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KSME Journal

, Volume 3, Issue 2, pp 153–158 | Cite as

Oscillatory behaviors in initial film boiling: Implications on the triggerability of single droplet vapor explosions

  • Byong-Joo Kim
Article

Abstract

A transient one-dimensional film boiling model was developed to study the film boiling dynamics that would occur when a hot spherical droplet is immersed in cold liquid. The focus of this study was to investigate the effects of noncondensible gas, liquid temperature, droplet temperature, and ambient pressure on film boiling during the initial growth phase. The results indicate that the film generally stablizes with more noncondensible gas present, higher liquid and lower droplet temperature. Small ambient pressurizations cause violent fluctuations of the film pressure while higher ambient pressure suppresses these oscillations. These qualitative behavior of film boiling around hot spherical droplet suggests that the spontaneous triggering of small-scale single droplet vapor explosions is led by the oscillatory characteristics of vapor film in its initial growth phase.

Key Words

Film Boiling Oscillatory Behaviors Single Droplet Vapor Explosions Triggerability 

Nomenclature

C

Noncondensible gas constant

Cp

Specific heat at constant pressure

d

Diameter of spherical droplet

G

Universal gas constant

h

Enthalpy

hfg

Latent heat of vaporization of cold liquid

k

Thermal conductivity

m

Mass

P

Pressure

Pco

Saturation pressure ofT co

q″

Heat transfer rate per unit area

R

Radius of spherical droplet

Re

Reynolds number

r

Radial coordinate

T

Temperature

Tco

Temperature of vapor-liquid interface at the liquid side

Tvs

Temperature of vapor-liquid interface at the vapor side

t

Time

u

Radial velocity of liquid at vapor-liquid interface

V

Volume

W

Mechanical work of film formation

Greek Symbols

α

Thermal diffusivity

β

Accommodation coefficient

γ

Specific heat ratio of gas

δ

Film thickness

ε

Emissivity of hot spherical droplet

θ

Surface tension

λ

Thermal boundary layer thickness

μ

Dynamic viscosity

ρ

Density

σ

Stefan-Boltzman constnat

Superscripts

*

Normalised variable

Subscripts

b

Base line parameter

c

Cold liquid

f

Film

h

Hot droplet

v

Vapor

g

Noncondensible gas

go

Nocondensible gas at intial state

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References

  1. Berenson, J.J., 1961, “Film Boiling Heat Transfer from a Horizontal Surface”, Journal of Heat Transfer, Trans. ASME, Series C, pp. 351–358.Google Scholar
  2. Bjornard, T.A., Rohsenow, W.M., Todreas, N.E., 1974, “The Pressure Behavior Accompanying the Fragmentation of Tin in Water”, Trans. ANS, Vol. 19, p. 247.Google Scholar
  3. Board, S.J. et al., 1971, “An Experimental Study of Energy Transfer Process Relevant to Thermal Exlosion”, International Journal of Heat and Mass Transfer, Vol. 14, pp. 1631–1641CrossRefGoogle Scholar
  4. Bromely, L.A., 1950, “Heat Transfer in Stable Film Boiling”, Journal of Heat Transfer, Vol. 90, pp. 478–481.Google Scholar
  5. Cole, R., 1979, “Homogeneous and Heterogeneous Nucleations”, Boiling Phenomena, Vol. 1, pp. 71–88.Google Scholar
  6. Corradini, M.L., 1981, “Phenomenological Modeling of the Triggering Phase of Small-Scale Steam Explosion Experiments”, Nuclear Science and Engineering, Vol. 78, pp. 154–170Google Scholar
  7. Kazimi, M.S., 1973, “Theoretical Studies of Some Aspects of Molten Fuel-Coolant Thermal Interactions”, Science Doctorate Thesis, MIT, Cambridge MassachusettsGoogle Scholar
  8. Kim, B., Corradini, M.L., 1984, “Recent Film Boiling Calculations: Implications on Fuel-Coolant Interactions”, 5th Int. Mtg. Thermal Nuclear Reactor Safety, Vol. 2, Karlsruhe, West Germany, pp. 1098–1107.Google Scholar
  9. Lance, G.N., 1960, Numerical Methods for High Speed Computer, Iliffe & Sons, pp. 54–57.Google Scholar
  10. Lednovich, S.L., Fenn, J.B., 1977, “Absolute Evaporation Rates for Some Polar and Non-Polar Liquids”, AIChE Journal, Vol. 23, No. 4, July, pp. 454–459.CrossRefGoogle Scholar
  11. Maa, J.R., 1970, “Rates of Evaporation and Condensation Between Pure Liquids and Their Own Vapor”, Industrial Engineering and Chemistry, Vol. 9, No. 2, pp. 283–287.Google Scholar
  12. McAdams, W.H., 1954, Heat Transmission, 3rd Edition. McGraw-Hill, New York.Google Scholar
  13. Nelson, L.S., Duda, P.M., 1981, “Steam Explosion Experiments with Single Drops of Iron Oxide Melted with CO2 Laser”, Sandia Laboratories, SAND81-1346, NUREG/CR-2295Google Scholar
  14. Nelson, L.S., Duda, 1982, “Steam Explosion Experiments with Single Drops of Iron Oxide Melted with a CO2 Laser; Part 2. Parametric Studies”, Sandia Laboratories, SAND82-1105, NUREG/CR-2718Google Scholar
  15. Pitts, D.R., Yen, H.H., Jackson, T.W., 1968, “Transient Film Boiling of Water on a Horizontal Wire”, Journal of Heat Transfer, Vol. 90, pp. 478–481.Google Scholar
  16. Rayleigh, 1917, Philo. Magazine, Vol. 34, pp. 34–37.Google Scholar
  17. Schrage, R.W., 1953. A Theoretical Studies of Interphase Mass Transfer. Columbia University Press, New York.Google Scholar
  18. Taylor, G.I., 1950, “The Instability of Liquid Surfaces When Accelerated in a Direction Perpendicular to Their Planes”, Proc. Roy. Soc. A 201, pp. 192–196.MATHCrossRefGoogle Scholar
  19. Wehmeyer, D.P., Jackson, T.W., 1972, “Transient Film Boiling of Carbon Tetrachloride and Freon-113 on a Horizontal Cylindrical Surface”, Journal of Heat Transfer, Vol. 94, pp. 367–370.Google Scholar

Copyright information

© The Korean Society of Mechanical Engineers (KSME) 1989

Authors and Affiliations

  • Byong-Joo Kim
    • 1
  1. 1.Department of Mechanical, EngineeringHongik UniversitySeoulKorea

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