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Radiation Parameter (radiation + parameter)
Selected AbstractsUnsteady free convection,radiation flow over a vertical wall embedded in a porous mediumINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2008Joaquín Zueco Abstract A numerical solution for the transient two-dimensional free convection flow of viscous dissipative fluid over an infinite vertical plate through a porous medium bounded, taking into account the thermal radiation, is analysed. The fluid is grey, and acts as a radiation emitting and absorbing (but non-scattering) medium. The influence of the non-dimensional parameters such as the Forchheimer coefficient (Fo), the permeability parameter (P), the Eckert number (Ec) and the radiation parameter (R) on the velocity, temperature, Nusselt number and on the time taken to reach the steady state is studied. The possibility of non-Darcy flow is also analysed. The numerical method employed, network simulation method, is based on an electro-thermal analogy and permits the direct visualization and evolution of the local and/or integrated transport variables (velocities, temperatures and fluxes) at any point or section of the medium. The numerical solutions of this work have been compared with the existing information in the literature with good agreement. Copyright © 2007 John Wiley & Sons, Ltd. [source] The lattice Boltzmann method and the finite volume method applied to conduction,radiation problems with heat flux boundary conditionsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 2 2009Bittagopal Mondal Abstract This article deals with the implementation of the lattice Boltzmann method (LBM) in conjunction with the finite volume method (FVM) for the solution of conduction,radiation problems with heat flux and temperature boundary conditions. Problems in 1-D planar and 2-D rectangular geometries have been considered. The radiating,conducting participating medium is absorbing, emitting and scattering. In the 1-D planar geometry, the south boundary is subjected to constant heat flux, while in the 2-D geometry the south and/or the north boundary is at constant heat flux condition. The remaining boundaries are at prescribed temperatures. The energy equation is solved using the LBM and the radiative information for the same is computed using the FVM. In the direct method, by prescribing temperatures at the boundaries, the temperature profile and heat flux are calculated. The computed heat flux values are imposed at the boundaries to establish the correctness of the numerical code in the inverse method. Effects of various parameters such as the extinction coefficient, the scattering albedo, the conduction,radiation parameter, the boundary emissivity and the total heat flux and boundary temperatures are studied on the distributions of temperature, radiative and conductive heat fluxes. The results of the LBM in conjunction with the FVM have been found to compare very well with those available in the literature. Copyright © 2008 John Wiley & Sons, Ltd. [source] Estimation of solar radiation parameters for Izmir, TurkeyINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2002K. Ulgen Abstract In this study, the solar radiation parameters (global and diffuse solar radiation) are correlated with respect to ambient temperatures in the fifth-order polynomial form for Izmir in Turkey. Experimental data were measured in the Solar-Meteorological Station of Solar Energy Institute in Ege University over a 5-yr period, 1994,1998. The ratios of the total daily diffuse to global radiation intensities for each month range from 0.38 to 0.45 averaged for the same period, with an average value of 0.41. It can be concluded that the present models predict the solar radiation parameters reasonably well with the correlation coefficients over 0.95 for the projections. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||