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
RADIATIVE EQUILIBRIUM
INCIDENT RADIATION G R
: ABSORPTIVITY T A
: REFLECTIVITY
: TRANSMISSIVITY
OPAQUE SURFACE
TRANSPARENT SURFACE
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

3. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
FOR AN OPAQUE SURFACE
REFLECTION MODELS
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

4. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
HEAT FLUX FOR OPAQUE SURFACE G B E
: RADIOSITY
(NO RELATION TO MAGNETIC FIELD)
: IRRADIATION
OPAQUE
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

5. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
AN OPAQUE BODY IN AN INSULATED ENCLOSURE UNDER EQUILIBRIUM, THE FIRST LAW YIELDS
, OR
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

6. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
By Definition
: Emissivity is a measure of how well a body can radiate energy as compared to a blackbody
Under Equilibrium
: Kirchhoff’s Law
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

7. RADIATIVE HEAT TRANSFER
RADIATIVE EQUILIBRIUM
ALSO
ELIMINATE
, OR
UNDER EQUILIBRIUM (OR ADIABATIC)
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

8. RADIATIVE HEAT TRANSFER
PART II. RADIATIVE NON-EQUILIBRIUM
ENCLOSURE RADIATION
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

9. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

10. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
EXAMPLE
APPLICATION TO THERMOS BOTTLE
ANY EFFECT OF CONVECTION?
EQUIVALENT CONDUCTION INSULATION
thick cork is needed!!!
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

11. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
OPTICAL APPROACH IS HOPELESS FOR ENCLOSURES INVOLVING MORE THAN THREE SURFACES
NEED ANOTHER APPROACH !!!
TWO METHODS…
ELECTRICAL ANALOGY
NET RADIATION METHOD
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

12. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
ELECTRICAL ANALOGY
(RADIATION NETWORK METHOD)
TWO CIRCUIT ELEMENTS (RESISTANCES)
SURFACE (COLOR)
VOLUME (VIEW)
SURFACE ELEMENT
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

13. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
2. VOLUME ELEMENT
FOR ENERGY LEAVING A SURFACE
IF I IS ISOTROPIC
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

14. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
VIEW FACTOR
A FRACTION OF TOTAL ENERGY LEAVING SURFACE INTERCEPTED BY SURFACE
ENERGY FROM
ENERGY FROM TO
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

15. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
BY DEFINITION
HERE
WITH
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

16. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
SIMILARLY
WHICH LEADS TO THE RECIPROCITY RELATION
CONSEQUENTLY,
THE RECIPROCITY RELATION BETWEEN AND
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

17. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
BETWEEN AND
AND BETWEEN AND
FOR AN ENCLOSURE
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

18. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
NOW, BACK TO THE VOLUME ELEMENT!!!
CONSIDER TWO SURFACES, SAY AND , OF
AN ENCLOSURE
RADIATION FROM TO
RADIATION FROM TO
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

19. RADIATIVE HEAT TRANSFER
RADIATIVE NON-EQUILIBRIUM
NET RADIATION (HEAT FLUX) BETWEEN AND
BY RECIPROCITY
THEN OR
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER