Heat transfer enhancement by external magnetic field for paramagnetic laminar pipe flow

Kaneda, Masayuki; Tsuji, Akira; Ooka, Hiroki; Suga, Kazuhiko

doi:10.1016/j.ijheatmasstransfer.2015.06.078

Cited by 19 publications

(6 citation statements)

References 19 publications

(22 reference statements)

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“…The velocity at the axis of the threedimensional cylindrical coordinates is treated using the method of Ozoe and Toh [14]. The profiles of induced magnetic field and resulting B 2 component are identical to those of Kaneda et al [11]. The pipe wall is either heated or cooled at constant heat flux:…”

Section: Schematic Model and Governing Equationsmentioning

confidence: 99%

“…Heat transfer in a straight tube occurs in various heat exchangers, the performance of which depends on the ability to control the heat transfer. Kaneda et al [11] considered heat-exchange tubes that are heated externally. In particular, they reported the effect of the magnetothermal force on the flow of heated paramagnetic fluid in a pipe at a constant flow rate (i.e., fixed Reynolds number).…”

Section: Introductionmentioning

confidence: 99%

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Magnetothermal force on heated or cooled pipe flow

Kaneda

Suga

2018

International Journal of Heat and Fluid Flow

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The effects of the magnetothermal force on the flows of heat and fluid through a pipe are investigated numerically when the pipe wall is either heated or cooled at constant heat flux. The flow is laminar and a paramagnetic fluid is presumed as the working fluid. Because the magnetic susceptibility of a paramagnetic fluid depends on the inverse of its temperature, the magnetothermal force is induced by coupling of the temperature field and magnetic induction. First, the effects are discussed using the case of a magnetic field induced by a single-turn concentrically placed electric coil. It is found that the effects of the magnetothermal force differ according to whether the pipe is cooled or heated. When cooled, the heat and fluid flows are affected behind the coil; the flow is repelled from the wall to the center and the thermal boundary layer thickens. By decomposing the force into the radial and axial directions in the heated and cooled cases, it is clarified that the axial force changes from positive to negative depending on the coil location in the heated case. Therefore, it can be concluded that the effects are not simply oppositional in the heated and cooled cases. In relation to the heat transfer, only when the coil is placed at the threshold of the heating/cooling zone do the effects on the local heat transfer become the opposite of each other. At other coil locations, the suppression of heat transfer is dominant ahead of the coil in the heated case, as indicated in previous work by our group. However, in the cooled case, this effect occurs behind the coil. For a more practical case, a solenoid coil is employed in the simulation. It is then found that the effect on the heat transfer becomes remarkable at the solenoid edges, especially for the heat-transfer suppression in both the heated and cooled cases.

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Section: Schematic Model and Governing Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Magnetothermal force on heated or cooled pipe flow

Kaneda

Suga

2018

International Journal of Heat and Fluid Flow

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“…Heat treatment technology ensures rail quality by eliminating thermal stress [ 7 , 8 , 9 ]. Eddy current heating technology, which has the advantages of high performance and environmental protection, has been widely applied [ 10 , 11 ]. In this paper, the eddy current heating technology is applied to the process of rail heat treatment.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Eddy Current Welding of Rail: Three-Dimensional Simulation

Sun

Liu

Song

et al. 2020

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In this paper is given a three-dimensional numerical simulation of the eddy current welding of rails where the longitudinal two directions are not ignored. In fact, usually it is considered a model where, in the two-dimensional numerical simulation of rail heat treatment, the longitudinal directions are ignored for the magnetic induction strength and temperature, and only the axial calculation is performed. Therefore, we propose the electromagnetic-thermal coupled three-dimensional model of eddy current welding. The induced eddy current heat is obtained by adding the z-axis spatial angle to the two-dimensional electromagnetic-thermal, thus obtaining some new results by coupling the numerical simulation and computations of the electric field and magnetic induction intensity of the three-dimensional model. Moreover, we have considered the objective function into a weak formulation. The three-dimensional model is then meshed by the finite element method. The electromagnetic-thermal coupling has been numerically computed, and the parametric dependence to the eddy current heating process has been fully studied. Through the numerical simulation with different current densities, frequencies, and distances, the most suitable heat treatment process of U75V rail is obtained.

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“…Electromagnetic induction heating technology not only merits in high performance and environment friendliness, but also precise electromagnetic heating is increasingly valued by people with continuous progress being made in computer digitization technique [6,7], and it, therefore, has been widely applied in a number of sectors [8][9][10]. For a welded steel pipe, high-frequency welding is subjected to skin effect, temperature difference between inside and outside surfaces of the steel pipe is very great, prone to plate edge overheat and cold weld core, and the higher the wall thickness, the more pronounced the overheat and cold weld phenomena [11].…”

Section: Introductionmentioning

confidence: 99%