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Effects of Droplet Temperature on Heat Transfer During Collision on a Heated Wall Above the Leidenfrost Temperature

Leidenfrost 온도 이상의 가열 벽면과 충돌 시 열전달에 대한 액적 온도의 영향

  • Received : 2016.03.15
  • Accepted : 2016.05.23
  • Published : 2016.06.30

Abstract

This study experimentally investigated the effects of droplet temperature on the heat transfer characteristics during collision of a single droplet on a heated wall above the Leidenfrost temperature. Experiments were performed by varying temperature from 40 to $100^{\circ}C$ while the collision velocity and wall temperature were maintained constant at 0.7 m/s at $500^{\circ}C$, respectively. Evolution of temperature distribution at the droplet-wall interface as well as collision dynamics of the droplet were simultaneously recorded using synchronized high-speed video and infrared cameras. The local heat flux distribution at the collision surface was deduced using the measured temperature distribution data. Various physical parameters, including residence time, local heat flux distribution, heat transfer rate, heat transfer effectiveness and vapor film thickness, were measured from the visualization data. The results showed that increase in droplet temperature reduces the residence time and increases the vapor film thickness. This ultimately results in reduction in the total heat transfer by conduction through the vapor film during droplet-wall collision.

Keywords

References

  1. J. G. Leidenfrost, "A tract about some qualities of common water", Int. J. Heat Mass Transfer, 9, 1966, pp. 1153-1166. https://doi.org/10.1016/0017-9310(66)90111-6
  2. L. H. J. Wachters and N. A. J. Westering, "The Heat Transfer from a Hot Wall to Impinging Water Drops in the Spheroidal State", Chemical Engineering Science, Vol. 21, 1966, pp. 1047-1056. https://doi.org/10.1016/0009-2509(66)85100-X
  3. F. K. Maginnis and J. P. Holman, "Individual droplet heat transfer rates for splattering on hot surface", International Journal of Heat Mass Transfer, Vol. 12, 1969, pp. 95-108. https://doi.org/10.1016/0017-9310(69)90081-7
  4. A. Prosperetti, C. Sun, D. Lohse, H. J. J. Staat and T. Tran, "Drop impact on superheated surfaces", Physical Review Letters, Vol. 108, No. 3, 2012, pp. 036101(5). https://doi.org/10.1103/PhysRevLett.108.036101
  5. M. Kanetsuki, T. Enomoto and T. Ueda, "Heat Transfer Characteristics and Dynamic Behavior of Saturated Droplets Impinging on a Heated Vertical Surface", Bulletin of the Japan Soc. Mech. Eng., Vol. 22, No. 167, 1979, pp. 724-732. https://doi.org/10.1299/jsme1958.22.724
  6. J. Song, S. Inada, S. Uchiyama and W. J. Yang, "Heat transfer effectiveness of saturated drops in the nonwetting regime impinging on a heated surface", International Journal of Japan society of Mechanical Engineers, Vol. 43, No. 3, 2000, pp. 468-477.
  7. C. P. Hale, D. Chatzikyriakou, G. F. Hewitt and S. P. Walker, "The Measurement of Heat Transfer from Hot Surfaces to Non-wetting Droplets", International Journal of Heat and Mass Transfer, Vol. 54, 2011, pp. 1432-1440. https://doi.org/10.1016/j.ijheatmasstransfer.2010.11.051
  8. D. Maillet, M. Gradeck, N. Seiler and P. Ruyer, "Heat transfer for Leidenfrost drops bouncing onto a hot surface", Experimental Thermal and Fluid Science, Vol. 47, 2013, pp. 14-25. https://doi.org/10.1016/j.expthermflusci.2012.10.023
  9. F. Lelong, G. Castanet, M. Gradeck, N. Seiler, P. Dunand and P. Ruyer, "Behavior of liquid droplets bouncing onto a hot slab", 23rd Annual conference on Liquid Atomiza-tion and Spray systems, Brno, Czech Republic, September, 2010.
  10. H. Kim and J. Park, "An experimental investigation on dynamics and heat transfer associated with a single droplet impacting on a hot surface above the Leidenfrost point temperature", Kerntechnik, Vol. 81, No. 3, 2016, pp. 1-11. https://doi.org/10.3139/124.016012
  11. K. Kim, H. Kim, J. Park and S. Bae, "The effect of impact velocity on Droplet-wall collision heat transfer above the Leidenfrost point temperature", Trans. Korean Soc. Mech. Eng. B, Vol. 39, No. 7, 2015, pp. 567-578. https://doi.org/10.3795/KSME-B.2015.39.7.567
  12. H. Kim, J. Jung and S. Jeoung, "Investigation of single-droplet/wall collision heat transfer characteristics using infrared thermometry", International Journal of Heat and Mass Transfer, Vol. 92, 2016, pp. 774-783. https://doi.org/10.1016/j.ijheatmasstransfer.2015.09.050
  13. A. Mittal and S. Bhardwaj, "A survey on various edge detector techniques", Proc. Technol., Vol. 4, 2012, pp. 220-226.
  14. C. Clanet, D. Richard and D. Quere, "Contact time of a bouncing drop", Nature, Vol. 417, 2002, pp. 811.
  15. S. Inada and Y. Miyasaki, "Transient heat transfer for a water drop impinging on a heated surface", Bulletin of Japan Society of Mechanical Engineers, Vol. 28, No. 245, 1985, pp. 2675-2681. https://doi.org/10.1299/jsme1958.28.2675
  16. A. L. Biance, C. Clanet and D. Quere, "Leidenfrost drops", Physics of Fluids, Vol. 15, No. 3, 2003, pp. 1632-1637. https://doi.org/10.1063/1.1572161