Conjugate heat transfer analysis of integrated brushless generators for more electric engines

In the paper a complete conjugate heat transfer analysis of a scaled-size prototype of an integrated, air-cooled, surface mounted, PM generator for “More Electric Engine” application is presented. The selected integration position inside the aircraft main gas turbine engine imposes the use of a unconventional cooling system, where the coolant directly flows through the machine airgap. To predict and prevent critical working conditions of the prototype, the adopted cooling system has been investigated by means of a complete fluid-thermal analysis. Thanks to the capabilities of computational fluid dynamic software, it has been possible to analyze the temperatures and flow fields inside the machine, giving an idea of the distribution of thermal quantities both inside the solid materials and above the surfaces. The numerical model validation has been provided comparing computed and experimental results: imposing the same working conditions, the predicted temperatures satisfactory agree with the measured ones.