An experimental performance comparison of Newtonian and non-Newtonian fluids on a centrifugal blood pump

The use of substitute fluid with similar rheological properties instead of blood is important due to ethical concerns and high blood volume consumption in pump performance test before clinical applications. The performance of a centrifugal blood pump with hydrodynamic journal bearing is experimentally tested using Newtonian 40% aqueous glycerin solution (GS) and non-Newtonian aqueous xanthan gum solution of 600 ppm (XGS) as working fluids. Experiments are performed at four different rotational speeds which are 2700, 3000, 3300, and 3600 rpm; experiments using GS reach between 8.5% and 37.2% higher head curve than experiments using the XGS for every rotational speed. It was observed that as the rotational speed and flow rate increase, the head curve difference between GS and XGS decreases. This result can be attributed to the friction reduction effect when using XGS in experiments at high rotation speed and high flow rate. Moreover, due to different fluid viscosities, differences in hydraulic efficiency were observed for both fluids. This study reveals that the use of Newtonian fluids as working fluids is not sufficient to determine the actual performance of a blood pump, and the performance effects of non-Newtonian fluids are remarkably important in pump performance optimizations.

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Modified Fabrication Techniques Lead to Improved Centrifugal Blood Pump Performance

ASAIO Journal ◽

10.1097/00002480-199407000-00103 ◽

1994 ◽

Vol 40 (3) ◽

pp. M767-M772 ◽

Cited By ~ 7

Author(s):

John J. Pacella ◽

Andrew H. Goldstein ◽

George J. Magovern ◽

Richard E. Clark

Keyword(s):

Blood Pump ◽

Centrifugal Blood Pump ◽

Pump Performance

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Evaluation of hydraulic force on a magnetically levitated impeller for improvement of a novel flow rate estimation method of a centrifugal blood pump

The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME ◽

10.1299/jsmebio.2019.31.2d33 ◽

2019 ◽

Vol 2019.31 (0) ◽

pp. 2D33

Author(s):

Shuya SHIDA ◽

Toru MASUZAWA ◽

Masahiro OSA

Keyword(s):

Flow Rate ◽

Estimation Method ◽

Blood Pump ◽

Centrifugal Blood Pump ◽

Rate Estimation ◽

Hydraulic Force ◽

Magnetically Levitated

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Estimation of the radial force using a disturbance force observer for a magnetically levitated centrifugal blood pump

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/09544119jeim628 ◽

2009 ◽

Vol 224 (7) ◽

pp. 913-924 ◽

Cited By ~ 5

Author(s):

C N Pai ◽

T Shinshi ◽

A Shimokohbe

Keyword(s):

Rotational Speed ◽

Fluid Dynamic ◽

Radial Force ◽

Magnetic Bearing ◽

Blood Pump ◽

Working Fluid ◽

Computational Fluid Dynamic Analysis ◽

Centrifugal Blood Pump ◽

Magnetically Levitated ◽

Radial Thrust

Evaluation of the hydraulic forces in a magnetically levitated (maglev) centrifugal blood pump is important from the point of view of the magnetic bearing design. Direct measurement is difficult due to the absence of a rotor shaft, and computational fluid dynamic analysis demands considerable computational resource and time. To solve this problem, disturbance force observers were developed, using the radial controlled magnetic bearing of a centrifugal blood pump, to estimate the radial forces on the maglev impeller. In order to design the disturbance observer, the radial dynamic characteristics of a maglev impeller were evaluated under different working conditions. It was observed that the working fluid affects the additional mass and damping, while the rotational speed affects the damping and stiffness of the maglev system. Based on these results, disturbance force observers were designed and implemented. The designed disturbance force observers present a bandwidth of 45 Hz. In non-pulsatile conditions, the magnitude of the estimated radial thrust increases in proportion to the flowrate, and the rotational speed has little effect on the force direction. At 5 l/min against 100 mmHg, the estimated radial thrust is 0.95 N. In pulsatile conditions, this method was capable of estimating the pulsatile radial thrust with good response.

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Effect of Reynolds Number on Performance of a Small Centrifugal Pump

Volume 1: Fora, Parts A, B, C, and D ◽

10.1115/fedsm2003-45686 ◽

2003 ◽

Cited By ~ 11

Author(s):

Steven W. Day ◽

Phillip P. Lemire ◽

Ronald D. Flack ◽

James C. McDaniel

Keyword(s):

Reynolds Number ◽

Numerical Study ◽

Internal Flow ◽

Blood Pump ◽

Viscous Effects ◽

Flow Curves ◽

Centrifugal Blood Pump ◽

Pump Performance ◽

Lower Reynolds Number ◽

Reynolds Number Flows

A study of a small centrifugal blood pump has been made to address the effectiveness of traditional pump affinity laws and the influence that viscous effects, as characterized by the Reynolds number, have on the pump performance. This was investigated both experimentally and numerically on models of a small implantable centrifugal blood pump, which has an impeller diameter of 46 mm with a log spiral volute. In the experiments, the Head-Flow curves were determined for speeds between 500 and 3000 rpm and for two different viscosity fluids. It was found that lower Reynolds number flows did not adhere to conventional pump affinity laws, whereas higher Reynolds number flows scale very effectively according to pump affinity laws. The numerical study consisted of comparing the generated head and internal flow field of the pump scaled based on traditional affinity laws with and without consideration of the Reynolds number. Like the experimental results, the numerical simulations indicate that consideration of the Reynolds number is necessary to insure accurate scaling in this small pump.

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