Effect of External Magnetic Field on the Flow and Heat Transfer in DC Arc Plasma Torch

2010 ◽  
Vol 97-101 ◽  
pp. 2797-2800
Author(s):  
Da Pei Tang ◽  
Qing Gao ◽  
Ying Hui Li ◽  
Fan Xiu Lu
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Temperature Field ◽  
External Magnetic Field ◽  
Flow Field ◽  
Electric Field ◽  
Diamond Film ◽  
Plasma Torch ◽  
Current Intensity ◽  
Flow And Heat Transfer

A multiple fields’ coupled model of new magnetic controlled DC plasma torch, which was used for CVD diamond film, was presented. In this model, the effects of electric field and magnetic field on the flow field and temperature field were taken into account, and the fluid dynamics equations were modified by the addition of some source terms relating to electromagnetic field, such as Lorentz force, joule heating, and radiative cooling. Conversely, the generalized ohm’s law was used to solve the current density, which reflected the effects of flow field and temperature field on the electric field and magnetic field. In addition, the rest Maxwell’s equations and external solenoid magnetic field equation were also modeled. In order to know the effect of external magnetic field on the torch, the current intensity of external solenoid was chosen to simulate its influence on the flow and heat transfer in the torch. Results show that external magnetic field plays a part in stirring the plasma, which is advantageous for the preparation of diamond film. The larger the external solenoid current intensity is, the better the uniformity of the temperature and velocity of plasma is.

Magneto-hydrodynamic Blasius flow and heat transfer from a flat plate in the presence of suspended carbon nanofluids

2017 ◽  
Vol 232 (1) ◽  
pp. 31-40
Author(s):  
Mahantesh M Nandeppanavar ◽  
Rama Subba Reddy Gorla ◽  
S Shakunthala
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
External Magnetic Field ◽  
Flat Plate ◽  
Linear Partial Differential Equation ◽  
Governing Equations ◽  
Linear Ordinary Differential Equations ◽  
Similarity Transformations ◽  
Flow And Heat Transfer ◽  
Non Linear

In this article, we have discussed the effect of external magnetic field and other governing parameters on the flow and heat transfer in the presence of suspended carbon nanotubes over a flat plate. The governing equations of flow and heat transfer are derived from the Navier–Stokes and Prandtl boundary layer concept. The derived governing equations of flow and energy are non-linear partial differential equation, and these equations are converted into non-linear ordinary differential equations with corresponding boundary conditions using some suitable similarity transformations and are solved numerically using fourth-order Runge–Kutta method with efficient shooting technique. Effects of governing parameters on flow and heat transfer are shown through various graphs and explained with physical interpretation in detail. This study has applications in glass-fiber production and technology. On observing the results of this study, we can conclude that external magnetic field shows opposite behaviors on velocity and temperature and it enhances the rate of heat transfer.

scholarly journals Microscale flow and heat transfer between the rotor and the flank for rotary engine

2019 ◽  
pp. 330-330
Author(s):  
Zhaoju Qin
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Flow Field ◽  
Velocity Slip ◽  
Coupling Model ◽  
Rotary Engine ◽  
Flow And Heat Transfer ◽  
Microscale Flow ◽  
Commercial Code ◽  
Steady Laminar

This paper is to investigate microscale flow and transfer between the rotor and the flank for rotary engine. The rotor and flank is simplified to two disks in order to study flow field and temperature field conveniently. The paper takes analysis of steady laminar flow and heat transfer between two disks separated by a gas-filled gap due to machining tolerance. A 3-D multi-physical coupling model is used, involving velocity slip, temperature jump, rarefaction and dissipation. A solution based on commercial code COMSOL is derived and the results are used to illustrate the effects to velocity field, temperature distribution, disks' torque and Nusselt number based on the governing parameters. The paper also investigates the effects of different modified Knudsen number on flow field and temperature field.

Fully Developed Flow and Heat Transfer in Ducts Having Streamwise-Periodic Variations of Cross-Sectional Area

1977 ◽  
Vol 99 (2) ◽  
pp. 180-186 ◽  
Author(s):  
S. V. Patankar ◽  
C. H. Liu ◽  
E. M. Sparrow
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Flow Field ◽  
Cross Sectional Area ◽  
Bulk Temperature ◽  
Sectional Area ◽  
Cross Sectional ◽  
Reduced Pressure ◽  
Fully Developed Flow ◽  
Flow And Heat Transfer

The concepts of fully developed flow and heat transfer have been generalized to accommodate ducts whose cross-sectional area varies periodically in the streamwise direction. The identification of the periodicity characteristics of the velocity components and of a reduced pressure function enables the flow field analysis to be confined to a single isolated module, without involvement with the entrance region problem. A similar modular analysis can be made for the temperature field, but the periodicity conditions are of a different nature depending on the thermal boundary conditions. For uniform wall temperature, profiles of similar shape recur periodically. On the other band, for prescribed wall heat flux which is the same for all modules, the temperature field itself is periodic provided that a linear term related to the bulk temperature change is subtracted. The concepts and solution procedure for the periodic fully developed regime were applied to a heat exchanger configuration consisting of successive ranks of isothermal plate segments placed transverse to the mainflow direction. The computed laminar flow field was found to be characterized by strong blockage effects and massive recirculation zones. The fully developed Nusselt numbers are much higher than those for conventional laminar duct flows and show a marked dependence on the Reynolds number.

scholarly journals Numerical analysis of flow and heat transfer in a thin film along an unsteady stretching cylinder

2021 ◽  
Vol 25 (Spec. issue 2) ◽  
pp. 441-448
Author(s):  
Azeem Shahzad ◽  
Bushra Habib ◽  
Muhammad Nadeem ◽  
Muhammad Kamran ◽  
Hijaz Ahma ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Heat Transfer ◽  
Boundary Layer ◽  
External Magnetic Field ◽  
Stretching Cylinder ◽  
Similarity Transformations ◽  
Flow And Heat Transfer ◽  
Governing System ◽  
The Impact

In this framework, the boundary-layer mass and heat flow in a liquid film over an unsteady stretching cylinder are discussed under the influence of a magnetic field. By means of the similarity transformations the highly non-linear governing system of PDE is converted to ODE. We use the built-in function bvp4c in MATLAB to solve this system of ODE. The impact of distinctive parameters on velocity and temperature profile in the existence of an external magnetic field is depicted via graphs and deep analysis is also presented.

Magnetic bubbles dynamics and heat transfer characteristics under influence of non-uniform magnetic fields

2021 ◽  
pp. 095440622110358
Author(s):  
MM Larimi ◽  
A Ramiar ◽  
H Ramyar ◽  
Hamid Kazemi Moghadam
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Boundary Layer ◽  
External Magnetic Field ◽  
Flow Field ◽  
Thermal Boundary Layer ◽  
Computational Study ◽  
Two Phase ◽  
Navier Stokes Equation ◽  
Vof Model

The computational study of transient immiscible and incompressible two-phase flows is one of the most common and desirable way for investigation of engineering phenomena and physics science. In the previous studies, generally bubbles current have been used as an active method for increasing heat transfer, however, due to existence of hydraulic boundary layers, the bubbles were not able to cross over this layer to thinning the thermal boundary layer and consequently the efficiency of this method was not very considerable. In this study, by considering potential of magnetic field, the effect of co-applying of external non uniform magnetic field and magnetic bubbles in enhancing the heat transfer efficiency in a 3-D tube has been investigated. The computational model consisted of the Navier–Stokes equation for liquid phase and VOF model for interface tracking are carried out by OpenFOAM. The external magnetic field has been considered non-uniform and time dependent. The results predicted that magnetic bubbles and external magnetic field due to their effect on thermal boundary layer increased significantly heat transfer and Nusselt number. Furthermore, results indicated magnetic bubbles can act as an active torbulators in the flow field and can be applied for increasing recirculation and secondary flow in the flow field. The average temperature and magnetic field over times for different cases have been discussed in the results.

Numerical Simulation for Flow and Heat Transfer Characteristics of LType Chaotic Channel

2015 ◽  
Vol 8 (1) ◽  
pp. 351-355
Author(s):  
Kan Cao ◽  
Minshan Liu ◽  
Yongqing Wang ◽  
Zunchao Liu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Flow Field ◽  
Cross Sections ◽  
Straight Channel ◽  
Flow And Heat Transfer ◽  
Periodic Model ◽  
Chaotic Convection ◽  
Better Than

In this paper, the author conducted numerical simulation on fluid flow and heat transfer of L-type chaotic channel with the use of periodic model, compared with common straight channel, analyzed and gained microscopic information flow field and temperature field distribution inside the channel, researched synergy of flow field and temperature field inside the channel with the use of synergy principle, and discussed influences of different Re figures on fluid heat transfer and flow inside the chaotic channel. Results show that L-type chaotic structure can generate chaotic convection under lower flow velocity, which increases disturbing degree of fluid inside the channel, so as to promote mixture and heat transfer of cold and hot fluid; synergy degree of velocity and temperature gradient on cross section of chaotic channel are better than that of straight channel, and average synergy angles for outlet cross sections of such two channels are respectively 66.3° and 88.0°; Nu number of L-type chaotic channel increases with the increase of Re. Particularly, increasing range is more obvious at low Reynolds number, but at the same time, friction coefficient inside the channel will increase.

Electrode Arrangement Effect on Natural Convection in a Horizontal Enclosure

2009 ◽  
Author(s):  
R. Ghazi ◽  
M. S. Saidi ◽  
M. H. Saidi
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Temperature Field ◽  
Natural Convection ◽  
Flow Field ◽  
Electric Field ◽  
Heat Transfer Enhancement ◽  
Temperature Fields ◽  
Transfer Enhancement ◽  
Rayleigh Numbers

The heat transfer enhancement of natural convection, using electrohydrodynamic technique inside a horizontal enclosure heated from below, is studied numerically. The interactions between electric field, flow field, and temperature field are investigated by CFD methods. The flow and temperature fields are affected by voltage applied at the wire electrodes. For different voltages and number of electrodes, it is noticed that the Nusselt number increased in all cases and the best enhancement is obtained at lower Rayleigh numbers. It is also shown that increasing the number of electrodes doesn’t always cause an increase in the heat transfer enhancement. Actually, when the number of electrodes is equal to the number of Be´nard cells, the best heat transfer enhancement is obtained.

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