International Scientific Journal

Thermal Science - Online First

online first only

Microscopic experimental study on acoustic agglomeration of the droplets on wall

Study on the effect of acoustic wave on droplet collision-coalescence process is interesting and helps to better understand acoustic agglomeration mechanism. This study designs and carries out a microscopic experiment to investigate the effect of acoustic wave on wall droplet collision-coalescence process. The derived microscopic images of droplets under the action of different sound waves at different moment are processed and analyzed by binaryzation with iterative threshold, cavity filling, morphological open arithmetic processing, and identification of connected regions, etc. Using a newly defined parameter, equivalent droplet size, the growth rates of the droplets in natural state and under the action of different acoustic parameters are compared and analyzed. The results show that the effect of sound wave greatly accelerates the collision-coalescence process of the droplet, and comparing with sound pressure level (SPL), the frequency of the sound wave is a more effective parameter in promoting the collision-coalescence process of wall droplets, and the lower the acoustic wave frequency results in larger collision-coalescence rate.
PAPER REVISED: 1970-01-01
PAPER ACCEPTED: 2020-08-16
  1. Xi B S, Wu J, Xu H Q. Experiments on tiny particles effected by in-tense standing wave field. Experiments and Measurements in Fluid Mechanics, 2000, 14(2): 49-53
  2. Hou S Q, Wu J, Xi B S. Experiments on acoustic dissipation of water fog at low frequency. Experiments and Measurements in Fluid Me-chanics, 2002, 16(4): 52-56
  3. Hoffmann T L. An extended kernel for acoustic agglomeration simula-tion based on the acoustic wake effect. J Aerosol Sci, 1997, 28(6): 919-936
  4. Hoffmann T L, Koopmann G H. Visualization of acoustic particle in-teraction and agglomeration: Theory and experiments. J. Acoust. Soc. Am, 1996, 99: 2130-2141
  5. Hoffmann T L. Environmental implications of acoustic aerosol ag-glomeration. Ultrasonics, 2000, 38(1-8): 353-357
  6. Gonzalez I, Gallego-Juarez J A, Riera E. The influence of entrainment on acoustically induced interactions between aerosol particles - an experimental study. J Aerosol Sci, 2003, 34(12): 1611-1631
  7. Caperan P, Somers J, Richter K, Fourcaudot S. Acoustic agglomeration of a glycol fog aerosol - influence of particle concentration and inten-sity of the sound field at 2 frequencies. J Aerosol Sci, 1995, 26(4): 595-612
  8. Gallego-Juárez J A, Riera-Franco de Sarabia E, Rodriguez-Corral G, et al. Application of acoustic agglomeration to reduce fine particle emis-sions from coal combustion plants. Environ Sci Technol, 1999, 33(21): 3843-3849
  9. Riera-Franco de Sarabia E, Gallego-Juárez J A, Acosta-Aparicio V M, et al. Acoustic agglomeration of submicron particles in diesel exhausts: First results of the influence of humidity at two acoustic frequencies. J Aerosol Sci, 2000, 31: 827-827
  10. Li F-F, Jia Y-H, Wang G-Q, et al. Mechanism of cloud droplet motion under sound wave actions. J Atmos Oceanic Technol, 2020, 1-37
  11. Liu J Z, Wang J, Zhang G X, et al. Frequency comparative study of coal-fired fly ash acoustic agglomeration. J Environ Sci-China, 2011, 23(11): 1845-1851
  12. Sun D S. Investigation into agglomeration processs of inhalable parti-cle in coupling acoustic wave and JET. Qingdao University of Science & Technology, Qingdao, China, 2009
  13. Zhou D. Experimental researches and simulation on acoustic agglom-eration of various particle sources. Zhejiang University, Hangzhou, China, 2016
  14. Chen H T, Zhao B, Xu J, et al. Experimental study on acoustic ag-glomeration of ultrafine fly ash particles. Proceedings of the CSEE, 2007, 27(35): 28-32
  15. Zhou D, Luo Z Y, Jiang J P, et al. Experimental study on improving the efficiency of dust removers by using acoustic agglomeration as pretreatment. Powder Technol, 2016, 289: 52-59
  16. Komarov S V, Yamamoto T, Uda T, et al. Acoustically controlled be-havior of dust particles in high temperature gas atmosphere. ISIJ In-ternational, 2004, 44(2): 275-284
  17. Scott D S. A new approach to the acoustic conditioning of industrial aerosol emissions. J Sound Vib, 1975, 43(4): 607-619
  18. Ma D G, Lin W Q, Zheng Q Q, et al. Pretreatment based on combined effect of acoustic agglomeration and atomization and its application in air filtration. Chinese Journal of Environmental Engineering, 2015, 9(5): 2353-2358
  19. Hoffmann T L, Chen W, Koopmann G H, et al. Experimental and numerical-analysis of bimodal acoustic agglomeration. J Vib Acoust, 1993, 115(3): 232-240
  20. Wei J H, Qiu J, Li T J, et al. Cloud and precipitation interference by strong low-frequency sound wave. Sci China Technol Sc, 2020, 63.