Thermal optimization for nature convection cooling performance of air core reactor with the rain cover

In this paper, a fluid‐thermal coupled finite element model is established to calculate the temperature rise of a dry type air‐core reactor, and it accuracy is verified by the experimental results obtained from a prototype. Taking the initial design parameters based on the equal height and the thermal flux design method, the detailed temperature field of the reactor is obtained both with and without the rain cover. It is shown that the maximum temperature rise of the inner encapsulations is different and higher after adding the rain cover. The reasons are given by analyzing the changes of the fluid velocity in the air ducts. In order to realize the same temperature rise and not more than the limit after adding the rain cover, two parameters of the rain cover are considered, which have five levels. The performance statistics analysis and optimal structure parameters of the rain cover are achieved. Meanwhile, a heat load optimization method is proposed for the inner encapsulations, and its correctness is validated by the temperature field simulation results. This is of great significance in guiding the thermal optimization of the reactor with rain cover. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.