Analysis of Viscous Fluid Flow in Micropump Elements for Circulatory Support Systems

2021 ◽  
pp. 135-145
Author(s):  
A.I. Khaustov ◽  
G.G. Boyarskiy
Keyword(s):  
Blood Flow ◽  
Viscous Fluid ◽  
Flow Simulation ◽  
Maximum Diameter ◽  
Circulatory Support ◽  
Shear Stresses ◽  
Entire Volume ◽  
Shear Rates ◽  
Micro Pump ◽  
Flow Part

The paper presents the results of developing a micro-pump for the circulatory support system. The maximum diameter of the micropump is 6.5 mm. This allows it to be introduced into the human body through the femoral artery, which ensures its minimally invasive use. The micropump draws blood from the left ventricle of the heart and pumps it into the aorta behind the aortic valve. The numerical analysis of the spatial flow of an incompressible viscous fluid (blood) in the developed elements of the micropump allowed us to prove that its flow path corresponds to the conditions of minimal hemolysis and thrombosis during blood pumping. The developed micropump ensures uniform distribution of pressure and blood flow velocity at the outlet, which guarantees a uniform blood supply to the aorta. There are no zones of stagnation of blood and vortices throughout the flow part of the micropump, which reduces thrombosis in the micropump. In the entire volume of blood flow, even in the peripheral section of the micropump impeller, shear rates and shear stresses do not exceed critical values, which leads to minimal blood hemolysis in the developed elements of the micropump. The obtained results of 3D flow simulation in the elements of the micropump made it possible to develop design documentation for the manufacture and testing of its prototype on hydraulic and hemodynamic stands

scholarly journals Enhanced discrete phase model for multiphase flow simulation of blood flow with high shear stress

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042110080
Author(s):  
Zheqin Yu ◽  
Jianping Tan ◽  
Shuai Wang
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Multiphase Flow ◽  
Experimental Verification ◽  
Flow Simulation ◽  
Turbulence Models ◽  
Phase Model ◽  
Force Model ◽  
Discrete Phase Model ◽  
Discrete Phase

Shear stress is often present in the blood flow within blood-contacting devices, which is the leading cause of hemolysis. However, the simulation method for blood flow with shear stress is still not perfect, especially the multiphase flow model and experimental verification. In this regard, this study proposes an enhanced discrete phase model for multiphase flow simulation of blood flow with shear stress. This simulation is based on the discrete phase model (DPM). According to the multiphase flow characteristics of blood, a virtual mass force model and a pressure gradient influence model are added to the calculation of cell particle motion. In the experimental verification, nozzle models were designed to simulate the flow with shear stress, varying the degree of shear stress through different nozzle sizes. The microscopic flow was measured by the Particle Image Velocimetry (PIV) experimental method. The comparison of the turbulence models and the verification of the simulation accuracy were carried out based on the experimental results. The result demonstrates that the simulation effect of the SST k- ω model is better than other standard turbulence models. Accuracy analysis proves that the simulation results are accurate and can capture the movement of cell-level particles in the flow with shear stress. The results of the research are conducive to obtaining accurate and comprehensive analysis results in the equipment development phase.

scholarly journals Obtaining Expressions for Time-Dependent Functions That Describe the Unsteady Properties of Swirling Jets of Viscous Fluid

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1860
Author(s):  
Eugene Talygin ◽  
Alexander Gorodkov
Keyword(s):  
Blood Flow ◽  
Viscous Fluid ◽  
Swirling Flow ◽  
Fluid Flows ◽  
Theoretical Method ◽  
Flow Channel ◽  
Navier Stokes ◽  
Swirling Jets ◽  
Continuity Equations ◽  
Dynamic Velocity

Previously, it has been shown that the dynamic geometric configuration of the flow channel of the left heart and aorta corresponds to the direction of the streamlines of swirling flow, which can be described using the exact solution of the Navier–Stokes and continuity equations for the class of centripetal swirling viscous fluid flows. In this paper, analytical expressions were obtained. They describe the functions C0t and Г0t, included in the solutions, for the velocity components of such a flow. These expressions make it possible to relate the values of these functions to dynamic changes in the geometry of the flow channel in which the swirling flow evolves. The obtained expressions allow the reconstruction of the dynamic velocity field of an unsteady potential swirling flow in a flow channel of arbitrary geometry. The proposed approach can be used as a theoretical method for correct numerical modeling of the blood flow in the heart chambers and large arteries, as well as for developing a mathematical model of blood circulation, considering the swirling structure of the blood flow.

A NUMERICAL STUDY ON THE HEMODYNAMIC AND SHEAR STRESS OF DOUBLE ANEURYSM THROUGH S-SHAPED VESSEL

2015 ◽  
Vol 27 (04) ◽  
pp. 1550033 ◽  
Author(s):  
Mahdi Halabian ◽  
Alireza Karimi ◽  
Borhan Beigzadeh ◽  
Mahdi Navidbakhsh
Keyword(s):  
Blood Flow ◽  
Mechanical Behavior ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Flow Simulation ◽  
The Body ◽  
Sweep Angle ◽  
Abdominal Aortic ◽  
Hemodynamic Characteristics ◽  
Refined Meshes

Abdominal aortic aneurysm (AAA) is a degenerative disease defined as the abnormal ballooning of the abdominal aorta (AA) wall which is usually caused by atherosclerosis. The aneurysm grows larger and eventually ruptures if it is not diagnosed and treated. Aneurysms occur mostly in the aorta, the main artery of the chest and abdomen. The aorta carries blood flow from the heart to all parts of the body, including the vital organs, the legs, and feet. The objective of the present study is to investigate the combined effects of aneurysm and curvature on flow characteristics in S-shaped bends with sweep angle of 90° at Reynolds number of 900. The fluid mechanics of blood flow in a curved artery with abnormal aortic is studied through a mathematical analysis and employing Cosmos flow simulation. Blood is modeled as an incompressible non-Newtonian fluid and the flow is assumed to be steady and laminar. Hemodynamic characteristics are analyzed. Grid independence is tested on three successively refined meshes. It is observed that the abrupt expansion induced by AAA results in an immensely disturbed regime. The results may have implications not only for understanding the mechanical behavior of the blood flow inside an aneurysm artery but also for investigating the mechanical behavior of the blood flow in different arterial diseases, such as atherosclerosis.

Virtual Training System with Physical Viscoelastic Model and Blood Flow Simulation Based on a Range-Based SPH Method

2015 ◽  
Vol 25 ◽  
pp. 41-53 ◽  
Author(s):  
Yi Dong Bao ◽  
Dong Mei Wu
Keyword(s):  
Blood Flow ◽  
Soft Tissue ◽  
Flow Simulation ◽  
Training System ◽  
Sph Method ◽  
Viscoelastic Creep ◽  
Blood Flow Simulation ◽  
Tissue Cutting ◽  
Creep Characteristics ◽  
Cutting Model

A physical mesh-less soft tissue cutting model with the viscoelastic creep characteristics has been proposed in this paper. The model is composed of filled spheres which are connected by Kelvin structure, so as to realize the cutting with viscoelastic creep characteristics. Then, it is further compared with the mass spring model in order to verify the effectiveness of the model. Secondly, a range-based Smoothed Particle Hydrodynamics (SPH) method with variable smoothing length is proposed, in order to simulate the blood flow simulation effect in the virtual surgery training system. Finally, the two are combined to be applied to the kidney soft tissue cutting experiment in surgery trainings. Experiments show there is a significant improvement on the cutting and simulation effect in terms of the viscoelasticity of the soft tissue cutting and the pressure and viscous force of blood flow.

Multiscale Modeling of Flow Induced Thrombogenicity Using Dissipative Particle Dynamics and Molecular Dynamics

2013 ◽  
Author(s):  
Danny Bluestein ◽  
João S. Soares ◽  
Peng Zhang ◽  
Chao Gao ◽  
Seetha Pothapragada ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Blood Flow ◽  
Red Blood Cells ◽  
Platelet Activation ◽  
Blood Cells ◽  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
Coagulation Cascade ◽  
Shear Stresses ◽  
Activated Platelets

The coagulation cascade of blood may be initiated by flow induced platelet activation, which prompts clot formation in prosthetic cardiovascular devices and arterial disease processes. While platelet activation may be induced by biochemical agonists, shear stresses arising from pathological flow patterns enhance the propensity of platelets to activate and initiate the intrinsic pathway of coagulation, leading to thrombosis. Upon activation platelets undergo complex biochemical and morphological changes: organelles are centralized, membrane glycoproteins undergo conformational changes, and adhesive pseudopods are extended. Activated platelets polymerize fibrinogen into a fibrin network that enmeshes red blood cells. Activated platelets also cross-talk and aggregate to form thrombi. Current numerical simulations to model this complex process mostly treat blood as a continuum and solve the Navier-Stokes equations governing blood flow, coupled with diffusion-convection-reaction equations. It requires various complex constitutive relations or simplifying assumptions, and is limited to μm level scales. However, molecular mechanisms governing platelet shape change upon activation and their effect on rheological properties can be in the nm level scales. To address this challenge, a multiscale approach which departs from continuum approaches, may offer an effective means to bridge the gap between macroscopic flow and cellular scales. Molecular dynamics (MD) and dissipative particle dynamics (DPD) methods have been employed in recent years to simulate complex processes at the molecular scales, and various viscous fluids at low-to-high Reynolds numbers at mesoscopic scales. Such particle methods possess important properties at the mesoscopic scale: complex fluids with heterogeneous particles can be modeled, allowing the simulation of processes which are otherwise very difficult to solve by continuum approaches. It is becoming a powerful tool for simulating complex blood flow, red blood cells interactions, and platelet-mediated thrombosis involving platelet activation, aggregation, and adhesion.

BLOOD FLOW SIMULATION USING SPH METHOD IN LS-DYNA, ANALYSIS OF ADVANTAGES AND DISADVANTAGES

2021 ◽  
Author(s):  
Marko Topalovic ◽  
◽  
Aleksandar Nikolic ◽  
Miroslav Zivkovic
Keyword(s):  
Blood Flow ◽  
Flow Simulation ◽  
Fem Analysis ◽  
Sph Method ◽  
Shell Elements ◽  
Advantages And Disadvantages ◽  
Fluid Analysis ◽  
Eulerian Formulation ◽  
Mesh Free ◽  
Modelling Methodology

The purpose of this research was to investigate the possibility of blood flow modelling in LS-DYNA using its SPH solver and SPH-FEM coupling. SPH and FEM methods are both based on the continuum mechanics, and SPH uses Lagrangian material framework, while FEM can use both Lagrangian for solid, and Eulerian formulation for fluid analysis. SPH implementation is mesh-free giving it the capability to model very large deformations without mesh distortions. However, this comes at a high computational price, so the number of SPH particles needs to be significantly lower in comparison to the number of FEM elements in the Eulerian analysis of the same fluid domain. In the case of combined SPH-FEM analysis, the blood vessel wall is modelled with FEM shell elements, while the blood inside is modelled with SPH particles. The contact between the two is done using nodes to surface algorithm, while if we use the SPH only, there is no need for the specific contact definition. The Lagrangian framework of the SPH method means that we need to generate particles at one end, and to destroy them on the other, in order to generate a continuous fluid flow. To do this we used activation and deactivation planes, which is a solution implemented in the commercial LS-Dyna SPH solver. In the results section of the paper, the velocity field of blood obtained by implementation of described modelling methodology is shown. SPH-FEM coupling offers greater possibilities to study the effects of wall deformations, tracking of movement of solid particle inclusion, or mixing two different fluids, but it requires elaborate contact definition, and prolonged analysis time in comparison to the FEM CFD analysis.

Effect of Blood Viscosity on Thrombosis Potential Near a Step Wall Transition

2009 ◽  
Author(s):  
Scott C. Corbett ◽  
Amin Ajdari ◽  
Ahmet U. Coskun ◽  
Hamid N.-Hashemi
Keyword(s):  
Blood Flow ◽  
Vessel Wall ◽  
Coagulation Factors ◽  
Artificial Organs ◽  
Physical Factors ◽  
Local Geometry ◽  
Induce Platelet Aggregation ◽  
Shear Rates ◽  
Chemical Factors ◽  
Low Shear

Thrombosis and hemolysis are two problems encountered when processing blood in artificial organs. Physical factors of blood flow alone can influence the interaction of proteins and cells with the vessel wall, induce platelet aggregation and influence coagulation factors responsible for the formation of thrombus, even in the absence of chemical factors in the blood. These physical factors are related to the magnitude of the shear rate/stress, the duration of the applied force and the local geometry. Specifically, high blood shear rates (or stress) lead to damage (hemolysis, platelet activation), while low shear rates lead to stagnation and thrombosis [1].

Challenges in Blood Flow Simulation: Numerical Methods and Image Processing Tools

2013 ◽  
Author(s):  
Andrea Dziubek ◽  
Edmond Rusjan ◽  
Bill Thistleton
Keyword(s):  
Blood Flow ◽  
Numerical Methods ◽  
Flow Simulation ◽  
Ocular Blood Flow ◽  
Curved Surfaces ◽  
Vascular Tree ◽  
Discrete Exterior Calculus ◽  
Exterior Calculus ◽  
Front End ◽  
Segmentation Methods

We report on recent results in modeling ocular blood flow (some parts were presented at ARVO 2013 [1]). For this simulations we used discrete exterior calculus based numerical methods. These methods aim to preserve the main features of the original analytical equations and are very suitable for curved surfaces. We will discuss the model and present the numerical methods. We will also give an overview of existing/available segmentation methods to extract the vascular tree from given retina images and our plans how to use them as a front end to our model.

Sign in / Sign up

Export Citation Format

Share Document