This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
A Comparison of the Entropy of Thermal Radiation to that of Heat Conduction
Technical Paper
1999-01-2672
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Many thermodynamic texts imply that the entropy flux for thermal radiation (TR) is the same as that for heat conduction, the heat flux divided by the local temperature (q/T). However, for blackbody radiation (BR) emission a 4/3 coefficient occurs and recently it was shown that for non-blackbody radiation (NBR) the coefficient is greater than 4/3 [1]. Some of the fundamental equations that are used in thermodynamics express the entropy flux of heat transfer in a q/T type form. In this paper we address the use of the Clausius equality, and expressions extended from it for irreversible processes, when TR is involved. We find that the Clausius equality for reversible processes is applicable, while the statements extended for irreversible processes are not applicable. Also, we present an alternative derivation of the 4/3 coefficient that shows in a direct way that it follows from the observable relation between BR energy and emission temperature (i.e., energy is proportional to T4). This is done without defining radiation pressure or using Planck’s spectral entropy radiance expression.
Recommended Content
Technical Paper | Development of Self-Contained Hydraulic Valve Lifter |
Technical Paper | Aircraft-Engine GEARS |
Technical Paper | Engine Cooling |
Topic
Citation
Wright, S., Scott, D., Haddow, J., and Rosen, M., "A Comparison of the Entropy of Thermal Radiation to that of Heat Conduction," SAE Technical Paper 1999-01-2672, 1999, https://doi.org/10.4271/1999-01-2672.Also In
References
- Wright S. E. Rosen M. A. Scott D. S. Haddow J. B. Developments on the Entropy of Thermal Radiation Proc. CSME Forum 1998, Vol. I: Thermal and Fluids Engineering Toronto 459 466
- Moran M.J. Shapiro H.N. 1995 Fundamentals of Engineering Thermodynamics 3 Wiley, NY
- Reynolds W.C. Perkins H.C. 1977 Engineering Thermodynamics 2 McGraw-Hill, USA
- McGovern J.A. 1996 The Essence of Engineering Thermodynamics Prentice Hall Europe London
- Planck Max 1914 The Theory of Heat Radiation Dover Publications NY
- Bejan A. 1997 Advanced Engineering Thermodynamics second John Wiley and Sons NY
- Jakob M. 1949 Heat Transfer I Wiley, New York