Temperaturas rotacionais de CH* em chamas de etanol com diferentes gases diluentes foram determinadas por emissão natural. Estruturas finas do espectro indicaram duas temperaturas rotacionais. Os resultados dos níveis de simetria A" foram ligeiramente maiores que os A'. Os valores também indicaram uma distribuição fora de equilíbrio.

Rotational temperatures of CH* species present in ethanol flames with different diluent gas compositions were determined using natural emission spectroscopy. Spectrum fine-structures showed two different rotational temperatures. The results of A" symmetry levels were slightly higher than A' for all flames investigated. The temperature values also indicated a non-equilibrium distribution.

OH LIF-thermometry was applied to premixed ethanol flames at atmospheric pressure in a burner for three flame conditions. Flame temperatures were simulated from energy equation with PREMIX code of CHEMKIN software package for comparison. A kinetic modeling based on a model validated through chemiluminescence measurements and on a set of reactions for nitrogen chemistry was evaluated. Marinov's mechanism was also tested. Sensitivity analysis was performed for fuel-rich flame condition with Φ = 1.34. Simulated temperatures from both reaction mechanisms evaluated were higher than experimental values. However, the proposed kinetic modeling resulted in temperature profiles qualitatively very close to the experimental.

A espectroscopia de emissão foi utilizada na determinação da temperatura de chamas pré-misturadas de GLP. Investigou-se a emissão natural de radicais CH* em três diferentes condições de queima: razão estequiométrica de combustível/oxidante, excesso de combustível (chama rica) e excesso de oxidante (chama pobre). O valor médio obtido para a temperatura rotacional de CH* foi de 2845 ± 70 K nas condições utilizadas nos experimentos. Esse valor não variou significativamente com os demais tipos de chama e é compatível com os cálculos de temperatura adiabática dos sistemas estudados. Essa temperatura também é concordante com resultados obtidos por via indireta, utilizando-se o método de linha reversa de sódio, que consiste em uma técnica bem estabelecida e independente da emissão natural. Temperaturas vibracionais de ca. 4600 K foram calculadas, indicando que o tempo de vida do CH* não é suficiente para que o equilíbrio entre os modos rotacionais e vibracionais seja estabelecido.

Emission spectroscopy was used in the temperature determination of LPG (liquefied petroleum gas) premixed flames. Natural emission of CH* radicals was investigated in flames under three different burning conditions: fuel/oxydizer stoichiometric ratio, fuel excess (rich flame), and oxidizer excess (lean flame). An average value of 2845 ± 70 K was obtained for CH* rotational temperature in the set up used in the experiments. This value did not show significant change with the type of flame analyzed and it is compatible with the calculated adiabatic flame temperatures of the investigated systems. This temperature value also agrees with that determined by an indirect measurement, using the sodium line reversal method, which is independent from the radical natural emission and well established in literature. Vibrational temperatures of ca. 4600 K were calculated, indicating that the CH* lifetime is insufficient for the establishment of an equilibrium state between the rotational and vibrational modes.