© 2012 The Japan Institute of Metals

Wettability of a solid by a liquid plays a key role in achieving the purpose of the process in moving bed-type reactors. In recent years, particle method has been proposed for the design of processes which include multiphase flows. Using this method, it is possible to analyze a free surface flow without explicitly tracking the interface. Although surface tension and wettability models using the particle method have already been proposed, the complexity of calculations of normal line and curvature of the surface particle has been pointed out as a problem. In this study, surface tension and wettability model were introduced in terms of interparticle potential, and theoretical and experimental verifications were performed for a 3-dimensional particle method which stabilizes the internal pressure distribution in fluids. The analytical solution for the droplet oscillation period by this method showed good agreement with the theoretical solution, and the surface tension between a gas and liquid could be calculated correctly. Because the difference in the number density of a liquid phase and solid phase becomes remarkable in a 3-dimensional space, a technique which corrects for this in particles at a three-phase interface was introduced. Time change in the droplet shape was compared with the experimental results by changing the droplet impact velocity to obtain agreement of the Weber number. It is considered possible to express the droplet shape correctly during rotating falling on a solid surface.

(Received 2011/10/25; Accepted 2012/01/19; Published 2012/03/25)

**Keywords:** droplet, numerical analysis, wettability, moving particle semi-implicit (MPS) method, contact angle

- S. M. Iveson, N. W. Page and J. D. Litster: Powder Technol. 130 (2003) 97-101.
- S. Ueda, S. Natsui, H. Nogami, J. Yagi and T. Ariyama: ISIJ Int. 50 (2010) 914-923.
- Z. Fan, S. Natsui, S. Ueda, T. Yang, J. Kano, R. Inoue and T. Ariyama: ISIJ Int. 50 (2010) 946-953.
- P. R. Austine, H. Nogami and J. Yagi: ISIJ Int. 37 (1997) 748-755.
- S. Natsui, H. Nogami, S. Ueda, J. Kano, R. Inoue and T. Ariyama: ISIJ Int. 51 (2011) 41-50.
- Š. Šikalo, H. D. Wilhelm, I. V. Roisman, S. Jakirlić and C. Tropea: Phys. Fluids 17 (2005) 062103.
- S. F. Lunkad, V. V. Buwa and K. D. P. Nigam: Chem. Eng. Sci. 62 (2007) 7214-7224.
- F. Augier, A. Koudil, A. Royon-Lebeaud, L. Muszynski and Q. Yanouri: Chem. Eng. Sci. 65 (2010) 255-260.
- S. M. Mousavi, A. Jafari, S. Yaghmaei, M. Vossoughi and P. Sarkomaa: Miner. Eng. 19 (2006) 1077-1083.
- S. Koshizuka and Y. Oka: Nucl. Sci. Eng. 123 (1996) 421-434.
- S. Adami, X. Y. Hu and N. A. Adams: J. Comp. Phys. 229 (2010) 5011-5021.
- M. Zhang: J. Comp. Phys. 229 (2010) 7238-7259.
- J. U. Brackbill, D. B. Kothe and C. Zemach: J. Comp. Phys. 100 (1992) 335-354.
- K. Nomura, S. Koshizuka, Y. Oka and H. Obata: J. Nucl. Sci. Technol. 38 (2001) 1057-1064.
- M. Matsumoto and S. Nakazawa: Therm. Sci. Eng. 15 (2007) 55-61.
- A. Tartakovsky and P. Meakin: Phys. Rev. E 72 (2005) 026301.
- M. Kondo, S. Koshizuka and M. Takimoto: Trans. JSCES 2007 (2007) 21.
- M. Tanaka and T. Masunaga: J. Comp. Phys. 229 (2010) 4279-4290.
- J. N. Israelachivili:
*Intermolecular and surface forces*, 3rd ed., (Academic Press, London, 2010) pp. 415-461. - Z. Sun, G. Xi and X. Chen: Nucl. Eng. Design 239 (2009) 612-627.
- J. Liu, S. Koshizuka and Y. Oka: J. Comp. Phys. 202 (2005) 65-93.
- Š. Šikalo, C. Tropea and E. N. Ganić: Exp. Therm. Fluid Sci. 29 (2005) 795-802.
- Š. Šikalo, C. Tropea and E. N. Ganić: J. Colloid Interf. Sci. 286 (2005) 661-669.
- N. Le Grand, A. Daerr and L. Limat: J. Fluid Mech. 541 (2005) 293-315.
- L. Reileigh: Proc. R. Soc. Lond. 29 (1879) p. 71.
- H. Lamb:
*Hydrodynamics*, 6th ed., (Cambridge Univ. Press, Cambridge, UK, 1932) pp. 471-475. - Y. Tanaka, Y. Washio, M. Yoshino and T. Hirata: JASCOME 8 (2008) 12-081128.

© 2012 The Japan Institute of Metals

Comments to us :
editjt@jim.or.jp