COMPARISON AND EXPERIMENTAL VALIDATION OF TURBULENCE MODELS FOR AN AXIAL FLOW BLOOD PUMP

2019 ◽  
Vol 19 (08) ◽  
pp. 1940063
Author(s):  
SHUAI WANG ◽  
JIANPING TAN ◽  
ZHEQIN YU
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Axial Flow ◽  
Turbulence Models ◽  
Internal Flow ◽  
Reynolds Stress Model ◽  
Blood Pump ◽  
Axial Flow Blood Pump ◽  
Standard Formula ◽  
Text Model

Computational fluid dynamics (CFD) has become an essential tool for designing and optimizing the structure of blood pumps. However, it is still questionable which turbulence model can better obtain the flow information for axial flow blood pump. In this study, the axial flow blood pump was used as the object, and the influence of the common turbulence models on simulation was compared. Six turbulence models (standard [Formula: see text]–[Formula: see text] model, RNG [Formula: see text]–[Formula: see text] model, standard [Formula: see text]–[Formula: see text] model, SST [Formula: see text]–[Formula: see text] model, Spalart–Allmaras model, SSG Reynolds stress model) were used to simulate the pressure difference and velocity field of the pump. In parallel, we designed a novel drive system of the axial flow blood pump, which allowed the camera to capture the internal flow field. Then we measured the flow field in the impeller region based on particle image velocimetry (PIV). Through the comparison of experiments and simulation results, the average errors of velocity field obtained by the above models are 30.97%, 19.40%, 24.25%, 15.28%, 28.51%, 23.00%, respectively. Since the SST [Formula: see text]–[Formula: see text] model has the smallest error, and the streamline is consistent with the experimental results, it is recommended to use SST [Formula: see text]–[Formula: see text] model for numerical analysis of the axial flow blood pump.

scholarly journals Multi-parameter analysis of the effects on hydraulic performance and hemolysis of blood pump splitter blades

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402092129
Author(s):  
Zheqin Yu ◽  
Jianping Tan ◽  
Shuai Wang
Keyword(s):  
Flow Field ◽  
Axial Length ◽  
Axial Flow ◽  
Hydraulic Performance ◽  
Parameter Analysis ◽  
Blood Pump ◽  
Computational Fluid Mechanics ◽  
Structural Improvement ◽  
Axial Flow Blood Pump ◽  
And Performance

The splitter blade can effectively optimize pump performance, but there is still insufficient research in blood pumps that cover both hydraulic and hemolysis performance. Thus, the aim of this study was to investigate the effect of key factors related to splitter blade on the performance and flow field of axial flow blood pump. In this study, the number of splitter blades, the axial length, and the circumferential offset were chosen as three objects of study. An analysis of the flow field and performance of the pump by orthogonal array design using computational fluid mechanics was carried out. A set of hydraulic and particle image velocimetry experiments of the model pumps were performed. The result showed that the pump had greater hydraulic performance without sacrificing its hemolytic performance when it had two splitter blades, the axial length ratio was 0.6, and the circumferential offset was 15°. Based on these reference data, the splitter blade may contribute to greater hydraulic performance of the pump and cause no side effect on the velocity distribution of the flow field. This finding provides an effective method for the research, development, and application of structural improvement of the axial flow blood pump.

Analysis of flow field and hemolysis index in axial flow blood pump by computational fluid dynamics–discrete element method

2020 ◽  
Vol 44 (1) ◽  
pp. 46-54
Author(s):  
Lizhi Cheng ◽  
Jianping Tan ◽  
Zhong Yun ◽  
Shuai Wang ◽  
Zheqin Yu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Calculation ◽  
Flow Field ◽  
Discrete Element Method ◽  
Axial Flow ◽  
Discrete Element ◽  
Blood Pump ◽  
Axial Flow Blood Pump ◽  
Element Method

To fully study the relationship between the internal flow field and hemolysis index in an axial flow blood pump, a computational fluid dynamics–discrete element method coupled calculation method was used. Through numerical analysis under conditions of 6000, 8000, and 10,000 r/min, it was found that there was flow separation of blood cell particles in the tip of the impeller and the guide vane behind the impeller. The flow field has a larger pressure gradient distribution, which reduces the lift ratio of the blood pump and easily causes blood cell damage. The study shows that the hemolysis index obtained by the computational fluid dynamics—discrete element method is 4.75% higher than that from the traditional computational fluid dynamics method, which indicates the impact of microcollision between erythrocyte particles and walls on hemolysis index and also further verifies the validity of the computational fluid dynamics–discrete element coupling method. Through the hydraulic and particle image velocimetry experiments of the blood pump, the coincidence between numerical calculation and experiment is analyzed from macro and micro aspects, which shows that the numerical calculation method is feasible.

scholarly journals Study on the influence of dynamic/static interface processing methods on CFD simulation results of the axial-flow blood pump

2020 ◽  
Vol 12 (3) ◽  
pp. 168781402091057
Author(s):  
Shuai Wang ◽  
Jianping Tan ◽  
Zheqin Yu
Keyword(s):  
Velocity Field ◽  
Cfd Simulation ◽  
Axial Flow ◽  
Field Analysis ◽  
Blood Pump ◽  
Sliding Mesh ◽  
Axial Flow Blood Pump ◽  
Image Velocimetry ◽  
Simulation Results ◽  
Flux Conservation

Computational fluid dynamics is an essential tool for the flow field analysis of the blood pump. The interface processing method between the dynamic/static regions will affect the accuracy of simulation results, but its influence on the simulation results is still unclear. In this study, the axial-flow blood pump was taken as the research object, and the effects of the mixing plane, frozen rotor, and sliding mesh methods on the following results were compared: flux conservation at the interface, hydraulic characteristics, and velocity field distribution. In parallel, the particle image velocimetry experiment was carried out to measure the velocity field of the impeller, the inlet, and the outlet area of the blood pump. The results show that the above methods have significant differences in flux conservation between the impeller and the back vane. The average surface energy flux’s error of frozen rotor and sliding mesh are 0.7% and 0.72%, respectively, while the mixing plane method reaches 3.6%. This nonconservative transfer affects the distribution of the downstream velocity field, and the velocity field predicted by the mixing plane at the outlet is quite different. It is suggested to use the frozen rotor method and the sliding mesh method in the simulation of the blood pump.

Clarification of Internal Flow Characteristics of an Axial Flow Blood Pump with Eccentric Drive

2019 ◽  
Vol 2019 (0) ◽  
pp. IS-41
Author(s):  
Yasumasa SUZUKI ◽  
Jun IWASAKI ◽  
Katsuhiro OHUCHI ◽  
Takafumi KUBO ◽  
Takahiro NAMBA
Keyword(s):  
Flow Characteristics ◽  
Axial Flow ◽  
Internal Flow ◽  
Blood Pump ◽  
Axial Flow Blood Pump

Performance of turbulence models for transonic flows in a diffuser

2016 ◽  
Vol 30 (25) ◽  
pp. 1650326 ◽  
Author(s):  
Yangwei Liu ◽  
Jianuo Wu ◽  
Lipeng Lu
Keyword(s):  
Shock Wave ◽  
Strong Shock ◽  
Turbulence Models ◽  
Predictive Performance ◽  
Reynolds Stress Model ◽  
Internal Flows ◽  
Transonic Flows ◽  
Standard Formula ◽  
Text Model ◽  
Better Than

Eight turbulence models frequently used in aerodynamics have been employed in the detailed numerical investigations for transonic flows in the Sajben diffuser, to assess the predictive capabilities of the turbulence models for shock wave/turbulent boundary layer interactions (SWTBLI) in internal flows. The eight turbulence models include: the Spalart–Allmaras model, the standard [Formula: see text] model, the RNG [Formula: see text] model, the realizable [Formula: see text] model, the standard [Formula: see text] model, the SST [Formula: see text] model, the [Formula: see text] model and the Reynolds stress model. The performance of the different turbulence models adopted has been systematically assessed by comparing the numerical results with the available experimental data. The comparisons show that the predictive performance becomes worse as the shock wave becomes stronger. The [Formula: see text] model and the SST [Formula: see text] model perform much better than other models, and the SST [Formula: see text] model predicts a little better than the [Formula: see text] model for pressure on walls and velocity profile, whereas the [Formula: see text] model predicts a little better than the SST [Formula: see text] model for separation location, reattachment location and separation length for strong shock case.

NUMERICAL STUDIES OF AN AXIAL FLOW BLOOD PUMP WITH DIFFERENT DIFFUSER DESIGNS

2013 ◽  
Vol 13 (03) ◽  
pp. 1350029 ◽  
Author(s):  
BOYANG SU ◽  
LEOK POH CHUA ◽  
LIANG ZHONG
Keyword(s):  
Flow Field ◽  
Axial Flow ◽  
Pressure Head ◽  
Blood Pump ◽  
Flow Conditions ◽  
Advantages And Disadvantages ◽  
Axial Flow Blood Pump ◽  
Numerical Studies ◽  
Blood Pumps ◽  
Computational Fluid Dynamics Cfd

Most axial flow blood pumps basically consist of a straightener, an impeller, and a diffuser. The diffuser plays a very important role in the performance of the pump to provide an adequate pressure head and to increase the hydraulic efficiency. During the development of an axial flow blood pump, irregular flow field near the diffuser hub is not desirable as it may induce thrombosis. In order to avoid this phenomenon, two approaches were adopted. In the first approach, the number of the diffuser blades was increased from three (B3, baseline model) to five (B5 model). It was observed that the flow field was improved, but the irregular flow patterns were not completely eliminated. In the second approach, we detached the blades from the diffuser hub (B3C2 model), which was integrated and rotated with the impeller hub. It was found that the rotary diffuser hub significantly improved the flow field, especially near the diffuser hub. Besides the detailed flow fields, the hydraulic and hematologic performances at various flow conditions were also estimated using computational fluid dynamics (CFD). Although each design has its own advantages and disadvantages, the B5 model was superior based on a comparative overview.

Five Month Survival in a Calf Supported With an Intraventricular Axial Flow Blood Pump

ASAIO Journal ◽  
1995 ◽  
Vol 41 (3) ◽  
pp. M333-M336 ◽  
Author(s):  
Steven M. Parnis ◽  
Michael P. Macris ◽  
Robert Jarvik ◽  
John L. Robinson ◽  
Jeffrey W. Kolff ◽  
...  
Keyword(s):  
Axial Flow ◽  
Blood Pump ◽  
Axial Flow Blood Pump

Induction of Ventricular Collapse by an Axial Flow Blood Pump

ASAIO Journal ◽  
1998 ◽  
Vol 44 (5) ◽  
pp. M685-M690 ◽  
Author(s):  
Devin V. Amin ◽  
James F. Antaki ◽  
Philip Litwak ◽  
Douglas Thomas ◽  
Zhongjun J. Wu ◽  
...  
Keyword(s):  
Axial Flow ◽  
Blood Pump ◽  
Axial Flow Blood Pump
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