Optical investigation of gas-liquid interaction inside a counterflow atomizer

Complex gas-liquid interaction in the minichannel passages of an internal mixing counterflow atomizer was optically investigated using quartz capillary tubing and a diffused pulsed laser backlight. Image binarization techniques quantified gas penetration length upstream of the injection plane, and results compared to recent flow-blurring literature. Downstream, imaging also tracked the development of an annular flow in the first ten diameters of discharge tube, estimating film surface speed via cross-correlation of image pairs. Knowledge of internal and exit orifice flow conditions contributes to understanding the physical operation and droplet size scaling behavior of counterflow atomizers.