Abstract

KIBICHO, K.  and  SAYERS, AT.. Measurements of Velocity Profiles and Static Pressure Recovery in a Wide-Angled Diffuser. R&D j. (Matieland, Online) [online]. 2008, vol.24, pp.16-22. ISSN 2309-8988.

The difficulties in understanding severely asymmetrical flows in wide-angled diffusers are associated with a lack of sufficient experimental data and accurate flow prediction methods. To address this inadequacy, experimental velocity profiles and static pressure recovery data, which were obtained in a wide-angled diffuser of divergence angle of 30°, are presented in this paper. The measurements were carried out at Reynolds numbers between 1.07 × 10^s and 2.14 × 10^s based on inlet hydraulic diameter and centreline velocity. Due to the adverse pressure gradient along the diffuser walls in wide-angled diffusers, the attached flow separates from one diverging wall and remains attached permanently to the other wall. Tests performed to determine the wall to which the flow remained attached led to the conclusion that the wall of preference was totally random. Results showed that regardless of the wall to which the flow was attached, both the velocity and pressure fields were replicated with discrepancies below 2 %. The experimental uncertainties were also below 2 %. Within these uncertainties, a reliable data bank contribution for flows in a 30° diffuser has been made.

Keywords : Two-dimensional; stall; separated flows; subsonic flows; diffuser flow regimes.

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