This study focuses on use of computational fluid dynamics (CFD) models to simulate a crystallizer vessel used in crystallization process. Simulation aims to determine variation of local crystal diameter and determine crystallizer's mean diameter in millimeters. Up to 240.9s, results indicate that mean crystal diameter is greater than local crystal diameter, and vice versa from 240 to 300s. Initial crystal size used in simulation was 0.1 nm; simulation's mean crystal size was 2.08 m, while experimental data's mean crystal size was 4.8 m. Fact that simulation and experimental crystal diameters are in same order indicates that crystallizer's CFD models are supported by experimental data. These tested CFD models can be used to investigate crystallization process's parameter sensitivity. Local crystal diamete's sporadic distributions, moment-3 distribution, and velocity distribution in crystallizer are shown in figures. Study concludes that validated CFD models for crystallizer can be used to study parameter sensitivity of crystallization process, which can help optimize process parameters to achieve desired product quality and yield.