Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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The Effect of Nozzle Characteristics on the Mist-Cooling Heat Transfer

노즐특성에 따른 MIST-COOLING 열전달에 관한 실험적 연구

  • Lee, J.W. (Department of Heat and Refrigeration, Joongkyong Technical Junior College) ;
  • Kang, Y.G. (Department of Mechanical Engineering, Chonbuk National University) ;
  • Baek, B.J. (Department of Precision Mechanical Engineering, Chonbuk National University) ;
  • Park, B.C. (Department of Machine Design Engineering, Chonbuk National University)
  • 이진원 (중경공업전문대학 열냉동관리과) ;
  • 강영규 (전북대학교 기계공학과) ;
  • 백병준 (전북대학교 정밀기계공학과) ;
  • 박복춘 (전북대학교 기계설계학과)
  • Published : 1992.09.30
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Abstract

The effect of nozzle characterristics on the mist-cooling heat transfer was investigated under the various flow conditions. Two different types of twin fluid nozzle were used, one is a $90^{\circ}$ angle tip nozzle with needle and the other is a $90^{\circ}$ angle tip non-needle nozzle. The cooling rate from the heated surface was measured and obtained the boiling curve as a function of surface temperature. An immersion sampling was employed for the measurement of droplet size of the spray. As a result of this experiment, the liquid sheet type nozzle shows better atomization when the mass ratio Mr>2.0, and collects more liquid droplets on the heated surface that results in better cooling effect. It was found that the maximum heat flux and heat transfer coefficient increased with increase in the volumetric flow rate, whereas the maximum heat flux decreased with increase in spray distance. The cooling effect depends upon the amount of collected droplet and droplet size, but it strongly depends upon the amount of collected droplet.

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