AEROSPACE ENGINEERING LABORATORY (MAE308) PROF. SEUNG WOOK BAEK Department of AEROSPACE ENGINEERING, KAIST, IN KOREA ROOM: Building N7-2 #3304 TELEPHONE: 3714 MOBILE: 010-5302-5934 swbaek@kaist.ac.kr http://procom.kaist.ac.kr TA : Jonghan Won ROOM: Building N7-2 #3315 TELEPHONE : 3754 MOBILE: 010-4705-4349 won1402@kaist.ac.kr

Observation of Radiation Emitted from Light Source Using Spectrometer Contents Background Experimental setup Objectives

Background Radiation Emission or transmission of energy in form of waves or particles Its importance becomes intensified at high temperature No medium required Radiative physical property depends on surface roughness, material, thickness of coating, temperature, angle, etc.

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 HEMISPHERICAL SPECTRAL EMISSIVE POWER OF BLACKBODY FOR SEVERAL DIFFERENT TEMPERATURES Wien’s (Displacement) Law : 𝜆𝑇=𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 Plank’s Distribution Law : 𝐸 𝑏𝜆 = 2ℎ 𝑐 2 𝜆 5 1 𝑒 ℎ𝑐 𝜆𝑘𝑇 −1 PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

RADIATIVE HEAT TRANSFER GAS RADIATION ATTENUATION BY EARTH’S ATMOSPHERE OF INCIDENT SOLAR SPECTRAL ENERGY FLUX PROPULSION AND COMBUSTION LABORATORY RADIATIVE HEAT TRANSFER

Background Fluorescence - - + External energy hits the electron Electron goes to higher orbital Elevated electron comes back to original orbital for a brief time Unique wavelength is emitted N=3 Unique wavelength N=2 - N=1 - + Energy 𝐸 𝑝ℎ𝑜𝑡𝑜𝑛 =ℎ𝑣 (𝐸:𝑒𝑛𝑟𝑔𝑦 𝑜𝑓 𝑝ℎ𝑜𝑡𝑜𝑛, 𝑣 :𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦, ℎ :𝑃𝑙𝑎𝑛 𝑘 ′ 𝑠 𝑐𝑜𝑛𝑠𝑡𝑛𝑎𝑡)

Background Incandescence Radiation from a hot body as a result of high temperature Thermal radiation Weak intensity in visible spectrum at low temperature

Experimental setup Specification Model name USB2000+VIS-NIR Dimensions 89.1*63.3*34.4 mm Detector Sony ILX511B (2048-element linear silicon CCD array) Detector range 348-1026 nm Best efficiency(>30%) 400-800 nm Optical resolution ~0.1-10 nm (configuration dependent)

Experimental setup Operation principle (Optional) (Optional) 4 8 6 7 9 10 3 5 2 (Optional) 1 (Optional)

Experimental setup Spectrometer Dark room Computer Optical fiber Radiation Computer Optical fiber 400 µm

Objectives Purpose of experiment 2nd week 1st week Observation of spectral radiation from light source Analysis of unique wavelength 1st week 2nd week Observation of spectral radiation from fluorescent lamp Observation of spectral radiation from incandescent lamp and Sun Estimation of the temperature