Hemodynamics and heat transfer in bifurcated blood vessels: Insights from a two-phase Eulerian-granular model on bifurcation angle and asymmetry effects

Abstract

Understanding the influence of geometrical configurations on blood flow and heat transfer is essential for vascular physiology and biomedical applications, such as in the thermal ablation process to destroy tumour cells. This study presents an extensive numerical investigation of the impact of bifurcation angle (${\Omega }_{bif}$) and asymmetry on hemodynamics and thermal transport in three-dimensional bifurcated arteries under realistic physiological pulsatile flow conditions. An Eulerian-granular two-phase model, incorporating the kinetic theory to account for red blood cell (RBC) particle mechanics, is employed in the present simulations. By incorporating particle mechanisms, the present model provides better predictive capabilities compared to single-phase Newtonian, non-Newtonian, and two-phase Euler–Euler models, showing better agreement with experimental data. The results indicate that increasing the bifurcation angle reduces blood velocity at the inlet of branch vessels, subsequently diminishing the heat sink effect due to a decrease in convective cooling. For symmetric configurations, RBC concentration near the inner walls of branch vessels decreases with increasing ${\Omega }_{bif}$, whereas for asymmetric configurations, RBC accumulation near the inner wall increases relative to the outer wall. A persistent thermal gradient between the inner and outer walls leads to differential heat dissipation, affecting local tissue cooling during thermal therapies. These findings of the present study highlight the critical role of vascular geometry in regulating hemodynamic and thermal interactions, with potential implications for cardiovascular diagnostics, vascular graft design, and targeted therapeutic applications.