Radially resolved measurement of stator heat transfer in a rotor–stator disc system

This paper describes a new experimental method for measuring stator heat transfer in a rotor–stator disc system using an electrical heater array. The system is partially blocked at the periphery, with radial outflow of rotor-pumped air from an inlet at stator centre. The aim is to improve thermal performance prediction for air-cooled disc type electrical machines. Local Nusselt numbers were measured for image at three non-dimensional gap ratios image and rotational Reynolds numbers image. Transition at the stator is observed to occur at image for all gap ratios. Increased Nusselt numbers at the periphery are observed for all image and G because of the ingress of ambient air along the stator due to the rotor pumping effect.