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

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## Abstract

**:**

## 1. Introduction

## 2. Numerical Methods and Modeling

#### 2.1. Numerical Method

_{m}and p′ represent the time-average pressure and time-average pulsating pressure, respectively.

#### 2.2. Geometry of BMHV

#### 2.3. Meshing Configurations and Mesh Independency Test

#### 2.4. Boundary Conditions

^{3}and 0.0035 Pa·s, respectively. Because the influence of the change of pressure and velocity boundary conditions on the phenomenon of leaflet fluttering is not clear, only part of the cardiac cycle was selected for simulation. The total transient simulation time was controlled, ranging from the 200th ms to the 500th ms in one cardiac cycle (Figure 2), and the 300 ms time was discretized with 1500 steps corresponding to a time step of 0.2 ms.

#### 2.5. Validation of the Computational Methods

## 3. Results and Discussion

#### 3.1. Effect of Different Flow Rate Conditions

^{4}s

^{−2}to 3.24 × 10

^{5}s

^{−2}. As the flow rate increased to more than 15 L/min, the velocity of the mainstream region increased and the vortices shed downstream from the trailing edges of the leaflets.

#### 3.2. Effect of Different Fully Opening Angles of Leaflets

^{4}s

^{−2}to 1.13 × 10

^{4}s

^{−2}. The results showed that, because of the larger opening angle and the lower average velocity, the vortices were more likely to stay at the surfaces of the leaflets than to shed downstream from the trailing edges.

## 4. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 1.**The perpendicular cut-plane view of the three-dimensional bileaflet mechanical heart valve (BMHV) geometry.

**Figure 4.**Velocity distribution and Q criterion of vortex core region of the 80° opening degree bileaflet mechanical heart valve (BMHV). (

**a**) Velocity vector distribution and (

**b**) Q criterion of vortex core region.

**Figure 5.**Coefficient distribution of pressure pulsation at the leading edge monitoring lines under different flow conditions at 80° opening degree. (

**a**) The complete view. (

**b**) The local enlarged view.

**Figure 6.**Coefficient distribution of pressure pulsation at the trailing edge monitoring lines under different flow conditions at 80° opening degree. (

**a**) The complete view. (

**b**) The local enlarged view.

**Figure 7.**Velocity vector distribution and Q criterion of the vortex core region of the different opening angle bileaflet mechanical heart valves (BMHVs) at a flow rate of 5 L/min. (

**a**) Velocity vector distribution. (

**b**) Q criterion of vortex core region.

**Figure 8.**Coefficient distribution of pressure pulsation at the leading edge monitoring lines under different fully opening angle conditions at a flow rate of 5 L/min.

**Figure 9.**Coefficient distribution of pressure pulsation at the trailing edge monitoring lines under different fully opening angle conditions at a flow rate of 5 L/min.

Number of Cells | Max. Velocity at Central Orifice (m/s) | Max. Velocity at Lateral Orifices (m/s) |
---|---|---|

368,935 | 1.16 | 0.91 |

655,422 | 1.19 | 0.92 |

850,131 | 1.21 | 0.95 |

1,020,373 | 1.21 | 0.96 |

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**MDPI and ACS Style**

Xu, X.-g.; Liu, T.-y.; Li, C.; Zhu, L.; Li, S.-x.
A Numerical Analysis of Pressure Pulsation Characteristics Induced by Unsteady Blood Flow in a Bileaflet Mechanical Heart Valve. *Processes* **2019**, *7*, 232.
https://doi.org/10.3390/pr7040232

**AMA Style**

Xu X-g, Liu T-y, Li C, Zhu L, Li S-x.
A Numerical Analysis of Pressure Pulsation Characteristics Induced by Unsteady Blood Flow in a Bileaflet Mechanical Heart Valve. *Processes*. 2019; 7(4):232.
https://doi.org/10.3390/pr7040232

**Chicago/Turabian Style**

Xu, Xiao-gang, Tai-yu Liu, Cheng Li, Lu Zhu, and Shu-xun Li.
2019. "A Numerical Analysis of Pressure Pulsation Characteristics Induced by Unsteady Blood Flow in a Bileaflet Mechanical Heart Valve" *Processes* 7, no. 4: 232.
https://doi.org/10.3390/pr7040232