Mechanism research on air mass flow rate distribution in rotor radial ducts of turbo generator with sub-slot ventilation

In order to reduce the axial temperature difference and the peak temperature in the rotor of the large turbo generator with air-coolant, it is expected that ventilation is uniform in rotor radial ducts along the sub-slot as far as possible. Three dimensional discrete equations of air turbulent flow in cooling duct were carried out by the Finite Volume Method according to computational fluid dynamics principle (CFD) , on the basis of a half axial rotor straight segment of a large turbo generator. Considering the same rotor geometry configuration, the change characteristic of parameters, such as the pressure inside the duct, was analyzed on condition that the axis was rotating or not, and the geometry configuration is variable. The effect of inlet angle with air entering from sub-slot to radial ducts, the number of radial ducts distributed along the rotor straight segment, and another geometry configuration on air mass flow rate distribution along radial ducts was analyzed. The results illustrate that the inlet angle and the quantity of the duct exist optimization value as for the uniform distribution of air mass flow rate. The conclusion is helpful for rotor duct design of larger turbo generator.