Radiative heat transfer with hydromagnetic flow and viscous dissipation over a stretching surface in the presence of variable heat flux

Thermo-mechanical failure of components in planar-type solid oxide fuel cells (SOFCs) depends strongly on the local temperature gradients at the interfaces of different materials. Therefore, it is of paramount importance to accurately predict the temperature fields within the stack, especially near the interfaces. Because of elevated operating temperatures (of the order of 1000 K or even higher), radiation heat transfer could become a dominant mode of heat transfer in the SOFCs. In this study, we extend our recent work on radiative effects in solid oxide fuel cells (Journal of Power Sources, Vol. 124, No. 2, pp. 453–458) by accounting for the spectral dependence of the radiative properties of the electrolyte material. The measurements of spectral radiative properties of the polycrystalline yttria-stabilized zirconia (YSZ) electrolyte we performed indicate that an optically thin approximation can be used for treatment of radiative heat transfer. To this end, the Schuster-Schwartzchild two-flux approximation is used to solve the radiative transfer equation (RTE) for the spectral radiative heat flux, which is then integrated over the entire spectrum using an N-band approximation to obtain the total heat flux due to thermal radiation. The divergence of the total radiative heat flux is then incorporated as a heat sink into a 3-D thermo-fluid model of a SOFC through the user-defined function utility in the commercial FLUENT CFD software. The results of sample calculations are reported and compared against the baseline cases when no radiation effects are included and when the spectrally gray approximation is used for treatment of radiative heat transfer.

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Spectral Radiative Heat Transfer Analysis of the Planar SOFC

Journal of Fuel Cell Science and Technology ◽

10.1115/1.2041667 ◽

2005 ◽

Vol 2 (4) ◽

pp. 258-262 ◽

Cited By ~ 19

Author(s):

David L. Damm ◽

Andrei G. Fedorov

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Fuel Cells ◽

Solid Oxide Fuel Cells ◽

Radiative Heat Transfer ◽

Radiative Heat ◽

Solid Oxide ◽

Radiative Properties ◽

Radiative Heat Flux ◽

Oxide Fuel

Thermo-mechanical failure of components in planar-type solid oxide fuel cells (SOFCs) depends strongly on the local temperature gradients at the interfaces of different materials. Therefore, it is of paramount importance to accurately predict the temperature fields within the stack, especially near the interfaces. Because of elevated operating temperatures (of the order of 1000K or even higher), radiation heat transfer could become a dominant mode of heat transfer in the SOFCs. In this study, we extend our recent work on radiative effects in solid oxide fuel cells [J. Power Sources, 124, No. 2, pp. 453–458] by accounting for the spectral dependence of the radiative properties of the electrolyte material. The measurements of spectral radiative properties of the polycrystalline yttria-stabilized zirconia electrolyte we performed indicate that an optically thin approximation can be used for treatment of radiative heat transfer. To this end, the Schuster–Schwartzchild two-flux approximation is used to solve the radiative transfer equation for the spectral radiative heat flux, which is then integrated over the entire spectrum using an N-band approximation to obtain the total heat flux due to thermal radiation. The divergence of the total radiative heat flux is then incorporated as a heat sink into a three-dimensional thermo-fluid model of a SOFC through the user-defined function utility in the commercial FLUENT computational fluid dynamics software. The results of sample calculations are reported and compared against the base line cases when no radiation effects are included and when the spectrally gray approximation is used for treatment of radiative heat transfer.

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MHD Free Convection and Heat Transfer Enhancement of Nanofluids Through a Porous Medium in the Presence of Variable Heat Flux

Journal of Nanofluids ◽

10.1166/jon.2017.1339 ◽

2017 ◽

Vol 6 (3) ◽

pp. 496-504 ◽

Cited By ~ 4

Author(s):

P. Durga Prasad ◽

S. V. K. Varma ◽

R. V. M. S. S. Kiran Kumar

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Porous Medium ◽

Free Convection ◽

Heat Transfer Enhancement ◽

Transfer Enhancement ◽

Convection And Heat Transfer ◽

Variable Heat ◽

Variable Heat Flux

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Effect of Radiative Heat Transfer Factor on the Temperature Distribution of a First Stage Vane

Volume 5B: Heat Transfer ◽

10.1115/gt2014-25711 ◽

2014 ◽

Cited By ~ 1

Author(s):

Hong Yin ◽

Mingfei Li ◽

Zhongran Chi ◽

Jing Ren ◽

Hongde Jiang

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Temperature Distribution ◽

Radiative Heat Transfer ◽

Radiative Heat ◽

Swirling Flow ◽

Inlet Temperature ◽

Radiative Effect ◽

Turbine Inlet Temperature ◽

Turbine Inlet

As the advanced heavy-duty gas turbine develops, the turbine inlet temperature and pressure have increased quite significantly to achieve better performance. The flow and heat transfer conditions of hot components including combustor and turbine become even more extreme than ever which need corresponding aerodynamic and cooling design development. The issue of combustor-turbine interaction has been proposed as a complicated research topic. Currently the hot streak, turbulence intensity, swirling flow, radiation are the four important factors for combustor-turbine interaction research according to the literature. Especially as the turbine inlet temperature increases, the radiative heat transfer plays a more and more important role. In this paper, a first stage vane is selected for the conjugate heat transfer simulation including radiative heat transfer since it is almost impossible to identify the radiative effect in experiment. The goal is to examine the effects of radiative heat flux and temperature increment caused by radiation. Several radiative factors including the inlet radiation, gas composition, vane surface emissivity and outlet reflection are investigated. The temperature distribution and heat flux enhancement under different conditions are compared, which can provide reference to the turbine heat transfer design. The general information of radiative effect can be summarized by quantitative analysis. Results show that the temperature increases obviously when considering the radiation effect as expected. However, these factors show distinct influence on the vane temperature distribution. The inlet radiation has significant impact on the vane leading edge and pressure side. Besides the gas radiation plays quite uniform on the whole vane surface.

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