Liquid-liquid mixing, extraction, reaction, separation, and beneficiation have found a wide range of industrial applications. New theoretical based models have been developed and validated to enable process intensification by properly predicting the mixing quality and the local dispersed phase hold-up distributions in the axial direction of a continuous liquid-liquid flow mixer. The models relate the mixing index and axial hold-up distributions to a Peclet Number, the average dispersed phase hold-up, the input flow rates and the physical properties of the dispersion. The developed models offer a new understanding of the nature of the mixing process in continuous mixers with two liquid-liquid immiscible phases in flow. Experimental work was also performed to investigate the mixing index and axial dispersed phase hold-up distribution using advanced Laser Transmission Technique (LTT) in a mixer setup. The experimental results were used in validating the models. The experimental and the predicted data agreed well for a wide range of impeller speeds/flow ratios. Furthermore, advanced Gamma-ray based visualization measurement techniques can be integrated to validate the model in an intensifying way.