On the representation of effective stress for computing hemolysis

Wu, Peng; Gao, Qi; Hsu, Po-Lin

doi:10.1007/s10237-018-01108-y

Cited by 30 publications

(39 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where S is the strain rate tensor and the

μ

is the effective viscosity, which is the sum of dynamic viscosity and the turbulent viscosity 30 . The hemolysis index, which is an important evaluation criterion for the blood pump, and it can be calculated by solving the scalar transport equation 29 :

\frac{\partial H I_{L}}{\partial t} + v \cdot \nabla H I_{L} = δ C^{\frac{1}{β}} τ^{\frac{α}{β}} (1 ‐ H I_{L})

…”

Section: Resultsmentioning

confidence: 99%

Research of flow dynamics and occlusion condition in roller pump systems used for ventricular assist

et al. 2020

View full text Add to dashboard Cite

Roller pumps have been widely used in the ventricular assist field for many years, while the significant hemolysis caused by its mechanical stress is still a fundamental problem. Although the usual under‐occlusion setting was considered as an effective method to reduce the hemolysis rate, its nonocclusive condition of the whole process may cause serious backflow results, which exactly places many restrictions on this method. In this study, the simulation experiments based on computational fluid dynamics (CFD) is conducted, and the occlusion angle is proposed and used to explore a more reliable adjustment form of the occlusion condition. The parameterized geometry of a roller pump is established based on the occlusion angle and other parameters. In order to simulate the motion of the roller, the dynamic mesh mode is introduced to the CFD model, and the analytic formulations used to determine the boundary position are derived. In the whole operation process of the roller pump, four feature positions of the rollers were focused and extracted, and the flow characteristics and the shear stress distribution at these positions were demonstrated. It was found that the entry and exit of the rollers could cause clear shear stress peak, especially when one roller entered, the peak got extremely high. Furthermore, the roller pumps with different occlusion angles were compared, and the results showed that decreasing the occlusion angle could lead to a notable decrease in the amplitude and range of high shear stress and the hemolysis index with a small loss of the occlusion duration. It can be concluded that appropriately decreasing the occlusion angle may be an effective method to alleviate the hemolysis which should be given more attention.

show abstract

“…where S is the strain rate tensor and the

μ

\frac{\partial H I_{L}}{\partial t} + v \cdot \nabla H I_{L} = δ C^{\frac{1}{β}} τ^{\frac{α}{β}} (1 ‐ H I_{L})

…”

Section: Resultsmentioning

confidence: 99%

Research of flow dynamics and occlusion condition in roller pump systems used for ventricular assist

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The turbulence effects have been shown to contribute to hemolysis. [47][48][49][50] It has been shown that the energy dissipation is a more appropriate metric than Reynold stress for evaluating hemolysis in turbulent flows. [47][48][49][50] Improperly modeling the turbulence effect leads to either overpredict or underpredict the hemolysis.…”

Section: Cg Rbc Modelmentioning

confidence: 99%

“…[47][48][49][50] It has been shown that the energy dissipation is a more appropriate metric than Reynold stress for evaluating hemolysis in turbulent flows. [47][48][49][50] Improperly modeling the turbulence effect leads to either overpredict or underpredict the hemolysis. [47][48][49][50] Incorporation of the turbulence effect on the RBC deformation is challenging and will be invested in the future.…”

Section: Cg Rbc Modelmentioning

confidence: 99%

“…[47][48][49][50] Improperly modeling the turbulence effect leads to either overpredict or underpredict the hemolysis. [47][48][49][50] Incorporation of the turbulence effect on the RBC deformation is challenging and will be invested in the future. To the best knowledge of the authors, the turbulence effects have not been analyzed in Lagrangian strain-based models yet.…”

Section: Cg Rbc Modelmentioning

confidence: 99%

“…In this study, we considered only mean shear stress and did not include the turbulence effect in our model. The turbulence effects have been shown to contribute to hemolysis . It has been shown that the energy dissipation is a more appropriate metric than Reynold stress for evaluating hemolysis in turbulent flows .…”

Section: Numerical Algorithmmentioning

confidence: 99%

See 2 more Smart Citations

Prediction of mechanical hemolysis in medical devices via a Lagrangian strain‐based multiscale model

et al. 2020

View full text Add to dashboard Cite

This work introduces a new Lagrangian strain-based model to predict the shear-induced hemolysis in biomedical devices. Current computational models for device-induced hemolysis usually utilize empirical fitting of the released free hemoglobin (Hb) in plasma from damaged red blood cells (RBCs). These empirical correlations contain parameters that depend on specific device and operating conditions, thus cannot be used to predict hemolysis in a general device. The proposed algorithm

show abstract

Turbulence and turbulent flow structures in a ventricular assist device—A numerical study using thelarge‐eddysimulation

Torner

Konnigk

Abroug

et al. 2021

Numer Methods Biomed Eng

View full text Add to dashboard Cite

Numerical flow simulations that analyze the turbulent flow characteristics within a turbopump are important for optimizing the efficiency of such machines. In the case of ventricular assist devices (VADs), turbulent flow characteristics must be also examined in order to improve hemocompatibility. Turbulence increases the shear stresses in the VAD flow, which can lead to an increased damage to the transported blood components. Therefore, an understanding of the turbulent flow patterns and their significance for the numerical blood damage prediction is particularly important for flow optimizations in VADs in order to identify and thus minimize flow regions where blood could be damaged due to high turbulent stresses. Nevertheless, the turbulence occurring in VADs and the local turbulent structures that lead to increased turbulent stresses have not yet been analyzed in detail in these machines. Therefore, this study aims to investigate the turbulence in an axial VAD in a comprehensive and double tracked way. First, the flow in an axial VAD was computed using the large‐eddy simulation method, and it was verified that the majority of the turbulence was directly resolved by the simulation. Then, the turbulent flow state of the VAD was quantified globally. For this purpose, a self‐designed evaluation method, the power loss analysis, was used. Subsequently, local flow regions and flow structures were identified where significant turbulent stresses prevail. It will be shown that the identified regions are universal and will also occur in other axial blood pumps as well, for example, in the HeartMate II.

show abstract

On the representation of effective stress for computing hemolysis

Cited by 30 publications

References 39 publications

Research of flow dynamics and occlusion condition in roller pump systems used for ventricular assist

Research of flow dynamics and occlusion condition in roller pump systems used for ventricular assist

Prediction of mechanical hemolysis in medical devices via a Lagrangian strain‐based multiscale model

Turbulence and turbulent flow structures in a ventricular assist device—A numerical study using thelarge‐eddysimulation

Contact Info

Product

Resources

About