Numerical study of the 3D internal flow field of effervescent atomizer at different aeration levels

Two-phase flow field upstream of the discharge orifice of effervescent atomizer has been numerically studied at 0.38 L/min liquid flow rate and different gas to liquid mass ratios of 0.32%, 0.62%, and 1.24%. The internal flow of the atomizer has been three-dimensionally simulated using the volume of fluid method. Aeration gas is considered as an ideal gas at all aeration levels due to the high velocity of it at the exits of the aerating tube. At any aeration level, the simulation results have been represented by the contours of nitrogen volume fraction at different times and the contours of velocity. At all considered aeration levels, according to experimental results, the contours of nitrogen volume fraction show the annular flow regime is dominant in the discharge passage of the simulated atomizer. Also, by increasing the aeration level, both the liquid film thickness in the discharge passage and changes of it along the passage will be decreased. Therefore, it can be expected the spray of the effervescent atomizer at high aeration levels be finer due to a reduction of the liquid film thickness in the discharge passage and more uniform due to fewer changes in the liquid film thickness in this passage.