Simulation of blood vessel surrounded by tissue during thermal theraphy

Abstract

The purpose of this study is to investigate the effects of an external heat flux applied to a bifurcated artery which surrounded by the human tissue during thermal therapy. Two different 2D models have simulated, first the bifurcated artery, and second the stenosed bifurcated artery with two symmetrical stenosis. Although previous researchers did the simulation numerically, but there is no experimental simulation on the human body during thermal therapy. This study helps a lot to determinate the principal data for achieving the goal of experimental simulation. The blood in the artery is assumed to be homogenous, incompressible, and a Newtonian fluid. GAMBIT 2.2.30 is the software which used for the mesh generated, and the FLUENT 6.3.26 is the software that used in order to export the results of this study. The pressure-based, unsteady first order implicit and simple pressure-velocity coupling with second order upwind discretization for momentum, used in this study. Three different external heat fluxes and three different durations and different physical properties have been investigated. Non-dimensional blood and tissue temperatures were plotted against the longitudinal and transverse coordinates. Some dynamic and physical properties of the flow and the tissue were investigated. Simulation results show that the amount of external heat flux, the porosity, and the heating period are the crucial factors determining the distribution of thermal dose for thermal therapy. In model 1, as the heating is increased from 100 to 200 and then to 250W/m2, both the tissue and blood temperatures increases. The increase in the blood is higher than that in the tissue since the thermal conductivity of the former is lower. In model 2 it can be concluded that by applying the optimum values observed from model 1, the critical values of velocity, tissue and blood temperatures for different location along the longitudinal axis, in order to cure cancer cells in thermal therapy in existence of stenosis, achieved.