Combined Effects of Magnetic Field and Thermal Radiation on Fluid Flow and Heat Transfer of Mixed Convection in a Vertical Cylindrical Annulus
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论文类型：期刊论文
发表时间：2016-06-01
发表刊物：JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
收录刊物：SCIE、EI、Scopus
卷号：138
期号：6
ISSN号：0022-1481
关键字：magnetic field; thermal radiation; mixed convection; heat transfer; vertical cylindrical annulus
摘要：Magnetohydrodynamic (MHD, also for magnetohydrodynamics) mixed convection of electrically conducting and radiative participating fluid is studied in a differentially heated vertical annulus. The outer cylinder is stationary, and the inner cylinder is rotating at a constant angular speed around its axis. The temperature difference between the two cylindrical walls creates buoyancy force, due to the density variation. A constant axial magnetic field is also imposed to resist the fluid motion. The nonlinear integro-differential equation, which characterizes the radiation transfer, is solved by the discrete ordinates method (DOM). The MHD equations, which describe the magnetic and transport phenomena, are solved by the collocation spectral method (CSM). Detailed numerical results of heat transfer rate, velocity, and temperature fields are presented for 0 <= Ha <= 100, 0: 1 <= tau(L) <= 10, 0 <= omega <= 1, and 0: 2 <= epsilon(W) <= 1. The computational results reveal that the fluid flow and heat transfer are effectively suppressed by the magnetic field as expected. Substantial changes occur in flow patterns as well as in isotherms, when the optical thickness and emissivity of the walls vary in the specified ranges. However, the flow structure and the temperature distribution change slightly when the scattering albedo increases from 0 to 0.5, but a substantial change is observed when it increases to 1.
发表时间：2016-06-01