An Experimental Study of Bubble Growth and Detachment Characteristics at an Orifice for an Electronic Atomizer

The formation of bubbles at an orifice is a key problem in gas–liquid two-phase flow. In the electronic atomizer, the bubble size and generation frequency formed at the gas exchange port are important factors affecting the heat and mass transfer efficiency and two-phase flow in the atomization process. Therefore, it is of great theoretical and practical significance to study the process of bubble growth and detachment at the orifice. In this work, the dynamic change in bubble volume during the periodic growth of the orifice is analyzed by visual experiments. The effects of outlet liquid flow rate, orifice parameter, and liquid properties on bubble detachment volume and detachment frequency are discussed. It is found that under different orifice diameters and outlet liquid flow rates, the bubble generation period can be divided into three forms: single-, double-, and triple-bubble periodicities based on the number of bubbles in the period. The detachment frequency and detachment volume of bubbles increase with the increase the in outlet flow rate. The change in liquid properties also affects the bubble growth and detachment characteristics. This work provides a theoretical basis for the design of an air exchange structure in an electronic atomizer.