Self-Preserving Size Distribution of Fire Soot Fractal Coagulation in Flaming Combustion

Abstract

In this work, by carefully calculating the different Knudsen numbers, the free molecular and continuum regimes of flaming combustion were first explicitly defined as the soot particle growth zone low in the flame and the upper zone near the ambient air in the plume respectively, and the fractal coagulation theory was applied to analyze the soot particle agglomeration in the two cluster–cluster aggregation-dominating regions. The accurate analytical simplicity solution obtained proved that self-preserving size distribution (SPSD) exists in the two regions. Additionally we got the relation between the normalized number concentration of the total particle aggregates and the dimensionless time as well as the actual lag-time from monodisperse distribution to SPSD. The results indicate that the fractal morphology of the soot particles affects the particle coagulation process to a large extent, especially has a great influence on soot particle SPSD, total aggregates number concentration in the growth region and the time needed from monodisperse distribution to SPSD above the flame region near the air conditions. The validation of our theoretical results was verified in comparison with previous work and our experimental results.

Get full access to this article

View all access options for this article.

References

1. Mountain, R.D., Mulholland, G.W. and Baum, Howard (1986). Journal of Colloid and Interface Science, 114: 67–81 .

2. Mulholland, G.W., Samson, R.J., Mountain, R.D. and Ernst, M.H. (1988). J. Energy Fuels, 2: 481–486 .

3. Wu, M.K. and Friedlander, S.K. (1993). J. Aerosol. Sci., 24: 273–282 .

4. Vemury, Srinivas and Pratsinis, Sotiris E.(1995). J. Aerosol Sci., 26(2): 175–185 .

5. Oh, C. and Sorensen, C.M. (1997). J. Aerosol. Sci., 28: 937–957 .

6. Samson, R.J., Mulholland, G.W. and Gentry, J.W. (1987). Langmuir 3: 272–281 .

7. Sorensen, C.M., Cai, J. and Lu, N. (1992a). Langmuir, 8: 2064–2069 .

8. Sorensen, C.M., Cai, J. and Lu, N. (1992b). Appl. Opt., 31: 6547–6557 .

9. Dobbins, R.A. et al. (1994). Atmospheric Environment, 28: 889–897 .

10.

10. Charalampopoulos, T.T. (1992). Prog. Energy Combust. Sci., 18: 13–45 .

11.

11. Mountain, R.D. and Mulholland, G.W.(1988). Langmuir, 4: 1321–1326 .

12.

12. Koylu, U.O. and Faeth, G.M. (1996). J. Heat Transfer Trans ASME, 118: 415–421 .

13.

13. Faeth, G.M. and Koylu, U.O. (1995). Combust. Sci. Technol., 108: 207–229 .

14.

14. Puri, R., Richardson, T.F. and Santoro, R.J. (1993). Combustion and Flame, 92: 320–333 .

15.

15. Snegirev, A.Yu., Makhviladze, G.M. and Roberts, J.P. (2000). Combust. Sci. Technol., 159: 315–349 .

16.

16. Hamins, Anthony (1993). Soot, Environmental Implications of Combustion Processes, CRC Press, Florida , pp. 71–95.

17.

17. Allen, M.D. and Raabe, O.G. (1985). Aerosol Sci. Technol., 4(3): 269–286 .

18.

18. Kostoglou, M. and Konstandopoulos, A.G. (2001). Journal of Aerosol Science, 32: 1399–1420 .

19.

19. Van Dongen, P.G.J. and Ernst, M.H. (1985). Phys. Rev. Lett., 54: 1396–1399 .