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Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Volumes per year:

various

Year 2006

DOI: 10.1615/IHTC13.p16

NOZZLE SIDE WALL GEOMETRY EFFECT ON THE NEAR FLOW FIELD MIXING

M. I. Khan
The University of Birmingham, Edgbaston, UK

M. Barigou
The University of Birmingham, Edgbaston, UK

T. Gilbert
Jet Environmental Techniques, Solihull, UK

ABSTRACT

The aim of the work was to investigate the effect of the nozzle side wall geometry on the turbulent flow jet and the near flow field mixing and temperature distribution in still air. Prototype experiments were carried out with the JETs (Jet Environmental Techniques) existing nozzle geometry in a test room was validated using RNG kappa-epsilon turbulence model under steady state conditions. In the next stage a range of nozzle surface profiles of similar inlet and contraction diameters have been tested under identical conditions similar to the prototype test room. Comparisons of the axial mean streamwise velocity decay, mass entrainment, turbulence characteristics and the temperature distribution in an enclosed space was reported for each of the nozzle geometry to evaluate its performance in the space. From the analysis of data, it was found that enhanced mixing between the jet flows and surrounding fluid was noticed for the nozzles which generated relatively higher turbulence kinetic energy in the near field transition region. Examination of the temperature profiles in the numerical space revealed that nozzles generating higher turbulence kinetic energy promoted diffusion of the temperature in the near flow field. The jets core length for these various circular outlet nozzles under consideration has significantly influenced the mixing process.