RADIATION AND COMBUSTION PHENOMENA PROF. SEUNG WOOK BAEK DEPARTMENT OF AEROSPACE ENGINEERING, KAIST, IN KOREA ROOM: Building N7-2 #3304 TELEPHONE : 3714 Cellphone : 010 – 5302 - 5934 swbaek@kaist.ac.kr http://procom.kaist.ac.kr TA : Jonghan Won ROOM: Building N7-2 # 3315 TELEPHONE : 3754 Cellphone : 010 - 4705 - 4349 won1402@kaist.ac.kr

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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