Prediction of turbulence quantities for swirling flow in conical diffusers

Turbulent swirling flow through 12 and 20 deg included angle diffusers, with moderate inlet swirl numbers sufficient to avoid wall flow separation, are predicted by a k-e and an algebraic Reynolds stress turbulence model with a two-layer wall function. Good agreement with experimental data for the mean velocities and turbulence quantities is obtained by using an algebraic Reynolds stress turbulence model and a k-e turbulence model with a suitable choice of the wall treatment. Both the amplification of the peak in turbulence quantitites and its increased distance from the diff user wall, when compared to those of fully attached flow, are predicted very well for solid-body rotation swirling flow. The effect of different inlet swirl profiles on the flow behavior is also discussed.