scholarly journals Geometric Optimization of an Extracorporeal Centrifugal Blood Pump with an Unshrouded Impeller Concerning Both Hydraulic Performance and Shear Stress

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1211
Author(s):  
Bo Huang ◽  
Miao Guo ◽  
Bin Lu ◽  
Qingyu Wu ◽  
Zhigang Zuo ◽  
...  
Keyword(s):  
Shear Stress ◽  
Vascular Diseases ◽  
Geometric Optimization ◽  
Blood Pump ◽  
Original Design ◽  
Centrifugal Blood Pump ◽  
Low Degree ◽  
Blood Pumps ◽  
Optimized Model ◽  
Computation Load

Centrifugal blood pumps have provided a powerful artificial support system for patients with vascular diseases. In the design process, geometrical optimization is usually needed to acquire a more biocompatible model for clinical uses. In the current paper, we propose a method for multi-objective optimization concerning both the hydraulic and the hemolytic performances of the pump based on the near-orthogonal array in which the traditional hemolysis index (HI) is replaced with the maximum scalar shear stress criteria to reduce the computation load. The method is demonstrated with the optimization of an extracorporeal centrifugal blood pump with an unshrouded impeller. CFD studies on the original and nine modified pump models are carried out. The calculated hydraulic performances of the optimized model are also compared against the experiments for validation of the numeric method, with an error of 3.6% at the original design point. The resulting blood pump with low maximum scalar shear stress (132.2 Pa) shows a low degree of calculated HI (1.69 × 10−3).

Flow characteristics and hemolytic performance of the new Breethe centrifugal blood pump in comparison with the CentriMag and Rotaflow pumps

2021 ◽  
pp. 039139882110416
Author(s):  
Ge He ◽  
Jiafeng Zhang ◽  
Aakash Shah ◽  
Zachary B Berk ◽  
Lu Han ◽  
...  
Keyword(s):  
Experimental Data ◽  
Shear Stress ◽  
Flow Characteristics ◽  
Pressure Head ◽  
Blood Pump ◽  
Assisted Circulation ◽  
Centrifugal Blood Pump ◽  
Blood Pumps ◽  
Flow Features

Blood pumps have been increasingly used in mechanically assisted circulation for ventricular assistance and extracorporeal membrane oxygenation support or during cardiopulmonary bypass for cardiac surgery. However, there have always been common complications such as thrombosis, hemolysis, bleeding, and infection associated with current blood pumps in patients. The development of more biocompatible blood pumps still prevails during the past decades. As one of those newly developed pumps, the Breethe pump is a novel extracorporeal centrifugal blood pump with a hybrid magnetic and mechanical bearing with attempt to reduce device-induced blood trauma. To characterize the hydrodynamic and hemolytic performances of this novel pump and demonstrate its superior biocompatibility, we use a combined computational and experimental approach to compare the Breethe pump with the CentriMag and Rotaflow pumps in terms of flow features and hemolysis under an operating condition relevant to ECMO support (flow: 5 L/min, pressure head: ~350 mmHg). The computational results showed that the Breethe pump has a smaller area-averaged wall shear stress (WSS), a smaller volume with a scalar shear stress (SSS) level greater than 100 Pa and a lower device-generated hemolysis index compared to the CentriMag and Rotaflow pumps. The comparison of the calculated residence times among the three pumps indicated that the Breethe pump might have better washout. The experimental data from the in vitro hemolysis testing demonstrated that the Breethe pump has the lowest normalized hemolysis index (NIH) than the CentriMag and Rotaflow pumps. It can be concluded based on both the computational and experimental data that the Breethe pump is a viable pump for clinical use and it has better biocompatibility compared to the clinically accepted pumps.

PIV Measurements of Flow in a Centrifugal Blood Pump: Steady Flow

2004 ◽  
Vol 127 (2) ◽  
pp. 244-253 ◽  
Author(s):  
Steven W. Day ◽  
James C. McDaniel
Keyword(s):  
Shear Stress ◽  
Artificial Heart ◽  
Heart Valves ◽  
Blood Pump ◽  
Reynolds Stresses ◽  
Centrifugal Blood Pump ◽  
Flow Rates ◽  
Blood Damage ◽  
Artificial Heart Valves ◽  
Stagnant Flow

Magnetically suspended left ventricular assist devices have only one moving part, the impeller. The impeller has absolutely no contact with any of the fixed parts, thus greatly reducing the regions of stagnant or high shear stress that surround a mechanical or fluid bearing. Measurements of the mean flow patterns as well as viscous and turbulent (Reynolds) stresses were made in a shaft-driven prototype of a magnetically suspended centrifugal blood pump at several constant flow rates (3–9L∕min) using particle image velocimetry (PIV). The chosen range of flow rates is representative of the range over which the pump may operate while implanted. Measurements on a three-dimensional measurement grid within several regions of the pump, including the inlet, blade passage, exit volute, and diffuser are reported. The measurements are used to identify regions of potential blood damage due to high shear stress and∕or stagnation of the blood, both of which have been associated with blood damage within artificial heart valves and diaphragm-type pumps. Levels of turbulence intensity and Reynolds stresses that are comparable to those in artificial heart valves are reported. At the design flow rate (6L∕min), the flow is generally well behaved (no recirculation or stagnant flow) and stress levels are below levels that would be expected to contribute to hemolysis or thrombosis. The flow at both high (9L∕min) and low (3L∕min) flow rates introduces anomalies into the flow, such as recirculation, stagnation, and high stress regions. Levels of viscous and Reynolds shear stresses everywhere within the pump are below reported threshold values for damage to red cells over the entire range of flow rates investigated; however, at both high and low flow rate conditions, the flow field may promote activation of the clotting cascade due to regions of elevated shear stress adjacent to separated or stagnant flow.

scholarly journals Geometric Optimization for Non-Thrombogenicity of a Centrifugal Blood Pump through Flow Visualization

2002 ◽  
Vol 45 (4) ◽  
pp. 1013-1019 ◽  
Author(s):  
Masahiro TOYODA ◽  
Masahiro NISHIDA ◽  
Osamu MARUYAMA ◽  
Takashi YAMANE ◽  
Tatsuo TSUTSUI ◽  
...  
Keyword(s):  
Flow Visualization ◽  
Geometric Optimization ◽  
Blood Pump ◽  
Centrifugal Blood Pump ◽  
Through Flow

Impeller (straight blade) design variations and their influence on the performance of a centrifugal blood pump

2020 ◽  
Vol 43 (12) ◽  
pp. 782-795
Author(s):  
Peng Fang ◽  
Jianjun Du ◽  
Shunzhou Yu
Keyword(s):  
Shear Stress ◽  
Pressure Head ◽  
Radial Force ◽  
Small Scale ◽  
Blade Angle ◽  
Axial Thrust ◽  
Centrifugal Blood Pump ◽  
Flow Passage ◽  
Straight Blade ◽  
Blood Pumps

Introduction: The miniaturization of blood pumps has become a trend due to the advantage of easier transplantation, especially for pediatric patients. In small-scale pumps, it is much easier and more cost-efficient to manufacture the impeller with straight blades compared to spiral-profile blades. Methods: Straight-blade impeller designs with different blade angles, blade numbers, and impeller flow passage positions are evaluated using the computational fluid dynamics method. Blade angles (θ = 0°, 20°, 30°, and 40°), blade numbers ( N = 5, 6, 7, and 8), and three positions of impeller flow passage (referred to as top, middle, and bottom) are selected as the studied parametric values. Results: The numerical results reveal that with increasing blade angle, the pressure head and the hydraulic efficiency increase, and the average scalar shear stress and the normalized index of hemolysis decrease. The minimum radial force and axial thrust are obtained when θ equals 20°. In addition, the minimum average scalar shear stress and normalized index of hemolysis values are obtained when N = 6, and the maximum values are obtained when N = 5. Regarding the impeller flow passage position, the axial thrust and the stagnation area forming in the impeller eye are reduced as the flow passage height declines. Conclusion: The consideration of a blade angle can greatly improve the performance of blood pumps, although the influence of the blade number is not very easily determined. The bottom position of the impeller flow passage is the best design.

In vitro hemocompatibility investigation for the development of low-flow centrifugal blood pumps with less platelet clogging

2021 ◽  
pp. 039139882110525
Author(s):  
Akiko Oota-Ishigaki ◽  
Takashi Yamane ◽  
Daisuke Sakota ◽  
Ryo Kosaka ◽  
Osamu Maruyama ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Low Flow ◽  
Blood Pump ◽  
Centrifugal Pumps ◽  
Aggregation Index ◽  
Centrifugal Blood Pump ◽  
Pump Design ◽  
Blood Pumps ◽  
Adhesion Rate

Low-flow blood pumps rated under 1 L/min are emerging for new medical applications, such as hemofiltration in acute use. In those pumps, platelet adhesion and aggregation have to be carefully considered because of clogging risk in the filter part. To find an acceptable hemocompatibility that can be applied to low-flow centrifugal blood pump design, the platelet aggregation index, clogging on a micromesh filter, and the hemolysis index were investigated using a low-flow blood pump designed for hemofiltration use. We conducted circulation testing in vitro using fresh porcine blood and two centrifugal pumps with different impeller inlet shapes. The Negative Log Platelet Aggregation Threshold Index (NL-PATI), which reflects the ability of residual platelets to aggregate, and flow rate were measured during reflux for 60 min, and the Normalized Index of Hemolysis (NIH (g/20 min)) was calculated. In addition, blood cell clogging after reflux was observed on the micromesh filter by SEM, and the adhesion rate was calculated. Our results showed that the platelet clogging on the micromesh filter occurred when the average NL-PATI was greater than 0.28 and the average NIH (g/20 min) was greater than 0.01. In contrast, platelet clogging on the micromesh was suppressed when NL-PATI was less than 0.17 and the NIH (g/20 min) was less than 0.003. These values might be used as acceptable hemocompatibility of low-flow centrifugal blood pumps with suppressed platelet clogging for hemofiltration pumps.

scholarly journals 306 Geometric optimization of Stepped Bearings of a Hydrodynamic Levitation Centrifugal Blood Pump

2008 ◽  
Vol 2008 (0) ◽  
pp. 69-70 ◽  
Author(s):  
Toru YADA ◽  
Ryo KOSAKA ◽  
Masahiro NISHIDA ◽  
Osamu MARUYAMA ◽  
Sake SAITO ◽  
...  
Keyword(s):  
Geometric Optimization ◽  
Blood Pump ◽  
Centrifugal Blood Pump

scholarly journals Mathematical evaluation of hemolysis in a channel centrifugal blood pump

2020 ◽  
Vol 22 (3) ◽  
pp. 79-85
Author(s):  
A. P. Kuleshov ◽  
G. P. Itkin ◽  
A. S. Buchnev ◽  
A. A. Drobyshev
Keyword(s):  
Mathematical Model ◽  
Shear Stress ◽  
The Body ◽  
Blood Pump ◽  
Adjacent Area ◽  
Centrifugal Blood Pump ◽  
Critical Areas ◽  
Speed Range ◽  
Mathematical Evaluation ◽  
Different Parts

The objective of this work is to conduct research on a mathematical model to assess hemolytic characteristics in a channel centrifugal blood pump developed by us with 2000–3400 rpm impeller speed range and 100–250 mmHg pressure drop in different parts of the pump flow path. Hemolysis index was measured at 1 to 10 L/min flow rate. The result was an estimate of the average magnitude of the shear stress (SS), taking into account the distribution in the pump, which ranged from 40 to 60 Pa. The most critical areas of the pump in terms of blood injury were evaluated. The maximum SSs were determined: 456 Pa in the impeller wheel zone and 533.3 Pa in the adjacent area of the body, with an exposure time of 0.0115 s and 0.0821 s respectively. In these zones, maximum hemolysis index values were 0.0420 and 0.0744 respectively. Based on the data obtained, these zones were optimized in terms of minimizing hemolysis.

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