• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권4호
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• pp.333-354
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• 2016

The present investigation deals, heat and mass transfer characteristics with the effect of slip on the hydromagnetic pulsatile flow through a parallel plate channel filled with saturated porous medium. Based on the pulsatile flow nature, exact solution of the governing equations for the fluid velocity, temperature and concentration are obtained by using two term perturbation technique subject to physically appropriate boundary conditions. The expressions of skin friction, Nusselt number and Sherwood number are also derived. The numerical values of the fluid velocity, temperature and concentration are displayed graphically whereas those of shear stress, rate of heat transfer and rate of mass transfer at the plate are presented in tabular form for various values of pertinent flow parameters. By increasing the slip parameter at the cold wall the velocity increases whereas the effect is totally reversed in the case of shear stress at the cold wall.

• Advances in nano research
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• 제15권3호
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• pp.191-201
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• 2023

In order to develop better method to enhance and control the flow and heat transfer inside the radiator of electronic device, the synergistic effect of MHD nanofluids and porous medium on the flow and heat transfer in rectangular opened channel is simulated using Lattice Boltzmann method. Three nanofluids of CuO-water, Al₂O₃-water and Fe₃O₄-water are studied to analyze the influence of the type of nanofluid on the synergistic effect. The simulation results show that the porous medium can increase the flow velocity in fluid zone adjacent to the porous medium and enhance the heat transfer on the surface of the channel. Under no magnetic field, when the porosity of porous medium is 0.8, the Nusselt number is 4.46% higher than when the porosity is 0.9. Al₂O₃-water has the best heat transfer effect among the three nanofluids. At Ф=0.06, Ha=100, θ=90°, ε=0.9, Nu of Al₂O₃-water is 6.51% larger than that of CuO-water and 5.05% larger than that of Fe₃O₄-water. Magnetic field enhances seepage in porous medium and inhibits heat transfer in the bottom wall. When Ha=30 and 60, the inhibiting effect is the most significant as the magnetic field angle is 90°. And when Ha=100, the inhibiting effect is the most significant as the magnetic field angle is 120°.

• 대한기계학회논문집B
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• 제34권6호
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• pp.579-586
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• 2010

MEMS 기술의 향상과 함께 $\mu$-TAS(Micro Total Analysis System)가 개발 되어 의료 및 생물학 분야가 급속하게 성장했다. $\mu$-TAS의 한 분야로 Chip 위에서 소량의 sample과 반응물을 가지고 혼합공정과 분석공정이 이루어지는 LOC(Lab on a chip)에 관한 연구는 활발하게 연구되어진다. LOC는 마이크로 펌프 와 마이크로 믹서와 같은 microfluidic 장치들로 구성된다. Microfluidic 시스템의 유동이 층류 유동이므로 유체상태의 반응물들을 효율적으로 혼합하고 공급하는 것이 어렵다. 본 논문은 이송 및 혼합이 동시에 이루어지는 MHD micropump의 설계와 제작에 관해 제시하였다. 최종 개선사양은 상용 CFD 프로그램의 해석결과를 통하여 결정하였다.

• 천문학회보
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• 제46권2호
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• pp.47.2-47.2
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• 2021

The present study is focused on origins of the flow and magnetic structure involved in the formation and eruption of a solar prominence. To clarify them, we performed an MHD simulation based on the 3-dimensional emerging flux tube (3DEFT) model, in which self-consistent evolution of a flow and magnetic field passing freely through the solar surface was obtained by seamlessly connecting subsurface dynamics with surface dynamics. By analyzing Lagrangian displacements of magnetized plasma elements, we demonstrate the flow structure which is naturally incorporated to the magnetic structure of the prominence formed via dynamic interaction between the flow and magnetic field.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1447-1451
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• 2004

The laminar impinging jet thermal fields were investigated with or without magnetic fields. The transient phenomenon from steady to unsteady flow was founded at specific Reynolds number ranges. In unsteady flow region, the magnetic fields make flow stable. So the characteristics of heat transfer at impingement wall are changed

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 춘계학술발표회요약집
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• pp.184.2-184
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• 2001

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.216.2-216.2
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• 2008

• 천문학회지
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• 제37권5호
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• pp.605-609
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• 2004

We present a set of high-resolution 3D MHD simulations exploring the evolution of light, supersonic jets in cluster environments. We model sets of high- and low-Mach jets entering both uniform surroundings and King-type atmospheres and propagating distances more than 100 times the initial jet radius. Through complimentary analyses of synthetic observations and energy flow, we explore the detailed interactions between these jets and their environments. We find that jet cocoon morphology is strongly influenced by the structure of the ambient medium. Jets moving into uniform atmospheres have more pronounced backflow than their non-uniform counterparts, and this difference is clearly reflected by morphological differences in the synthetic observations. Additionally, synthetic observations illustrate differences in the appearances of terminal hotspots and the x-ray and radio correlations between the high- and low-Mach runs. Exploration of energy flow in these systems illustrates the general conversion of kinetic to thermal and magnetic energy in all of our simulations. Specifically, we examine conversion of energy type and the spatial transport of energy to the ambient medium. Determination of the evolution of the energy distribution in these objects will enhance our understanding of the role of AGN feedback in cluster environments.

• Journal of applied mathematics & informatics
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• 제42권3호
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• pp.607-623
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• 2024

This article studies the effects of heat generation/absorption and thermal radiation on the unsteady magnetohydrodynamic (MHD) Casson fluid flow past a vertical plate through rotating porous medium with constant temperature and mass diffusion. It is assumed that the plate temperature and concentration level are raised uniformly. For finding the exact solution, a set of non-dimensional partial differential equations is solved analytically using the Laplace transform technique. The influence of various non-dimensional parameters on the velocity are discussed, including the effects of the magnetic parameter M, heat generation/absorption Q, thermal radiation parameter R, Prandtl number Pr, Schmidt number Sc, permeability of porous medium parameter, Casson fluid parameter γ, on velocity, temperature, and concentration profiles, which are discussed through several figures. It is found that velocity, temperature, and concentration profiles in the case of heat generation parameter Q, Casson fluid parameter γ, thermal Grashof number Gr, mass Grashof number Gc, Permeability Porous medium parameter K, and time t have retarding effects. It is also seen that the magnetic field M, Thermal Radiation parameter R, Prandtl field Pr, Schmidt number Sc have reverse effects on it.

• Transactions on Electrical and Electronic Materials
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• 제17권5호
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• pp.252-256
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• 2016

This paper deals the study of a linear MHD pump solution used to eliminate and to avoid the dangers of the mercury appearing through pollution and contamination. The formulation of the magnetohydrodynamic phenomena is derived from Maxwell and Navier-Stokes equations are solved using the finite volume method. Simulation results highlight the performance of the pump such as the electromagnetic force, the velocity, and the pressure, the application of Ansys-Fluent software validation these results.