Investigation of Flow Characteristics of a Turbulent Annular Impinging Jet.

Document Type : Research Studies

Authors

1 Mechanical Power Engineering Department., Shoubra Faculty of Engineering., Zagazig University.

2 Mechanical Power Engineering Department., Benha Higher Institute of Technology.

Abstract

The structure of a curved flow created by an annular jet impinging on a flat plate has been  investigated in the present experimental model. As the curvature of the jet can be controlled by the  gap between the jet exit and the impingement plate hence the flow can be simply analyzed in terms of the internal pressure which is generated by the rate of change of moinenturn due to the jet being  turned through 90°. Measurements of the velocity profiles across the jet and tile pressure distribution  along the impingement plate have been conducted for different jet curvature and inlet velocity. The  velocity profiles across the jet and the turbulence parameters were measured using a Fiber Optics  back scattering Laser Doppler Anemometer(LDA) system connected to a Burst Spectrum Analyzer  (BSA) [or data processing.  
Examination of (he velocity measurements and pressure distribution along Ute impingement plate  indicated a strong curvature of the jet and high turbulence circulation and swirl within various vortex  regions across the flow field. It is found that the difference in the jet entrained rate and the pressure field in the outer and the inner annular regions are responsible for the difference in the displacement of both  the mean velocity and the turbulence intensity profiles outward the central axis of the jet.
  The variation of the pressure field from slightly sub-atmospheric to a maximum at the stagnation  point and into the recirculation bubble is detected. The variation of the normalized stagnation pressure is correlated with the normalized ground height by a linear equation. within the range of the  present experimental data. 

Main Subjects

MEJ- Mansoura Engineering Journal
Volume 20, Issue 2
VOL 20 has Two Issues Issue 2 Consist of Two Parts from ( March to June)
June 1995
Pages 48-60

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