Thermal Radiation Thermal Engineering Lab ME-4111 Professor: Eduardo Cabrera Damian Luna Yetziel Sandoval – Alberto Gonzales – Fernando Fresse – Jaen Soto – 51080

Outline  Introduction and objective definition  Experimental Procedure  Experimental Result  Conclusion  Recommendations

Introduction  The thermal radiation is a forma for heat transfer.  Differential and the intensity of the thermal radiation from semiconductor layers studies and theatrically.  The Calculation of the Stefan-Boltzmann law obtain in the experiment will be discuses.  Comparison Charts of the experimental results, showing the comparison with the our environment and body.

Objective  Our objective is comparing the heat emission of thermal radiation emitted from different types of surfaces Black mate, silver and polish.  The calculation of the Stefan-Boltzmann law  Comparison of heat versus our experimental heat.

Experimental Procedure  Inverse Square Law for Heat 1. Set the radiometer at a initial distance of 100(mm) from the heat source 2. Turn on the power control unit and set the power control knob to 6 mark. This setting will be maintained throughout the entire task. 3. Allow the radiometer reading stabilizes and then note the value of distance and power reading. 4. Move the radiometer away of the heat source by increasing the distance in 100(mm) 5. Repeat step 4 until you have 7 values

Experimental Procedure  Stefan-Boltzmann Law 1.Set the matt black plate at a distance of 50 mm from the heat source. 2.Set the radiometer at a distance of 110 mm from the heat source. 3.Turn on the power control unit and set the power control knob to maximum. 4.After radiometer reading stabilizes, note the value of the plate’s temperature and radiometer readings simultaneously. Also note the value of the ambient temperature at the same time since this value will be used in the equations. 5.Decrease the temperature of the plate by turning down the power control knob to the next mark and repeat step d until you record at least 5 data points.

Experimental Procedure  Emissivity 1 1. Metal plate distance set to 50 mm 2. Radiometer distance set to 110 mm 3. Turn on power and set to max 4. Allow radiometer to stabilize and take note of readings of temp in plate and radiometer readings 5. Decrease the power with the knob and repeat the previous step 5 times. 6. Change plate and repeat procedure.

Experimental Procedure  Emissivity 2 1. Set Matt Black Plate at 50mm from the heat source 2. Set the Radiometer at 110mm from the heat source 3. Turn on the power control unit and put in the max mark 4. Allow for the radiometer reading to stabilize and note the temperature and read the radiometer 5. The silver plate at 20mm from the first plate

Experimental Procedure  Area factors 1. Black plate distance set to 50mm. 2. Aperture plate distance set to 200mm. 3. Radiometer distance set to 300mm. 4. Turn on the power and set to the maximum position. 5. Aperture plate set at 60mm. 6. Close the aperture by 10mm relative to track 7. Repeat the step 6 with increments of 10mm until 0 mm

Experimental Results

Results: Grafts and Calculations

Results: Calculations

Results: Graphics and Calculations

Results: Calculations

Conclusion  In conclusion we performed various measurements to see how much radiation gets emitted in different types of surfaces. We utilized the Stefan-Boltzmann law to help us understand the principles of heat transfer by way of radiation and in which way different surfaces absorb and reflect energy been received by radiation. We used three different plates: black plate, silver anodized plate and polished plate.  With the black plate, the majority of the energy that was emitted by the source got absorbed, an average emissivity of 1 was calculated. When we used the polished plate, the majority of the emitted energy was reflected, the average emissivity of 0.1 was calculated, and finally with the Silver anodized plate we noticed an average emissivity of 0.9.  When we verified the Area Factor test, we observed the readings from the radiometer was directly affected by the aperture. The closer the radiometer to the aperture the least amount of energy that was emitted.

Recommendation  For this experiment is necessary that the temperature of the environment stay at a constant state at all time, do to the unstable state of the temperature it will influence the data acquired and affect heat transfer of the plates, the readings will keep increasing and decreasing constantly and will not reach a steady state. This is more related with the air conditioner of the classroom that is always turning on and off. Also the ambient thermometer must be positioned in a good spot to avoid any variation from the humans around.  Is very important to inspect the plates to avoid getting loose and also keep checking the power from the power supply to acquired fair readings.