# 복사가열조건에서 표면 거칠기에 따른 액적의 증발 냉각

• Published : 2004.09.01
• 49 4

#### Abstract

The objective of the present work is to examine evaporation cooling of droplet due to surface roughness under radiative heat input condition. The surface temperatures varied from $80\~160^{\circ}C$ on aluminum alloy (AL 2024) and surface roughness was $0.18{\mu}m,\;1.36{\mu}m$. The results are as follows; Regardless of surface roughness under radiative heat input condition, as droplet diameter is larger, the in-depth temperature of solid decreases and evaporation time increases. In the case of $0.18{\mu}m\;and\;1.36{\mu}m$ of surface roughness, the larger the surface roughness is, the less the evaporation time is and the larger the temperature within the solid is. In the case of $Ra=0.18{\mu}m$ evaporation time and time averaged heat flux for radiative heat input case is shorter than for the conductive case.

#### Keywords

droplet radiative heat input;surface roughness;evaporation cooling

#### References

1. 방창훈, 양창호,' 액적의 Weber 수에 따른 냉각특성의 변화', 산업안전학회지, 제18권, 제1호, pp. 33-37, 2002
2. John R .Thome, Enhanced Boiling Heat Transfer, Hemisphere publishing Co.. 1990
3. 방창훈, 권진순, '표면거칠기에 의한 액적의 증발냉각,' 산업안전학회지, 제18권, 제3호, pp.29-33, 2003
4. Bonacina, C., DelGiudice, S., Comini, G., 'Dropwise Evaporation', J. of Heat Transfer, Vol. 101, pp. 441-446, 1979 https://doi.org/10.1115/1.3451004
5. Toda, S, 'A Study of Mist cooling 1st Report: Investigation of Mist Cooling', Heat Transfer Jap. Res., col. 1, pp. 39-50, 1972
6. Rizza, J.,'A Numerical Solution to Dropwise Evaporation', J of Heat Transfer, Vol. 103, pp. 501-507, 1981 https://doi.org/10.1115/1.3244492
7. DiMarzo, M, Evans, D. D., 'Evaporation of a Water Droplet Deposited on a Hot High Thennal Conductivity Surface', J. of Heat Transfer, Vol. 111, pp. 210-213, 1989 https://doi.org/10.1115/1.3250652
8. Makino, K., Michiyoshi, I., 'Discussions of Transient Heat Transfer to a Water Droplet on Heated Surfaces under Atmospheric Pressure', Int. J. of Heat Mass Transfer, Vol. 30, No.9, pp. 1895-1905, 1989 https://doi.org/10.1016/0017-9310(87)90249-3
9. Abu-Zaid, M, Atreya, A, 'Transient Cooling of Hot Porous and Nonporous Ceramic Solids by Droplet Evaporation', J. of Heat Transfer, Vol. 116, pp. 694-701, 1994 https://doi.org/10.1115/1.2910924
10. Cengel Y. A., Boles M .A., Thermodynamics, McGraw-Hill, Int. ed, 1994
11. Michiyoshi, I., Makino, K,'Heat Transfer Characteristics of Evaporation of a Liquid Droplet on the Heated Surfaces', Int. J. of Heat Mass Transfer, Vol. 21, pp. 605-613, 1978 https://doi.org/10.1016/0017-9310(78)90057-1
12. Seki, M, Kawamura, H., Sanokawa, K, 'Transient Temperature Profile of a Hot Wall due to an Impinging Liquid Droplet', J. of Heat Transfer, Vol. 100, pp. 167-169, 1978 https://doi.org/10.1115/1.3450494