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

Xiao-Gang Xu,Shu-Xun Li,Cheng Li,Tai-Yu Liu,Lu Zhu

doi:10.3390/pr7040232

Xiao-Gang Xu, Shu-Xun Li + Show 3 more

Open Access

https://doi.org/10.3390/pr7040232

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Journal: Processes	Publication Date: Apr 24, 2019
Citations: 9	License type: CC BY 4.0

Affiliation: Lanzhou University of Technology

Abstract

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°.

Highlights

Bileaflet mechanical heart valves (BMHVs) are designed and used to replicate the function of natural human heart valves to maintain a unidirectional blood flow, depending on the pressure difference in the upstream and downstream sides of the leaflets
The major potential complications that remain as drawbacks to mechanical heart valves include hemolysis, damage of blood elements, and thrombosis, as a result of the high-velocity jet flow through the narrow passage between the leaflets [3,4]
Another noticeable phenomenon associated with mechanical valves is unsteady, blood flow-induced leaflet vibration, which leads to the complex interaction of flow dynamics and leaflet kinematics

Summary

Introduction

Bileaflet mechanical heart valves (BMHVs) are designed and used to replicate the function of natural human heart valves to maintain a unidirectional blood flow, depending on the pressure difference in the upstream and downstream sides of the leaflets. The major potential complications that remain as drawbacks to mechanical heart valves include hemolysis, damage of blood elements, and thrombosis, as a result of the high-velocity jet flow through the narrow passage between the leaflets [3,4]. Another noticeable phenomenon associated with mechanical valves is unsteady, blood flow-induced leaflet vibration, which leads to the complex interaction of flow dynamics and leaflet kinematics. One of the main reasons for leaflet vibration is the unsteady blood flow pressure pulsation, which is induced by the turbulent flow instabilities [5,6]

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