We've Moved!
Visit SDSU’s new digital collections website at https://digitalcollections.sdsu.edu
Description
The following research investigates thermal radiation emitted by stabilized downward spreading flames in an effort to study the role radiative heat transfer plays in an opposed-flow flame spread configuration. Thermal radiation profiles are generated for thin sheets of polymethyl methacrylate (PMMA) and cellulose, with thickness being the primary parameter other than fuel identity. Additionally, a brief look is taken into the role of fuel color in the case of radiation emitted by thicker sheets of PMMA. Temperature and carbon dioxide fields are obtained in effort to better understand and explain the behavior of the measured radiation profiles. Experimental radiation trends are qualitatively compared to those predicted computationally by a radiation and CFD program. The studied flames were stabilized on SDSU’s Flame Stabilizer device via a radiometer fitted with a faceplate to approximate line-of-sight and a PID control system controlled by MATLAB. Thermal radiation profiles are generated with a similarly fitted line-of-sight radiometer probe for both stabilized and transient flames on this apparatus. A baseline case for a radiation profile is established using stabilized data after it is proved to be consistent with transient data. Subsequent radiation profiles are compared to this baseline. The surface and gas radiation contributions to the overall radiative profile are attempted to be separated in order to explain a distinct discontinuity observed when measuring the emission of PMMA fuels of a sufficient thickness. This is achieved by creating a hole in the fuel sample slightly larger than the field of view of the probe radiometer so as to remove the solid contribution. These findings are compared to radiation profiles computed by an existing flame simulation program. The lack of this discontinuity observation in cellulosic fuels lends itself towards further investigation. Data for temperature fields and CO2 profiles is also gathered on the Flame Stabilizer, this time using a K-Type thermocouple and CO 2 sensor, respectively. A set of MATLAB GUIs is developed for both data collection and processing.
