Light-guiding effect in a two-fluid model of laser angioplasty

Mixing and optical characteristics of blood and optical fluid, utilized in laser angioplasty, are investigated with a two-fluid model. Transport equations are solved for the zone-averaged variables of each fluid with allowance for momentum transport at the interface. The predicted volume fractions of the fluids are used as weight functions to calculate the mixture refractive index. A set of light rays are traced through the fluids to the plaque, utilizing the mixture refractive index. The results indicate significant effect of flow characteristics on the focusing of the rays.