This work describes the development and testing of a real-time three-dimensional computational fluid dynamics simulation of thrombosis and embolization to be used in the design of blood-contacting devices. Features of the model include the adhesion and aggregation of blood platelets on device material surfaces, shear and chemical activation of blood platelets, and embolization of platelet aggregates due to shear forces. As thrombus develops, blood is diverted from its regular flow field. If shear forces on a thrombus are sufficient to overcome the strength of adhesion, the thrombus is dislodged from the wall. Development of the model included preparing thrombosis and embolization routines to run in a parallel processing configuration, and estimating necessary parameters for the model including the adhesion strength of platelet conglomerations to the device surfaces and the criterion threshold for the coalescence of neighboring thrombi. Validation of the model shows that the effect of variations in geometry may be accurately predicted through computational simulation. This work is based on previous work by Paul Goodman, Daniel Lattin, Jeff Ashton, and Denzel Frost.