Pulsatile Blood Flow and Gas Exchange Across a Cylindrical Fiber Array

Chan, Kit Yan; Fujioka, Hideki; Hirshl, Ronald B; Bartlett, Robert H.; Grotberg, James B.

doi:10.1115/1.2768105

Cited by 9 publications

(5 citation statements)

References 26 publications

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“…Larger shear rate often appears in the areas close to fiber walls, and that is why the wall shear stress distribution is of great interest. One of the criteria for good oxygenator design is to ensure the peak wall shear stress to be within the critical threshold in order to decrease the potential of blood damages [38]. Although the random array has the larger maximum shear stress than the square and diagonal arrays, the percentage of the area with the high shear stress (i.e., >40.0 Pa when Re ¼ 5.0) is very small.…”

Section: Discussionmentioning

confidence: 99%

Computational Study of the Blood Flow in Three Types of 3D Hollow Fiber Membrane Bundles

Zhang¹,

Xiao-bing²,

Ding³

et al. 2013

Journal of Biomechanical Engineering

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The goal of this study is to develop a computational fluid dynamics (CFD) modeling approach to better estimate the blood flow dynamics in the bundles of the hollow fiber membrane based medical devices (i.e., blood oxygenators, artificial lungs, and hemodialyzers). Three representative types of arrays, square, diagonal, and random with the porosity value of 0.55, were studied. In addition, a 3D array with the same porosity was studied. The flow fields between the individual fibers in these arrays at selected Reynolds numbers (Re) were simulated with CFD modeling. Hemolysis is not significant in the fiber bundles but the platelet activation may be essential. For each type of array, the average wall shear stress is linearly proportional to the Re. For the same Re but different arrays, the average wall shear stress also exhibits a linear dependency on the pressure difference across arrays, while Darcy's law prescribes a power-law relationship, therefore, underestimating the shear stress level. For the same Re, the average wall shear stress of the diagonal array is approximately 3.1, 1.8, and 2.0 times larger than that of the square, random, and 3D arrays, respectively. A coefficient C is suggested to correlate the CFD predicted data with the analytical solution, and C is 1.16, 1.51, and 2.05 for the square, random, and diagonal arrays in this paper, respectively. It is worth noting that C is strongly dependent on the array geometrical properties, whereas it is weakly dependent on the flow field. Additionally, the 3D fiber bundle simulation results show that the threedimensional effect is not negligible. Specifically, velocity and shear stress distribution can vary significantly along the fiber axial direction.

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Section: Discussionmentioning

confidence: 99%

Computational Study of the Blood Flow in Three Types of 3D Hollow Fiber Membrane Bundles

Zhang¹,

Xiao-bing²,

Ding³

et al. 2013

Journal of Biomechanical Engineering

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“…These two fluids had the same viscosity at high shear rates [17]. This nonNewtonian model has also been used previously by others [8,30]. Both walls of the aneurysm and ICA were assumed to be rigid.…”

Section: Numerical Investigationmentioning

confidence: 99%

Timing and size of flow impingement in a giant intracranial aneurysm at the internal carotid artery

Jou

Mawad

2011

Med Biol Eng Comput

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Flow impingement is regarded as a key factor for aneurysm formation and rupture. Wall shear stress (WSS) is often used to evaluate flow impingement even though WSS and impinging force are in two different directions; therefore, this raises an important question of whether using WSS for evaluation of flow impingement size is appropriate. Flow impinging behavior in a patient-specific model of a giant aneurysm (GA) at the internal carotid artery (ICA) was analyzed by computational fluid dynamics simulations. An Impingement Index (IMI) was used to evaluate the timing and size of flow impingement. In theory, the IMI is related to the WSS gradient, which is known to affect vascular biology of endothelial cells. Effect of non-Newtonian fluid, aneurysm size, and heart rate were also studied. Maximum WSS is found to be proportional to the IMI, but the area of high wall shear is not proportional to the size of impingement. A faster heart rate or larger aneurysm does not produce a larger impinging site, and the Newtonian assumption overestimates the size of impingement. Flow impingement at the dome occurs approximately 0.11 s after the peak of flow waveform is attained. This time delay also increases with aneurysm size and varies with heart rate and waveform.

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“…In this work, the mathematical expression for the total amount of gas in blood is adopted from the work of Chan et al [34]. The mathematical formulations for both O 2 and CO 2 are being expressed as physically dissolved and chemically bounded to haemoglobin.…”

Section: Governing Equations For Oxygenationmentioning

confidence: 99%

“…This developed region is known as the concentration boundary layer. The oxygenation process in blood is governed by the convection-diffusion equation [26,34], expressed as…”

Section: Governing Equations For Oxygenationmentioning

confidence: 99%

Formulation of Generalized Mass Transfer Correlations for Blood Oxygenator Design

Low

Loon

Rolland

et al. 2017

Journal of Biomechanical Engineering

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This paper numerically investigates non-Newtonian blood flow with oxygen and carbon dioxide transport across and along an array of uniformly square and staggered arranged fibers at various porosity (ε) levels, focussing on a low Reynolds number regime (Re < 10). The objective is to establish suitable mass transfer correlations, expressed in the form of Sherwood number (Sh = f(ε, Re, Sc)), that identifies the link from local mass transfer investigations to full-device analyses. The development of a concentration field is initially investigated and expressions are established covering the range from a typical deoxygenated condition up to a full oxygenated condition. An important step is identified where a cut-off point in those expressions is required to avoid any under- or over-estimation on the Sherwood number. Geometrical features of a typical commercial blood oxygenator is adopted and results in general show that a balance in pressure drop, shear stress, and mass transfer is required to avoid potential blood trauma or clotting formation. Different definitions of mass transfer correlations are found for oxygen/carbon dioxide, parallel/transverse flow, and square/staggered configurations, respectively. From this set of correlations, it is found that transverse flow has better gas transfer than parallel flow which is consistent with reported literature. The mass transfer dependency on fiber configuration is observed to be pronounced at low porosity. This approach provides an initial platform when one is looking to improve the mass transfer performance in a blood oxygenator without the need to conduct any numerical simulations or experiments.

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Pulsatile Blood Flow and Gas Exchange Across a Cylindrical Fiber Array

Cited by 9 publications

References 26 publications

Computational Study of the Blood Flow in Three Types of 3D Hollow Fiber Membrane Bundles

Computational Study of the Blood Flow in Three Types of 3D Hollow Fiber Membrane Bundles

Timing and size of flow impingement in a giant intracranial aneurysm at the internal carotid artery

Formulation of Generalized Mass Transfer Correlations for Blood Oxygenator Design

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