Numerical study of the effect of the mixing chamber length on the effervescent atomizer internal two-phase flow and the liquid film thickness at the exit the atomizer

The present study investigates the effect of the mixing chamber length on the effervescent atomizer internal two-phase flow and the liquid film thickness at the exit of the atomizer at different gas-to-liquid mass ratios. Therefore, the internal flow of this atomizer simulated for three different lengths of the mixing chamber, at the gas-to-liquid mass ratios of 0.08%, 0.32%, and 1.24% and at the liquid flow rate of 0.38 L / min by the volume of fluid interface following model. The simulation results show that the mixing chamber length does not have much effect on the dominant flow regime in the discharge passage. However, by increasing the mixing chamber length, the two-phase flow inside this chamber more expanded before entering into the discharge passage. Therefore, the two-phase interface instabilities in the discharge passage are lower for the atomizer with the longer mixing chamber. In addition, based on the measuring results of the liquid film thickness at the exit of the atomizer, the effect of the mixing chamber length on the thickness of this film depends on the gas-to-liquid mass ratio. Increasing the mixing chamber length at low gas-to-liquid mass ratio increases the liquid film thickness at the exit of the effervescent atomizer. While at high gas-to-liquid mass ratio, it's inverse. At middle gas-to-liquid mass ratio, the changes of the liquid film thickness at the exit of the atomizer with the mixing chamber length do not show a steady trend.