Calculation of Surface Radiation Entropy Generation by Developing the Net Radiation Method in an Inclined Enclosure with Natural Convection

Articles in Press

Document Type : Original Article

Authors

• Ali Safavinejad ¹
• Mehdi Fathipour ²

¹ Department of Mechanical Engineering, University of Birjand

² Ph.D. Student, Department of Mechanical Engineering, University of Birjand, Birjand, Iran

10.22067/jacsm.2023.80207.1151

Abstract

In this article, by developing the net radiation method, the entropy generation of surface radiation in an inclined enclosure with natural convection has been investigated. The governing equations are solved by the stream-vorticity function with the finite difference method and the surface radiation equations are solved with the net spectral radiation method. Surface radiation entropy generation includes radiation entropy in the field and in the matter. In this method, by solving the equations of net radiation in a spectral form, the intensity of the incoming and outgoing radiation from the surfaces is obtained, then the radiation entropy in the matter and the intensity of the spectral radiation entropy are calculated, and finally, the radiation entropy in the field is calculated using the intensity of the spectral radiation entropy. In order to accurately calculate the entropy generation of surface radiation, the developed net radiation method has been validated with the second law of thermodynamics. The effect of Rayleigh number, emissivity and enclosure angle on entropy generation is investigated. The results show that the surface radiation entropy generation decreases with the increase of the enclosure angle. The lowest entropy generation occurs at an angle of 90 degrees, when the hot wall is the lower wall of the enclosure. Also, 85% of the total entropy generation is due to surface radiation. So that the entropy generation due to the effect of surface radiation increases by 520% compared to the case where surface radiation is ignored.

Keywords

• surface radiation entropy
• developed net radiation method
• An inclined enclosure

Main Subjects

• Heat transfer

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