A coupled three-dimensional finite-volume computational model has been developed to simulate the transient fluid flow, heat transfer and solidification processes in a vertical-bending continuous casting caster. The turbulence of molten steel inside the liquid pool is calculated using the large eddy simulation (LES). The enthalpy-porosity approach is used to simulate the heat transfer and solidification of steel in the caster. Based on the fractal theory and the conservation of mass, a kind of inclusion cluster model was developed. A new criterion was developed using the user-defined functions to model the motion and entrapment of inclusion cluster in the caster based on the Lagrangian approach. Firstly, the predicted growth of solidified shell was compared with the plant measurements, and the asymmetrical flow pattern was compared with the dye-injection observations of water model experiments. Secondly, the validated model was used to predict the instantaneous motion and entrapment distribution, statistical data, escape and entrapment positions of different inclusion clusters in the caster. Many known phenomena and other new predictions were-reproduced in this part, and the center inclusion band defects in the steel plates found by the UT method can be interpreted using the current model. Finally, two methods were proposed to optimize the inclusion cluster motion and entrapment in the caster. (C) 2015 Elsevier B.V. All rights reserved.