Natural convection from flat side's of coil system

This paper presents a thermal study to determine the convective heat transfer coefficient over the flat side of a permanent magnet synchronous generator coil in horizontal and vertical directions by using the empirical correlations. To validate the results, an experimental setup is developed for both horizontal and vertical orientations and different input currents. The experimental results are compared with the analytical method, based on correlations proposed in the literature. The results show that the analytical calculation based on empirical correlation for the horizontal case and Mac Adams as well as Churchill I correlations for the vertical case have a good agreement with the experimental data.