Investigations of Chemiluminescence Characteristics in CH₄/O₂ Jet Diffusion Flames Impinging on the Flat Plate

ABSTRACT

Chemiluminescence information of the excited state radicals is significant for flame spectral diagnostics of practical diffusion flames. According to OH*, CH*, and C₂* emissions, the effects of different conditions on the flame chemiluminescence and structure characteristics were discussed in this study. The results showed that, with the increase of burner-to-plate distance (L/D_e), the flame changes from envelope shape to conical shape, which affects the reaction region of a flame. The reaction region of an impinging flame could be divided into two parts: the jet core section near the nozzle exit and the impinging section near the flat plate. Due to the change of flow field, the size of the reaction region in impinging section increases first and then decreases with the increase of L/D_e. Moreover, the equivalence ratio [O/C]_e and L/D_e are the two factors influencing the size of the reaction region, and the length of a reaction region can be predicted by these two parameters.

KEYWORDS:

• Chemiluminescence
• Diffusion flame
• Equivalence ratio
• Flame structure
• Impinging

Funding

This work has been partially supported by the National Natural Science Foundation of China (51406056), the Fundamental Research Funds for the Central Universities (222201514336), and the Shanghai Pujiang Program (15PJD011).

Additional information

Funding

This work has been partially supported by the National Natural Science Foundation of China (51406056), the Fundamental Research Funds for the Central Universities (222201514336), and the Shanghai Pujiang Program (15PJD011).