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

2009 ◽  
Vol 224 (7) ◽  
pp. 913-924 ◽  
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.

scholarly journals Experimental and numerical investigation of different geometrical parameters in a centrifugal blood pump

2022 ◽  
Author(s):  
Seyed Ehsan Hosseini ◽  
Amir Keshmiri
Keyword(s):  
Rotational Speed ◽  
Pressure Difference ◽  
Left Ventricular ◽  
Blood Pump ◽  
Working Fluid ◽  
Geometrical Parameters ◽  
Fluid Temperature ◽  
Hydraulic Efficiency ◽  
Centrifugal Blood Pump ◽  
Overall Performance

Abstract Purpose Due to the importance of public health and economics, cardiovascular disease has become one of the most important debates and challenges for scientists. However, few studies have been done to address this challenge. The main objective of this document is to provide an optimal model to improve the performance of the left ventricular assist device and reduce costs. In this way, in the present study, the experimental and numerical procedures were developed to analyze the effects of the geometrical features and operational parameters on the performance of a centrifugal blood pump (CBP). Methods In order to achieve this aim, first, experimental tests were carried out to study the influence of the working fluid temperature and the rotational speed on the CBP. Subsequently, the performance of the CBP was assessed using computational fluid dynamics (CFD), and comparison was made against the experimental data. In addition, the influence of mounting an inducer on the overall performance of CBP was also investigated. Results Good agreement between the CFD and the data was obtained. The CFD results showed that increasing the fluid temperature and rotational speed leads to an increase in the hydraulic efficiency, pressure difference, and power. In addition, the reduction of the pressure difference and hydraulic efficiency with increasing the surface roughness was observed. While mounting an inducer on the pump did not significantly impact its overall performance, the highest value of the wall shear stress dropped moderately on the impeller and, therefore, unveiled the possibility of improving the performance of such designs.

Hydraulic Analysis and Optimization in Impeller of Magnetically Levitated Centrifugal Blood Pump

2011 ◽  
Vol 121-126 ◽  
pp. 1204-1208 ◽  
Author(s):  
Hui Min Zhang ◽  
Qi Zhu
Keyword(s):  
Fluid Dynamic ◽  
Pressure Head ◽  
Blood Pump ◽  
Hydraulic Analysis ◽  
Optimization Analysis ◽  
Centrifugal Blood Pump ◽  
Optimization Of Parameters ◽  
Fluid Field ◽  
Ansys Cfx ◽  
Magnetically Levitated

This article, on the basis of the magnetically levitated pumps developed by Ibaraki University, talks about fluid dynamic analysis of pump and optimization of parameters of the impellers. The pump uses blood as medium, with a flow rate Q of 5L/min, a pressure head H of 100mmHg. By using software of ANSYS CFX, the article analyzes the effect of shape, angle, height, length and thickness of the impeller on performance chart and fluid field distribution inside the pump. To fulfill the human requirements in blood pump, an optimization analysis is conducted to improve the uniformity of fluid field, reduce power and efficiency of the pump. As result, meeting the flow and pressure head condition, single curvature impeller is found to have lower speed, better efficiency and more uniform flow field, this helps to prevent the generation of thrombus and hemolytic.

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

2022 ◽  
pp. 095441192110576
Author(s):  
Ahmet Onder ◽  
Rafet Yapici ◽  
Omer Incebay
Keyword(s):  
Flow Rate ◽  
Rotational Speed ◽  
Performance Test ◽  
Newtonian Fluids ◽  
Friction Reduction ◽  
Blood Pump ◽  
Actual Performance ◽  
Centrifugal Blood Pump ◽  
Working Fluids ◽  
Pump Performance

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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