Wärme - und Stoffübertragung

, Volume 20, Issue 1, pp 69–75 | Cite as

Dynamics of and heat transfer to a butane droplet evaporating in water

  • M. R. Mokhtarzadeh-Dehghan
  • A. A. El-Shirbini
Article

Abstract

The dynamics and the associated heat transfer process of butane droplets evaporating in water are investigated experimentally. New data are presented for the instantaneous growth, rise velocity and the heat transfer coefficient. The behaviour of the bubble-droplet, from the initial to the final stages of evaporation, is divided into four regions and is described with reference to similarities with the behaviour of a spherical droplet, spheroidal bubble-droplet, large spheroidal bubble and spherical cap bubble. The equations which represent the results for the heat transfer coefficient are given.

Keywords

Heat Transfer Heat Transfer Coefficient Apply Physic Final Stage Transfer Process 

Nomenclature

A

Equivalent spherical area of bubble-droplet (m2)

D

Equivalent spherical diameter of bubble-droplet (mm)

d

Equivalent spherical diameter of initial droplet (mm)

Fr

Froude number,Fr=U/(gDI2)1/2

h

Instantaneous heat transfer coefficient (J/s m2 K)

hfg

Heat of vaporisation (J/kg)

mv

Mass of vapour (kg)

m0

Initial mass of droplet (kg)

Nuc

Nusselt number

Pec

Peclet number

q

Rate of heat transfer (J/s)

Rec

Reynolds number

t

Time (s)

T

Saturation temperature (°C)

ΔT

Temperature difference (°C)

ΔT0

Overall temperature difference (°C)

U

Rise velocity (m/s)

Vv

Vapour volume (m3)

V

Bubble-droplet volume (m3)

ξ

Vaporisation ratio,=mv/m0

ξv

Volume ratio,=Vv/V

Subscripts

c

Continuous phase

v

Vapour

av

Average

Dynamik und Wärmetransport an einen in Wasser verdampfenden Butan-Tropfen

Zusammenfassung

Die Dynamik und der damit verbundene Wärmeübertragungsprozeß an einen in Wasser verdampfenden Butan-Tropfen werden experimentell untersucht. Es werden Meßergebnisse für die Dampfentwicklung, die Aufstiegsgeschwindigkeit und den Wärmeübergangskoeffizienten mitgeteilt. Das Verhalten des „Blasen-Tropfens“ vom Beginn bis zum Ende seiner Verdampfung wird in vier Abschnitte unterteilt und wird in Anlehnung an einen kugelförmigen Tropfen, einen spheroidalen BlasenTropfen, eine große spheroidale Blase und eine kugelkalottenförmige Blase beschrieben. Es werden Gleichungen angegeben, welche die gemessenen Wärmeübergangskoeffizienten nachvollziehen.

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References

  1. 1.
    Howe, E. D.: Fundamental of water desalination. New York: Marcel Dekker 1974Google Scholar
  2. 2.
    Nene, R.: Heat transfer to evaporating drops, Office of Saline Water, R & D No. 823 (1972) 16–20Google Scholar
  3. 3.
    Rice, P. A.; Nene, R. G.; Barduhn, A. J.: Prediction of the heat transfer rate in crystallisers, 5th Int. Symp. on Fresh Water from the Sea, 3 (1976) 285–291Google Scholar
  4. 4.
    Klipstein, D. H.: Heat transfer to a vaporising immiscible drop, D.Sc. Thesis, Massachusetts Institute of Technology 1963Google Scholar
  5. 5.
    Sideman, S.; Taitel, Y.: Direct contact heat transfer with change of phase: Evaporation of drops in an immiscible liquid medium. Int. J. Heat Mass Transfer 7 (1964) 1273–1289Google Scholar
  6. 6.
    Prakash, C. B.; Pinder, K. L.: Direct contact heat transfer between two immisible liquids during vaporisation. Part I: Measurement of heat transfer coefficient. Can. J. Chem. Eng. 45(1967)210–214Google Scholar
  7. 7.
    Prakash, C. B.; Pinder, K. L.: Direct contact heat transfer between two immiscible liquids during vaporisation. Part II: Total evaporation time. Can. J. Chem. Eng. 45 (1967) 215–220Google Scholar
  8. 8.
    Nazir, M.: Direct contact heat transfer, evaporation of butane drops in brine, Ph.D. Thesis, University of Strathclyde, Glasgow 1972Google Scholar
  9. 9.
    Adams, A. E. S.; Pinder, M. L.: Average heat transfer coefficient during the direct evaporation of a liquid drop. Can. J. Chem. Eng. 50 (1972) 707–713Google Scholar
  10. 10.
    Simpson, H. C.; Beggs, G. C.; Nazir, M.: Evaporation of butane drops in brine. Desalination 15 (1974) 11 -23Google Scholar
  11. 11.
    Tochitani, Y.; Mori, Y. H.; Komotori, K: Vaporisation of single liquid drops in an immiscible liquid. Part I: Forms and motions of vaporising drops. Wärme-Stoffübertrag. 10 (1977) 51–59Google Scholar
  12. 12.
    Tochitani, Y.; Mori, Y. H.; Komotori, K: Vaporisation of single liquid drops in an immiscible liquid. Part II: Heat transfer characteristics. Wärme-Stoffübertrag. 10 (1977) 71–79Google Scholar
  13. 13.
    Tochitani, Y; Mori, Y. H.; Komotori, K: Voporisation of a liquid injected into an immiscible liquid through a single nozzle. Wärme-Stoffübertrag. 8 (1975) 249–259Google Scholar
  14. 14.
    Sideman, S.; Gat, Y.: Direct contact heat transfer with change of phase: Spray-column studies of a three-phase heat exchanger. A. I. Ch.E. Jl. 12(2) (1965) 296–303Google Scholar
  15. 15.
    Simpson, H. C.; Beggs, G. C.; Nazir, M.: Evaporation of a droplet of one liquid rising through a second immiscible liquid. A new theory of the heat transfer process, Heat Transfer, Proc. 5th Int. Heat Transfer Conf. 5 (1974) 59–63Google Scholar
  16. 16.
    Selecki, A.; Gradon, L.: Equation of motion of an expanding vapour drop in an immiscible liquid medium. Int. J. Heat Mass Transfer 19 (1976) 925–929Google Scholar
  17. 17.
    Mokhtarzadeh, M. R.; El-Shirbini, A. A.: A theoretical analysis of evaporating droplets in an immiscible liquid. Int. J. Heat Mass Transfer 22 (1979) 27–38Google Scholar
  18. 18.
    Moalem-Maron, D.; Sokolov, M.; Sideman, S.: A closed periodic condensation-evaporation cycle of an immiscible, gravity driven bubble. Int. J. Heat Mass Transfer 23 (1980) 1417–1424Google Scholar
  19. 19.
    Raina, G. K.; Grover, P. D.: Direct contact heat transfer with change of phase. Theoretical model. A.I.Ch.E. Jl. 28 (1982) 515–517Google Scholar
  20. 20.
    Mokhtarzadeh, M. R.; El-Shirbini, A. A.: Motion of bubbles and bubble-droplets in an immiscible liquid. Wärme-Stoff- übertrag. 12(1979)25–33Google Scholar
  21. 21.
    Gradon, L.; Selecki, A.: Evaporation of a liquid drop immersed in another immiscible liquid. The case of σc < σ d. Int. J. Heat Mass Transfer 20 (1977) 459–466Google Scholar
  22. 22.
    Selecki, A.; Gradon, L.: Über den Verdampfungsmechanismus eines sich in einer nicht mischbaren Flüssigkeit bewegenden Flüssigkeitstropfens. Chem. Ing. Techn. 44/18 (1982) 1077–1081Google Scholar
  23. 23.
    Mori, Y. H.; Komotori, K: Boiling modes of volatile liquid drops in an immiscible liquid, depending on degree of superheat. ASME Pub. 76-HT-13 (1976)Google Scholar
  24. 24.
    Pinder, K. L.: Surface area prediction for two phase drops in an immiscible liquid. Can. J. Chem. Eng. 58 (1982) 318–324Google Scholar
  25. 25.
    Simpson, H. C; Beggs, G. C; Sohal, M. S.: Nucleation of butane drops in flowing water. 6th Int. Heat Transfer Conf. 4 (1978)Google Scholar
  26. 26.
    Mokhtarzadeh-Dehghan, M. R.: Study of an evaporating droplet in an immiscible liquid. Ph.D. Thesis, University of London 1980Google Scholar
  27. 27.
    Harmathy, T. Z.: Velocity of large drops and bubbles in media of infinite or restricted extent. A.I.Ch.E. Jl. 6/2 (1960) 281–288Google Scholar
  28. 28.
    Klee, A. J.; Treybal, R. E.: Rate of rise or fall of liquid drops. A.I.Ch.E. Jl. 2/4 (1956) 444–447Google Scholar
  29. 29.
    Peebles, F. N.; Garber, H. J.: Studies on the motion of gas bubbles on liquids. Chem. Eng. Prog. 2/49 (1953) 88–97Google Scholar
  30. 30.
    Wegener, P. P.: Parlange, J. Y.: Spherical cap bubbles. Annual Rev. Fluid Mech. 5 (1973) 79–100Google Scholar
  31. 31.
    Wallis, G. B.: One-dimensional two-phase flow. McGraw-Hill 1969Google Scholar
  32. 32.
    Collins, R.: The effect of a containing cylindrical boundary on the velocity of a large bubble in a liquid. J. Fluid Mechanics 28/1 (1967) 97–112Google Scholar
  33. 33.
    Handlos, A. E.; Baron, T.: Mass and heat transfer from drops in liquid-liquid extraction. A.I.Ch. E. Jl. 3/1 (1957) 127–136Google Scholar
  34. 34.
    Elzinga, E. R., Jr.; Banchero, J. T.: Film coefficients for heat transfer to liquid drops. Chem. Eng. Progr., Symp. Ser. 55 (1959) 149–161Google Scholar

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • M. R. Mokhtarzadeh-Dehghan
    • 1
  • A. A. El-Shirbini
    • 2
  1. 1.Department of Mechanical EngineeringBrunel UniversityMiddlesexEngland
  2. 2.Department of Mechanical EngineeringImperial College of Science and TechnologyLondonEngland

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