1 Introduction 1
1.1 Importance of thermal radiation ............................................. 1
1.2 Nature of radiation ................................................................. 6
2 Black body and its characteristics 11
2.1 Solid angle - dco ...................................................................... 18
2.2 Spectral or monochromatic radiation intensity, IA, e . . . ............. 23
2.3 Spectral hemispherical emissive power .................................... 24
2.4 Radiation pressure ................................................................... 28
2.5 Relationship between the intensity, I and temperature, T 33
2.6 Planck's distribution ................................................................. 38
2.7 The Rayleigh Jeans distribution................................................ 39
2.8 Planck's distribution - salient features ...................................... 52
PROBLEMS ................................................................................... 65
3 Radiative properties of non-black surfaces 67
3.1 Spectral directional emissivity, '(A, T, 0, 0) ........................ 70
3.2 Hemispherical spectral emissivity, ), (A, T) .......................... 72 3.3 Directional total emissivity, '(T, 0, 0) .................................. 73
3.4 Hemispherical total emissivity, (T) ......................................... 74
3.5 Absorptivity, a ......................................................................... 84
3.6 Spectral directional absorptivity, a'A .................................................................................... 87
3.7 Hemispherical spectral absorptivity, a), (A, TA) ......................... 91
3.8 Directional total absorptivity, a(TA,0,0) ................................... 92
3.9 Hemispherical total absorptivity, a(TA) .................................... 93
3.10 Reflectivity, p ...................................................................... 100
3.11 Transmissivity, r .................................................................. 103
3.12 Spectral transmissivity r), (A, t) .............................................. 104
3.13 Optical pyrometry ................................................................ 110
PROBLEMS ................................................................................. 112
4 Radiation heat transfer between surfaces
About the Author: Dr. C Balaji is currently the T.T.Narendran Chair Professor in the Department of Mechanical Engineering at the Indian Institute of Technology (IIT) Madras, India. He graduated in Mechanical Engineering from Guindy Engineering College, Chennai, in 1990 and obtained his M.Tech (1992) and Ph.D. (1995) from IIT Madras in the area of heat transfer. His areas of interest include heat transfer, computational radiation, optimization, inverse problems, satellite meteorology and atmospheric sciences. He has more than 200 international journal publications to his credit and has guided 30 students so far. Prof. Balaji has several awards to his credit and notable among them include Young Faculty Recognition Award of IIT Madras (2007) for excellence in teaching and research, K.N. Seetharamu Award and Medal for excellence in Heat Transfer Research (2008), Swarnajayanthi Fellowship Award of the Government of India (2008-2013), Tamil Nadu Scientist Award (2010) of the Government of Tamilnadu, Marti Gurunath Award for excellence in teaching (2013) and Mid-Career Research Award (2015) both awarded by IIT Madras. He is a Humboldt Fellow and an elected Fellow of the Indian National Academy of Engineering. Prof.Balaji has authored 8 books thus far. He is currently the Editor-in-Chief of the International Journal of Thermal Sciences.
