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 GAS RADIATION IMPORTANT DISTINCTION A CRUDE ANALOGY PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION THIN GAS, THIS SOLUTION IS OBTAINED FROM THE INTEGRATION OF ITS COMPARISON TO REVEALS THAT FOR THIN GAS ONLY ENERGY EMISSION WITHIN THE MEDIUM IS CONSIDERED. EMISSION APPROXIMATION (S&H, P745) PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION THEN, THE RADIATIVE CONSTITUTION IS REDUCED TO INTRODUCE THE PLANCK MEAN ABSORPTION COEFFICIENT WHICH, HOWEVER, CAN BE APPLIED FOR THE EMISSION TERM IN A GAS OF ANY OPTICAL THICKNESS (S&H, P.745) PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION THEN OR CONSTITUTION EQ FOR THIN GAS RADIATION ACCORDINGLY, THE RADIATION AFFECTED THERMOMECHANICS OF THIN GAS ARE PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION WHICH GIVES PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION THICK GAS, ASSUME CONSTANT PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION NOTE CONSIDER TAYLOR EXPANSION TRUNCATION OF THE SERIES AFTER A FEW TERMS WILL GIVE AN ADEQUATE REPRESENTATION OF THE AT NEAR . PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION THEN, INTENSITY BECOMES OR OR FOR (OR ) , FOR THICK GAS PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION FOR THICK GAS, A LOCAL INTENSITY DEPENDS ONLY ON THE MAGNITUDE AND GRADIENT OF THE LOCAL BLACKBODY INTENSITY (S&H, P.751) PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION HEAT FLUX FOR THICK GAS: DIFFUSION APPROXIMATION REARRANGE OR PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION OR IN TERMS OF THE ROSSELAND MEAN PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION HEAT FLUX BECOMES OR CONSTITUTION EQ FOR THICK GAS RADIATION ACCORDINGLY, THE RADIATION AFFECTED THERMOMECHANICS OF THICK GAS ARE OR PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION WHICH GIVES HW#4 [REF.1] P.593 #12-1~4 PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

HW#4 [REF.1] P.593 #12-1~4 12-1. A spectral beam of radiation at and with intensity enters a gas layer 20 cm thick. The gas is at 1000K and has an absorption coefficient . What is the intensity of the beam emerging from the gas layer? Neglect scattering, but include emission from the gas. 12-2. Radiation from a blackbody source at 3000K is passing through a layer of air at 12,000K and 1 atm. Considering only the transmitted radiation (that is, not accounting for emission by the air), what path length is required to attenuate by 25% the energy at the wavelength corresponding to the peak of the blackbody radiation? 12-3. Radiation with a wavelength of is passing through a gas at a temperature of 10,000K. What is the ratio of the true absorption coefficient to the absorption coefficient? 12-4. A gas layer at constant pressure P has a linearly decreasing temperature across the layer and a constant mass absorption coefficient (no scattering). For radiation passing in a normal direction through the layer, what is the ratio as a function of T1, T2, and L? The temperature range T2 to T1 is low enough that emission from the gas can be neglected, and the gas constant is R.

RADIATIVE HEAT TRANSFER GAS RADIATION DIMENSIONAL ARGUMENTS 1) THIN GAS INTRODUCE , PLANCK NUMBER THEN PLANCK MEAN OPTICAL THICKNESS PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION 2) THICK GAS INTRODUCE , ROSSELAND MEAN OPTICAL THICKNESS THEN HOW TO INTERPRET THIN GAS AND THICK GAS TOGETHER? PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION INTRODUCE THEN PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION INTRODUCE , GEOMETRIC MEAN OPTICAL THICKNESS THIN GAS DESCRIBED BY THICK GAS BY FOR AN ARBITRARY OPTICAL THICKNESS, BY INSPECTION. PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION thin thick FOR ANY OPTICAL THICKNESS PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION thin thick FOR ANY OPTICAL THICKNESS PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION FOR ANY OPTICAL THICKNESS (ENTIRE SPECTRUM) CONSIDER INTEGRATE OVER AND RECALL PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION INTRODUCE UNDER LOCAL EQUILIBRIUM, PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION (REF.1 S&H, CH.14, P.697 EQ.14-36, 14-42, 14-64) THEN ① CAN BE APPLIED FOR THE EMISSION TERM IN A GAS OF ANY OPTICAL THICKNESS. (S&H, P.745) EQ.(1) IS TRUE FOR AN ISOTROPIC SCATTERING. BUT J IS A FUNCTION OF SCATTERING. EQ.(1) IS ALSO TRUE FOR AN ANISOTROPIC SCATTERING INDEPENDENT OF INCIDENCE ANGLE (RANDOMLY ORIENTED PARTICLES). MULTIPLY TRANSFER EQUATION BY PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION INTEGRATE OVER AND INTRODUCE PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION FOR ANY OPTICAL THICKNESS FOR OPTICALLY THICK MEDIUM OR (REF.1 S&H) P.766, EQ.15-82 SO THAT PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION FOR GRAY GAS ( : INDEPENDENT OF ) (S&H, P.767) THEN ② FOR ISOTROPIC CONDITION ③ PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION ② ③ ELIMINATE BETWEEN ② AND ③ ④ FOR GENERAL THERMOMECHANICS OF FOR ISOTROPIC GRAY GAS ⓞ PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION ⓞ ① ④ NOW, ELIMINATE J BETWEEN ① AND ④ OR, INSERT ④ INTO ⓞ, AND ELIMINATE BETWEEN ① AND ④ PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION NOTE THAT FOR 1D PROBLEMS, AND FORMULATIONS ARE OF SIMILAR COMPLEXITY. HOWEVER, FOR 3D PROBLEMS, FORMULATION (CONSISTING OF TWO SCALAR EQUATIONS) IS MORE CONVENIENT THAN FORMULATION (CONSISTING OF FOUR SCALAR EQUATIONS). PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER