The injector nozzle is one of the most imperative parts of the diesel engine. The engine performance and the spray characterization are dependent on the geometry and the internal flow of the injector nozzle. In this work, the influence of geometry on the internal flow and the behavior of spray have been studied using CFD tools. Detailed flow analyses were carried out inside the nozzle with different conicity factors and inlet rounding. Interesting observations on the interaction of conicity factors and inlet rounding on the hydraulic flow rate was made. Influence of cavitation and turbulent intensity on the spray cone angle were qualitatively analyzed by using an energy based CFD model for the primary breakup of high-pressure Diesel jets.