A direct numerical simulation (DNS) method is proposed to evaluate the general incompressible flow behaviors in the centrifugal vaneless diffusers. This method is then applied to three kinds of centrifugal vaneless diffusers. In this way, it is confirmed that the flow pattern predicted based on the present DNS method agrees with experiments not only under the rotating stall condition but also under the diffuser stall condition. In addition, the predictions for rotating stall limit are shown to agree with the authors’ previously proposed criterion for rotating stall limit. Finally, it is clarified both experimentally and numerically that the authors’ previously proposed criterion for diffuser stall is correct; that is, when the zone of inward swirl flow reaches the exit of the diffuser, diffuser stall begins.
Numerical Simulation on the Flow Pattern of a Gas–Liquid Two-Phase Swirl Flow
