Numerical Representation Of The Operating Behavior Of A Crossflow Friction Turbomachine

Based on the Tesla-type turbomachinery principle of operation, a fan consisting of flat, round discs arranged in between two separate channels, which generate two air flows in opposite directions, is investigated. Simulations of a model with one disc as well as a five-channel model at different grids were performed. With almost unthrottled operation, secondary flows could be determined at velocity magnitudes of up to 20 % of the mean main flow velocity, with secondary currents reaching up to 50 % in throttled operation. Besides high dissipation and recirculation, these secondary currencies are found to be capable of reducing the overall efficiency of the system. Thus, topic of further investigations is the potential of increasing efficiency by means of straighteners and geometric adaptions.