Unsteady velocity field measurements at the outlet of an automotive supercharger using particle image velocimetry (PIV)
- Department of Mechanical Engineering, Iowa State University, 3025 H.M. Black Engineering Bldg, Ames, IA 50011 (United States)
Particle image velocimetry (PIV) was used to study air flow characteristics at the outlet of an automotive supercharger. Instantaneous velocity fields were analyzed to yield ensemble-averaged velocities and Reynolds stresses, and the ensemble-averages were used to determine maximum velocity and exit flow angle as a function of blade position for various speeds and pressure ratios. The results show that the flow exits the supercharger as a high-speed jet that not only varies in the parallel plane but also in the perpendicular plane, generating a complex three-dimensional flow. The flow varies in the magnitude and the angle at which it leaves the supercharger with the change in blade position and follows a periodic behavior. The maximum velocity at which the flow exits the supercharger also follows a periodic behavior with a variation of 25-30% observed for all the cases. In the parallel plane, the exit angles are periodic every 60 deg of blade rotation and vary by as much as 40 deg, whereas periodic behavior with every 120 deg of blade rotation and a variation of 60 deg is observed in the perpendicular plane. Variation in flow with blade position is also observed in the velocity and turbulence profiles, with periodic behavior with every 60 blade rotation. The velocity and velocity fluctuation profiles show that the unsteady nature of the flow is most significant close to the outlet, and these unsteady variations diminish 58 mm downstream of the outlet. An exit flow pattern of a figure 8 is generated as the flow leaves the blades with one complete blade rotation of 120 for all the cases, except 4000 rpm, pressure ratio 1.4, where the flow exits in a circular pattern. (author)
- OSTI ID:
- 21151211
- Journal Information:
- Experimental Thermal and Fluid Science, Vol. 33, Issue 3; Other Information: Elsevier Ltd. All rights reserved; ISSN 0894-1777
- Country of Publication:
- United States
- Language:
- English
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