Thermal Radiative Properties of Complex Media: Theoretical Prediction Versus Experimental Identification

Abstract In many engineering applications and natural phenomena, thermal radiation interacts with complex media composed of dispersed phases that may be of different type: solid/solid, solid/gas, or liquid/gas. Most of them are semitransparent media that emit, absorb, and scatter thermal radiation. Heat transfer by combined radiation with conduction or convection in such media is a problem of high practical importance, mostly in situations where radiation is a dominant mode. Improvement of thermal performance of such materials or of the manufacturing processes that involve these media requires the availability of efficient methods (i) for radiative transfer modeling, and (ii) to predict and to experimentally determine the thermophysical properties intended to feed the models. This paper is focused on radiative properties assessment. After a brief overview of the materials and properties of interest, the emphasis is put on methodology of property investigation combining both theoretical prediction and experimental identification. Examples related to different particulate media are presented, showing recent advances and needs for further investigation. Acknowledgments The author gratefully acknowledges Dr. Leonid Dombrovsky and Dr. Dominique Baillis for the clarifying discussions and the material and information provided that have been very helpful in the preparation of this paper. Jean-François Sacadura is Emeritus Professor of Mechanical Engineering and Thermal Sciences at INSA Lyon (National Institute of Applied Sciences) in Lyon, France. He received his mechanical engineering degree in 1963 from INSA Lyon, his Ph.D. in 1969 from the University of Lyon, and the doctor-ès-sciences physiques degree from INSA Lyon in 1980. He started his academic career in 1963 as a teaching and research assistant at INSA Lyon, where he reached the position of full professor of mechanical engineering with tenure in 1983. He has been an emeritus professor since 2005. Dr. Sacadura was dean of the master and PhD programs in thermal engineering at INSA Lyon (1998–2005) and director of the Thermal Science Centre of Lyon (CETHIL) from 1997 to 2003. His research interests include thermal radiation and combined mode of heat transfer, thermophysical properties, particulate media, semitransparent media, high temperatures, modeling and experimental characterization by direct and inverse methods, and radiative–convective design of water-spray fire protections for oil and chemical plants. He has co-authored more than 120 refereed publications, and is co-editor and/or co-author of four books. He serves on several editorial boards and is co-chief-editor of High Temperatures–High Pressures (2008–). He is a member of the boards of Société Française de Thermique (SFT, 1970–, chairman 1997–1999), Association Française de Mécanique (AFM), European Conference in Thermophysical Properties (ECTP, chairman 1993–1996), Eurotherm Committee (founding and honorary member), and ICHMT Scientific Council and Executive Committee. His efforts in engineering education and research have been recognized with several awards: Chevalier des Palmes Académiques, 1986; Prix Academ-INSA as an outstanding PhD promotor and advisor, 1989; Officier des Palmes Académiques, 1998; and Commandeur des Palmes Académiques, 2005 (Palmes Académiques are French Ministry of Education awards for performance in higher education and research).