1. AEROSPACE ENGINEERING LABORATORY (MAE308)
PROF. SEUNG WOOK BAEK
Department of AEROSPACE ENGINEERING, KAIST, IN KOREA
ROOM: Building N7-2 #3304
TELEPHONE: 3714
MOBILE:
TA : Jonghan Won
ROOM: Building N7-2 #3315
TELEPHONE : 3754
MOBILE:

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

3. 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.

4. 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

5. 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 𝑒 ℎ𝑐 𝜆𝑘𝑇 −1
PROPULSION AND COMBUSTION LABORATORY
RADIATIVE HEAT TRANSFER

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

7. 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)

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

9. 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 nm
Best efficiency(>30%) nm
Optical resolution
~ nm
(configuration dependent)

10. Experimental setup Operation principle (Optional) (Optional) 4 8 6 7 910 3 5 2
(Optional) 1
(Optional)

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

12. 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