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Search Results: 1 - 10 of 1024 matches for " Joule heating "
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Magnetohydrodynamic (MHD) Free Convective Flow past an Infinite Vertical Porous Plate with Joule Heating  [PDF]
Sigey K. Johana, Okelo A. Jeconia, Gatheri K. Francis, Ngesa O. Joel
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.45113
Abstract:

This work addresses the problem of Magnetohydrodynamic laminar unsteady flow of an incompressible electrically conducting fluid past an infinite vertical porous plate. It investigates how joule heating affects the velocity and temperature profiles of the fluid flow subjected to transverse magnetic field. The research examines specific equations of MHD flow which are solved numerically by finite difference approximations, using computer programme. The numerical results of this study reveal that an increase in joules heating parameter causes an increase in the velocity and temperature profiles uniformly near the plate but remain constantly distributed away from the plate, implying that the flow field of the MHD free convective flow is influenced substantially by the strength of Joules heating near the wall of the plate and at the mainstream.

Investigation of Flow Behavior of Joule-Heating Flow in a 2-D Model of a Reprocessing Glass Melter Cavity  [PDF]
Jiaju Zhou, Hideharu Takahashi, Nobuyoshi Tsuzuki, Hiroshige Kikura
Journal of Flow Control, Measurement & Visualization (JFCMV) , 2018, DOI: 10.4236/jfcmv.2018.64016
Abstract: Flow behavior was observed in a simplified model cavity of a multiphase High Level Liquid Waste (HLLW) reprocessing glass melter. Electrodes were set to generate Joule-heating flow in the cavity. A chaotic flow occurred because the lower part of the cavity was heated while the top surface of the cavity was cooled. Downflow and upflow occurred alternately in cavities. The shape of the cavity was a sloping bottom cavity, which was similar in shape to the real glass melter. To know the flow behavior in the cavity, 1-D flow behavior and 2-D flow behavior were measured in an experiment and simulated by an original CFD code. In the sloping bottom cavity, chaotic flow occurred in the upper part of the cavity. In the case of the sloping bottom cavity which had the same set of electrodes as the glass melter, the effect of the downflow near the electrodes decreased. The same phenomena could be predicted in the melter. The experimental results were also used to validate the CFD code, which will be helpful for developing a multiphase Joule-heating flow predicting.
Viscous and Joule Heating Effects over an Isothermal Cone in Saturated Porous Media
H. M. Duwairi,Osama Abu-Zeid,Rebhi A. Damseh
Jordan Journal of Mechanical and Industrial Engineering , 2007,
Abstract: In this paper, the magnetohydrodynamic mixed convection flow about an isothermal cone embedded in a saturated porousmedium is considered. The Darcian model including the viscous dissipation effects in the energy equation is used. Thegoverning equations are transformed by using a set of nonsimilarity variables and solved by using Keller box method. Theentire mixed convection regime is covered by nonsimilarity parameter χ, where χ=0 corresponds to pure free convection andχ=1 corresponds to pure forced convection. Numerical results for the dimensionless velocity and temperature profiles and thelocal Nusselt number for various values of the mixed convection parameter χ, the cone angle parameter m, the magnetic fieldstrength parameter H, and the modify Gebhart number Ge* are drawn. It is found that increasing the magnetic strengthdecreased the heat transfer rates, while increasing the cone angle increased the heat transfer rates.
Conjugate Effects of Radiation and Joule Heating on Magnetohydrodynamic Free Convection Flow along a Sphere with Heat Generation  [PDF]
Md Miraj Ali, Md Abdul Alim, Laek Sazzad Andallah
American Journal of Computational Mathematics (AJCM) , 2011, DOI: 10.4236/ajcm.2011.11003
Abstract: The conjugate effects of radiation and joule heating on magnetohydrodynamic (MHD) free convection flow along a sphere with heat generation have been investigated in this paper. The governing equations are transformed into dimensionless non-similar equations by using set of suitable transformations and solved numerically by the finite difference method along with Newton’s linearization approximation. Attention has been focused on the evaluation of shear stress in terms of local skin friction and rate of heat transfer in terms of local Nusselt number, velocity as well as temperature profiles. Numerical results have been shown graphically for some selected values of parameters set consisting of heat generation parameter Q, radiation parameter Rd, magnetic parameter M, joule heating parameter J and the Prandtl number Pr.
An Analytical Model of Joule Heating in Piezoresistive Microcantilevers
Mohd Zahid Ansari,Chongdu Cho
Sensors , 2010, DOI: 10.3390/s101109668
Abstract: The present study investigates Joule heating in piezoresistive microcantilever sensors. Joule heating and thermal deflections are a major source of noise in such sensors. This work uses analytical and numerical techniques to characterise the Joule heating in 4-layer piezoresistive microcantilevers made of silicon and silicon dioxide substrates but with the same U-shaped silicon piezoresistor. A theoretical model for predicting the temperature generated due to Joule heating is developed. The commercial finite element software ANSYS Multiphysics was used to study the effect of electrical potential on temperature and deflection produced in the cantilevers. The effect of piezoresistor width on Joule heating is also studied. Results show that Joule heating strongly depends on the applied potential and width of piezoresistor and that a silicon substrate cantilever has better thermal characteristics than a silicon dioxide cantilever.
Effect of the deposition conditions of platinum electrodes on their performance as resistive heating elements
Mardare, Andrei Ionut;Mardare, Cezarina Cela;Joanni, Ednan;
Materials Research , 2004, DOI: 10.1590/S1516-14392004000300009
Abstract: the performance of different platinum electrodes used as resistive heating elements was studied. pt films having different thickness were deposited by rf magnetron sputtering at room temperature followed by post-deposition annealing at 700 oc or made in-situ at 700 oc. the pt films were deposited over oxidized silicon, using ti or zr buffer layers. the resistance dependence on temperature was studied by applying increasing currents (up to 2a) to the pt films. changes in the microstructure of the pt films account for the changes in the temperature coefficient of resistance as a function of the deposition parameters. the maximum substrate temperature (675 oc) was obtained when using 200 nm pt films deposited at 700 oc over ti, with a power consumption of only 16 w.
Effect of the deposition conditions of platinum electrodes on their performance as resistive heating elements
Mardare Andrei Ionut,Mardare Cezarina Cela,Joanni Ednan
Materials Research , 2004,
Abstract: The performance of different platinum electrodes used as resistive heating elements was studied. Pt films having different thickness were deposited by RF magnetron sputtering at room temperature followed by post-deposition annealing at 700 oC or made in-situ at 700 oC. The Pt films were deposited over oxidized silicon, using Ti or Zr buffer layers. The resistance dependence on temperature was studied by applying increasing currents (up to 2A) to the Pt films. Changes in the microstructure of the Pt films account for the changes in the temperature coefficient of resistance as a function of the deposition parameters. The maximum substrate temperature (675 oC) was obtained when using 200 nm Pt films deposited at 700 oC over Ti, with a power consumption of only 16 W.
A Thermal Model for Carbon Nanotube Interconnects
Kaji Muhammad Mohsin,Ashok Srivastava,Ashwani K. Sharma,Clay Mayberry
Nanomaterials , 2013, DOI: 10.3390/nano3020229
Abstract: In this work, we have studied Joule heating in carbon nanotube based very large scale integration (VLSI) interconnects and incorporated Joule heating influenced scattering in our previously developed current transport model. The theoretical model explains breakdown in carbon nanotube resistance which limits the current density. We have also studied scattering parameters of carbon nanotube (CNT) interconnects and compared with the earlier work. For 1 μm length single-wall carbon nanotube, 3 dB frequency in S 12 parameter reduces to ~120 GHz from 1 THz considering Joule heating. It has been found that bias voltage has little effect on scattering parameters, while length has very strong effect on scattering parameters.
Joule Heating and Thermal Radiation Effects on MHD Boundary Layer Flow of a Nanofluid over an Exponentially Stretching Sheet in a Porous Medium  [PDF]
Jakkula Anand Rao, Gandamalla Vasumathi, Jakkula Mounica
World Journal of Mechanics (WJM) , 2015, DOI: 10.4236/wjm.2015.59016
Abstract: A numerical study on boundary layer flow behaviour, heat and mass transfer characteristics of a nanofluid over an exponentially stretching sheet in a porous medium is presented in this paper. The sheet is assumed to be permeable. The governing partial differential equations are transformed into coupled nonlinear ordinary differential equations by using suitable similarity transformations. The transformed equations are then solved numerically using the well known explicit finite difference scheme known as the Keller Box method. A detailed parametric study is performed to access the influence of the physical parameters on longitudinal velocity, temperature and nanoparticle volume fraction profiles as well as the local skin-friction coefficient, local Nusselt number and the local Sherwood number and then, the results are presented in both graphical and tabular forms.
Effect of Magnetic Field on Entropy Generation Due to Laminar Forced Convection Past a Horizontal Flat Plate
Mohammed Q. Al-Odat,Renhe A. Damseh,Moh\'d A. Al-Nimr
Entropy , 2004, DOI: 10.3390/e6030293
Abstract: Magnetic field effect on local entropy generation due to steady two-dimensional laminar forced convection flow past a horizontal plate was numerically investigated. This study was focused on the entropy generation characteristics and its dependency on various dimensionless parameters. The effect of various dimensionless parameters, such as Hartmann number (Ha), Eckert number (Ec), Prandtl number (Pr), Joule heating parameter (R) and the free stream temperature parameter (θ∞) on the entropy generation characteristics is analyzed. The dimensionless governing equations in Cartesian coordinate were solved by an implicit finite difference technique. The solutions were carried out for Ha2=0.5-3, Ec=0.01-0.05, Pr=1-5 and θ∞=1.1-2.5. It was found that, the entropy generation increased with increasing Ha, Ec and R. While, increasing the free stream temperature parameter, and Prandtl number tend to decrease the local entropy generation.
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