A single sweep method for the solution of Navier-Stokes equations is used for numerical investigation of flow in annular diffusers formed by a cylindrical casing and a converging conical hub, with the presence of inlet swirl and/or hub rotation. It is shown that counter-swirlwise hub rotation prevents reverse flow from appearing. The paper discusses the efficiency characteristics of diffusers installed at the exit of hydraulic machines. It is shown that the energy losses in a diffuser and in a channel behind the diffuser become minimal in the presence of small inlet swirl in the opposite direction to hub rotation.
Issue Section:
Technical Papers
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.Copyright © 2001
by ASME
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