Surface heat-transfer coefficients of salient poles in a blast-cooled alternator

THERE are few data available on which the calculation of heat-transfer coefficients of blast-cooled rotating machine structures and adjacent stationary internal component surfaces can be based. The application of fundamental heat-transfer relationships, derived from stationary simple configurations, is impractical because of the significant effects of rotation and their variations with density of the cooling air, which may occur in machine passages. From temperature measurements on actual machines, heat-transfer coefficients cannot be derived reliably because of the usual difficulties in determining the heat-flow distribution among the various surfaces of a component whose heat dissipation may be known.