Numerical simulation of opening process in a bileaflet mechanical heart valve under pulsatile flow condition.
OBJECTIVE
Most previous computational fluid dynamics (CFD) studies of blood flow in mechanical heart valves (MHVs) have not efficiently addressed the important features of moving leaflet and blood-leaflet interaction. Herein, computationally efficient approaches were developed to study these features and to obtain better insight into the pulsatile flow field in bileaflet MHVs.


METHODS
A simple and effective method to track the moving boundary was proposed, and an efficient method for calculating the blood-leaflet interaction applied. In this way, a CFD code was developed to study the pulsatile flow field around bileaflet MHVs. The CFD code was parallelized on a supercomputer to reduce turn-around time in the simulation. The solver was then used to study the opening process in a St. Jude Medical (SJM) size 29 bileaflet MHV.


RESULTS
CFD results showed that, in the opening process, the flow field was consistently partitioned into two side channels and a central channel due to the presence of the two leaflets. In the flow field near the surface of the two leaflets, the fluid velocity followed the local surface velocity of the leaflets, thus showing a strong blood-leaflet interaction effect. Throughout the valve-opening process, peak velocities were always observed near the tips of the valve leaflet. The CFD simulation showed that the opening process took approximately 0.044 s, which compared well with experimental findings.


CONCLUSIONS
The new computational approaches were efficient and able to address the moving leaflet and blood-leaflet interaction. The flow field in the opening process of a SJM 29 bileaflet MHV was successfully simulated using the developed solver.
Shi
Yubing
Y
School of Mechanical and Production Engineering, Nanyang Technological University, Singapore.
Zhao
Yong
Y
Yeo
Tony Joon Hock
TJ
Hwang
Ned H C
NH
D001783:Blood Flow Velocity / Q000502:physiology; D003198:Computer Simulation; D006350:Heart Valve Prosthesis; D006801:Humans; D008955:Models, Cardiovascular; D009716:Numerical Analysis, Computer-Assisted; D011312:Pressure; D011474:Prosthesis Design; D011673:Pulsatile Flow / Q000502:physiology*; D013314:Stress, Mechanical; D013995:Time