COLLISIONS OF LIQUID DROPLETS IN A FLOW OF FLUE GASES

Results of experimental investigations on the collision of water droplets and droplets of solutions with a lower surface tension (0.0361 N/m) and a higher dynamic viscosity (0.0108 Pa·s), as compared to those of water, in a fl ow of typical fl ue gases, e.g., the combustion products of kerosene, are presented. To meet the advanced industrial applications, the parameters of the collision of liquid droplets were varied within wide ranges: 0.1–0.7 mm for the radii of droplets, 0.1–7 m/s for the velocities of their movement, and 0–90^o for the angles of attack of the droplets. Video frames of realization of the four regimes of collision of liquid droplets: their coagulation, fl ying-off , breakage, and rebound, were analyzed. Signifi cant diff erences between the characteristics of the surface transformation of water droplets and droplets of solutions as a result of their collision were revealed. A comparison of the collisions of liquid droplets in the fl ue gases and in the air at room temperature has shown that these gases infl uence the characteristics of the liquid droplets colliding in them. The positions of the boundaries between the regimes of collision of liquid droplets on the charts of their interaction regimes were determined with regard for the dynamic viscosity and surface tension of the liquid in the droplets, the dimensionless parameter of their interaction, and the Weber number of the droplets. The main diff erences between the liquids in number and size of the secondary droplets formed as a result of the collision of their primary droplets were ascertained.
   
Author:  S. S. Kropotova, N. E. Shlegel′, P. A. Strizhak
Keywords:  colliding droplets, high-temperature gases, combustion products, interaction regimes, chart of interaction regimes, secondary liquid fragments
Page:  328