Preliminary Analysis of Swirl Effervescent Atomization Droplet Diameter Distribution
Main Article Content
Abstract
A swirl effervescent atomizer capable of producing fine droplets with relatively low injection pressures. A critical aspect of atomization is the resultant droplet diameter distribution, which portrays the efficiency of the atomization process. Dimensional analysis was conducted to identify the most significant parameters influencing the droplet diameter distribution. Three dimensionless numbers were selected considering their importance, which are the liquid Reynolds number, Re, the gas Reynolds number, and the swirl chamber length to discharge orifice diameter ratio. A test rig was fabricated to test the atomizer. Water acts as the working fluid, and air acts as the atomization assistance. The resultant spray images were captured using the shadowgraph technique. The images were analysed for droplet diameter measurement. The liquid Reynolds number and gas Reynolds number were found to have a significant impact on the droplet diameter distribution, particularly with an increase in the percentage of fine droplets. However, the dependence of the droplet diameter distribution on the geometrical ratio is less significant. This result is important for a preliminary understanding of the swirl effervescent atomization mechanics.
Article Details

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
References
W. Lee, D. Hwang, K. Ahn and Y. Yoon, “Spray Characteristics of Effervescent Swirl Injectors for Variable Thrust,” J. Kor. Soc. Propul. Eng., vol. 23, no. 2, pp. 1–12, 2019.
M. E. C. Ferreira, J. J. G. Martins and J. C. F. Teixeira, “Optimization of an Effervescent Atomizer to the Combustion of Residue Oils,” in ASME Heat Transfer Summer Conf., vol. 1, pp. 751-757, San Francisco, CA, 2005.
A. H. Lefebvre and V. G. McDonell, Atomization and Sprays, 2nd Edn., Boca Raton: CRC Press, 2017.
B. Zohuri, Dimensional Analysis Beyond the Pi Theorem, Cham, Switzerland, Springer International Publishing, 2017.
J. J. Chinn, “Dimensional Analysis and The Buckingham-II Theorem Applied to The Inviscid Swirl Atomizer Governing Equations,” in Proc. the 21st ILASS-Europe Meeting, ILASS, 2007.
K. Lachin, C. Turchiuli, V. Pistre, G. Cuvelier, S. Mezdour and F. Ducept, “Dimensional Analysis Modeling of Spraying Operation – Impact of Fluid Properties and Pressure Nozzle Geometric Parameters on The Pressure-Flow Rate Relationship,” Chem. Eng. Res. Des., vol. 163, pp. 36–46, 2020.
M. Shafaee, S. A. Banitabaei, V. Esfahanian and M. Ashjaee, “An Investigation on Effect of Geometrical Parameters on Spray Cone Angle and Droplet Size Distribution of A Two-Fluid Atomizer,” J. Mech. Sci. Technol., vol. 25, no. 12, pp. 3047–3052, 2011.
L. Gödeke, W. Oswald, N. Willenbacher and P. Ehrhard, “Dimensional Analysis of Droplet Size and Ligament Length During High-Speed Rotary Bell Atomization,” J. Coat. Technol. Res., vol. 18, no. 1, pp. 75–81, 2021.
J. M. Conahan, “High Reynolds Number Millimeter-Scale Jet Impingement Phenomena,” MS Thesis, Northeastern University, 2021.
F. Hormozinezhad, C. Barnes, A. Fabregat, S. Cito and F. Del Giudice, “Dimensional Analysis Meets AI for Non-Newtonian Droplet Generation,” Lab Chip, vol. 25, pp. 1681-1693, 2025.
R. A. Mugele and H. D. Evans, “Droplet Size Distribution in Sprays,” Ind. Eng. Chem., vol. 43, no. 6, pp. 1317–1324, 1951.
Z. A. Ghaffar, S. Kasolang, Ahmad Hussein Abdul Hamid and Zolkapli Eshak, “Experimental Analysis of Tangential-Vane Swirl Atomizer Spray Angle,” J. Adv. Res. Fluid Mech. Therm. Sci., vol. 101, no. 2, pp. 1–7, 2023.
Z. A. Ghaffar, “Characterization of Swirl Effervescent Spray at Low Reynolds Numbers Using Response Surface Methodology,” PhD Thesis, Universiti Teknologi MARA, 2023.
Z. A. Ghaffar, S. Kasolang, A. H. Abdul Hamid and M. H. Mamat, “Box-Behnken Design Application to Optimize Swirl Effervescent Droplet Mean Diameter,” J. Mech. Eng. Sci., vol. 18, no. 4, pp. 10233–10246, 2024.
M. Lörcher, F. Schmidt and D. Mewes, “Effervescent Atomization of Liquids,” At. Sprays, vol. 15, no. 2, pp. 145–168, 2005.
M. Popp, J. Hulka, V. Yang and M. Habiballah, Liquid Rocket Thrust Chambers, American Institute of Aeronautics and Astronautics, 2004.
S. Kim, T. Khil, D. Kim and Y. Yoon, “Effect of Geometric Parameters on The Liquid Film Thickness and Air Core Formation in A Swirl Injector,” Meas. Sci. Technol., vol. 20, no. 1, pp. 015403, 2009.
K. O. Fong, X. Xue, R. Osuna-Orozco and A. Aliseda, “Gas–liquid Coaxial Atomization with Swirl in High-Pressure Environments,” Int. J. Multiphase Flow, vol. 174, pp. 104767, 2024.
H. Liu, Science and Engineering of Droplets: Fundamentals and Applications, New York, Noyes Publications, 2000.
Y. A. Cengel and J. M. Cimbala, Fluid Mechanics - Fundamentals and Applications, McGraw-Hill, New York, 2006.