Simulation of blood flow in bi-leaflet mechanical heart valve
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Date
2018-05-01
Authors
Noorhafizah Mokhtar
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Abstract
Our heart can be affected by several diseases during its lifetime that consequently result to heart valve malfunctioned. For this reason, bi-leaflet mechanical heart valve (BMHV) is used as a replacement that consist of two semi-circular leaflets and a valve housing. In this research, the design of the BMHV will be optimized in providing suitable replacement for the malfunctioned mitral valve. Simulation results from Lattice Boltzmann method (LBM) code will be used and validated using particle image velocimetry (PIV) experiment. LBM simulations have shown that the leaflet with higher gap distance between leaflets have an improved hemodynamic flow. Additionally, different leaflet curvatures will be compared to further optimize the blood flow dynamics. Based on the Doppler velocity index (DVI) criteria, all six different designs managed to record DVI values within the allowable limit with values of less than 2.2. The result of the velocity contour and vorticity revealed great similarity in the leaflet motion and flow fields between both simulation and experiment. The percentage difference of velocity profile on DVI between both simulation and experiment data is shown to be less than 15%. With regards to the vortex formation, 0.6mm curved inward is found to have the smallest vortex value compared to five other leaflet designs. In terms of the pressure profile and computed wall shear stress, all of the computed pressure results show approximately similar value for all designs used. The maximum wall shear stress computed from this study is about 26.46 Pa. Of all the cases studied, the leaflet with the 0.6mm inward curvature shows the lowest wall shear stress which is beneficial since it reduces thrombosis.