1. RADIATION AND COMBUSTION PHENOMENA
PROF. SEUNG WOOK BAEK
DEPARTMENT OF AEROSPACE ENGINEERING, KAIST, IN KOREA
ROOM: Building N7-2 #3304
TELEPHONE : 3714
Cellphone : 010 –
TA : Jonghan Won
ROOM: Building N7-2 # 3315
TELEPHONE : 3754
Cellphone :

2. RADIATIVE HEAT TRANSFER
GRADING SYSTEM
Homework (20%), 1 Final Exam (80%)
TEXT : None
REFERENCES…
Siegel, R. and Howell, J.R., Thermal radiation heat transfer, 4th, Taylor&Francis, 2002
Sparrow, E.M. and Cess, R.D., Radiation heat transfer, Brooks/Cole Publishing Company, 1970
Michael F. Modest, Radiative Heat transfer, 2nd Academic Press, 2003
M. Quinn Brewster, Thermal Radiative Heat Transfer and Properties, Wiley-Interscience, 1992
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

3. RADIATIVE HEAT TRANSFER
OUTLINE…
PART I. RADIATIVE EQUILIBRIUM
PART II. RADIATIVE NON-EQUILIBRIUM
ENCLOSURE (SURFACE) RADIATION
GAS RADIATION
PART III. RADIATIVE PROPERTIES
PART IV. RADIATION AFFECTED TRANSPORT PHENOMENA
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

4. RADIATIVE HEAT TRANSFER
INTRODUCTION
THERMAL RADIATION
Conduction
Radiation
Temporal
Spatial
Specular
Distribution
A fundamental difference between conduction and radiation is in their distribution.
Quantum mechanics
Geometry
Optics
Explicitly,
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

5. RADIATIVE HEAT TRANSFER
INTRODUCTION
Its importance becomes intensified at high temperature levels: furnaces, combustion chamber, rocket nozzle, nuclear power plant, etc.
No medium required
With conduction and convection – nonlinear integro-differential equation : Difficult to solve!!!
Radiative physical property depends on surface roughness, material, thickness of coating, temperature, angle, etc.
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

6. RADIATIVE HEAT TRANSFER
INTRODUCTION
THEORY OF RADIANT ENERGY PROPAGATION
Classical electromagnetic wave theory
EXCEPTIONS
Spectral distribution of the energy emitted from a body and the radiative properties of gases - explained by only quantum mechanics [particle(photon) theory]
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

7. RADIATIVE HEAT TRANSFER
INTRODUCTION
SPECTRUM OF ELECTROMAGNETIC RADIATION
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

8. RADIATIVE HEAT TRANSFER
INTRODUCTION
SPECTRUM OF ELECTROMAGNETIC RADIATION
NEAR VISIBLE RAY REGION
Wavelength [ ㎛ ]
1000
100 10 1
0.1
0.01
0.001
Red
Violet
0.7
0.4
Infra-red
Visible
Ultraviolet
Thermal
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

9. RADIATIVE HEAT TRANSFER
PART I. RADIATIVE EQUILIBRIUM
A DIRECTIONAL VOLUME
SOLID ANGLE
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

10. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
TWO MORE DEFINITIONS
DIFFERENTIATE WITH RESPECT TO
FROM THIS RELATION
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

11. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
FOR ISOTROPIC RADIATION AT EQUILIBRIUM
THERMAL
OPTICS
projected area
DIVIDE BY , DIFFERENTIATE WITH RESPECT TO
emissive power
unprojected area
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

12. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
FOR ISOTROPIC BLACKBODY RADIATION AT EQUILIBRIUM
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

13. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
THERMAL
OPTICS
Stefan-Boltzmann Law
: Stefan-Boltzmann Constant
THEN,
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

14. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
BLACKBODY
DEFINITION…
An ideal body that allows all the incident radiation to pass into it ( no reflected energy) and absorbs internally all the incident radiation ( no transmitted energy) ; perfect absorber of incident radiation.
PERFECT EMITTER IN EACH DIRECTION AND AT EVERY WAVE LENGTH
In equilibrium condition, the blackbody must radiate exactly as much energy as it absorbs.
The intensity of radiation from a blackbody is independent of the direction of emission.
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

15. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
SPECTRAL DISTRIBUTION OF
BLACKBODY EMISSIVE POWER
RADIATIVE EQUILIBRIUM
USING
UNIFORM
ISOTROPIC
SIMILARLY
MATTER
RADIATION
FOR SPHERE
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

16. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
At a higher temperature, the peak intensity shifts to a shorter wavelength
: Wien’s (DISPLACEMENT) LAW
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

17. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
MONOCHROMATIC (SPECTRAL) BLACKBODY EMMISIVE
POWER AT EQUILIBRIUM
WITH ,
FROM Wien’s LAW
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

18. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
HAS A MAXIMUM AT WAVELENGTH FOR A GIVEN TEMPERATURE
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

19. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
HEMISPHERICAL SPECTRAL EMISSIVE POWER OF
BLACKBODY FOR SEVERAL DIFFERENT TEMPERATURES
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

20. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
When radiation travels from one medium into another, the frequency remains constant while the wavelength changes because of the change in propagation velocity.
Wave number :
the number of waves per unit length.
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

21. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
FROM ORIGIN OF QUANTUM MECHANICS
BLACKBODY EMISSION INTO VACUUM
THE Planck DISTRIBUTION OF THE MONOCHROMATIC EMISSIVE POWER
WHERE
Plank constant :
Boltzmann constant :
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

22. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
FOR
THE Rayleigh-Jeans DISTRIBUTION
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

23. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
SPECTRAL DISTRIBUTION OF BLACKBODY
HEMISPHERICAL EMISSIVE POWER
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

24. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
CHARACTERISTICS…
Energy emitted at all wave lengths increases as the temperature increases.
Peak spectral emissive power shifts toward a smaller wavelength as the temperature is increased.
Red light becomes visible first as the temperature is raised – at sufficiently high temperature, the light emitted becomes white.
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

25. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
TEMPERATURE MEASUREMENT
USING 4 WAVELENGTH PYROMETER
Planck’s DISTRIBUTION LAW
FOR NON-BLACKBODIES,
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

26. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
THE INTENSITY OF RADIATION MEASURED BY A PHOTODIODE
a calibration factor including all radiation absorbed between the emission source and the photodiode (e.g. windows, optical elements, filter, etc.)
FOR GRAY BODIES
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

27. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
FOR NON-GRAY BODY
SHOULD DETERMINE FOR CALIBRATION USING GRAPHS FOR
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

28. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
EMISSIVITY OF TUNGSTEN RIBBON AS A FUNCTION
OF TEMPERATURE FOR DIFFERENT WAVELENGTH
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

29. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
RELATIVE EMISSIVE POWER AS A FUNCTION
OF WAVELENGTH FOR DIFFERENT TEMPERATURES
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

30. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
RELATIVE VOLTAGE OUTPUTS USING TUNGSTEN LAMP
AS A FUNCTION OF TEMPERATURE
DEPENDING ON DIFFERENT CHANNELS AND DIFFERENT SETUPS
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER