Pulsatile blood flow effects on temperature distribution and heat transferin rigid vessels

The effect of blood velocity pulsations on bioheat transfer is studied. A s imple model of a straight rigid blood vessel with unsteady periodic flow is considered. A numerical solution that considers the fully coupled Navier-S tokes and energy equations is used for the simulations. The influence of th e pulsation rate on the temperature distribution and energy transport is st udied for four typical vessel sizes: aorta, large arteries, terminal arteri al branches, and arterioles. The results show that: the pulsating axial vel ocity produces a pulsating temperature distribution: reversal ( flow occurs in the aorta and in large vessels, which produces significant time variati on in the temperature profile. Change of the pulsation rate yields a change of the energy transport between the vessel wall and fluid for the large ve ssels. For the thermally important terminal arteries (0.04-1 mm), velocity pulsations have a small influence on temperature distribution and on the en ergy transport out of the vessels (8 percent for the Womersley number corre sponding to a normal heart rate). Given that there is a small difference be tween the time-averaged unsteady heat flux due to a pulsating blood velocit y, and an assumed nonpulsating blood velocity, it is reasonable to assume a nonpulsating blood velocity for the purposes of estimating bioheat transfe r