Thin filament pyrometry is a proven technique used to measure flame temperature by capturing the spectral radiance produced by the immersion of silicon carbide filaments in a hot gas environment. In this study a commercially available CMOS color camera was used, and the spectral response of each color channel was integrated with respect to the assumed graybody radiation spectrum to form a look up table between color ratio and temperature. Interpolated filament temperatures are then corrected for radiation losses via an energy balance to determine the flame temperature. Verification of the technique was performed on the Holthuis and Associates Flat Flame Burner, formerly known as the Mckenna Burner, and the results are directly compared to literature values measured on a similar burner. The results are also supported by radiation corrected measurements taken using a type B thermocouple on the same burner setup. An error propagation analysis was performed to determine which factors contribute the most to the final measurement uncertainty and confidence intervals are calculated for the results. Uncertainty values for a single point measurement were determined to be between ±15 and ±50 K depending on the color ratio and the total uncertainty associated with day-to-day changes in the measurement setup was found to be ±55 K. / Master of Science / Determination of flame temperature is an important aspect of combustion research and is often critical to the evaluation of combustion systems as well as the integration of those systems into more complex devices. In this thesis the technique of thin filament pyrometry was implemented and verified through the use of a well characterized calibration flame. This technique involves placing thin filaments usually made from silicon carbide into the flame and capturing the spectrum of light they emit with a detector. Since the amount of light emitted as well as which wavelengths the light is concentrated in is a strong function of temperature, this methodology may be used to calculate the temperature of the flame. Thin filament pyrometry has the advantage compared to other techniques in that it is extremely cheap to implement and requires no advanced scientific equipment. The SiC filaments have been shown to have a very high resistance to the flame environment and do not face many of the same challenges that can cause problems for other techniques. A statistical analysis of the method implemented in this work was also performed and the expected uncertainty was similar to many of the alternative techniques which necessitate a more complex or expensive setup.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/115680 |
| Date | 07 July 2023 |
| Creators | Hagmann, Kai Alexander |
| Contributors | Aerospace and Ocean Engineering, Meadows, Joseph, Lowe, Kevin T., Young, Gregory |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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