An Initial Parametric Study on Fluid Flow Through Bileaflet Mechanical Heart Valves Using Computational Fluid Dynamics

1994 ◽  
Vol 208 (2) ◽  
pp. 63-72 ◽  
Author(s):  
M J King ◽  
T David ◽  
J Fisher
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Volumetric Flow Rate ◽  
Flow Fields ◽  
Opening Angle ◽  
Bileaflet Mechanical Heart Valve ◽  
Flow Through

The effect of leaflet opening angle on flow through a bileaflet mechanical heart valve has been investigated using computational fluid dynamics (CFD). Steady state, laminar flow for a Newtonian fluid at a Reynolds number of 1500 was used in the two-dimensional model of the valve, ventricle, sinus and aorta. This computational model was verified using one-dimensional laser Doppler velocimetry (LDV). Although marked differences in the flow fields and energy dissipation of the jets downstream of the valve were found between the CFD predictions and the three-dimensional experimental model, both methods showed similar trends in the changes of the flow fields as the leaflet opening angle was altered. As the opening angle increased the area of recirculating fluid downstream of the leaflets, the pressure drop across the valve and the volumetric flow rate through the outer orifice decreased. For opening angles greater than 80° the jet through the outer orifice recombined with the central jet downstream of the leaflet; for an opening angle of 78° the jet through the outer orifice impinged on the aortic wall before recombining with the central jet. This study suggests that the opening angle has a marked effect on the flow downstream of the bileaflet mechanical heart valve and that valves with opening angles greater than 80° are preferable.

Smoothed Particle Hydrodynamics Simulation of Flow Through a Bileaflet Mechanical Heart Valve: Advantages and Prospects

2011 ◽  
Author(s):  
Shahrokh Shahriari ◽  
Hoda Maleki ◽  
Ibrahim Hassan ◽  
Lyes Kadem
Keyword(s):  
Heart Valve ◽  
Smoothed Particle Hydrodynamics ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Particle Method ◽  
Generation Process ◽  
Bileaflet Mechanical Heart Valve ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Flow Through

A numerical simulation of pulsatile flow through a bileaflet mechanical heart valve is presented using smoothed particle hydrodynamics (SPH), a meshfree particle method. In SPH, the flow is modeled using fluid particles moving within the domain in which there is no mesh generation process and the conservation of mass is satisfied automatically. SPH showed a good capability to capture the main hemodynamic trend. The particle based nature of SPH allows also blood particle tracking, an important component in order to analysis the level of hemolysis induced by bileaflet mechanical heart valves.

Flow Patterns Downstream of a Mechanical Heart Valve During Systole

2007 ◽  
Author(s):  
P. Oshkai ◽  
F. Haji-Esmaeili
Keyword(s):  
Turbulent Flow ◽  
Heart Valve ◽  
Large Scale ◽  
Cardiac Cycle ◽  
Mechanical Heart Valve ◽  
Opening Angle ◽  
Image Velocimetry ◽  
Imaging Approach ◽  
Systolic Phase ◽  
Flow Through

Digital particle image velocimetry is employed to study turbulent flow through a bileaflet mechanical heart valve during systolic phase of a cardiac cycle. Unsteady vortex shedding from the valve’s leaflets displays distinct characteristic frequencies, depending on the opening angle of each leaflet. Small- and large-scale transverse oscillations of the separated shear layers are studied using global quantitative flow imaging approach. Turbulent flow structures including jet-like regions and shed vortices are characterized in terms of patterns of instantaneous and time-averaged velocity, vorticity, and turbulence statistics.

scholarly journals Impact of superhydrophobicity on the fluid dynamics of a bileaflet mechanical heart valve

2020 ◽  
Vol 110 ◽  
pp. 103895
Author(s):  
Hoda Hatoum ◽  
Sravanthi Vallabhuneni ◽  
Arun Kumar Kota ◽  
David L. Bark ◽  
Ketul C. Popat ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Heart Valve ◽  
Mechanical Heart Valve ◽  
Bileaflet Mechanical Heart Valve

scholarly journals Stereoscopic PIV of Steady Flow Through a Bileaflet Mechanical Heart Valve

2008 ◽  
Author(s):  
C. Hutchison ◽  
P. E. Sullivan ◽  
C. R. Ethier
Keyword(s):  
Steady Flow ◽  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Shear Stresses ◽  
Stereoscopic Piv ◽  
Bileaflet Mechanical Heart Valve ◽  
Component Particle

Each year over 180,000 mechanical heart valves are implanted worldwide, with the bileaflet mechanical heart valve (BiMHV) accounting for approximately 85% of all valve replacements [1,2]. Although much improved from previous valve designs, aortic BiMHV design is far from ideal, and serious complications such as thromboembolism and hemolysis often result. Hemolysis and platelet activation are thought to be caused by turbulent Reynolds shear stresses in the flow [1]. Numerous previous studies have examined aortic BiMHV flow using LDA and two component Particle Image Velocimetry (PIV), and have shown the flow to be complex and three-dimensional [3,4]. Stereoscopic PIV (SPIV) can obtain all three velocity components on a flow plane, and hence has the potential to provide better understanding of three dimensional flow characteristics. The objective of the current study was to use SPIV to measure steady flow, including turbulence properties, downstream of a BiMHV in a modeled aorta. The resulting dataset will be useful for CFD model validation, and the intent is to make it publicly available.

Finite Element Analysis of a Mechanical Heart Valve in Assembly

2012 ◽  
Vol 569 ◽  
pp. 487-490
Author(s):  
Liang Liang Wu ◽  
Guo Jiang Wan ◽  
Feng Zhou ◽  
Jie Yang ◽  
Nan Huang
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Mechanical Valve ◽  
Mechanical Method ◽  
Assembly Quality ◽  
Element Analysis ◽  
Bileaflet Mechanical Heart Valve ◽  
Valve Assembly ◽  
Ansys Workbench

The Bileaflet Mechanical Heart Valve (BMHV) has been the most successful replacement mechanical heart valve, and is currently the most commonly implanted mechanical valve. Although the BMHV is an improvement over previous mechanical heart valves, there are still serious associated complications with its use that must be eliminated. After the completion of the processing and surface modification, heart valve ring and heart valve leaflets constitute a single whole with mechanical method to achieve its function process. In order to ensure that the heart valve is stable and reliable in service, it is particularly important to improve the assembly quality. The theoretical analysis and simulation used of ANSYS Workbench software for the behavior of the heart valve assembly have been done, the experimental results were verified by testing apparatus, which is a helpful tool used to simulate the new structure of the heart valve assembly, and play a certain significance to improve the accuracy of the assembly.

scholarly journals Statistical Characteristics of Flow Field through Open and Semi-Closed Bileaflet Mechanical Heart Valve

2020 ◽  
Vol 2 (4) ◽  
pp. 184-196
Author(s):  
Oleksandr Voskoboinyk ◽  
Lidiia Tereshchenko ◽  
Vladimir Voskoboinick ◽  
Gabriela Fernandez ◽  
Andrey Voskoboinick ◽  
...  
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Pressure Sensors ◽  
Jet Flow ◽  
Operating Conditions ◽  
Mechanical Heart Valves ◽  
Statistical Characteristics ◽  
Diagnostic Tools ◽  
Bileaflet Mechanical Heart Valve

The formation of thrombi on the streamlined surface of the bileaflet mechanical heart valves is one of the main disadvantages of such valves. Thrombi block the valve leaflets and disrupt the cardiovascular system. Diagnosis of thrombosis of the bileaflet mechanical heart valves is relevant and requires the creation of effective diagnostic tools. Hydroacoustic registration of the heart noise is one of the methods for diagnosing the operation of a mechanical heart valve. The purpose of the research is to determine the statistical characteristics of the vortex and jet flow through the open and semi-closed bileaflet mechanical heart valve, to identify hydroacoustic differences and diagnostic signs to determine the operating conditions of the valve. Experimental studies were conducted in laboratory conditions on a model of the left atrium and left ventricle of the heart between which there was the bileaflet mechanical heart valve. Hydrodynamic noise was recorded by miniature pressure sensors, which were located downstream of the valve. The vortex and jet flow behind the prosthetic heart valve were non-linear, random processes and were analyzed using the methods of mathematical statistics and probability theory. The integral and spectral characteristics of the pressure field were obtained and the differences in the noise levels and their spectral components near the central and side jets for the open and semi-closed mitral valve were established. It was shown that hydroacoustic measurements could be an effective basis for developing diagnostic equipment for monitoring the bileaflet mechanical heart valve operation. Doi: 10.28991/SciMedJ-2020-0204-1 Full Text: PDF

Effect of Blood Pressure on Closing Dynamics of Bileaflet Mechanical Heart Valves

2012 ◽  
Author(s):  
Marcio H. Forleo ◽  
Brennan M. Johnson ◽  
Lakshmi P. Dasi
Keyword(s):  
Blood Pressure ◽  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Mechanical Heart Valves ◽  
Thromboembolic Complications ◽  
Stress Gradients ◽  
Bileaflet Mechanical Heart Valve ◽  
Sharp Stress ◽  
Rigid Design

Implantation of a bileaflet mechanical heart valve (BMHV) continues to be associated with a risk of thromboembolic complications despite anti-coagulation therapy1. This has been attributed to the structurally rigid design of the leaflets and valve mechanics combined with an intricate hinge mechanism for the rigid leaflets. The lack of a built in compliance within the valve mechanics presumably leads to sharp stress gradients within the flow as well as a violent closure of the valve often associated with the audible impact of the leaflets to the housing, and a potential for momentary cavitation of blood in the wake of leaflet impact.

scholarly journals A Numerical Analysis of Pressure Pulsation Characteristics Induced by Unsteady Blood Flow in a Bileaflet Mechanical Heart Valve

Processes ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 232 ◽  
Author(s):  
Xiao-gang Xu ◽  
Tai-yu Liu ◽  
Cheng Li ◽  
Lu Zhu ◽  
Shu-xun Li
Keyword(s):  
Blood Flow ◽  
Heart Valves ◽  
Pressure Pulsation ◽  
Flow Direction ◽  
Mechanical Heart Valve ◽  
Opening Angle ◽  
Trailing Edges ◽  
Main Flow Direction ◽  
Flow Through ◽  
Unsteady Blood Flow

The leaflet vibration phenomenon in bileaflet mechanical heart valves (BMHVs) can cause complications such as hemolysis, leaflet damage, and valve fracture. One of the main reasons for leaflet vibration is the unsteady blood flow pressure pulsation induced by turbulent flow instabilities. In this study, we performed numerical simulations of unsteady flow through a BMHV and observed pressure pulsation characteristics under different flow rates and leaflet fully opening angle conditions. The pressure pulsation coefficient and the low-Reynolds k-ω model in CFD (Computational Fluid Dynamics) software were employed to solve these problems. Results showed that the level of pressure pulsation was highly influenced by velocity distribution, and that the higher coefficient of pressure pulsation was associated with the lower flow velocity along the main flow direction. The influence of pressure pulsation near the trailing edges was much larger than the data obtained near the leading edges of the leaflets. In addition, considering the level of pressure pulsation and the flow uniformity, the recommended setting of leaflet fully opening angle was about 80°.

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