This document summarizes a study on magnetohydrodynamic (MHD) flow in parallel pipes with parallel and counter flow patterns using computational fluid dynamics (CFD) analysis. The study models liquid metal flow through two parallel pipes with either parallel or counter flow, subjected to a magnetic field. For parallel flow, the velocity profile at the centerline shows higher velocities at the ends and lower velocity in the middle due to current flow patterns. For counter flow, the centerline velocity profile is inverted with higher velocity in the middle. Current density profiles also differ between the two flow patterns. The CFD analysis was performed using ANSYS Fluent software to analyze the effects of MHD on velocity profile, pressure, and current density for
Effect of Mobility on (I-V) Characteristics of Gaas MESFET Yayah Zakaria
We present in this paper an analytical model of the current–voltage (I-V) characteristics for submicron GaAs MESFET transistors. This model takes into account the analysis of the charge distribution in the active region and incorporate a field depended electron mobility, velocity saturation and charge
build-up in the channel. We propose in this frame work an algorithm of simulation based on mathematical expressions obtained previously. We propose a new mobility model describing the electric field-dependent. predictions of the simulator are compared with the experimental data [1] and
have been shown to be good.
Central Electric Field and Threshold Voltage in Accumulation Mode Junctionles...IJECEIAES
Transfer characteristics is presented using analytical potential distribution of accumulation-mode junctionless cylindrical surrounding-gate (JLCSG) MOSFET, and deviation of center electric field at threshold voltage is analyzed for channel length and oxide thickness. Threshold voltages presented in this paper is good agreement with results of other compared papers, and transfer characteristics is agreed with those of two-dimensional simulation. The most important factor to determine threshold voltage is center electric field at source because the greater part of electron flows through center axis of JLCSG MOSFET. As a result of analysis for center electric field at threshold voltage, center electric field is decreased with reduction of channel length due to drain induced barrier lowering. Center electric field is increased with decrease of oxide thickness, and deviation of center electric field for channel length is significantly occurred with decrease of oxide thickness.
This paper presents a study on a new full bridge series resonant converter (SRC) with wide zero voltage switching (ZVS) range, and higher output voltage. The high frequency transformer is connected in series with the LC series resonant tank. The tank inductance is therefore increased; all switches having the ability to turn on at ZVS, with lower switching frequency than the LC tank resonant frequency. Moreover, the step-up high frequency (HF) transformer design steps are introduced in order to increase the output voltage to overcome the gain limitation of the conventional SRC. Compared to the conventional SRC, the proposed converter has higher energy conversion, able to increase the ZVS range by 36%, and provide much higher output power. Finally, the a laboratory prototypes of the both converters with the same resonant tank parameters and input voltage are examined based on 1 and 2.2 kW power respectively, for veryfing the reliability of the performance and the operation principles of both converters.
Effect of Mobility on (I-V) Characteristics of Gaas MESFET Yayah Zakaria
We present in this paper an analytical model of the current–voltage (I-V) characteristics for submicron GaAs MESFET transistors. This model takes into account the analysis of the charge distribution in the active region and incorporate a field depended electron mobility, velocity saturation and charge
build-up in the channel. We propose in this frame work an algorithm of simulation based on mathematical expressions obtained previously. We propose a new mobility model describing the electric field-dependent. predictions of the simulator are compared with the experimental data [1] and
have been shown to be good.
Central Electric Field and Threshold Voltage in Accumulation Mode Junctionles...IJECEIAES
Transfer characteristics is presented using analytical potential distribution of accumulation-mode junctionless cylindrical surrounding-gate (JLCSG) MOSFET, and deviation of center electric field at threshold voltage is analyzed for channel length and oxide thickness. Threshold voltages presented in this paper is good agreement with results of other compared papers, and transfer characteristics is agreed with those of two-dimensional simulation. The most important factor to determine threshold voltage is center electric field at source because the greater part of electron flows through center axis of JLCSG MOSFET. As a result of analysis for center electric field at threshold voltage, center electric field is decreased with reduction of channel length due to drain induced barrier lowering. Center electric field is increased with decrease of oxide thickness, and deviation of center electric field for channel length is significantly occurred with decrease of oxide thickness.
This paper presents a study on a new full bridge series resonant converter (SRC) with wide zero voltage switching (ZVS) range, and higher output voltage. The high frequency transformer is connected in series with the LC series resonant tank. The tank inductance is therefore increased; all switches having the ability to turn on at ZVS, with lower switching frequency than the LC tank resonant frequency. Moreover, the step-up high frequency (HF) transformer design steps are introduced in order to increase the output voltage to overcome the gain limitation of the conventional SRC. Compared to the conventional SRC, the proposed converter has higher energy conversion, able to increase the ZVS range by 36%, and provide much higher output power. Finally, the a laboratory prototypes of the both converters with the same resonant tank parameters and input voltage are examined based on 1 and 2.2 kW power respectively, for veryfing the reliability of the performance and the operation principles of both converters.
ANALYSIS OF SMALL-SIGNAL PARAMETERS OF 2-D MODFET WITH POLARIZATION EFFECTS F...VLSICS Design
An improved analytical two dimensional (2-D) model for AlGaN/GaN modulation doped field effect
transistor (MODFET) has been developed. The model is based on the solution of 2-D Poisson’s equation.
The model includes the spontaneous and piezoelectric polarization effects. The effects of field dependent
mobility, velocity saturation and parasitic resistances are included in the current voltage characteristics of
the developed two dimensional electron gas (2-DEG) model. The small-signal microwave parameters have
been evaluated to determine the output characteristics, device transconductance and cut-off frequency for
50 nm gate length. The peak transconductance of 165mS/mm and a cut-off frequency of 120 GHz have been
obtained. The results so obtained are in close agreement with experimental data, thereby proving the
validity of the model.
Effect of mesh grid structure in reducing hot carrier effect of nmos device s...ijcsa
This paper presents the critical effect of mesh grid that should be considered during process and device
simulation using modern TCAD tools in order to develop and optimize their accurate electrical
characteristics. Here, the computational modelling process of developing the NMOS device structure is
performed in Athena and Atlas. The effect of Mesh grid on net doping profile, n++, and LDD sheet
resistance that could link to unwanted “Hot Carrier Effect” were investigated by varying the device grid
resolution in both directions. It is found that y-grid give more profound effect in the doping concentration,
the junction depth formation and the value of threshold voltage during simulation. Optimized mesh grid is
obtained and tested for more accurate and faster simulation. Process parameter (such as oxide thicknesses
and Sheet resistance) as well as Device Parameter (such as linear gain “beta” and SPICE level 3 mobility
roll-off parameter “ Theta”) are extracted and investigated for further different applications.
Quantum Current in Graphene Nano Scrolls Based Transistortheijes
Graphene based material application as a new centuery material are growing rappidly its carrier transport phenomenon with fast mobility have been focused resently. In the graphene family nanoscrolls because of their especial structure need to be explored. In the presented work a theoretical model for carrier transport in the arcemedus graphene nanoscrolls is reported. Graphene nanoscroll chairal dependent electrical property is considered and then schottky transistor based platform is modeled. The transport coeficient as a fundamental transport factor is discussed. The geometrical paprameter effect on the working phenomenon is considered as well.
The main stake is to detect a defective component or likely to become it during manufacture or inservice inspections, while improving control productivity. In this context, we develop a simulation tool of EC fastened structures testing, integrated to the ANSYS platform, aimed at conceiving testing methods, optimizing and qualifying it. The finite element method has been chosen, it is suitable for this type of problem. Various configurations have been considered for the inspection of a target with a defect in different thicknesses. Due to the impossibility to detect a defect located at a distance much greater than the skin depth δ. Indeed, the eddy currents amplitude are less than 95% of the maximum amplitude beyond a depth greater than 3 δ. We are interested in the detection of defects located at depths higher to three times the skin depth.
Algorithm for Fault Location and Classification on Parallel Transmission Line...IJECEIAES
This paper proposed a new algorithm for fault location and classification using wavelet based on Clarke’s transformation to obtain the fault current. This novel method of fault current approach is studied by comparing the use of the glide path of the fault voltage. The current alpha and beta (Current Mode) were used to transform the signal using discrete wavelet transform (DWT). The fault location was determined by using the Clarke’s transformation, and then turned into a wavelet, which was very precise and thorough. The most accurate was the mother wavelet Db4 which had the fastest time and smallest error detection when compared with the other wavelet mothers. In this study, the Clarke’s transformation is also compared with the Karenbauer’s, which has produced results with similar error percentage. The simulation results using PSCAD / EMTDC software showed that the proposed algorithm could distinguish internal and external faults to get the current signal in the transformation of a signal fault.
Comparision of flow analysis through a different geometry of flowmeters using...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Thermohydraulic Performance of a Series of In-Line Noncircular Ducts in a Par...Carnegie Mellon University
Heat transfer and fluid flow characteristics for two-dimensional laminar flow at low Reynolds number for five in-line ducts of
various nonconventional cross-sections in a parallel plate channel are studied in this paper.The governing equations were solved
using finite-volumemethod.CommercialCFDsoftware,ANSYS Fluent 14.5,was used to solve this problem.Atotal of three different
nonconventional, noncircular cross-section ducts and their characteristics are compared with those of circular cross-section ducts.
Shape-2 ducts offered minimum flow resistance and maximum heat transfer rate most of the time. Shape-3 ducts at Re < 100 and Shape-2 ducts at Re > 100 can be considered to give out the optimum results.
In this paper a novel control technique for switching-frequency-modulated switch-mode power converters (SMPC) operating in discontinuous conduction mode is proposed. The use of the technique leads to significant reduction in peak-to-peak output voltage and peak currents increased due to straightforward application of switching frequency modulation (SFM). The technique is based on hybrid modulation scheme in which both switching frequency and duty ratio are modulated simultaneously by the same modulation signal. Theoretical analysis and experimental verification of the proposed technique are presented in details. Both computer simulations and experiments show that switching-frequency-modulated SMPC with the proposed control technique in comparison to SMPC without SFM has appreaciably lower conducted electromagnetic emissions, at the cost of slightly increased peak-to-peak output voltage and peak currents.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
ANALYSIS OF SMALL-SIGNAL PARAMETERS OF 2-D MODFET WITH POLARIZATION EFFECTS F...VLSICS Design
An improved analytical two dimensional (2-D) model for AlGaN/GaN modulation doped field effect
transistor (MODFET) has been developed. The model is based on the solution of 2-D Poisson’s equation.
The model includes the spontaneous and piezoelectric polarization effects. The effects of field dependent
mobility, velocity saturation and parasitic resistances are included in the current voltage characteristics of
the developed two dimensional electron gas (2-DEG) model. The small-signal microwave parameters have
been evaluated to determine the output characteristics, device transconductance and cut-off frequency for
50 nm gate length. The peak transconductance of 165mS/mm and a cut-off frequency of 120 GHz have been
obtained. The results so obtained are in close agreement with experimental data, thereby proving the
validity of the model.
Effect of mesh grid structure in reducing hot carrier effect of nmos device s...ijcsa
This paper presents the critical effect of mesh grid that should be considered during process and device
simulation using modern TCAD tools in order to develop and optimize their accurate electrical
characteristics. Here, the computational modelling process of developing the NMOS device structure is
performed in Athena and Atlas. The effect of Mesh grid on net doping profile, n++, and LDD sheet
resistance that could link to unwanted “Hot Carrier Effect” were investigated by varying the device grid
resolution in both directions. It is found that y-grid give more profound effect in the doping concentration,
the junction depth formation and the value of threshold voltage during simulation. Optimized mesh grid is
obtained and tested for more accurate and faster simulation. Process parameter (such as oxide thicknesses
and Sheet resistance) as well as Device Parameter (such as linear gain “beta” and SPICE level 3 mobility
roll-off parameter “ Theta”) are extracted and investigated for further different applications.
Quantum Current in Graphene Nano Scrolls Based Transistortheijes
Graphene based material application as a new centuery material are growing rappidly its carrier transport phenomenon with fast mobility have been focused resently. In the graphene family nanoscrolls because of their especial structure need to be explored. In the presented work a theoretical model for carrier transport in the arcemedus graphene nanoscrolls is reported. Graphene nanoscroll chairal dependent electrical property is considered and then schottky transistor based platform is modeled. The transport coeficient as a fundamental transport factor is discussed. The geometrical paprameter effect on the working phenomenon is considered as well.
The main stake is to detect a defective component or likely to become it during manufacture or inservice inspections, while improving control productivity. In this context, we develop a simulation tool of EC fastened structures testing, integrated to the ANSYS platform, aimed at conceiving testing methods, optimizing and qualifying it. The finite element method has been chosen, it is suitable for this type of problem. Various configurations have been considered for the inspection of a target with a defect in different thicknesses. Due to the impossibility to detect a defect located at a distance much greater than the skin depth δ. Indeed, the eddy currents amplitude are less than 95% of the maximum amplitude beyond a depth greater than 3 δ. We are interested in the detection of defects located at depths higher to three times the skin depth.
Algorithm for Fault Location and Classification on Parallel Transmission Line...IJECEIAES
This paper proposed a new algorithm for fault location and classification using wavelet based on Clarke’s transformation to obtain the fault current. This novel method of fault current approach is studied by comparing the use of the glide path of the fault voltage. The current alpha and beta (Current Mode) were used to transform the signal using discrete wavelet transform (DWT). The fault location was determined by using the Clarke’s transformation, and then turned into a wavelet, which was very precise and thorough. The most accurate was the mother wavelet Db4 which had the fastest time and smallest error detection when compared with the other wavelet mothers. In this study, the Clarke’s transformation is also compared with the Karenbauer’s, which has produced results with similar error percentage. The simulation results using PSCAD / EMTDC software showed that the proposed algorithm could distinguish internal and external faults to get the current signal in the transformation of a signal fault.
Comparision of flow analysis through a different geometry of flowmeters using...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Thermohydraulic Performance of a Series of In-Line Noncircular Ducts in a Par...Carnegie Mellon University
Heat transfer and fluid flow characteristics for two-dimensional laminar flow at low Reynolds number for five in-line ducts of
various nonconventional cross-sections in a parallel plate channel are studied in this paper.The governing equations were solved
using finite-volumemethod.CommercialCFDsoftware,ANSYS Fluent 14.5,was used to solve this problem.Atotal of three different
nonconventional, noncircular cross-section ducts and their characteristics are compared with those of circular cross-section ducts.
Shape-2 ducts offered minimum flow resistance and maximum heat transfer rate most of the time. Shape-3 ducts at Re < 100 and Shape-2 ducts at Re > 100 can be considered to give out the optimum results.
In this paper a novel control technique for switching-frequency-modulated switch-mode power converters (SMPC) operating in discontinuous conduction mode is proposed. The use of the technique leads to significant reduction in peak-to-peak output voltage and peak currents increased due to straightforward application of switching frequency modulation (SFM). The technique is based on hybrid modulation scheme in which both switching frequency and duty ratio are modulated simultaneously by the same modulation signal. Theoretical analysis and experimental verification of the proposed technique are presented in details. Both computer simulations and experiments show that switching-frequency-modulated SMPC with the proposed control technique in comparison to SMPC without SFM has appreaciably lower conducted electromagnetic emissions, at the cost of slightly increased peak-to-peak output voltage and peak currents.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
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THE EFFECTS OF UNIFORM TRANSVERSE MAGNETIC FIELD ON LOCAL FLOW AND VELOCITY P...IAEME Publication
A numerical model studied the effects of uniform transverse magnetic field for two fluids (pure water and water with electric conductivity), two different non-magnetizable duct and two flow velocities (steady flow for laminar and incompressible) was examined and The results showed an increase in the magnetic field caused a decrease in the local flow and effected on velocity profile. The result also showed that the water with electrical conductivity more affected than pure water.
International Journal of Mathematics and Statistics Invention (IJMSI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJMSI publishes research articles and reviews within the whole field Mathematics and Statistics, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
International Journal of Mathematics and Statistics Invention (IJMSI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJMSI publishes research articles and reviews within the whole field Mathematics and Statistics, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The Effect of High Zeta Potentials on the Flow Hydrodynamics in Parallel-Plat...CSCJournals
This paper investigates the effect of the EDL at the solid-liquid interface on the liquid flow through a micro-channel formed by two parallel plates. The complete Poisson-Boltzmann equation (without the frequently used linear approximation) was solved analytically in order to determine the EDL field near the solid-liquid interface. The momentum equation was solved analytically taking into consideration the electrical body force resulting from the EDL field. Effects of the channel size and the strength of the zeta-potential on the electrostatic potential, the streaming potential, the velocity profile, the volume flow rate, and the apparent viscosity are presented and discussed. Results of the present analysis, which are based on the complete Poisson-Boltzmann equation, are compared with a simplified analysis that used a linear approximation of the Poisson-Boltzmann equation.
Magneto-Convection of Immiscible Fluids in a Vertical Channel Using Robin Bou...IJERA Editor
The effects of viscous dissipation on fully developed two fluid magnetohydrodynamic flow in the presence of
constant electric field in a vertical channel is investigated using Robin boundary conditions. The fluids in both
the regions are incompressible, electrically conducting and the transport properties are assumed to be constant.
The plate exchanges heat with an external fluid. Both conditions of equal and different reference temperatures of
the external fluid are considered. First, the simple cases of the negligible Brinkman number or the negligible
Grashof number are solved analytically. Then, the combined effects of buoyancy forces and viscous dissipation
are analyzed by a perturbation series method valid for small values of perturbation parameter. To relax the
condition on the perturbation parameter, the flow fields are solved by using the differential transform method.
The results are presented graphically for different values of the mixed convection parameter, Hartman number,
perturbation parameter, viscosity ratio, width ratio, conductivity ratio and Biot numbers for both open and short
circuit. The effects of these parameters on the Nusselt number at the walls is also drawn. It is found that the
solutions obtained by perturbation method and differential transform method agree very well for small values of
perturbation parameter.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
MHD Nanofluid Flow Analysis in a Semi-Porous Channel by a Combined Series Sol...A Behzadmehr
In this paper, Least Square Method (LSM) and Differential Transformation Method (DTM) are used to solve the problem of laminar nanofluid flow in a semi-porous channel in the presence of transverse magnetic field. Due to existence some shortcomings in each method, a novel and efficient method named LS-DTM is introduced which omitted those defects and has an excellent agreement with numerical solution. In the present study, the effective thermal conductivity and viscosity of nanofluid are calculated by Maxwell–Garnetts (MG) and Brinkman models, respectively. The influence of the three dimensionless numbers: the nanofluid volume friction, Hartmann number and Reynolds number on non-dimensional velocity profile are considered. The results show that velocity boundary layer thickness decrease with increase of Reynolds number and nanoparticle volume friction and it increases as Hartmann number increases.
Similarity Solution of an Unsteady Heat and Mass Transfer Boundary Layer Flow...iosrjce
The unsteady hydromagnetic boundary layer flow of an incompressible and electrically conducting
fluid through a porous medium bounded by a moving surface has been considered. It is assumed that the moving
surface has a velocity profile with respect to time and fluid flow is taken under the influence of a transverse
magnetic field. The similarity solution is used to transform the system of partial differential equations,
describing the problem under consideration, into a boundary value problem of coupled ordinary differential
equations and an efficient numerical technique is implemented to solve the reduced system. The effects of the
parameters such as Magnetic parameter, Prandtl number and Eckert number are discussed graphically on
velocity and temperature distributions
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The understanding of two-phase flow and heat transfer
with phase change in minichannels is needed for the design and
optimization of heat exchangers and other industrial
applications. In this study a three-dimensional numerical model
has been developed to predict filmwise condensation heat
transfer inside a rectangular minichannel. The Volume of Fluid
(VOF) method is used to track the vapor-liquid interface. The
modified High Resolution Interface Capture (HRIC) scheme is
employed to keep the interface sharp. The governing equations
and the VOF equation with relevant source terms for
condensation are solved. The surface tension is taken into
account in the modeling and it is evaluated by the Continuum
Surface Force (CSF) approach. The simulation is performed
using the CFD software package, ANSYS FLUENT, and an inhouse
developed code. This in-house code is specifically
developed to calculate the source terms associated with phase
change. These terms are deduced from Hertz-Knudsen equation
based on the kinetic gas theory. The numerical results are
validated with data obtained from the open literature. The
standard k-ω model is applied to model the turbulence through
both the liquid and vapor phase. The numerical results show
that surface tension plays an important role in the condensation
heat transfer process. Heat transfer enhancement is obtained
due to the presence of the corners. The surface tension pulls the
liquid towards the corners and reduces the average thermal
resistance in the cross section.
Magnetohydrodynamic mixed convection flow and boundary layer control of a nan...IAEME Publication
This research work is focused on the numerical solution of steady MHD mixed convection boundary layer flow of a nanofluid over a semi-infinite flat plate with heat generation/absorption and viscous dissipation effects in the presence of suction and injection. Gyarmati’s variational principle developed on the thermodynamic theory of irreversible processes is employed to solve the problem
numerically. The governing boundary layer equations are approximated as simple polynomial functions, and the functional of the variational principle is constructed.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The steady laminar two dimensional stagnation point flow of an incompressible electrically conducting magneto-micropolar fluid over a permeable stretching surface with heat source/sink and viscous dissipation in the presence of mass transfer and chemical reaction has been studied. Using the similarity transformations, the governing equations have been transformed into a system of ordinary differential equations. These differential equations are highly nonlinear which cannot be solved analytically. Therefore, forth order Runge-Kutta method along with shooting technique has been used for solving it. Numerical results are obtained for the skin-friction coefficient, the local Nusselt number and Sherwood number as well as the velocity, temperature and concentration profiles for different values of the governing parameters, namely, velocity ratio parameter, boundary parameter, material parameter, magnetic parameter, Prandtl number, Eckert number, heat source/sink parameter, Schmidt number and chemical reaction parameter.
MHD Stagnation Point Flow of A MICROPOLAR Fluid over a Stretching Surface wit...
Ja3116861689
1. Prof. Dhumal Vishal S., Prof. Kulkarni Mohan M. / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1686-1689
Study of MHD Flow in Parallel Pipe with Parallel and Counter
Flow Pattern Using CFD Analysis
Prof. Dhumal Vishal S. Prof. Kulkarni Mohan M.
Assistant professor, Automobile Department IOK COE, Pune, Maharashtra, India
Assistant professor, Mechanical Department IOK COE, Pune, Maharashtra, India
Abstract—
Magneto hydrodynamics is the study of research in engineering by using MHD analysis of
interaction of moving conducting fluids with electrically conducting fluid can be done. The
electric and magnetic fields. Effects from such electrically conducting fluids are like plasmas, liquid
interactions can be observed in liquids, gases, two- metal like Pb-Li, salt water, etc.
phase mixtures, or plasma. MHD technology is Now this electric current in the liquid metal and
based on a fundamental law of electromagnetism: applied magnetic field induces the Lorenz force which
When a magnetic field and an electric current is in opposite direction of flow at core of channel. This
intersect in a liquid, their repulsive intersection will retards the velocity of flow at core and to balance
propels the liquid in a direction perpendicular to the mass conservation the flow, velocity increases
both the field and the current. At the time of near the boundary of fluid due to Lorentz force will
studying flow through parallel channels in parallel act in direction of flow at boundary. Hence the
and counter manner then it shows difference in velocity profile shows ‘M’ like shape. As in this
basic nature of velocity profile. Similarly the analysis flow of liquid is in parallel channel due to
current density profile is also showing interesting that there is short circuiting of current is taken place.
difference for parallel flow and counter flow fluids. Mixing of current in the wall make impact on velocity
This paper is produced to make focus on the profile. For parallel flow as well as for counter flow it
difference of several properties like current shows different nature of velocity profile, pressure and
density, velocity etc. When there is change in current density.
velocities of MHD fluid and change in magnetic
field applied then proportionate change is II. GOVERNING EQUATIONS OF MHD
appeared in all profiles and results. Here in this Governing equations of MHD is given by the
paper for studying MHD impact on fluid flow, fundamental CFD equations after coupling with
CFD analysis is carried out with the help of Ansys Maxwell’s equations and generalise Ohm’s law. Mass
FLUENT Software. conservation equation for incompressible fluids is
gives as,
Keywords- Magneto hydrodynamic, parallel and ∇. U = 0
counter manner, CFD analysis, current density & The conservation of momentum gives rise to
velocity Profile, Ansys FLUENT. Navier-Stroke’s equation as follows,
∂ρU
I. INTRODUCTION + ∇. ρUU = −∇p + ∇. ϑ∇U + J × B
∂t
Magneto-Hydrodynamics (MHD) is the Where, J × B is the Lorentz force density.
combination of the fluid mechanics and the
electrodynamics which deals with study of flows of The generalise Ohm’s law is written as,
electrically conducting fluids which are subjected to
magnetic field. The fundamental concept behind MHD J = σ(E + U × B)
Maxwell’s equation can write as,
is that when magnetic fields is applied to moving
electrically conducting fluid there is voltage difference ∇ × B = μmJ
is produced, which can induce electrical currents in a There are 2 methods for solving MHD problems
moving electrically conductive fluid. This electrical depending on the nature of magnetic field taking into
current and magnetic field in turn creates forces which consideration, one is Magnetic Induction method and
act on the fluid and also changes the magnetic field another is Electrical Potential method. Here problem
itself. is analyzed with the help of Electric Potential Method.
Basically MHD equation is the combination of
the Navier-Stokes equations of fluid III. PROBLEM DEFINITION
dynamics and Maxwell's For the study of MHD effect on the parallel
equations of electromagnetism. Now a day’s MHD is channel having combined wall structure with parallel
very vastly growing branch whose principle can be and counter flow, here CFD analysis is carried out
applied to physical science and also fundamental with help of Ansys Fluent. Pre-processing is
completed in the gambit. Both the channels having
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2. Prof. Dhumal Vishal S., Prof. Kulkarni Mohan M. / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1686-1689
same cross section area 40*40 mm and same length For capturing accurate profile near the Hartmann
400mm, thickness of pipe is 5mm for every wall wall and side wall very fine meshing is needed near
including combined wall. Here solid material for wall section. Core section is not going to vary rapidly
channel is considered as stainless steel (ss380) and so no need of fine meshing in the core region. The
liquid material is taken as LiPb having 350° Celsius layers formed at the wall parallel to the magnetic field
temperature and all properties respective to that are called side layers which have the thickness 𝛿~1/
temperature, like electrical conductivity 0.776e6 𝐻𝑎 , where Ha is the Hartmann number. The layers
(ohm-m)-1, density 9779.4 (Kg/m3), Dynamic that appear at the walls perpendicular to the magnetic
Viscosity 0.00177 (Pa-sec) etc. with velocity of field are very thin and are called Hartmann layers and
0.1m/s. have a thickness 𝛿~1/𝐻𝑎. For meshing of channels
For first case inlet for both pipe is at section A-A successive ratio of 1.2 is used. The following figure 2
and for second case inlet for first channel is A-A and shows the nature of meshing at the cross section of the
inlet for second channel is B-B. For these two channel. For the accuracy of problem, 380,000 finite
conditions velocity of inlet fluid is same. For further hexahedral elements are created at the time of
study the velocity of fluid is changed from 0.1m/s to meshing.with having worst element of 1.33e-10 which
0.2m/s (case 2). Magnetic field for both cases is same is nearly equals to zero.
and it is 1 Tesla.
IV. SOLVER SETTINGS
A. Pre-Processing
Geometry and mesh is generated by using
GAMBIT software. Gambit have various pre-
processing technologies in one environment such as,
generating model, mesh generation, boundary
condition defining, and zones defining. GAMBITS
provide advance tools for edit and conveniently replay
model building session for parametric studies.
GAMBIT can able to import geometry from several
CAD/CAE software in Para solid, ACIS, STEP, IGES
or CATIA V4/V5 formats. Similarly, gambit able to Fig. 2 Meshing of Channels
generate data which is suitable for other software by
exporting platform. B. Solver and Post Processing
Channels have 400mm length in -z direction.
Magnetic field is applying in the x direction. Fluid There are several types of models present in the
flow come into the parallel channels with velocity fluent. This fluid is acting as laminar fluid after
0.1m/s from section A-A and exit is at atmospheric applying magnetic field due to Lorentz forces so
pressure from section B-B for the parallel flow choose viscous laminar model for analysis. Fluent
condition. For counter flow analysis fluid enters in 12 solver is used for analysis this case with MHD
channel 1 from section A-A and leave from another interface. Post processing is also completed in the
section whereas section B-B allows fluid entry for same software.
channel 2 and its exit from section A-A.
V. RESULTS AND ANALYSIS
Here two cases are treated in such a way that
one flow is in same direction while other case is with
two opposite direction flow. So there is great change
in properties of the middle line and plane of the
parallel channel sections.
Fig. 1 Geometry with mesh
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3. Prof. Dhumal Vishal S., Prof. Kulkarni Mohan M. / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1686-1689
Fig. 3 velocity profile for middle line for case 1
Fig. 5 velocity profile for middle line for case 2
In this figure change of ‘M’ shapes of velocity
This change is happen due to the modified pattern
profile due to the parallel flow channels is seen clearly
of the induced current flow which is exact opposite to
where, end of midline shows high amplitude while
nature of current pattern for case one. In case two
common wall is nearly shown negligible amplitude.
current of both tubes of the structure is passes through
This is happen due to the induced current ‘j’ flow
the combine middle wall and hence small area is there
through the combine wall as like fluid medium (i.e.
for moving of current ‘j’ from wall, so we get large
short circuit happen in common wall region) and
amplitude of velocity at the middle wall instead of
current complete loops in end walls instead of middle
side wall. Following figure shows pattern of current
common wall. Following figure shows the nature of
passes through the channels.
current ‘j’ passing through mid plane of channels.
Fig. 4 current density profile for middle plane for case 1
Fig. 6 current density profile for middle plane for case
Now similarly when study is carried on second case
2
results are dramatically changed. For the opposite or
counter flow from channels, midline shows the perfect For better understanding of the case1 and
‘M’ shape with some amount of large amplitude of case 2 velocity changes figure 7 is shown the
velocity at middle common wall while end walls are
comparative graphical data where red dots represent
relatively have small amplitude. Following figure 5
data for case 1 and black dots representing data for
shows the nature of velocity profile for case 2 at the case 2.
midline.
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4. Prof. Dhumal Vishal S., Prof. Kulkarni Mohan M. / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1686-1689
Fig. 7 velocity profile comparison for case 1 and case
2 middle lines
Case 2 gives comparatively more accurate
‘M’ shape profile than the case 1. Still core portion of
the channels in both cases shows similar velocity
magnitude only change occur in the wall portions of
the channels clearly shown by figure 7.
REFERENCES
[1] J.A. SHERCLIFF, ENTRY OF CONDUCTING AND
NON-CONDUCTING FLUIDS IN PIPES, JOURNAL OF
MATHEMATICAL PROC. OF THE CAMBRIDGE
PHILOSOPHICAL SOC., 52 (1956), 573-583.
[2] D.G. Drake, On the flow in a channel due to a
periodic pressure gradient, Quart. J. of Mech.
and Appl. Math’s., 18, No. 1 (1965).
[3] C.B. Singh, P.C. Ram, Unsteady
Magnetohydrodynamic Fluid Flow through a
Channel’: Journal of Scientific Research.
XXVIII, No. 2 (1978).
[4] P.C. Ram, C.B. Singh, U. Singh, Hall effects on
heat and mass transfer flow through porous
medium, Astrophysics Space Science, 100
(1984), 45-51.
[5] Y. Shimomura, Large eddy simulation of
Magnetohydrodynamic turbulent channel flow
under uniform magnetic field, Physics Fluids,
A3, No. 12 (1991), 3098.
[6] C.B. Singh, Magnetohydrodynamic steady flow
of liquid between two parallel plates, In: Proc.
of First Conference of Kenya Mathematical
Society (1993), 24-26..
[10] S. Ganesh, S. Krishnambal, Unsteady MHD
Stokes flow of viscous fluid between two
parallel porous plates, Journal of Applied
Sciences, 7 (2007),374-379.
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