MICRO-PIV FLOW MEASUREMENTS NEAR SINGULAR POINTS INSIDE A DIAMOND-SHAPED CYLINDER BUNDLE

2006 ◽  
Vol 26 (Supplement2) ◽  
pp. 237-240
Author(s):  
Sinzaburo UMEDA ◽  
Shinji SHIGEYAMA ◽  
Wen-Jei YANG
Keyword(s):  
Singular Points ◽  
Flow Measurements ◽  
Micro Piv

scholarly journals Micro-PIV Flow Measurements near an Interference Knot Point inside a Diamond-Shaped Cylinder Bundle

2007 ◽  
Vol 27 (Supplement1) ◽  
pp. 153-154
Author(s):  
Shinji SHIGEYAMA ◽  
Tomonori Wakabayashi ◽  
Sinzaburo UMEDA ◽  
Wen-Jei YANG
Keyword(s):  
Flow Measurements ◽  
Micro Piv

Infrared Micro-Particle Image Velocimetry of Fluid Flow in Silicon-Based Microdevices

Volume 4 ◽  
2004 ◽  
Author(s):  
Dong Liu ◽  
Suresh V. Garimella ◽  
Steve T. Wereley
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Capillary Tube ◽  
Surface Flow ◽  
Mems Devices ◽  
Flow Measurements ◽  
Micro Particle Image Velocimetry ◽  
Micro Piv ◽  
Image Velocimetry ◽  
Silicon Based

A non-intrusive diagnostic technique, infrared micro-particle image velocimetry (IR-PIV), is developed for measuring flow fields within MEMS devices with micron-scale resolution. This technique capitalizes on the transparency of silicon in the infrared region, and overcomes the limitation posed by the lack of optical access with visible light to sub-surface flow in silicon-based micro-structures. Experiments with laminar flow of water in a circular micro-capillary tube of hydraulic diameter 255 μm demonstrate the efficacy of this technique. The experimental measurements agree very well with velocity profiles predicted from laminar theory. Cross-correlation and auto-correlation algorithms are employed to measure very-low and moderate-to-high velocities, respectively; the former approach is suitable for biomedical applications while the latter would be needed for measurements in electronics cooling. The results indicate that the IR-PIV technique effectively extends the application of regular micro-PIV techniques, and has great potential for flow measurements in silicon-based microdevices.

scholarly journals Numerical simulation and in vitro examination of the flow behaviour within coronary stents

2019 ◽  
Vol 5 (1) ◽  
pp. 541-544
Author(s):  
Helena-Sophie Melzer ◽  
Ralf Ahrens ◽  
Andreas E. Guber ◽  
Jakob Dohse
Keyword(s):  
Design Parameters ◽  
Experimental Investigations ◽  
Metallic Stent ◽  
Flow Measurements ◽  
Micro Particle Image Velocimetry ◽  
Micro Piv ◽  
Stent Restenosis ◽  
Image Velocimetry ◽  
Stent Strut

AbstractThis paper discusses the influence of different design parameters of stents by mathematical flow simulations and flow measurements using micro-particle image velocimetry (micro-PIV). A stent strut may cause recirculation areas, which are considered to be the source of thrombosis and the process of in-stent restenosis. The simulations showed that a reduced strut height and a chamfering of the struts reduce these recirculation zones. The numerically determined results were compared with experimental investigations. For this purpose metallic stent structures were transferred into transparent channel systems made of PDMS. The experimental investigations confirm the results of numerical simulations.

A PZT Micropump With Planar Passive Valves and its Flow Measurements

2009 ◽  
Author(s):  
Chia-Jui Hsu ◽  
Horn-Jiunn Sheen
Keyword(s):  
Flow Rate ◽  
Excitation Frequency ◽  
Maximum Flow ◽  
Driving Frequency ◽  
Flow Measurements ◽  
Piv Measurements ◽  
Optimum Flow Rate ◽  
Micro Piv ◽  
Valve Motion ◽  
Pumping Efficiency

In this paper, a simply-designed reciprocating-type micropump is presented. We also report the coupling effects between the valve motion and the flow behaviors, which were studied using a micro-PIV technique. The fluids were easily driven by a PZT plate and net flow was directed toward the outlet after rectification by two planar passive valves. The results revealed that good pumping performance was obtained even at a low excitation voltage of 10V. The optimum flow rate was measured at a frequency of 0.8kHz and the maximum flow rate was 275μl/min at 30V. The micropump was uniquely characterized by the existence of a linear relationship between the flow rate and the driving frequency, which enabled this micropump to be easily operated and controlled. The experimental results showed that the micropump was reliable in terms of the high linearity and repeatability, which is very favorable for portable microfluidic systems. The micro-PIV measurements of the transient motions of the valve and the flow behaviors clearly revealed that the valve efficiency depended on the mass inertia of the moving part, excitation frequency, and voltage. The present results are useful for the optimum design of this planar passive valve to improve the pumping efficiency.

scholarly journals Turbulent Flow in a Micro-Channel

2006 ◽  
Author(s):  
Tomasz A. Kowalewski ◽  
Slawomir Blonski ◽  
Piotr M. Korczyk
Keyword(s):  
Experimental Data ◽  
Energy Dissipation ◽  
Turbulent Flow ◽  
High Speed ◽  
Pure Water ◽  
Nano Particles ◽  
Flow Measurements ◽  
Micro Particle Image Velocimetry ◽  
Micro Piv ◽  
Numerical Predictions

Turbulent flow of water in a narrow gap of an emulsifier is investigated experimentally using micro-PIV (micro Particle Image Velocimetry) technique and compared with numerical predictions performed using the commercial code Fluent. The purpose of the investigations is to develop a procedure for well-controlled generation of mono-disperse suspension of micro droplets. These droplets will form a matrix for collection of nano-particles into well-structured configuration [1]. The micro-flow measurements are based on epi-fluorescence illumination and high-speed imaging. The experimental data are compared with the numerical results obtained using both turbulent and laminar flow models. It was found that, due to small channel dimensions and very small flow development length, the turbulent energy dissipation takes place mainly in the gap and shortly behind it. Very low amount of oil-phase fraction in investigated emulsions justifies us to use mean energy dissipation estimated for pure water to predict mean diameter of oil droplets. These predictions are validated using experimental data for the emulsion.

Binary diagrams of mesomorphous compounds exhibiting singular points

1978 ◽  
Vol 3 ◽  
pp. 381-386 ◽  
Author(s):  
F. Hardouin ◽  
G. Sigaud ◽  
M.-F. Achard ◽  
H. Gasparoux
Keyword(s):  
Singular Points

Clinical and Experimental Analysis of 201Thallium Uptake of the Heart

1978 ◽  
Vol 17 (04) ◽  
pp. 142-148
Author(s):  
U. Büll ◽  
S. Bürger ◽  
B. E. Strauer
Keyword(s):  
Oxygen Consumption ◽  
Left Ventricle ◽  
Muscle Mass ◽  
Myocardial Oxygen Consumption ◽  
Animal Experiments ◽  
Left Ventricular ◽  
Left Ventricular Wall ◽  
Ventricular Wall ◽  
Flow Measurements ◽  
Myocardial Flow

Studies were carried out in order to determine the factors influencing myocardial 201T1 uptake. A total of 158 patients was examined with regard to both 201T1 uptake and the assessment of left ventricular and coronary function (e. g. quantitative ventriculography, coronary arteriography, coronary blood flow measurements). Moreover, 42 animal experiments (closed chest cat) were performed. The results demonstrate that:1) 201T1 uptake in the normal and hypertrophied human heart is linearly correlated with the muscle mass of the left ventricle (LVMM);2) 201T1 uptake is enhanced in the inner (subendocardial) layer and is decreased in the outer (subepicardial) layer of the left ventricular wall. The 201T1 uptake of the right ventricle is 40% lower in comparison to the left ventricle;3) the basic correlation between 201T1 uptake and LVMM is influenced by alterations of both myocardial flow and myocardial oxygen consumption; and4) inotropic interventions (isoproterenol, calcium, norepinephrine) as well as coronary dilatation (dipyridamole) may considerably augment 201T1 uptake in accordance with changes in myocardial oxygen consumption and/or myocardial flow.It is concluded that myocardial 201T1 uptake is determined by multiple factors. The major determinants have been shown to include (i) muscle mass, (ii) myocardial flow and (iii) myocardial oxygen consumption. The clinical data obtained from patient groups with normal ventricular function, with coronary artery disease, with left ventricular wall motion abnormalities and with different degree of left ventricular hypertrophy are correlated with quantitated myocardial 201T1 uptake.

Partition Coefficient of 133Xe between Blood and Eye Tissues

1975 ◽  
Vol 14 (04) ◽  
pp. 301-309
Author(s):  
A. Marczak ◽  
A. Moszczyńska-Kowalska ◽  
H. Kowalski
Keyword(s):  
Partition Coefficient ◽  
Aqueous Humour ◽  
Vitreous Body ◽  
Flow Measurements ◽  
Solubility Coefficient ◽  
Eye Muscles ◽  
Eye Tissues ◽  
Relative Solubility ◽  
Blood Flow Measurements

SummaryThe relative solubility coefficient of 133Xe and the tissue-blood partition coefficient for the aqueous humour vitreous body, conjunctiva and external eye muscles of the rabbit were determined in vitro at 37° C and at various haematocrit values. The partition coefficient for haematocrit 40 was: for the aqueous humour 0,49 ml/ml, for the vitreous body 0,50 ml/ml, for the conjunctiva 0,81 ml/g and for the external eye muscles 0,77 ml/g. It was found that the solubility of 133Xe in rabbit erythrocytes is about 50 per cent higher than that in human red cells. The consequences of this fact for the precision of blood flow measurements by the method of tissue clearance are discussed.

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