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Heat and Mass Transfer

, 46:53 | Cite as

Flow structure and heat transfer of impingement jet

  • K. Oyakawa
  • A. Umeda
  • M. D. IslamEmail author
  • N. Saji
  • S. Matsuda
Original

Abstract

This paper presents the characteristics of flow behavior and thermal fields of both free and impingement jets issued from circular orifice nozzle at Re = 9,700. The flow behavior of a single round jet and impingement jet were observed by smoke flow visualization recorded by a high speed video camera with 5,000 frames per second. Heat transfer coefficient on the impingement surface was calculated varying the Reynolds number and the separation distance between nozzle exit and plate. Time-series analysis was applied to the visualization image to get the information of time variation of flow behavior. Probability distribution of vortex scale induced by the jet at discrete positions was investigated. Experimental results show that the potential core is not a continuous phenomenon with time and the frequency of vortex ring formation have similar features regardless of whether the impingement plate was set on or not, furthermore the time-series analysis with flow visualization images makes clear the detailed flow behavior.

Keywords

Vortex Ring Target Plate Impingement Plate High Speed Video Camera Laser Light Sheet 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols

D

Diameter of circular nozzle

H

Separation distance between a nozzle exit and an impingement plate

q

Supplied heat flux

hx

Heat transfer coefficient

Re

Reynolds number ≡ UD/ν

Nu

Nusselt number ≡ h x D/κ

r

Distance of radial direction from origin on impingement plate

tj

Nozzle exit temperature

tw

Local wall temperature on impingement plate

U

Mean velocity at nozzle exit

X

Vertical direction coordinates from nozzle exit

Greek symbols

κ

Thermal conductivity of fluid

ν

Kinematic viscosity of fluid

Notes

Acknowledgments

This is to acknowledge that this paper is not considered for publishing in any other journal.

References

  1. 1.
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  3. 3.
    Oyakawa K, Yaga M, Nasu K, Senaha I, Matsuda S, Azama T (1998) Impingement heat transfer by jet issuing from a cross-shaped nozzle. Heat Transf Jpn Res 27(3):192–204CrossRefGoogle Scholar
  4. 4.
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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • K. Oyakawa
    • 1
  • A. Umeda
    • 1
  • M. D. Islam
    • 2
    Email author
  • N. Saji
    • 1
  • S. Matsuda
    • 1
  1. 1.Department of Mechanical Systems Engineering, Faculty of EngineeringUniversity of the RyukyusNishiharaJapan
  2. 2.Department of Mechanical EngineeringThe Petroleum InstituteAbu DhabiUnited Arab Emirates

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