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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2021, Vol. 42 ›› Issue (S1): 726360-726360.doi: 10.7527/S1000-6893.2021.26360

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Influencing parameters and film flow mechanism of spray droplet impacting liquid film

BAO Jun, WANG Yu, NIU Qian, ZHU Xidong, CHENG Jianjie   

  1. College of Urban Construction, Nanjing Tech University, Nanjing 210009
  • Received:2021-09-01 Revised:2021-09-14 Published:2021-10-09
  • Supported by:
    National Natural Science Foundation of China (51806096);General Program of China Postdoctoral Science Foundation(2019M661812);Key Laboratory of Aircraft Environmental Control and Life Support, Nanjing University of Aeronautics and Astronautics(KLAECLS-E-201902)

Abstract: The impact of droplets on the wall is the most common phenomenon in spray cooling. The Volume of Fluid (VOF) method in computational fluid dynamics software was used to carry out numerical simulation studies on the process of droplets impacting the wall surface, and the splash shape characteristics of the process of droplets impacting the wall surface liquid film with different parameters were studied. According to the height and diameter of the splash, the influence of droplet parameters and film thickness on splash parameters were analyzed. Combined with the change of splash parameters, the motion discontinuity theory and the change of the dimensionless parameter Re and We were used to analyze the effects of different parameters on the flow characteristics of the liquid film, the shape of the splash and the mechanism of the splash generation. The results showed that when large droplets hit the liquid film, the fluidity of the liquid film can be improved, while the film thickness will be increased. Excessive droplet velocity will produce much splashing and dry up the surface. Increasing the surface tension properly can reduce the formation of secondary droplets and promote the flow of liquid film. Better fluidity of the liquid film can be achieved when the droplets hit a thin liquid film. When the non-dimensional film height is between 0.6 and 1.2, the fluidity of the liquid film does not change with the thickness of the liquid film.

Key words: spray cooling, numerical simulation, computational fluid dynamics, VOF, liquid films, splash parameters

CLC Number: