Published 6 issues per year
ISSN Print: 2152-5102
ISSN Online: 2152-5110
Indexed in
INFLUENCE OF NOZZLE EXIT CONDITIONS ON THE NEAR-FIELD MEAN FLOW CHARACTERISTICS OF LOW-ASPECT-RATIO RECTANGULAR JETS
ABSTRACT
The present study reports a systematic investigation of the effect of aspect ratio and Reynolds number on the mixing characteristics of low-aspect-ratio rectangular jets issuing from orifice plate nozzles. The nozzle aspect ratio (AR) is varied from 2 to 7, while the Reynolds number (with a constant equivalent diameter) is varied from 1 × 104 to 5 × 104. Particle image velocimetry (PIV) is used to determine the jet centerline mean velocity decay, jet velocity half-width spread, and potential core length, which are used to characterize the mechanisms of jet spreading in the near (x/De < 4) and mid (4 < x/De < 10) fields. The results show a distinctive difference in the mixing characteristics in the very near field (x/De < 2) for the low-AR range (AR = 2−7) examined in the present study. Jet entrainment is found to decrease in the near field with increasing AR for AR < 5. For AR > 4, however, the trend is reversed, that is, jet entrainment increases with increasing AR. Additionally, the results show that, in the midfield, the magnitude of jet decay and spreading rates increases with increasing AR and remains relatively constant with varying Reynolds number. In conclusion, Reynolds number is found to have a lesser impact than the AR on the mixing characteristics of a rectangular jet, suggesting a stronger aspect ratio dependence for low-aspect-ratio rectangular jets.
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Kim Won Hyun, Park Tae Seon, Influence of inlet vorticity and aspect ratio on axis-switching and mixing characteristics of heated rectangular jets, International Journal of Heat and Mass Transfer, 155, 2020. Crossref
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Kim Won Hyun, Park Tae Seon, Inflow characteristics for generating axis-switching phenomenon of heated rectangular jets, Computers & Mathematics with Applications, 86, 2021. Crossref