to investigate the multi-physical fields. Firstly, the wind resistance network considering complicated ventilation circuit and rotor rotation is established, and the fluid pressure and velocity distributions are solved. The accuracy is validated by comparing with experimental results. Secondly, three-dimensional fluid flowing and heat transfer coupling mathematical model of the rotor is established to solve multi-physical fields based on the calculation results of the wind resistance network above. The rotor winding and the fluid variables are investigated and the rotor windings temperature is measured to verify the accuracy of the calculation model. Lastly, the gradient of velocity, heat transfer coefficient, fluid velocity components and resultant velocity are analyzed. The contents can provide theoretical basis for design of super capacity turbine generator. •The rotor is designed as unequal tooth spacing and unequal slot height.•The fluid network and heat transfer model cooperative coupling method is provided.•The ventilation test and temperature test are made.•The fluid velocity components distribution are investigated.•The relations between the fluid velocity and heat transfer coefficient are studied.