Parametric Study of Blade Tip Clearance, Flow Rate, and Impeller Speed on Blood Damage in Rotary Blood Pump

Kim, Nahn Ju; Diao, Chenguang; Ahn, Kyung Hyun; Lee, Seung Jong; Kameneva, Marina V.; Antaki, James F.

doi:10.1111/j.1525-1594.2009.00754.x

Cited by 23 publications

(24 citation statements)

References 26 publications

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“…Results from application of correlations to predict hemolysis quantitatively have been disappointing, and for various reasons some researchers have proposed amendments of the power-law model or the use of entirely different models. 4,5,10,18,21,22,26,28,37 One of the problems with these empirical models relates to the cell's exposure. Differences in the nature of shear stress exposure in controlled laboratory conditions compared to the reality of clinical settings contribute to inaccuracies of the power-law model of hemolysis estimation.…”

Section: Introductionmentioning

confidence: 99%

Significance of Extensional Stresses to Red Blood Cell Lysis in a Shearing Flow

2011

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Traditionally, an empirical power-law model relating hemolysis to shear stress and exposure time has been used to estimate hemolysis related to flow--however, this basis alone has been insufficient in attempts to predict hemolysis through computational fluid dynamics. Because of this deficiency, we sought to re-examine flow features related to hemolysis in a shearing flow by computationally modeling a set of classic experiments performed in a capillary tube. Simulating 21 different flows of varying entrance contraction ratio, flowrate and viscosity, we identified hemolysis threshold streamlines and analyzed the stresses present. Constant damage thresholds for radial and axial extensional stresses of approximately 3000 Pa for exposure times on the order of microseconds were observed, while no such threshold was found for the maximum shear stress or gradient of the shear stress. The extensional flow seen at the entrance of the capillary appears to be most consistently related to hemolysis. An account of how extensional stresses can lead to lysis of a red cell undergoing tank-tread motion in a shearing flow is provided. This work shows that extensional components of the stress tensor are integral in causing hemolysis for some flows, and should be considered when attempting to predict hemolysis computationally.

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Section: Introductionmentioning

confidence: 99%

Significance of Extensional Stresses to Red Blood Cell Lysis in a Shearing Flow

2011

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“…The potential for error was illustrated in this study in Figure 7 for the case of blood flow in a tube. This prompts caution when simulating flow in vessels or channels of small diameter, as well as disturbed flow, small gaps such as the occluder of a prosthetic valve, or blade tips of a rotodynamic blood pump [4], and even Couette devices . In the current study, the hematocrit profiles were explicitly prescribed.…”

Section: Discussionmentioning

confidence: 99%

“…The latter property is important for simulating rheological anomalies that may occur in disease. The former property is important to account for the effect of hemodilution or hemo-concentration, as well as the non-uniform distribution of red blood cells in several situations, such as capillary tubes [1], plasma skimming [2], bifurcations [3], rotary blood pumps [4], and sudden expansions [5][6][7]. Several of the models presented in Tables 1 and 2 exhibit mathematical discontinuities with respect to shear rate and/or hematocrit.…”

Section: Introductionmentioning

confidence: 99%

A Quasi-Mechanistic Mathematical Representation for Blood Viscosity

Hund

Kameneva

Antaki

2017

Fluids

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Blood viscosity is a crucial element for any computation of flow fields in the vasculature or blood-wetted devices. Although blood is comprised of multiple elements, and its viscosity can vary widely depending on several factors, in practical applications, it is commonly assumed to be a homogeneous, Newtonian fluid with a nominal viscosity typically of 3.5 cP. Two quasi-mechanistic models for viscosity are presented here, built on the foundation of the Krieger model of suspensions, in which dependencies on shear rate, hematocrit, and plasma protein concentrations are explicitly represented. A 3-parameter Asymptotic Krieger model (AKM) exhibited excellent agreement with published Couette experiments over four decades of shear rate (0-1000 s −1 , root mean square (RMS) error = 0.21 cP). A 5-parameter Modified Krieger Model (MKM5) also demonstrated a very good fit to the data (RMS error = 1.74 cP). These models avoid discontinuities exhibited by previous models with respect to hematocrit and shear rate. In summary, the quasi-mechanistic, Modified-Krieger Model presented here offers a reasonable compromise in complexity to provide flexibility to account for several factors that affect viscosity in practical applications, while assuring accuracy and stability.

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“…Wu et al [50] analyzed the impact of tip clearance on hemolysis in a centrifugal ventricular assist device; the hemolysis first decreased and then increased as the tip clearance increased from 50 μm to 200 μm, and the minimum value was found at 100 μm. The difference between References [49] and [50] is likely due to the different impeller diameters. This discrepancy suggests that the relative size of tip clearance (i.e., the ratio of tip clearance to impeller diameter) may be the key parameter for hemolysis performance, which needs to be studied further.…”

Section: Energy Characteristics In Pumpsmentioning

confidence: 99%

“…However, increasing the solid proportion results in a stronger efficiency decline caused by the tip clearance. The observation of a rotary blood pump [49] shows that hemolysis is significantly intensified by the decreasing tip clearance from 50 to 200 µm. Wu et al [50] analyzed the impact of tip clearance on hemolysis in a centrifugal ventricular assist device; the hemolysis first decreased and then increased as the tip clearance increased from 50 to 200 µm, and the minimum value was found at 100 µm.…”

Section: Energy Characteristics In Hydroturbinesmentioning

confidence: 99%

A Review of Tip Clearance in Propeller, Pump and Turbine

2018

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Propellers, pumps, and turbines are widely applied in marine equipment, water systems, and hydropower stations. With the increasing demand for energy conservation and environmental protection, the high efficiency and the stable operation of pumps and turbine have been drawing great attention in recent decades. However, the tip clearance between the rotating impeller and the stationary shroud can induce leakage flow and interact with the main stream, introducing complex vortex structures. Consequently, the energy performance and the operation stability of pumps and turbines deteriorate considerably. Constant efforts are exerted to investigate the flow mechanism of tip-clearance flow and its induced influence on performance. However, due to various pump and turbine types and the complexity of tip-clearance flow, previous works are usually focused on a specific issue. Therefore, a systematic review that synthesizes the related research is necessary and meaningful. This review investigates related research in the recent two decades in the perspectives from fundamental physics to engineering applications. Results reveal the vortex types, trajectory, evolution, and cavitation behaviors induced by tip-clearance flow. It is concluded that the influence characteristics of tip clearance on energy performance are closely related to the machinery type. Tip-clearance size and tip shape are found to be crucial parameters for tip-leakage vortex (TLV). The proposed optimization schemes are also demonstrated to provide inspiration for future research. Overall, this review article provides a coherent insight into the characteristics of tip-clearance flow and the associated engineering-design applications. On the basis of these understandings, comments on conducted research and ideas on future research are proposed.

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Parametric Study of Blade Tip Clearance, Flow Rate, and Impeller Speed on Blood Damage in Rotary Blood Pump

Cited by 23 publications

References 26 publications

Significance of Extensional Stresses to Red Blood Cell Lysis in a Shearing Flow

Significance of Extensional Stresses to Red Blood Cell Lysis in a Shearing Flow

A Quasi-Mechanistic Mathematical Representation for Blood Viscosity

A Review of Tip Clearance in Propeller, Pump and Turbine

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