Conjugate Heat Transfer Analysis of Integrated Brushless Generators for More Electric Engines

In this paper, a complete conjugate heat transfer analysis of a scaled-sized prototype of an integrated air-cooled surface-mounted permanent-magnet generator for the “more-electric engine” application is presented. The selected integration position inside the aircraft´s main gas turbine engine imposes the use of an unconventional cooling system, where the coolant directly flows through the machine air gap. To predict and prevent the critical working conditions of the prototype, the adopted cooling system has been investigated using a complete fluid-thermal analysis. Due to the capabilities of computational fluid dynamic software, it has been possible to analyze the temperature and flow fields inside the machine, giving an idea about the distribution of the thermal quantities both inside the solid materials and above the surfaces. The numerical model validation has been provided, comparing computed and experimental results, i.e., imposing the same working conditions, the predicted temperatures satisfactorily agree with the measured temperatures.