Dissertation
Development of an optical thermography system using a pumped two-dye fluorescence technique
Doctor of Philosophy (Ph.D.), Drexel University
Mar 2023
DOI:
https://doi.org/10.17918/00001601
Abstract
A novel backside thermography technique has been developed based on the temperature sensitivity of laser-induced fluorescence in flowing two-dye solutions. The approach utilizes visible light and optically transparent packaging materials to obtain spatially resolved transient thermal measurements. This makes it a relatively simple, inexpensive, and flexible approach for lab-scale experimental characterizations using economical cameras and optics. Additionally, this technique is compatible with optically transparent water-cooled packaging, which will allow for the characterization of processes where heat is added as well as removed. A custom-built experimental setup was designed, constructed, and used to study the performance of seven two-dye Rhodamine B (RhB)-Rhodamine 110 (Rh110) fluorescent solutions. The effect of dye concentration ratio on sensitivity, maximum frame rate, and excitation area was characterized. Using an optimal dye concentration of unity, it was shown that frame rates of 265 to 3200 Hz are achievable for excitation areas with diameters of 15.5 to 4.3 mm, respectively, using the current setup. The calibrated system was used to demonstrate in-situ temperature measurements, showing the importance of two-dye light compensation, as well as backside thermography using a simple droplet contact method to investigate temporal response. Droplet contact experiments were conducted on actively heated and cooled surfaces to study local temperature and heat flux behavior during phase change. Experiments were conducted in the range of 15 to 55 °C with a spatial resolution of 25 to 30 [mu]m. The experimental uncertainty of the temperature and heat flux measurements was calculated to be ±2.1 °C and ±0.03 W/cm2, respectively. Good agreement was found between the experimental and predicted results, showing the technique's ability to account for error due to light fluctuations and non-uniform illumination. Finally, the effect of dye photobleaching during prolonged testing was studied and it was shown that photobleaching can be reduced, and even eliminated, by maintaining a nominal low flow rate of the pumped two-dye solution.
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Details
- Title
- Development of an optical thermography system using a pumped two-dye fluorescence technique
- Creators
- Deborah Kapilow Price
- Contributors
- Matthew McCarthy (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xiii , 106 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Engineering (1970-2026); Mechanical Engineering (and Mechanics) (1970-2026); Drexel University
- Other Identifier
- 991020215915704721