Numerical and In Vitro Investigations of Pressure Rise in a New Hydrodynamic Blood Bearing

Chan, W.K.; Ooi, Kim Tiow; Loh, Yan-Chuan

doi:10.1111/j.1525-1594.2007.00406.x

Cited by 7 publications

(6 citation statements)

References 11 publications

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“…However, this simplification may not apply to blood, due to its different density and viscosity. This was observed by Chan et al., who presented a correction to the pressure at one bearing point showing good correlation to experiments and numerical simulation for a SGB with no crossflow .…”

supporting

confidence: 71%

“…For instance, an SGB with blood as a fluid medium (viscosity of 3.6 mPa·s) in a 100 μm gap and rotating at 2500 rpm, has a modified Reynolds number equal to 0.77, which may suggest a significant influence of fluid inertia. In his investigation of the pressure at radius r 1 of a fully grooved bearing with no leakage flow, Chan suggested the following correction to Muijderman's equations :

{(p_{r} - p_{r 2})}_{c o r} = (p_{r} - p_{r 2}) - \frac{1}{2} ρ {(ϖ r_{1})}^{2}

…”

Section: Methodsmentioning

confidence: 99%

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The Spiral Groove Bearing as a Mechanism for Enhancing the Secondary Flow in a Centrifugal Rotary Blood Pump

Amaral¹,

Groß-Hardt²,

Timms³

et al. 2013

Artificial Organs

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The rapid evolution of rotary blood pump (RBP) technology in the last few decades was shaped by devices with increased durability, frequently employing magnetic or hydrodynamic suspension techniques. However, the potential for low flow in small gaps between the rotor and pump casing is still a problem for hemocompatibility. In this study, a spiral groove hydrodynamic bearing (SGB) is applied with two distinct objectives: first, as a mechanism to enhance the washout in the secondary flow path of a centrifugal RBP, lowering the exposure to high shear stresses and avoiding thrombus formation; and second, as a way to allow smaller gaps without compromising the washout, enhancing the overall pump efficiency. Computational fluid dynamics was applied and verified via bench-top experiments. An optimization of selected geometric parameters (groove angle, width and depth) focusing on the washout in the gap rather than generating suspension force was conducted. An optimized SGB geometry reduced the residence time of the cells in the gap from 31 to 27 ms, an improvement of 14% compared with the baseline geometry of 200 μm without grooves. When optimizing for pump performance, a 15% smaller gap yielded a slightly better rate of fluid exchange compared with the baseline, followed by a 22% reduction in the volumetric loss from the primary pathway. Finally, an improved washout can be achieved in a pulsatile environment due to the SGB ability to pump inwardly, even in the absence of a pressure head.

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supporting

confidence: 71%

{(p_{r} - p_{r 2})}_{c o r} = (p_{r} - p_{r 2}) - \frac{1}{2} ρ {(ϖ r_{1})}^{2}

…”

Section: Methodsmentioning

confidence: 99%

The Spiral Groove Bearing as a Mechanism for Enhancing the Secondary Flow in a Centrifugal Rotary Blood Pump

Amaral¹,

Groß-Hardt²,

Timms³

et al. 2013

Artificial Organs

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“…Weng‐Kong Chan et al. (28) of the Nanyang Technological University (Singapore) carried out numerical and in vitro investigations of pressure rise in a new hydrodynamic blood bearing for a rotary blood pump. The simplified analytical model overpredicted the pressure rise across the bearing while the results from a more comprehensive 3D CFD model agreed well with the measurements due to the inclusion of the fluid inertia effects.…”

Section: Cardiac Support and Blood Pumpsmentioning

confidence: 99%

Artificial Organs 2007: A Year in Review

Malchesky¹

2008

Artificial Organs

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“…Chan et al. (12) investigated the pressure rise in an SGB considering fluid inertia effects and nonlinear distribution of pressure at the groove inlet, showing the pressure generated by SGB is sufficient to lift the rotor in a blood pump. Yamane et al.…”

mentioning

confidence: 99%

“…SGB was first introduced by Kink and Reul (11) to the conceptual design of miniature blood pumps. Chan et al (12) investigated the pressure rise in an SGB considering fluid inertia effects and nonlinear distribution of pressure at the groove inlet, showing the pressure generated by SGB is sufficient to lift the rotor in a blood pump. Yamane et al (13) applied SGB in a centrifugal blood pump to suspend the rotor in thrust direction, and changes to groove shapes were made to increase the flow rate through SGB, resulting in a reduced thrombus formation.…”

mentioning

confidence: 99%

A Novel Design of Spiral Groove Bearing in a Hydrodynamically Levitated Centrifugal Rotary Blood Pump

Han¹,

Zou²,

Ruan³

et al. 2012

Artificial Organs

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Good washout is very important in spiral groove bearing (SGB) designs when applied to blood pumps due to the micrometer scales of lubrication films and groove depths. To improve washout, flow rate or leakage through SGBs should be as large as possible. However, this special goal violates conventional SGB designs in which no leakage is desired as the leakage would decrease load-carrying capacity significantly. So, a design concept is formed fulfilling the two goals of high load-carrying capacity and large flow rate: let groove width decrease along flow path and the mating surface of the rotor rotate with a direction facilitating the flow through the grooves. Under this concept, a novel SGB is designed, contrary to conventional ones, with groove width decreasing with increasing spiral radius. This SGB is mounted on the motionless upper plate of our designed centrifugal blood pump, with the mating surface of rotor rotating with a direction facilitating the outward flow. To assess SGB designs, a characteristic plane is originally presented relating to pressure-normalized load-carrying capacity and flow rate. Comparisons between various kinds of SGB designs are made, and computational fluid dynamics (CFD) results are plotted in this characteristic plane from which load/flow performances can be directly read out. CFD and comparison results show that the new designs have superior load/flow characteristics. However, the impact of SGB designs upon hemolysis/thrombus formation is still to be verified according to the concept presented.

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Numerical and In Vitro Investigations of Pressure Rise in a New Hydrodynamic Blood Bearing

Cited by 7 publications

References 11 publications

The Spiral Groove Bearing as a Mechanism for Enhancing the Secondary Flow in a Centrifugal Rotary Blood Pump

The Spiral Groove Bearing as a Mechanism for Enhancing the Secondary Flow in a Centrifugal Rotary Blood Pump

Artificial Organs 2007: A Year in Review

A Novel Design of Spiral Groove Bearing in a Hydrodynamically Levitated Centrifugal Rotary Blood Pump

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