Basic Study for Micro Pump Using Electroosmotic Flow

2003 ◽  
Author(s):  
Tamio Fujiwara ◽  
Akinori Kamiya ◽  
Osami Kitoh ◽  
Tatsuo Ushijima
Keyword(s):  
Pressure Gradient ◽  
Flow Rate ◽  
Applied Voltage ◽  
Electroosmotic Flow ◽  
Great Influence ◽  
Smoluchowski Equation ◽  
Flow Meter ◽  
Flow Rates ◽  
Micro Pump ◽  
Gap Width

The characteristic features of electroosmotic flow have been studied to obtain important information for applying the flow to a micro pump as a driving device. Here, an electroosmotic flow of water was generated in a donut channel constructed by a gap between two parallel donut-shaped glass plates. The flow rate was measured in relation to the applied voltage, the gap width of the channel, the pressure gradient and the properties of the fluid. The experimental results were compared with a theoretical equation of electroosmosis, the Helmholtz-Smoluchowski equation, which predicts that the electroosmotic flow rate is proportional to the applied voltage as well as to the gap width. The Electroosmotic flow rate increased linearly with the applied voltage. however, there appeared some particular voltage ranges of nonlinear relation unlike the Helmholtz-Smoluchowski equation. The water properties (the conductivity and the kinds of impurities included) had a great influence on the electroosmotic flow rate characteristics including the degree of non-linearity and even the flow direction. The cause of these phenomena has not been clarified. It is conjectured that the zeta potential of the glass-water interface was altered by the applied electric field. It is confirmed that the electroosmotic flow rate is proportional to the gap size of the channel. When a pressure gradient existed in the direction of the electroosmotic flow, the total flow rate was given as a sum of the flow rates of the electroosmotic and Poiseuille flows. These findings provide important information for micro pumps. For measuring the electroosmotic flow rate, we developed a micro flow meter consisting of a capillary and two fine wires. This flow meter makes it possible to measure a flow rate the order of 1×10−3 mm3/sec (= 1 nl/sec) and has a potential ability to measure even much smaller flow rates.

Research on Electrospinning Process of Pullulan Nanofibers

2012 ◽  
Vol 268-270 ◽  
pp. 198-201 ◽  
Author(s):  
Xiao Bin Sun ◽  
D. Jia ◽  
Wei Min Kang ◽  
Bo Wen Cheng ◽  
Ya Bin Li
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Great Influence ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
Diameter Distribution ◽  
Optimal Parameters ◽  
Redistilled Water ◽  
Water As Solvent

A kind of pullulan biopolymer nanofibers with diameter of 100～700nm were obtained using redistilled water as solvent through electrospinning technology in this paper. The effects of the spinning solution concentration, applied voltage, flow rate and capillary–screen distance on morphology and diameter distribution of pullulan nanofiber were studied by SEM. The results show that, different parameters had great influence on nanofibers’ morphology and diameter. The optimal parameters of pullulan nanofibers electrospinning were: 22wt.% spinning solution concentration, 31 kV voltage, 20 cm capillary–screen distance and 0.5ml/h flow rate.

scholarly journals Electroosmotic Flow of Non-Newtonian Fluid in Porous Polymer Membrane at High Zeta Potentials

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1046
Author(s):  
Shuyan Deng ◽  
Yukun Zeng ◽  
Mingying Li ◽  
Cuixiang Liang
Keyword(s):  
Zeta Potential ◽  
Newtonian Fluid ◽  
Flow Rate ◽  
Applied Voltage ◽  
Electroosmotic Flow ◽  
Polymer Membrane ◽  
Porous Polymer ◽  
Total Flow ◽  
Total Flow Rate ◽  
Zeta Potentials

To help in the efficient design of fluid flow in electroosmotic pumps, electroosmotic flow of non-Newtonian fluid through porous polymer membrane at high zeta potentials is studied by mainly evaluating the total flow rate at different physical parameters. Non-Newtonian fluid is represented by the power-law model and the porous polymer membrane is considered as arrays of straight cylindrical pores. The electroosmotic flow of non-Newtonian fluid through a single pore is studied by solving the complete Poisson–Boltzmann equation and the modified Cauchy momentum equation. Then assuming the pore size distribution on porous polymer membrane obeys Gaussian distribution, the performance of electroosmotic pump operating non-Newtonian fluid is evaluated by computing the total flow rate of electroosmotic flow through porous polymer membrane as a function of flow behavior index, geometric parameters of porous membrane, electrolyte concentration, applied voltage, and zeta potential. It is found that enhancing zeta potential and bulk concentration rather than the applied voltage can also significantly improve the total flow rate in porous polymer membrane, especially in the case of shear thinning fluid.

Lymphatic pump function curves in awake sheep

1996 ◽  
Vol 270 (2) ◽  
pp. R486-R488 ◽  
Author(s):  
R. E. Drake ◽  
S. Dhother ◽  
V. M. Oppenlander ◽  
J. C. Gabel
Keyword(s):  
Pressure Gradient ◽  
Mathematical Models ◽  
Flow Rate ◽  
Lymphatic Vessels ◽  
Ringer Solution ◽  
Nonlinear Flow ◽  
Flow Rates ◽  
Passive Flow ◽  
Lymphatic Pumping ◽  
The Relationship

We determined the relationship between flow rate and inflow pressure for intestinal lymphatic vessels in six sheep. First we anesthetized the sheep and cannulated both ends of a 6- to 10-cm-long segment of intestinal lymphatic. We allowed the sheep to recover from the anesthesia for 2-24 h. To determine the flow rate-inflow pressure relationship, we recorded the inflow pressure and infused Ringer solution into the lymphatic at rates from 34 to 510 microliters/min. The flow rate-pressure relationship was not linear and it had two regions. For flow rates less than approximately 150 microliters/min, inflow pressure was greater than outflow pressure. Thus the lymphatic pumped fluid against a pressure gradient. For flow rates > 150 microliters/min, inflow pressure was greater than outflow pressure, and we attributed most of the flow to the favorable inflow-outflow pressure gradient (passive flow). When we used verapamil to inhibit lymphatic pumping, we found no flow for inflow pressure less than outflow pressure, and flow increased linearly for inflow pressure greater than outflow pressure. Our data for actively pumping lymphatic vessels are consistent with the flow vs. pressure relationships derived from mathematical models of the lymphatic pump. Furthermore, our data with verapamil confirm that active lymphatic pumping was responsible for the nonlinear flow vs. pressure relationship for the lymphatic vessels.

Numerical Prediction of the Pipeline Flow Characteristics of Thixotropic Liquids

1967 ◽  
Vol 7 (04) ◽  
pp. 369-376 ◽  
Author(s):  
R.A. Ritter ◽  
J.P. Batycky
Keyword(s):  
Shear Rate ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Pressure Gradient ◽  
Rheological Properties ◽  
Flow Rate ◽  
Time Dependent ◽  
Flow Rates ◽  
Instantaneous Pressure ◽  
Pipeline Design

Abstract A numerical technique has been developed to permit establishing the pressure gradient associated with laminar flow of thixotropic liquids through long pipelines. For this purpose the pipeline is divided into a number of radial and longitudinal increments within which rheological properties of the fluid may be considered as constant at any time. Then, provided only that the fluid flow curve is defined at every duration of shear, it is possible to predict the instantaneous pressure gradient at any cross-section along the pipeline for each desired flow rate and pipe size. The technique consists of an iterative integration of shear rate to establish the appropriate value of the wall shear stress at each location. Consistency of fluid in the increment is determined by the flow history of that increment, while the radial flow) associated with variations in velocity profile is accounted for by adjusting the width and radial position of the increment. A number of pressure profiles, computed at each of several flow rates, provide a convenient basis for pipeline design and pump selection. Introduction In recent years, considerable attention has been given to predicting pressure drop associated with the isothermal laminar flow of time-independent non-Newtonian fluids in pipes and annuli. The approach generally has been m develop analytical relationships between flow rate and pressure drop based on simple constitutive models which hopefully provide an approximate description of the rheological properties of the fluid. Analytical solutions are highly desirable since the influence of all pertinent parameters can be readily determined. Unfortunately, however, this approach is restricted to simple flow geometries and frequently leads to erroneous results due to inadequacies in the model. In certain cases a solution may be obtained through applying appropriate numerical techniques For example, a digital computer program is available for predicting the velocity profile and pressure drop encountered by any Newtonian or time-independent non-Newtonian fluid flowing under laminar conditions in a cylindrical pipe or annulus. In this paper the consistency behavior of the fluid need only be described in terms of basic rheological data. Analyzing flow systems involving fluids with time-dependent rheological characteristics is considerably more complicated since substantial changes in consistency may occur because of sustained shear action. This sensitivity to shear frequently persists for several hours. Consequently, variations in pressure drop and/or flow rate resulting from the aging process and addition of unsheared or partially sheared fluid to the system must be considered for purposes of pipeline design. This paper outlines a numerical method for predicting the transient and steady-state laminar flow behavior of a thixotropic liquid in a pipeline of arbitrary length (i.e., at a specified constant flow rate, the instantaneous pressure gradient may be determined at any time after start up and at any location along the pipeline). Several such pressure gradient profiles computed at several flow rates, may be combined to produce a complete portrait of the system response. This flow portrait provides a reasonable basis for pipeline design and for selecting a suitable pump characteristic. TIME-DEPENDENT RHEOLOGICAL BEHAVIOR The most familiar time-dependent rheological properties are those exhibited by thixotropic liquids. Many of these materials, particularly thixotropic crude oils, generally display an apparent yield stress in that a finite pressure gradient is required to initiate flow. Then, under the influence of sustained shear at a constant shear rate, the consistency systematically decreases to some final limiting value. SPEJ P. 369ˆ

Comparing Piezoelectric and Electroosmotic Micropumps for Biomedical Devices

2008 ◽  
Author(s):  
Omer San ◽  
Sinan Eren Yalcin ◽  
Oktay Baysal
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Biomedical Applications ◽  
Low Voltage ◽  
Check Valve ◽  
Back Pressure ◽  
Driving Voltage ◽  
Major Drawback ◽  
Dominant Type ◽  
Flow Rates

A micropump is an essential component of a microfluidic lab-on-a-chip device, especially for their biomedical applications. Based on their actuation method to drive the fluid flow, pumps may be categorized as mechanical or non-mechanical devices. In our proposed paper, we will report our comparative study of the most promising micropumps in each of these categories: a piezoelectrically-actuated micropump (PAμP) and an electroosmotic micropump (EOμP). A PAμP requires relatively high applied voltage, but provides high flow rates and has emerged to be the dominant type of micropump in biomedical applications. A valveless diffuser-nozzle micropump, driven by an oscillating membrane, has an important advantage, since the fabrication of any additional moving part, such as a check valve, would add significantly to its cost and render a more failure-prone device. The piezoelectrically actuated, valveless micropumps use moving mechanical parts to pump fluid and control the flow with optimized actuation frequency and applied voltage. In the present study, the microflow-structure interaction in the PAμP is modeled using an arbitrary Lagrangian-Eulerian method including a parametric study of applied voltage and frequency. An EOμP consists of multiple micron-scale channels in parallel that are subjected to the electroosmotic effect. However, a major drawback in the conventional design of an EOμP is the need for a high driving voltage to increase the flow rate or to overcome the back pressure. In the present study, a low-voltage EOμP is proposed and computationally modeled. Our simulations are performed in order to study the low-voltage EOμP for its various flow rate and back pressure characteristics. In the proposed paper, we will discuss our comparisons of PAμP and EOμP, with respect to their actuation mechanisms, applied voltages, pump sizes, flow rates and back pressures.

scholarly journals Modeling of a Passive-Valve Piezoelectric Micro-Pump: A Parametric Study

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 752
Author(s):  
Akam Aboubakri ◽  
Vahid Ebrahimpour Ahmadi ◽  
Ali Koşar
Keyword(s):  
Optimum Condition ◽  
Flow Rate ◽  
Attack Angle ◽  
Design Parameters ◽  
Operating Voltage ◽  
Flow Rates ◽  
Micro Pump ◽  
Length Width ◽  
External Power ◽  
Optimum Width

Piezoelectric micro-pumps offer many applications and could provide considerable flow rates in miniature systems. This study parametrically investigates the effects of major parameters, namely the length, width and attack angle of valves, piezoelectric length, and applied voltage. The results show that these parameters significantly affect the performance of the designed micro-pump. Even though increasing the piezoelectric length and operating voltage raise the flow rate, the modification of valve dimensions is more efficient since these parameters do not rely on any external power. According to the obtained results, as the length of the working valves increases, the provided flow rate becomes larger. There is an optimum condition for the width and attack angle of the valves. This optimum width is not dependent on the flow rate. With the use of the attack angle and the length of the valves as design parameters, the studied design shows promising results.

scholarly journals Utilization of the dethridge wheel as a low head power generator and loss analysis

2018 ◽  
Vol 204 ◽  
pp. 04003
Author(s):  
Dan Mugisidi ◽  
Oktarina Heriyani ◽  
Rizal Andi Luhung ◽  
Moh. Ramdani Dwi Andrian
Keyword(s):  
Power Generation ◽  
Flow Rate ◽  
Small Scale ◽  
Flow Meter ◽  
Hydro Power ◽  
Flow Rates ◽  
Power Generator ◽  
Loss Analysis ◽  
Low Head ◽  
Water Wheel

Utilization of low head flow water has long been used to generate power by using water wheels and low head turbines. Dethridge wheel which is usually used as a tool to measure the flow of water has also been studied its potential to become hydro power generation. Therefore, this study aims to compare performance between overshot Dethridge wheel and undershot Dethridge wheel. For this purpose, a small scale channel for the operation of a water wheel is equipped with a digital flow meter, a pump that has a debit of up to 25 l/s, a pony brake for a torque meter, and an inverter to adjust the flow rate by changing the pump rotation. The research was conducted at Laboratory of Mechanical Engineering, UHAMKA in Jakarta, Indonesia. Flow rates vary from 5 to 11 l/s with head of 10 cm and 537 cm. The efficiency of undershot and overshot, at the peak, are 21% and 18%, respectively.

scholarly journals Non-linear filtration models and the effect of nonlinearity parameters on flow rates in low-permeability reservoirs

Georesursy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 44-50
Author(s):  
Mikhail Zaitsev ◽  
Nikolai Mikhailov ◽  
Ekaterina Tumanova
Keyword(s):  
Experimental Data ◽  
Pressure Gradient ◽  
Flow Rate ◽  
Initial Pressure ◽  
Low Permeability ◽  
Nonlinear Filtration ◽  
Flow Rates ◽  
Non Linear ◽  
Linear Filtration ◽  
Low Permeability Reservoirs

Filtration of oil in low-permeable reservoirs is considered. The experimental data of dependence of filtration velocity on pressure gradient are analysed. It is shown that the filtration law in low-permeability reservoirs differs from the linear Darcy’s law and from the non-linear law with an initial pressure gradient. The power law of filtration in low-permeability reservoirs is experimentally substantiated. Models of nonlinear filtration influence on flow rate are proposed. The analysis of influence of nonlinear filtration parameters on flow rate in technogenically modified near-wellbore zone is carried out.

Hydraulic model of a water cooling system in a chemical plant

1988 ◽  
Vol 53 (4) ◽  
pp. 788-806
Author(s):  
Miloslav Hošťálek ◽  
Jiří Výborný ◽  
František Madron
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Cooling Water ◽  
Graph Algorithm ◽  
Automatic Generation ◽  
Hydraulic Calculation ◽  
Return Flow ◽  
Flow Rates ◽  
Pressure Losses ◽  
Controlled Flow

Steady state hydraulic calculation has been described of an extensive pipeline network based on a new graph algorithm for setting up and decomposition of balance equations of the model. The parameters of the model are characteristics of individual sections of the network (pumps, pipes, and heat exchangers with armatures). In case of sections with controlled flow rate (variable characteristic), or sections with measured flow rate, the flow rates are direct inputs. The interactions of the network with the surroundings are accounted for by appropriate sources and sinks of individual nodes. The result of the calculation is the knowledge of all flow rates and pressure losses in the network. Automatic generation of the model equations utilizes an efficient (vector) fixing of the network topology and predominantly logical, not numerical operations based on the graph theory. The calculation proper utilizes a modification of the model by the method of linearization of characteristics, while the properties of the modified set of equations permit further decrease of the requirements on the computer. The described approach is suitable for the solution of practical problems even on lower category personal computers. The calculations are illustrated on an example of a simple network with uncontrolled and controlled flow rates of cooling water while one of the sections of the network is also a gravitational return flow of the cooling water.

scholarly journals Geometrical Optimization of a Venturi-Type Microbubble Generator Using CFD Simulation and Experimental Measurements

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 4
Author(s):  
Dillon Alexander Wilson ◽  
Kul Pun ◽  
Poo Balan Ganesan ◽  
Faik Hamad
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Air Flow ◽  
Bubble Diameter ◽  
Diameter Ratio ◽  
Experimental Measurements ◽  
Cfd Model ◽  
Flow Rates ◽  
Throat Diameter

Microbubble generators are of considerable importance to a range of scientific fields from use in aquaculture and engineering to medical applications. This is due to the fact the amount of sea life in the water is proportional to the amount of oxygen in it. In this paper, experimental measurements and computational Fluid Dynamics (CFD) simulation are performed for three water flow rates and three with three different air flow rates. The experimental data presented in the paper are used to validate the CFD model. Then, the CFD model is used to study the effect of diverging angle and throat length/throat diameter ratio on the size of the microbubble produced by the Venturi-type microbubble generator. The experimental results showed that increasing water flow rate and reducing the air flow rate produces smaller microbubbles. The prediction from the CFD results indicated that throat length/throat diameter ratio and diffuser divergent angle have a small effect on bubble diameter distribution and average bubble diameter for the range of the throat water velocities used in this study.

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