Pulsatile blood flow effects on temperature distribution and heat transfer in rigid vessels.
The effect of blood velocity pulsations on bioheat transfer is studied. A simple model of a straight rigid blood vessel with unsteady periodic flow is considered. A numerical solution that considers the fully coupled Navier-Stokes and energy equations is used for the simulations. The influence of the pulsation rate on the temperature distribution and energy transport is studied for four typical vessel sizes: aorta, large arteries, terminal arterial branches, and arterioles. The results show that: the pulsating axial velocity produces a pulsating temperature distribution; reversal of flow occurs in the aorta and in large vessels, which produces significant time variation 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 vessels. For the thermally important terminal arteries (0.04-1 mm), velocity pulsations have a small influence on temperature distribution and on the energy transport out of the vessels (8 percent for the Womersley number corresponding to a normal heart rate). Given that there is a small difference between the time-averaged unsteady heat flux due to a pulsating blood velocity and an assumed nonpulsating blood velocity, it is reasonable to assume a nonpulsating blood velocity for the purposes of estimating bioheat transfer.
Craciunescu
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Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA. oana@radonc.duke.edu
Clegg
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D001696:Biomechanical Phenomena; D001698:Biomedical Engineering; D001808:Blood Vessels / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D003198:Computer Simulation; D018056:Hemorheology; D006801:Humans; D006979:Hyperthermia, Induced; D008955:Models, Cardiovascular; D009369:Neoplasms / Q000503:physiopathology / Q000628:therapy; D011673:Pulsatile Flow