This paper concentrates on the wall shear stress discussion of implanting bi-leaflet aortic valve and concludes a better valve design. To simulate the haemodynamic characteristics of the blood flow, ANSYS CFX10.0 software was utilized to analyze the three-dimensional Reynolds-averaged Navier-Stokes equations. With a quasi-steady analysis model, we predict values of the blood velocity and the wall shear stress both over the valve leaflets and the endothelial lining. Analysis results highlight that leaflet opening angle and valve geometry affect the shear stress distribution and vortex flow regime. An analysis of haemodynamic study for the St. Jude valve with various openingangles is presented first and the sewing ring geometry change is then recommended. It is found that the wall shear stress decreases significantly after modifying the sewing ring geometry. Maximum shear stress reduces 18.5% compared to that of the original St. Jude model at peak systole. This would ease possible damage of endothelial lining of the aorta.
