Numerical simulations of particle dynamics in a poststenotic blood vessel region within the scope of extracorporeal ultrasound stenosis treatment

A numerical model was developed to predict the dynamics of a solid particle in a poststenotic blood vessel region. The flow through a 3D axisymmetric stenosis with 75% reduction in cross-section area was considered for inlet Reynolds numbers of 500 and 1000, which corresponds to typical values for the blood flow in human large arteries. Spherical particles were injected in the flow from the stenosis and tracked using the Discrete Phase Model (DPM) based on a Lagrangian approach. Within the scope of the development of ultrasound thrombolysis methods, the hydrodynamical forces predicted were used to evaluate the residence time of the particle and the minimal ultrasonic intensity required to keep it in the treatment region. For particle sizes larger than 400 μm, the intensity required appeared to be compatible with extracorporeal therapeutic ultrasound.