Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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A Study on Cooling of Hot Steel Surface by Water-Air Mixed Spray(I) -The Effect of Air Mass Flux on Film Boiling Heat Transfer-

물-공기 혼합분무에 의한 고온 강판 냉각에 대한 연구 (I) -막비등 열전달에 대한 공기질량유속의 영향-

  • 이필종 (포스코 기술연구소 공정제어 연구그룹) ;
  • 진성태 (부산대학교 기계공학과 대학원) ;
  • 이승홍 (부산대학교 기계공학과)
  • Published : 2004.03.01
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Abstract

The cooling characteristic of water-air mixed spray for high water mass flux is not well defined, compared to that of highly pressurized spray. A series of research program was planned to develop the boiling correlation for whole temperature range in case of water-air mixed spray with high water mass flux. The cooling experiments of hot steel surface with initial temperature of 820$^{\circ}C$ were conducted in unsteady state with relatively high water mass flux. A computer program was developed to calculate the heat flux inversely from measured data by three inserted thermocouples. Finally the effects of water and air mass flux on the averaged film boiling heat flux and wetting temperature were studied. In this 1st report, it is found that the boiling curve was similar to that of highly pressurized spray and the decreased slope of heat flux in film boiling region with respect to surface temperature became steep by increasing air mass flux. Also it is shown that, by increasing air mass flux, the averaged heat flux in film boiling region was increased, and then saturated and the wetting temperature was increased, and then decreased. Finally when the heat flux in film boiling region is compared with that of highly pressurized spray, it is known that the cooling is improved by introducing air up to 60%.

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References

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