The effect of diffuser aperture angle on turbulent flow characteristics with varying swirl degrees
D.A. Suslov, S.G. Skripkin, S.I. Shtork
Kutateladze Institute of Thermophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: vortex core precession, laser Doppler anemometer (LDA), diffusers, swirl parameter
Abstract
The influence of the diffuser aperture angle and the flow swirl degree on the characteristics of a turbulent flow and the precessing vortex core forming within it was experimentally studied. Laser Doppler anemometry was used to analyze the flow. It was shown that the effects associated with changes in the diffuser aperture angle depend significantly on swirl. With strong swirl, nonmonotonic behavior of the integral swirl parameter in the far wake was observed, which is interpreted as a change in flow regimes. Increasing the aperture angle enhances velocity fluctuations associated with vortex precession. The results form the basis for validating computational models and optimizing diffusers in power plants.
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