Chemiluminescence spectroscopy to explore the flame temperature

Abstract

To explore the behavior of near-extinction flamelets in turbulent premixed flames, emission intensities of OH, CH and C2 radicals of hydrocarbon-air premixed flames have been examined using the newly developed emission spectroscopy system. It has been shown in our previous study that the emission intensity ratio of 515.5 nm/470.5 nm bands of C2 radical uniquely depends on the temperature of unstrained methane/air and propane/air flames. In the present study, to establish the technique that estimates the temperature of the near-extinction flamelet of turbulent premixed flames, the relation between the temperature and the emission intensity ratio of 515.5 nm/470.5 nm bands of C2 radical of strained flames has been sought by using a counter-flow burner. The unique relation between the flame temperature and the emission intensity ratio of 515.5 nm/470.5 nm bands of C2 radical has been found to exist for the Propane-air and the Butane-air strained flames. Therefore, it can be concluded that the temperature of flamelets of the Propane-air and the Butane-air turbulent premixed flames can be estimated by using the relation between the temperature of the strained flame and the emission intensity ratio of 515.5 nm/470.5 nm bands of C2 radical obtained in the present study.

Effects of fuel on the performance of miniature vortex combustion power system

“…The possible factor which can cause such incomplete combustion and thus, the drastic decrease in the output power is well-known "Lewis number effects" as the combustion tend to be weakened in fuel lean conditions for propane, butane / air mixture whereas maintained for methane / air mixture. Again, the flame temperature cannot be measured in a significantly narrow combustion chamber as its diameter is on the same order of quenching diameter, therefore, the only way to elucidate the Lewis number effect in a small combustion chamber is direct flame observation (Kawasoe et al, 2017). The Lewis number effect directly appears as strengthening / weakening of flame luminosity, the flame observation experiments are conducted in the next step with a perfectly optically accessible micro vortex combustor fabricated with quartz.…”