The effervescent atomizer is a gas-liquid two-phase atomizer. Due to the discrete distribution of gas phase

the gas-liquid flow parameters at the atomizer exit fluctuate violently. In this study

characteristics of both bubbly flow pattern and spray pulsating characteristics were investigated by experimental and simulation methods. A visual effervescent spray system and a gas-liquid two-phase flow simulation model were established

and the operating conditions corresponding to bubbly flow were determined based on the gas-liquid flow regime map. The results show that the bubble size is approximately normal distribution in bubble flow

and the bubble size decreased with the increase of liquid mass flow rate and gas-liquid mass ratio. Under the same operation conditions

spray morphology and gas-liquid flow parameters at the exit orifice section at various times were observed with great difference

and the spray half cone angle varied larger than 10°. When the number density of bubbles was small and the bubble diameter was large at the same time

the spray cone angle was relatively small

and the spray pulsation was intense as well. With the increase of bubble number density

the average spray half cone angle showed a rapid increase followed by a slowly increasing trend

whereas the variation coefficient of the spray half cone angle increased rapidly first

then gradually decreased and tended to stable. Complex flow field structure was the main reason for the variation of bubble shape in the atomizer and the pulsation of gas-liquid flow parameters at the exit section of the atomizer.