Rotor Air-Cooling Efficiency of Powerful Turbogenerator

The article presents a calculation of a turbogenerator rotor air-cooling system with self-ventilation of the rotor winding from a sub-slot duct. The mathematical model proposed in the article reflects all the significant geometric parameters of the physical model as well as the gas dynamics of the cooling process. Research has been done into the impact of the profile of a sub-slot duct along the length of the rotor on air velocity distribution in radial ducts and on the efficiency of heat transfer in a 320 MW turbogenerator. The research has also shown that the maximum temperature of the rotor winding may be lowered by means of a sub-slot duct smoothly tapering to the middle of the axial rotor length (17% of the inlet section area of the sub-slot duct). Such configuration compensates air heat up along the rotor sub-slot duct due to the forced unevenness of air distribution in the radial ducts.