AC7-03: Difference between revisions
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Revision as of 13:38, 2 June 2022
Turbulent Blood Flow in a Ventricular Assist Device
Application Area 7: Biomedical Flows
Application Challenge AC7-03
Abstract
Heart failure is a cardiovascular disease, which affects millions of people worldwide. If the heart failure is too severe, a heart transplantation is the gold standard for treatment. Unfortunately, a significant shortage of donor hearts exists worldwide. A technical solution to overcome this gap between demand and availability are Ventricular Assist Devices (VADs). The VADs are mainly implanted within the body of the patients and assist the weak heart by creating the needed pressure to sufficiently supply the circulatory systems.
The device must be designed in such a way that the VAD's operating range is such that it can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head must be built up at a certain blood flow rate . Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow condition. This can be checked by analysing the fluid dynamical stresses through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters described later).
In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a --SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question shall be answered to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES.
Contributed by: Benjamin Torner — University of Rostock, Germany
© copyright ERCOFTAC 2022