901 publications from this institution
Rotating electric machines generate heat volumetrically, and are cooled by forced convection aided by the self-pumping effect. In this paper we focus on the fundamental relationship between the internal flow architecture of the gas cooled winding and its thermal performance, which is represented by the nearly uniform distribution of peak temperature throughout the winding volume. We show that the cooling passages can be sized such that the volumetric cooling is most effective. From this finding follows the number of passages and their distribution through the heat generating volume. The principle is developed analytically, and it is then validated based on numerical simulations of the cooling architecture. The paper also reports the thermodynamics basis of the self-pumping effect, and its natural occurrence as free convection in general, which includes atmospheric circulation.
This paper describes human application of their knowledge and technological ability to fly and continue to enhance that power. Through application of their knowledge and technological ability, human beings have evolved the ability to fly and continue to enhance that power. Aircraft technology evolution is about the evolving design of the human movement on the Earth’s surface: people, goods, materials, and everything else. As the whole vehicle or animal evolves toward becoming better at moving mass on the landscape, the organs remain imperfect, because each represents a compromise. The whole vehicle or animal is a construct of organs that are ‘imperfect’ only when examined in isolation. The vehicle design evolves over time and becomes a better construct for moving the vehicle mass on the world map. Flow architectures are evolving right now, throughout nature and in technologies. The legacy of all flow systems (animate and inanimate) is: they have moved weight horizontally and improved the efficiency of that movement because of design evolution.
