scholarly journals Nozzle-Shaped Electrode Configuration for Dielectrophoretic 3D-Focusing of Microparticles

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 585 ◽  
Author(s):  
Krishna ◽  
Alnaimat ◽  
Mathew
Keyword(s):  
Mathematical Model ◽  
Microfluidic Device ◽  
Flow Rate ◽  
Electric Potential ◽  
Performance Metrics ◽  
Volumetric Flow Rate ◽  
Electrode Configuration ◽  
Electrode Length ◽  
The Mathematical Model ◽  
Applied Electric Potential

: An experimentally validated mathematical model of a microfluidic device with nozzle-shaped electrode configuration for realizing dielectrophoresis based 3D-focusing is presented in the article. Two right-triangle shaped electrodes on the top and bottom surfaces make up the nozzle-shaped electrode configuration. The mathematical model consists of equations describing the motion of microparticles as well as profiles of electric potential, electric field, and fluid flow inside the microchannel. The influence of forces associated with inertia, gravity, drag, virtual mass, dielectrophoresis, and buoyancy are taken into account in the model. The performance of the microfluidic device is quantified in terms of horizontal and vertical focusing parameters. The influence of operating parameters, such as applied electric potential and volumetric flow rate, as well as geometric parameters, such as electrode dimensions and microchannel dimensions, are analyzed using the model. The performance of the microfluidic device enhances with an increase in applied electric potential and reduction in volumetric flow rate. Additionally, the performance of the microfluidic device improves with reduction in microchannel height and increase in microparticle radius while degrading with increase in reduction in electrode length and width. The model is of great benefit as it allows for generating working designs of the proposed microfluidic device with the desired performance metrics.

scholarly journals Modeling a Dielectrophoretic Microfluidic Device with Vertical Interdigitated Transducer Electrodes for Separation of Microparticles Based on Size

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 563 ◽  
Author(s):  
Fadi Alnaimat ◽  
Bobby Mathew ◽  
Ali Hilal-Alnaqbi
Keyword(s):  
Mathematical Model ◽  
Microfluidic Device ◽  
Separation Efficiency ◽  
Equations Of Motion ◽  
Volumetric Flow Rate ◽  
Flow Profile ◽  
Heterogeneous Mixture ◽  
Electric Voltage ◽  
Positive Dielectrophoresis ◽  
The Mathematical Model

This article conceptualizes and mathematically models a dielectrophoretic microfluidic device with two sets of interdigitated transducer vertical electrodes for separation of a binary heterogeneous mixture of particles based on size; each set of electrodes is located on the sidewalls and independently controllable. To achieve separation in the proposed microfluidic device, the small microparticles are subjected to positive dielectrophoresis and the big microparticles do not experience dielectrophoresis. The mathematical model consists of equations describing the motion of each microparticle, fluid flow profile, and electric voltage and field profiles, and they are solved numerically. The equations of motion take into account the influence of phenomena, such as inertia, drag, dielectrophoresis, gravity, and buoyancy. The model is used for a parametric study to understand the influence of parameters on the performance of the microfluidic device. The parameters studied include applied electric voltages, electrode dimensions, volumetric flow rate, and number of electrodes. The separation efficiency of the big and small microparticles is found to be independent of and dependent on all parameters, respectively. On the other hand, the separation purity of the big and small microparticles is found to be dependent on and independent of all parameters, respectively. The mathematical model is useful in designing the proposed microfluidic device with the desired level of separation efficiency and separation purity.

Design of the Stator Inner Contour for a Compressor

2005 ◽  
Author(s):  
Yuan Mao Huang ◽  
Chen Sheng Chung
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Rotary Compressor ◽  
Envelope Theorem ◽  
Motion Characteristics ◽  
The Mathematical Model

A rotary compressor with a single sliding-vane was designed. A specific stator inner contour was designed by using the envelope theorem for the vane to have good motion characteristics. The mathematical model was generated, and the stator contour with three lobes was selected for a specified volumetric flow rate.

scholarly journals Analysis of the Binding of Analyte-Receptor in a Micro-Fluidic Channel for a Biosensor Based on Brownian Motion

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 570
Author(s):  
Sunghak Choi ◽  
Woo Il Lee ◽  
Gyu Hee Lee ◽  
Yeong-Eun Yoo
Keyword(s):  
Mathematical Model ◽  
Brownian Motion ◽  
Flow Rate ◽  
Channel Height ◽  
Micro Channel ◽  
Analyte Concentration ◽  
Fluidic Channel ◽  
Binding Characteristics ◽  
Detection Characteristics ◽  
The Mathematical Model

This study experimentally analyses the binding characteristics of analytes mixed in liquid samples flowing along a micro-channel to the receptor fixed on the wall of the micro-channel to provide design tools and data for a microfluidic-based biosensor. The binding or detection characteristics are analyzed experimentally by counting the number of analytes bound to the receptor, with sample analyte concentration, sample flow rate, and the position of the receptor along the micro-channel length as the main variables. A mathematical model is also proposed to predict the number of analytes transported and bound to the receptor based on a probability density function for Brownian motion. The coefficient in the mathematical model is obtained by using a dimensionless mathematical model and the experimental results. The coefficient remains valid for all different conditions of the sample analyte concentration, flow rate, and the position of the receptor, which implies the possibility of deriving a generalized model. Based on the mathematical model derived from mathematical and experimental analysis on the detection characteristics of the microfluidic-based biosensor depending on previously mentioned variables and the height of the micro-channel, this study suggests a design for a microfluidic-based biosensor by predicting the binding efficiency according to the channel height. The results show the binding efficiency increases as the flow rate decreases and as the receptor is placed closer to the sample-injecting inlet, but is unaffected by sample concentration.

scholarly journals Dielectrophoretic Microfluidic Device for Separating Microparticles Based on Size with Sub-Micron Resolution

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 653
Author(s):  
Salini Krishna ◽  
Fadi Alnaimat ◽  
Ali Hilal-Alnaqbi ◽  
Saud Khashan ◽  
Bobby Mathew
Keyword(s):  
Mathematical Model ◽  
Microfluidic Device ◽  
Separation Efficiency ◽  
Finite Size ◽  
Dielectrophoretic Force ◽  
Degree Of Separation ◽  
Two Samples ◽  
Downstream Section ◽  
Polystyrene Microparticles ◽  
The Mathematical Model

This article details the mathematical model of a microfluidic device aimed at separating any binary heterogeneous sample of microparticles into two homogeneous samples based on size with sub-micron resolution. The device consists of two sections, where the upstream section is dedicated to focusing of microparticles, while the downstream section is dedicated to separation of the focused stream of microparticles into two samples based on size. Each section has multiple planar electrodes of finite size protruding into the microchannel from the top and bottom of each sidewall; each top electrode aligns with a bottom electrode and they form a pair leading to multiple pairs of electrodes on each side. The focusing section subjects all microparticles to repulsive dielectrophoretic force, from each set of the electrodes, to focus them next to one of the sidewalls. This separation section pushes the big microparticles toward the interior, away from the wall, of the microchannel using repulsive dielectrophoretic force, while the small microparticles move unaffected to achieve the desired degree of separation. The operating frequency of the set of electrodes in the separation section is maintained equal to the cross-over frequency of the small microparticles. The working of the device is demonstrated by separating a heterogeneous mixture consisting of polystyrene microparticles of different size (radii of 2 and 2.25 μm) into two homogeneous samples. The mathematical model is used for parametric study, and the performance is quantified in terms of separation efficiency and separation purity; the parameters considered include applied electric voltages, electrode dimensions, outlet widths, number of electrodes, and volumetric flowrate. The separation efficiencies and separation purities for both microparticles are 100% for low volumetric flow rates, a large number of electrode pairs, large electrode dimensions, and high differences between voltages in both sections.

Low-cost flow-rate estimate in separate layers along gas wells from temperature and pressure profiles

2013 ◽  
Vol 53 (1) ◽  
pp. 285
Author(s):  
Emile Barrett ◽  
Imran Abbasy ◽  
Chii-Rong Wu ◽  
Zhenjiang You ◽  
Pavel Bedrikovetsky
Keyword(s):  
Thermal Conductivity ◽  
Mathematical Model ◽  
Flow Rate ◽  
Low Cost ◽  
Pressure Sensors ◽  
Gas Wells ◽  
Production Rates ◽  
Pressure Profiles ◽  
Temperature And Pressure ◽  
The Mathematical Model

Estimation of rate profile along the well is important information for reservoir characterisation since it allows distinction of the production rates from different layers. The temperature and pressure sensors in a well are small and inexpensive; while flow meters are cumbersome and expensive, and affect the flow in the well. The method presented in this peer-reviewed paper shows its significance in predicting the gas rate from temperature and pressure data. A mathematical model for pressure and temperature distributions along a gas well has been developed. Temperature and pressure profiles from nine well intervals in field A (Cooper Basin, Australia) have been matched with the mathematical model to determine the flow rates from different layers in the well. The presented model considers the variables as functions of thermal properties at each location, which is more accurate and robust than previous methods. The results of tuning the mathematical model to the field data show good agreement with the model prediction. Simple and robust explicit formulae are derived for the effective estimation of flow rate and thermal conductivity in gas wells. The proposed approach has been applied to determine the well gas rate and formation thermal conductivity from the acquired well pressure and temperature data in field A. It allows for recommending well stimulation of layers with low production rates.

MATHEMATICAL MODELING OF BLOOD FLOW IN A POROUS VESSEL HAVING DOUBLE STENOSES IN THE PRESENCE OF AN EXTERNAL MAGNETIC FIELD

2011 ◽  
Vol 04 (02) ◽  
pp. 207-225 ◽  
Author(s):  
J. C. MISRA ◽  
A. SINHA ◽  
G. C. SHIT
Keyword(s):  
Mathematical Modeling ◽  
Magnetic Field ◽  
Mathematical Model ◽  
Blood Flow ◽  
Shear Stress ◽  
External Magnetic Field ◽  
Volumetric Flow Rate ◽  
Hematocrit Level ◽  
Flow Through ◽  
The Mathematical Model

In this paper, a mathematical model has been developed for studying blood flow through a porous vessel with a pair of stenoses under the action of an externally applied magnetic field. Blood flowing through the artery is considered to be Newtonian. This model is consistent with the principles of ferro-hydrodynamics and magnetohydrodynamics. Expressions for the velocity profile, volumetric flow rate, wall shear stress and pressure gradient have been derived analytically under the purview of the model. The above said quantities are computed for a specific set of values of the different parameters involved in the model analysis. This serves as an illustration of the validity of the mathematical model developed here. The results estimated on the basis of the computation are presented graphically. The obtained results for different values of the parameters involved in the problem under consideration, show that the flow is appreciably influenced by the presence of magnetic field and the rise in the hematocrit level.

scholarly journals Mathematical model of a steam turbine condenser

2021 ◽  
Vol 80 (2) ◽  
pp. 41-46
Author(s):  
N. G. Borissova ◽  
◽  
M. D. Shavdinova ◽  
Keyword(s):  
Mathematical Model ◽  
Vapor Pressure ◽  
Steam Turbine ◽  
Flow Rate ◽  
Cooling Water ◽  
Calculation Methods ◽  
Turbine Condenser ◽  
Passport Data ◽  
Steam Turbine Condenser ◽  
The Mathematical Model

The paper analyses the existing calculation methods for steam turbine condenser. The refined methods for calculating the condenser have also been considered. The dependency of the vapor pressure in the condenser on the temperature of the cooling water and the steam flow rate into the condenser have been considered. It can be seen from the obtained dependencies that the calculation of the condenser according to the ARTI and HEI (USA) methods coincides with the passport data. It is recommended to use the ARTI and HEI (USA) techniques for equipment diagnostics, and to use the KTP and USTU-UPI techniques when studying ways to increase the efficiency of the condenser. The mathematical model of the KG2-6200 condenser has been tested at the Almaty СHPP-2.

Sea Water Pump Station Basin Mathematical Hydraulic Model Test (CFD Analysis)

2009 ◽  
Author(s):  
Sadegh Barzegar ◽  
Alireza Elhami Amiri ◽  
Pooyan Rahbar ◽  
Mehdi Assadi Niazi
Keyword(s):  
Mathematical Model ◽  
Free Surface ◽  
Model Test ◽  
Flow Rate ◽  
Sea Water ◽  
Water Pump ◽  
Pumping Station ◽  
Water Pumping ◽  
Pump Station ◽  
The Mathematical Model

Background and aim: A sea water intake, with original design of the six drum screen and twenty sea water pump intake with very different flow rate connected to header bay. The capacity of Origin Sea water intake including huge pump station and drum screen is 200,000 m3/hr. The purpose of the mathematical hydraulic model test of the sea water pumping station is to verify that the basin allows a good operating condition for each pump. To ensure a good operating condition for each pump, the design of the seawater basin has to insure: • A correct filter working; • Low transversal velocities; • A flow without vortex. Method and material: The mathematical model of the basin allows to know the flow and to verify: • The main dimensions of the pumping station; • The distance between the inlet ducts and the filters; • The distance between the filters and pump chambers. Result: in the first basin, the flow patterns no problems. Only swirl at the exit of culverts and near the free surface, and two areas where the flow has no velocity were observed. In the downstream other filters, we observe also a circulation that generates a tangential velocity. Conclusion: The mathematical model of the sea water pumping station has allowed calculating three cases (without and with filter stopped) for the low water level and nominal flow rate. In most difficult case, we observe some recirculation, mainly near the free surface, without more influence on principal flow. In the three cases, the distribution of the flow rate between the drum screens is uniform; the gap is inferior to 2%. At the entry of the pump chambers, the velocity fluctuations and the angle are low. Consequently, the secondary flows in pump chambers will be limited.

Experimental and Theoretic Research on Solar Power Membrane Distillation

2010 ◽  
Vol 97-101 ◽  
pp. 2300-2305
Author(s):  
Hong Jiang Cui ◽  
Pei Ting Sun ◽  
Ming Hai Li
Keyword(s):  
Mathematical Model ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Solar Power ◽  
Membrane Distillation ◽  
Working Fluid ◽  
Air Gap Membrane Distillation ◽  
The Mathematical Model

Air gap membrane distillation experiments of different temperature and mass flow rate of working fluid were done for the use of solar power and setting up the mathematical model of AGMD’ heat and mass transfer. The calculation correctness of mathematical model was discussed and the thermal efficiency of membrane distillation system was calculated. The results showed that the experimental flux of membrane distillation reached 49kg/m2•h and the biggest relative error is less than 9% between results of experiment and mathematical model calculation. The mathematical model can be used to forecast the process parameters of membrane distillation. The highest thermal efficiency of this system is 68% and the main influencing factors of thermal efficiency are temperature and mass flow rate of working fluid.

The Design and Analyses of Magnetorheological Fluid Throttle Valve

2011 ◽  
Vol 383-390 ◽  
pp. 1208-1214
Author(s):  
Rong Wu ◽  
Wen Xiang Lin ◽  
Wen Tang
Keyword(s):  
Mathematical Model ◽  
Computational Model ◽  
Flow Rate ◽  
Electromagnetic Induction ◽  
Fluid Model ◽  
Scientific Research ◽  
Magnetorheological Fluid ◽  
Research Field ◽  
Throttle Valve ◽  
The Mathematical Model

Magnetorheological (MR) Fluid is an intellectual material with comprehensive prospect. In recent years, it is widely attended in the scientific-research field. Flow rate computational model of the MR throttle valve is derived by using Binham fluid model. The mathematical model of electromagnetic induction intensity for the MR throttle valve is established. The designed magnetorheological throttle valve is simple, compact and has some creativity. Proposed use of magnetorheological hydraulic components presents a problem.

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