Flow kinematics in a rotating axial diffuser

• Published in: Experimental thermal and fluid science 2003-09, Vol.27 (7), p.769-780
• Main Authors: Bajcar, Tom, Širok, Brane, Trenc, Ferdinand
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Flows in ducts, channels, nozzles, and conduits; Fluid dynamics; Fundamental areas of phenomenology (including applications); Instrumentation for fluid dynamics; Laser Doppler anemometry; Phenomenological model; Physics; Rotating axial diffuser; Swirl flow; Velocity field
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/S0894-1777(02)00314-X

A study of the flow velocity field inside a rotating axial diffuser with a circular cross-section is presented in the paper. Measurements of the flow velocity components were performed by the LDA system and confirmed the existence of two types of the flow: a rotating region near the spinning wall and a non-rotating region near the longitudinal axis of the diffuser. Significant increase of all three-velocity components was observed in a thin layer at the rotating diffuser wall. Influence of the diffuser rotation and its geometry on the radial outflow was observed as well. In addition, a phenomenological model for prediction of the distribution of the velocity components in the diffuser near-wall region was developed. Exponential law was applied to the phenomenological model, which included the dimensionless velocity component as a function of two Reynolds numbers––axial and tangential. The developed model confirmed experimental results and showed substantial influence of axial and tangential Reynolds numbers on all velocity components in the vicinity of the diffuser wall.