Validation by measurements of a windage losses model for very-high-speed machines

When designing a very-high-speed (VHS) machine, it is crucial to evaluate the windage losses accurately, because they are an important part of the total losses. It is therefore important to validate a reliable model, further used for the design and optimization of the motor. In this paper, an empirical windage loss model has been compared to measurements on a motor running up to 155 krpm in a pressure chamber. Indeed, in order to simulate the behavior of a motor running at higher speed, the air pressure surrounding the motor has been elevated up to 9 bars. The error encountered was 16 % at most compared to measurements.