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Measurements and analysis of atomic emission from atomic Li, Na, and K seeded in different flames for potential application to temperature sensing

Zhang, Yuhe LU (2017) FYSK02 20171
Department of Physics
Combustion Physics
Abstract
Alkali metal atoms, especially sodium and potassium, show an intense fluorescence in hot flue gases. The bright fluorescence emitted by alkali metal atoms offers a large potential for spectroscopic combustion analysis. In this thesis, the temperature dependence of the two-component fluorescence intensity ratio Na/K, as well as the three-component ratio Na·Li/K2 was investigated in the flames with known relative concentrations of seeded alkali elements. A theoretical simulation based on thermal radiation excitation was performed to describe the temperature dependence of fluorescence intensity ratios Na/K and Na·Li/K2 in burned gas region. However, measurements show that the two-component fluorescence intensity ratio Na/K is pretty sensitive... (More)
Alkali metal atoms, especially sodium and potassium, show an intense fluorescence in hot flue gases. The bright fluorescence emitted by alkali metal atoms offers a large potential for spectroscopic combustion analysis. In this thesis, the temperature dependence of the two-component fluorescence intensity ratio Na/K, as well as the three-component ratio Na·Li/K2 was investigated in the flames with known relative concentrations of seeded alkali elements. A theoretical simulation based on thermal radiation excitation was performed to describe the temperature dependence of fluorescence intensity ratios Na/K and Na·Li/K2 in burned gas region. However, measurements show that the two-component fluorescence intensity ratio Na/K is pretty sensitive to the gas temperature whereas the three-component ratio Na·Li/K2 is less temperature dependent. The hot flue gas environment was provided by a modified Perkin-Elmer burner and the alkali metal atoms (Na, K, and Li) were provided through Na2CO3, K2CO3, and Li2CO3 water solution seeding. (Less)
Popular Abstract
Are you curious about what is happening when you look upon the sky seeing beautiful fireworks? Have you ever stared at the candle wondering what is inside the flame when you enjoy a candlelit dinner? They are all about combustion physics.

People are not strange to combustion since our ancestors firstly knew how to generate a fire. What you may not know is flame can emit colorful fluorescence when metal atoms are added. Different metal atoms show different flame color. For sodium, the flame color is yellow; while for potassium, it is purple red. This bright fluorescence emitted by the metal atoms can provide us with abundant information about the flame.

This project aims to find the relationship between the flame temperature and the... (More)
Are you curious about what is happening when you look upon the sky seeing beautiful fireworks? Have you ever stared at the candle wondering what is inside the flame when you enjoy a candlelit dinner? They are all about combustion physics.

People are not strange to combustion since our ancestors firstly knew how to generate a fire. What you may not know is flame can emit colorful fluorescence when metal atoms are added. Different metal atoms show different flame color. For sodium, the flame color is yellow; while for potassium, it is purple red. This bright fluorescence emitted by the metal atoms can provide us with abundant information about the flame.

This project aims to find the relationship between the flame temperature and the alkali metal fluorescence intensities. It is possible to develop a temperature-measurement method based on this relationship. We established a theoretical model to describe the temperature dependence of the three-component fluorescence intensity ratio Na·Li/K2 and the two-component ratio Na/K based on the understanding of involved physical and chemical process. The temperature dependence of those two ratios was also measured from experiments and compared to the prediction.

The cheapest and most common way to measure the temperature in laboratory today is using a temperature sensor called "thermocouple", which, however, is unstable and inaccurate. If a more accurate temperature is needed, it is very expensive. Therefore, it is valuable to investigate the temperature sensing of alkali metal or other atoms and hopefully develop a novel temperature-measurement method based on related researches. Imagine how convenient it will be if we can obtain the temperature of flame by just spraying some fuel additives to it! (Less)
Please use this url to cite or link to this publication:
author
Zhang, Yuhe LU
supervisor
organization
course
FYSK02 20171
year
type
M2 - Bachelor Degree
subject
keywords
Flame Emission Spectroscopy, temperature measurement, alkali metal atoms
language
English
id
8912194
date added to LUP
2017-06-16 11:30:45
date last changed
2017-06-16 11:30:45
@misc{8912194,
  abstract     = {Alkali metal atoms, especially sodium and potassium, show an intense fluorescence in hot flue gases. The bright fluorescence emitted by alkali metal atoms offers a large potential for spectroscopic combustion analysis. In this thesis, the temperature dependence of the two-component fluorescence intensity ratio Na/K, as well as the three-component ratio Na·Li/K2 was investigated in the flames with known relative concentrations of seeded alkali elements. A theoretical simulation based on thermal radiation excitation was performed to describe the temperature dependence of fluorescence intensity ratios Na/K and Na·Li/K2 in burned gas region. However, measurements show that the two-component fluorescence intensity ratio Na/K is pretty sensitive to the gas temperature whereas the three-component ratio Na·Li/K2 is less temperature dependent. The hot flue gas environment was provided by a modified Perkin-Elmer burner and the alkali metal atoms (Na, K, and Li) were provided through Na2CO3, K2CO3, and Li2CO3 water solution seeding.},
  author       = {Zhang, Yuhe},
  keyword      = {Flame Emission Spectroscopy,temperature measurement,alkali metal atoms},
  language     = {eng},
  note         = {Student Paper},
  title        = {Measurements and analysis of atomic emission from atomic Li, Na, and K seeded in different flames for potential application to temperature sensing},
  year         = {2017},
}