Influence of Impeller Design on Hemolysis of an Axial Blood Pump

2011 ◽  
Vol 140 ◽  
pp. 162-166
Author(s):  
Lei Liu ◽  
Fang Qun Wang ◽  
Qin Lin Wu ◽  
Wen Jue Wu ◽  
Kun Xi Qian ◽  
...  
Keyword(s):  
Traditional Method ◽  
Blood Compatibility ◽  
Three Dimensional ◽  
Axial Flow ◽  
Blood Pump ◽  
Design Parameters ◽  
Rotating Speed ◽  
Blood Damage ◽  
Axial Pump ◽  
Blood Pumps

Compared to centrifugal blood pumps, the high rotating speed of axial blood pumps lead to blood damage more easily. In order to improve blood compatibility of the axial blood pump developed by the authors, traditional method and three-dimensional streamlined method are used for axial impeller design, and rapid prototyping with ABS organic materials are adopted. Finally, hydraulic experiments and hemolysis tests have been conducted. The results reveal that the impeller design and the design parameters (diameter and length) affect the hydraulic performance and hemolysis of the axial pump obviously. The hemolysis index in axial flow impeller pump using traditional method is 0.12, while the minimum value of hemolysis index in the streamlined axial blood pump is 0.06, below the permitted hemolysis value of 0.1.

Experimental Research on Hard and Crack-Free Electrodeposited Chromium Coatings

2014 ◽  
Vol 1044-1045 ◽  
pp. 47-52 ◽  
Author(s):  
Xue Lei Li ◽  
Xiao Hang Liu ◽  
Hao Bin Tian ◽  
Wen Jing Yuan
Keyword(s):  
Traditional Method ◽  
Salt Spray ◽  
Three Dimensional ◽  
Chromium Coating ◽  
Micro Hardness ◽  
Rotating Speed ◽  
Hard Particles ◽  
Micro Cracks ◽  
Chromium Electroplating ◽  
Novel Method

In order to eliminate cracks in the chromium coating, a novel method named flexible extrusion assisted chromium electroplating was proposed. The bright and crack-free chromium coatings were electrodeposited by using the perturbation and extrusion of hard and insulating particles. The prepared deposits were characterized by scanning electron microscope (SEM) and three-dimensional topography. The testing results showed that the surface was very smooth and there was no micro cracks in the coating. Micro hardness of the electrodeposited layer was also tested. It was confirmed that the chromium coating electrodeposited with rotating cathode in hard particles had high micro hardness as to 850HV and the micro hardness could be controlled by the process parameters. The rule of the micro hardness was concluded by analyzing current density and rotating speed. In addition the results of salt spray test and electrochemical polarization curve showed that the coating deposited by new method had higher corrosion resistance than that by traditional method.

Research on the Geometry Parameters of Diffuser Vane Influence on the Performance of Bulb Tubular Pumping System

2017 ◽  
Author(s):  
Yan Jin ◽  
Junxin Wu ◽  
Hongcheng Chen ◽  
Chao Liu
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Design Parameters ◽  
Hydraulic Loss ◽  
Three Dimensional Flow ◽  
Pump System ◽  
Pumping System ◽  
Axial Flow Pump ◽  
Cfd Method ◽  
Flow Pump

Diffuser vane of tubular pump is different with that of the axial flow pump, since the diffusion angle after the impeller is larger than as usual, which is an important part of bulb tubular pump system. By calculating the hydraulic loss of each part of bulb tubular pump system, it is found that the hydraulic loss of diffuser vane is in large proportion of the whole hydraulic loss. For this situation, focuses on the design parameters of diffuser vane such as diffuser vane length, unilateral edge diffusion angle, equivalent diffusion angle are necessary. In this paper, CFD method is used to simulate the turbulent flow in a bulb tubular pumping system with two different diffuser vanes. The three dimensional flow fields in the whole passage of pumping system with different diffuser vanes are obtained. The results show that all the main geometry parameters of the diffuser vane design affect the performances of tubular pumping system, it should be chosen the parameters reasonably based on the actual situation.

Computational Prediction of Hemolysis by Blade Flow Field of Micro-Axial Blood Pump

2006 ◽  
Author(s):  
Xin Chen ◽  
Jianping Tan
Keyword(s):  
Blood Flow ◽  
Flow Field ◽  
Fluid Dynamic ◽  
Computational Prediction ◽  
Blood Pump ◽  
Navier Stokes ◽  
Initial Attempt ◽  
Navier Stokes Equation ◽  
Blood Damage ◽  
Blood Pumps

By analyzing fluid dynamics of blood in an artificial blood pump and simulating the flow field structure and the flow performance of blood, the blood flow and the damages in the designed blood pump would be better understood. This paper describes computational fluid dynamic (CFD) used in predicting numerically the hemolysis of blade in micro-axial blood pumps. A numerical hydrodynamical model, based on the Navier-Stokes equation, was used to obtain the flow in a micro-axial blood pump. A time-dependent stress acting on blood particle is solved in this paper to explore the blood flow and damages in the micro-axial blood pump. An initial attempt is also made to predict the blood damage from these simulations.

R&D of a Pulsatile Rotary Heart Pump Imitating the Native Ventricle

2012 ◽  
Vol 190-191 ◽  
pp. 1234-1237
Author(s):  
K.X. Qian ◽  
T. Jing ◽  
H.Y. Yuan ◽  
H. Wang ◽  
F.Q. Wang ◽  
...  
Keyword(s):  
Pulsatile Flow ◽  
Animal Experiments ◽  
Pulsatile Pump ◽  
Rotating Speed ◽  
Blood Damage ◽  
Axial Pump ◽  
Heart Pump ◽  
Pump Inlet ◽  
Blood Elements ◽  
Main Factor

It is evident that a pulsatile flow is important for blood circulation because the flow pulsatility can reduce the resistance of peripheral vessels. It is difficult, however, to produce a pulsatile flow with an impeller pump, since blood damage will occur when a pulsatile flow is produced. Further investigation has revealed that the main factor for blood damage is turbulence shear, which tears the membranes of red blood cells, resulting in free release of haemoglobin into the plasma, and consequently lead to haemolysis. Therefore, the question for producing a pulsatile flow with low haemolysis becomes how to develop a pulsatile impeller pump with less turbulence? The authors have successively developed a pulsatile axial pump and a pulsatile centrifugal pump. In the pulsatile axial pump, the impeller reciprocates axially and rotates simultaneously. The reciprocation is driven by a pneumatic device and the rotation by a DC motor. For a pressure of 40mm Hg pulsatility, about 50mm axially reciprocation amplitude of the impeller is desirable. In order to reduce the axial amplitude, the pump inlet and the impeller both have cone-shaped heads, thus the gap between the impeller and the inlet pipe changes by only 2mm, that is, the impeller reciprocates up to 2mm, a pressure pulsatility of 40mmHg can be produced. As the impeller rotates with a constant speed, low turbulence in the pump can be expected. In the centrifugal pulsatile pump, the impeller changes its rotating speed periodically; the turbulence is reduced by designing an impeller with twisted vanes which enable the blood flow to change its direction rather than its magnitude during the periodic change of the rotating speed. In this way, a pulsatile flow is produced and the turbulence is minimized. Compared to the axial pulsatile pump, the centrifugal pulsatile pump needs only one driver and thus has more application possibilities. The centrifugal pulsatile pump has been used in animal experiments. The pump assisted the circulation of calves for several months without harm to the blood elements and the organ functions of the experimental animal. The experiments demonstrated that the pulsatile impeller is the most efficient pump for assisting heart recovery, because it can produce a pulsatile flow like a diaphragm pump and has no back flow as what occurs in a non-pulsatile rotary pump; the former reduces the circulatory resistance and the later increases the diastole pressure in aorta, and thus increase the perfusion of coronary arteries of the natural heart.

Mechanical axial flow blood pump to support cavopulmonary circulation

2008 ◽  
Vol 31 (11) ◽  
pp. 970-982 ◽  
Author(s):  
A.L. Throckmorton ◽  
J. Kapadia ◽  
D. Madduri
Keyword(s):  
Residence Time ◽  
Axial Flow ◽  
Operating Conditions ◽  
Blood Pump ◽  
Blood Damage ◽  
Fluid Forces ◽  
Axial Flow Blood Pump ◽  
Numerical Predictions ◽  
Computational Fluid Dynamics Analysis ◽  
Scalar Stress

We are developing a collapsible, percutaneously inserted, axial flow blood pump to support the cavopulmonary circulation in infants with a failing single ventricle physiology. An initial design of the impeller for this axial flow blood pump was performed using computational fluid dynamics analysis, including pressure-flow characteristics, scalar stress estimations, blood damage indices, and fluid force predictions. A plastic prototype was constructed for hydraulic performance testing, and these experimental results were compared with the numerical predictions. The numerical predictions and experimental findings of the pump performance demonstrated a pressure generation of 2–16 mm Hg for 50–750 ml/min over 5,500–7,500 RPM with deviation found at lower rotational speeds. The axial fluid forces remained below 0.1 N, and the radial fluid forces were determined to be virtually zero due to the centered impeller case. The scalar stress levels remained below 250 Pa for all operating conditions. Blood damage analysis yielded a mean residence time of the released particles, which was found to be less than 0.4 seconds for both flow rates that were examined, and a maximum residence time was determined to be less than 0.8 seconds. We are in the process of designing a cage with hydrodynamically shaped filament blades to act as a diffuser and optimizing the impeller blade shape to reduce the flow vorticity at the pump outlet. This blood pump will improve the clinical treatment of patients with failing Fontan physiology and provide a unique catheter-based therapeutic approach as a bridge to recovery or transplantation.

Three Dimensional Design and Optimization of a Transonic Rotor in Axial Flow Compressors

2011 ◽  
Author(s):  
Hidetaka Okui ◽  
Tom Verstraete ◽  
R. A. Van den Braembussche ◽  
Zuheyr Alsalihi
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Design Parameters ◽  
Negative Effects ◽  
Stall Margin ◽  
Design And Optimization ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Differential Evolutionary Algorithm ◽  
The Impact

This paper presents a 3-D optimization of a moderately loaded transonic compressor rotor by means of a multi-objective optimization system. The latter makes use of a Differential Evolutionary Algorithm in combination with an Artificial Neural Network and a 3D Navier-Stokes solver. Operating it on a cluster of 30 processors enabled the optimization of a large design space composed of the tip camber line and spanwise distribution of sweep and chord length. Objectives were an increase of efficiency at unchanged stall margin by controlling the shock waves and off-design performance curve. First, tests on a single blade row allowed a better understanding of the impact of the different design parameters. Forward sweep with unchanged camber improved the peak efficiency by only 0.3% with a small increase of the stall margin. Backward sweep with an optimized S shaped camber line improved the efficiency by 0.6% with unchanged stall margin. It is explained how the camber line control could introduce the forward sweep effect and compensate the negative effects of the backward sweep. The best results (0.7% increase in efficiency and unchanged stall margin) have been obtained by a stage optimization that also considered the spanwise redistribution of the rotor flow and loading to reduce the Mach number at the stator hub.

scholarly journals Study on Driving Performance of the Axial-Flow Blood Pump under the Condition of Large Gap

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Yan Xu ◽  
Lizhi Cheng ◽  
Liang Liang
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Driving Performance ◽  
Silicon Steel ◽  
Drive System ◽  
Core Material ◽  
Blood Pump ◽  
Steel Sheets ◽  
Axial Flow Blood Pump ◽  
Magnetic Drive

The paper demonstrates an improvement of the simulation and computational methods for research on the system magnetic field and driving performance of the large gap magnetic drive system, which is used to drive the axial flow blood pump. The operational principle and structure of large gap magnetic drive system are narrated. Ansoft is adopted to simulate a three-dimensional driving torque to improve accuracy of computation. Experiments and theoretical study show that the use of Z10-T25 oriented silicon steel sheets as the electromagnetic core material can remarkably improve the system driving performance as well as optimize the volume and weight of the electromagnets. So the electromagnet made with oriented silicon steel sheets is conducive to improving the driving performance.

scholarly journals Influence of guide vanes on the flow fields and performance of axial pump under unsteady flow conditions: Numerical study

2020 ◽  
Vol 14 (2) ◽  
pp. 6570-6593 ◽  
Author(s):  
Ahmed Ramadhan Al-Obaidi
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Numerical Study ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Axial Flow ◽  
Internal Flow ◽  
Design Flow ◽  
Guide Vanes ◽  
Axial Pump

Influence of different guide vanes on structural of flow field and axial pump performance under unsteady flow is carried out using numerical method. A three-dimensional axial flow pump model is numerically simulated using computational fluid dynamics (CFD) method with four number of impeller blades and 3, 4, 5 and 6 guide vanes depend on the SIMPLE code, standard turbulence k-ε model as well as sliding mesh method (SMM). The static, dynamic, total pressures, shear stress, velocity magnitude and turbulent kinetic energy are the important features which affecting instability operation in the pump. By monitoring above parameters and setting different measurement pressure points, the average pressures in the pump are discussed and the effect of guide vanes on the average pressure is analyzed. The results demonstrate that the numerical calculations can provide good accurately prediction for the characteristics of internal flow in the pump. The numerical results are closed to experimental results the minimum errors of pressure differences can reach 2.5% and the maximum errors 6.5%. The guide vanes have more effect on the flow field and pressure variations especially at outlet region in the axial pump. As compared with the using various guide vanes, the pressure increases as number of vanes increase that can lead the performance of pump also increases. Pressure differences in the pump at variety mass flow for vane 6 is higher than other vanes 3, 4 and 5 by 14.13, 11.35 and 3.85% for flow of 5 L/min. Further, the dynamic pressure differences for design flow between different vanes 6, 5, 4 and 3 are about by 2.87, 7.26 and 8.51% respectively.

HYDRODYNAMIC AND HEMOLYSIS ANALYSIS ON DISTANCE AND CLEARANCE BETWEEN IMPELLER AND DIFFUSER OF AXIAL BLOOD PUMP

2016 ◽  
Vol 16 (02) ◽  
pp. 1650014 ◽  
Author(s):  
JIAJIA YU ◽  
XIWEN ZHANG
Keyword(s):  
Hydraulic Performance ◽  
Blood Pump ◽  
Hydraulic Characteristics ◽  
Empirical Power ◽  
Heartmate Ii ◽  
Blood Damage ◽  
Damage Models ◽  
Blood Pumps ◽  
Patients With Heart Failure ◽  
Hemolytic Property

Low hemolysis and hydraulic performance are important factors for an axial blood pump, which have been transplanted in patients with heart failure (HF). The distance and clearance between impeller and diffuser play a key role in hemolytic properties and hydraulic performances of axial blood pumps that were developed by our group inspired by the design features of HeartMate II. In the present study, we aimed to investigate the appropriate distance and clearance between impellers and diffusers of axial blood pumps, which contains the best low hemolytic property and hydraulic performance using the computational fluid dynamics (CFDs) approach. Specially, the hemolysis of the pump was calculated by using two different empirical power-law hemolytic blood damage models with two sets of parameters. The two hemolytic blood damage models with two sets of parameters were analyzed and compared. Further, the different distances and clearances between impellers and diffusers that affect hemolytic and hydraulic characteristics were also analyzed. The results showed that the pump with distance of 2[Formula: see text]mm and clearance of 0.2[Formula: see text]mm between impeller and diffuser exhibited the best hemolytic property and better hydraulic performance.

Summary of Experimental Investigation of Three Axial-Flow Pump Rotors Tested in Water

1967 ◽  
Vol 89 (4) ◽  
pp. 589-599 ◽  
Author(s):  
M. J. Miller ◽  
J. E. Crouse ◽  
D. M. Sandercock
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Flow Conditions ◽  
Unstable Flow ◽  
Axial Flow Pump ◽  
And Performance ◽  
Loading Parameter ◽  
Tip Radius

Three rotors were tested, to study flow and performance across loaded axial-flow blade rows. Principal design parameters varied were flow coefficient (0.29 < φ < 0.45), blade loading parameter at tip (0.25 < Dt < 0.66), and hub-tip radius ratio (0.4 < rh/rt < 0.8). Overall and blade element performances under noncavitating flow conditions are discussed in detail. Comparisons between the measured, three-dimensional design parameters and those computed from two-dimensional cascade correlations are made. A limited amount of performance obtained during operation of the rotors in unstable flow and cavitating flow conditions is presented.

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