Measurements of steady flow through a bileaflet mechanical heart valve using stereoscopic PIV

Abstract

Computational modeling of bileaflet heart valve (BiMHV) flow requires experimentally validated datasets and improved knowledge of BiMHV fluid mechanics. In this study, flow was studied downstream of a model BiMHV in an axisymmetric aortic sinus using stereoscopic particle image velocimetry. The inlet flow was steady and the Reynolds number based on the aortic diameter was 7600. Results showed the outof-plane velocity was of similar magnitude as the transverse velocity. Although additional studies are needed for confirmation, analysis of the out-ofplane velocity showed the possible presence of a four-cell streamwise vortex structure in the mean velocity field. Spatial data for all six Reynolds stress components were obtained. Reynolds normal stress profiles revealed similarities between the central jet and free jets. These findings are important to BiMHV flow modeling, though clinical relevance is limited due to the idealized conditions chosen. To this end, the dataset is publicly available for CFD validation purposes.

Use of Computational Fluid Dynamics to Analyze Blood Flow, Hemolysis and Sublethal Damage to Red Blood Cells in a Bileaflet Artificial Heart Valve

“…From the plot, it can be seen that the peak velocity just past the leaflets increased from around 1.2 m/s for the functioning valve to 2.1 m/s for the malfunctioning valve. This is expected because closing one of the leaflets (the leaflet in the negative y-axis) means more fluid is forced The velocity profiles just past the leaflet tips (at 414 mm downstream of the inlet) using the Hutchinson et al run settings and fluid [60] are compared for the two valves in Figure 8. This point was chosen because it was the location of the velocity data available from Blackmore et al [59] for comparison.…”

“…In this work a CFD-based, three-dimensional model of a bileaflet artificial heart valve was created in both a functioning and malfunctioning position. The results of simulations were compared with literature [57,59,60] to evaluate the accuracy of the various computational methods. Velocity profiles and contours were also compared between the two valves.…”

“…CFD simulations for turbulent flow were carried out with both k-ε and k-ω models for the fully open, functioning valve. The selection of specific CFD simulation results to be used for eddy analysis was based on comparison of the different model results with velocity profiles in the literature for this system [59,60].…”

“…For initial literature comparisons and results, properties in the simulation were set to match the values of the test fluid used in the Hutchinson et al experimental system [50]: a kinematic viscosity of 1.57 × 10 −6 m 2 /s and a density of 1796 kg/m 3 . Based on the density, viscosity, and diameter of the system, the inlet velocity was set to 0.445 m/s to obtain a Reynolds number of 7600 (as was used by Hutchinson et al) [60]. The purpose of these runs was to develop validated computational methods before carrying out simulations of blood flow through the valve.…”

Hemodynamic Evaluation of a Biological and Mechanical Aortic Valve Prosthesis Using Patient‐Specific MRI‐Based CFD

“…Some hemodynamic differences between different valve types are well known since commercial valve prostheses are normally evaluated in vitro according to ISO 5840. Furthermore, hemodynamics of different valve types were investigated in a number of studies . These in vitro and in silico studies were, however, usually done with the prostheses being mounted in a straight pipe and/or generic geometry of the aorta.…”