Critical additively manufactured (AM) parts must be formally qualified prior to use. We have developed an in-house software,AM-CFD, for AM process simulation and rapid part qualification. AM-CFD focuses on melt pool scale and thus can accurately capture melt pool geometries and thermal-fluid dynamics, which are critical features for predicting lack-of-fusion porosity, microstructure, and resulting mechanical properties. AM-CFD can simulate numerous cases in parallel and search for the optimal process condition enabling additively manufactured parts with fine-grained microstructures and favorable mechanical properties. To validate the AM-CFD, blind benchmark tests have been independently conducted by National Institute of Standards and Technology (NIST) and Air Force Research Laboratory (AFRL). Our AM-CFD won three 1st place prizes in the NIST AM-Bench (2018) and identified as Top Performer in AFRL AM Modeling Challenge Series (2020). The AM-CFD is very flexible and can be linked with other optimizers for materials design and engineering optimization.