Exergy destroyed in the arteries due to stenosis

Resumo

© 2016 University of Ljubljana.Arteries can be compared to industrial pipes, being also susceptible to local pressure drops that may occur due to narrowing of the artery at some point, which is called stenosis. This phenomenon is taken as a singularity in the blood flow that leads to a localized head loss and, consequently, irreversibilities. In the present work, the exergy destruction in a given artery due to a stenosis is determined as a function of the diameter reduction taking into account the exergy variation of the flow between the inlet and the outlet, caused by distributed and localized head losses. The contribution of the stenosis is determined based on experimental results available in the literature. Arteries located in four different segments of the body are evaluated: trunk, leg, arm and neck. From the results, it can be noted that the effect of the severity of the stenosis is more pronounced for reductions higher than 55%. From this point on, the exergy destruction increases exponentially. It is also observed that, despite showing different behaviors for individual parcels, the total destroyed exergy rate of stenotic arteries of the leg and the trunk are very similar for high severities. Meanwhile, the arm presents the lowest values. About the contribution of the stenosis to the total destroyed exergy, the segment less susceptible was the trunk. When the specific destroyed exergy due to the stenosis is analyzed, it becomes clearer the impact of the mass flow rate. In this case, the highest values are obtained in the leg, followed by the neck, the trunk and the arm.

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