scholarly journals Optimizing pressure-driven pulsatile flows in microfluidic devices

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Steffen Michael Recktenwald ◽  
Christian Wagner ◽  
Thomas John
Keyword(s):  
Microfluidic Devices ◽  
Flow Conditions ◽  
Physiological Flow ◽  
Pulsatile Flows ◽  
Pressure Driven

Unsteady and pulsatile flows receive increasing attention due to their potential to enhance various microscale processes. Further, they possess significant relevance for microfluidic studies under physiological flow conditions. However, generating...

scholarly journals Measurement and control of pressure driven flows in microfluidic devices using an optofluidic flow sensor

2014 ◽  
Vol 8 (5) ◽  
pp. 054123 ◽  
Author(s):  
Mohammad Sadegh Cheri ◽  
Hamidreza Shahraki ◽  
Jalal Sadeghi ◽  
Mohammadreza Salehi Moghaddam ◽  
Hamid Latifi
Keyword(s):  
Microfluidic Devices ◽  
Flow Sensor ◽  
And Control ◽  
Measurement And Control ◽  
Pressure Driven

scholarly journals Rheology and microstructural evolution in pressure-driven flow of a magnetorheological fluid with strong particle–wall interactions

2012 ◽  
Vol 23 (9) ◽  
pp. 969-978 ◽  
Author(s):  
Murat Ocalan ◽  
Gareth H. McKinley
Keyword(s):  
Microfluidic Devices ◽  
Magnetorheological Fluid ◽  
Time Dependent ◽  
Mr Fluid ◽  
Flow Through ◽  
Fluid Particles ◽  
And Performance ◽  
Pressure Driven Flow ◽  
Actuator Design ◽  
Pressure Driven

The interaction between magnetorheological (MR) fluid particles and the walls of the device that retain the field-responsive fluid is critical as this interaction provides the means for coupling the physical device to the field-controllable properties of the fluid. This interaction is often enhanced in actuators by the use of ferromagnetic walls that generate an attractive force on the particles in the field-on state. In this article, the aggregation dynamics of MR fluid particles and the evolution of the microstructure in pressure-driven flow through ferromagnetic channels are studied using custom-fabricated microfluidic devices with ferromagnetic sidewalls. The aggregation of the particles and the time-dependent evolution in the microstructure is studied in rectilinear, expansion and contraction channel geometries. These observations help identify methods for improving MR actuator design and performance.

Tomographic PIV analysis of physiological flow conditions in a patient-specific arteriovenous fistula

2020 ◽  
Vol 61 (12) ◽  
Author(s):  
Sanjiv Gunasekera ◽  
Olivia Ng ◽  
Shannon Thomas ◽  
Ramon Varcoe ◽  
Charitha de Silva ◽  
...  
Keyword(s):  
Arteriovenous Fistula ◽  
Patient Specific ◽  
Flow Conditions ◽  
Tomographic Piv ◽  
Physiological Flow ◽  
Piv Analysis

scholarly journals Oxygen mass transfer in a model three-dimensional artery

2008 ◽  
Vol 5 (26) ◽  
pp. 1067-1075 ◽  
Author(s):  
G Coppola ◽  
C Caro
Keyword(s):  
Mass Transfer ◽  
Shear Stress ◽  
Vessel Wall ◽  
Three Dimensional ◽  
Oxygen Mass Transfer ◽  
Dimensional Model ◽  
Flow Conditions ◽  
Human Coronary Artery ◽  
Three Dimensional Model ◽  
Physiological Flow

Arterial geometry is commonly non-planar and associated with swirling blood flow. In this study, we examine the effect of arterial three-dimensionality on the distribution of wall shear stress (WSS) and the mass transfer of oxygen from the blood to the vessel wall in a U-bend, by modelling the blood vessels as either cylindrical or helical conduits. The results show that under physiological flow conditions, three-dimensionality can reduce both the range and extent of low WSS regions and substantially increase oxygen flux through the walls. The Sherwood number and WSS distributions between the three-dimensional helical model and a human coronary artery show remarkable qualitative agreement, implying that coronary arteries may potentially be described with a relatively simple idealized three-dimensional model, characterized by a small number of well-defined geometric parameters. The flow pattern downstream of a planar bend results in separation of the Sh number and WSS effects, a finding that implies means of investigating them individually.

scholarly journals A Novel Bioreactor for Mechanobiological Studies of Engineered Heart Valve Tissue Formation Under Pulmonary Arterial Physiological Flow Conditions

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Sharan Ramaswamy ◽  
Steven M. Boronyak ◽  
Trung Le ◽  
Andrew Holmes ◽  
Fotis Sotiropoulos ◽  
...  
Keyword(s):  
Shear Stress ◽  
Laminar Flow ◽  
Heart Valve ◽  
Tissue Formation ◽  
Flow Conditions ◽  
Physiological Flow ◽  
Valve Tissue ◽  
Engineered Tissue ◽  
Heart Valve Tissue

The ability to replicate physiological hemodynamic conditions during in vitro tissue development has been recognized as an important aspect in the development and in vitro assessment of engineered heart valve tissues. Moreover, we have demonstrated that studies aiming to understand mechanical conditioning require separation of the major heart valve deformation loading modes: flow, stretch, and flexure (FSF) (Sacks et al., 2009, "Bioengineering Challenges for Heart Valve Tissue Engineering," Annu. Rev. Biomed. Eng., 11(1), pp. 289–313). To achieve these goals in a novel bioreactor design, we utilized a cylindrical conduit configuration for the conditioning chamber to allow for higher fluid velocities, translating to higher shear stresses on the in situ tissue specimens while retaining laminar flow conditions. Moving boundary computational fluid dynamic (CFD) simulations were performed to predict the flow field under combined cyclic flexure and steady flow (cyclic-flex-flow) states using various combinations of flow rate, and media viscosity. The device was successfully constructed and tested for incubator housing, gas exchange, and sterility. In addition, we performed a pilot experiment using biodegradable polymer scaffolds seeded with bone marrow derived stem cells (BMSCs) at a seeding density of 5 × 106 cells/cm2. The constructs were subjected to combined cyclic flexure (1 Hz frequency) and steady flow (Re = 1376; flow rate of 1.06 l/min (LPM); shear stress in the range of 0–9 dynes/cm2) for 2 weeks to permit physiological shear stress conditions. Assays revealed significantly (P < 0.05) higher amounts of collagen (2051 ± 256 μg/g) at the end of 2 weeks in comparison to similar experiments previously conducted in our laboratory but performed at subphysiological levels of shear stress (<2 dynes/cm2; Engelmayr et al., 2006, "Cyclic Flexure and Laminar Flow Synergistically Accelerate Mesenchymal Stem Cell-Mediated Engineered Tissue Formation: Implications for Engineered Heart Valve Tissues," Biomaterials, 27(36), pp. 6083–6095). The implications of this novel design are that fully coupled or decoupled physiological flow, flexure, and stretch modes of engineered tissue conditioning investigations can be readily accomplished with the inclusion of this device in experimental protocols on engineered heart valve tissue formation.

scholarly journals 3D artificial round section micro-vessels to investigate endothelial cells under physiological flow conditions

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Riccardo Sfriso ◽  
Shengye Zhang ◽  
Colette Andrea Bichsel ◽  
Oliver Steck ◽  
Alain Despont ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Flow Conditions ◽  
Physiological Flow ◽  
Round Section
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