In this study, flow in a rectangular shape nozzle has been simulated. Fully hexahedral mesh elements are utilized with having boundary layer mesh in order to avoid excessive mesh destiny in the orifice area. It was found that velocity magnitude, axial velocity and vorticity magnitude increases intensely at the beginning of the orifice area which makes it possible for the cavitation phenomena to occur rapidly. The cavitation that occurs inside diesel fuel injector nozzles has a significant impact on atomization, and modelling this phenomenon will be useful in future injector development. The Schnerr cavitation model was chosen among three distinct cavitation models available in Ansys Fluent v21 because it is capable of properly forecasting choke conditions in cavitating flow. The two-phase flow inside a nozzle is assumed to be a homogenous combination of vapor, liquid, and noncondensable gas in this model. The pressure and velocity profiles derived from the simulations were compared to planar throttle flow experimental findings.