Mathematical model for turbulent blood flow through a disk-type prosthetic heart valve.

Abstract

Computational fluid dynamic techniques are used to construct a mathematical model for turbulent blood flow through a disk-type prosthetic heart valve in the aortic position. The TEACH computer code is used to solve the k-6 turbulence model numerically over the axisymmetric flow field of the valve during systole. Stream function, mean axial velocity profiles, turbulent shear stresses and wall shear stress distributions are computed for Reynolds numbers between ReD=600 and 10 000 (corresponding to steady flow rates of 2·63 lmin−1 and 43·89lmin−1, respectively). The location, length and maximum reverse flow velocities of separated, flow regions are presented and compared with experimental observations. The largest computed mean axial velocities are 4·4 to 4·8 times the inflow velocity and occur near the downstream corner of the sewing ring. The maximum wall shear stress computed is 229·7 Nm−2 at the upstream corner of the disk occluder for ReD=10000. The location of maximum walls shear stress occurs at the downstream corner of the sewing ring for ReD≤2000. Turbulent shear stresses of up to 380·7 Nm−2 are computed in the region between the sewing ring and the disk occluder for the physiological Reynolds number ReD=6054. The numerical solutions are shown to compare favourably with available experimental measurements.