This study involves the use of the CFD code, FLUENT, to predict the formation of droplets in a piezo inkjet printhead. Specifically, the velocity and diameter of the droplets formed is to be determined. There have been no solutions to such a problem using FLUENT and its capability to handle such a problem is assessed. Measurements of the actual droplet size and velocity are obtained using a Phase Doppler Particle Analyzer, PDPA. This has been established as a non-intrusive method of simultaneously measuring diameter and velocity of droplet distributions on the order of microns in size. These measurements were compared with the CFD solutions to determine the success of the CFD models. Three different CFD models were used, each differing in complexity. The most complex, full three-dimensional model revealed very good results. The diameters predicted by the CFD model average 47 um, which only differed by 15% from the measured values of the PDPA, which averaged 41 um. The velocity that was predicted by the CFD model was approximately 0.87 m/s, which was within 30% of the measured average of 0.68 m/s. These are acceptable results considering the complex nature of the problem and the lack of previous solutions. The deviations in the other CFD models were larger but results were still reasonable. This study has established the use of FLUENT CFD software as a potential tool in the study and design of piezo inkjet printing systems
