Burning velocity and flame structure of CH4/NH3/air turbulent premixed flames at high pressure

• Published in: International journal of hydrogen energy Vol. 44; no. 13; pp. 6991 - 6999
• Main Authors: Ichikawa, Akinori, Naito, Yuji, Hayakawa, Akihiro, Kudo, Taku, Kobayashi, Hideaki
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 08.03.2019
• Subjects: Ammonia; High pressure; Methane; Turbulent burning velocity; Turbulent combustion; Methane; Ammonia; Turbulent burning velocity; Turbulent combustion; High pressure
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2019.01.193

Ammonia is one of the most promising alternative fuels. In particular, ammonia combustion for gas turbine combustors for power generation is expected. To shift the fuel for a gas turbine combustor to ammonia step-by-step, the partial replacement of natural gas by ammonia is considered. To reveal the turbulent combustion characteristics, CH4/NH3/air turbulent premixed flame at 0.5 MPa was experimentally investigated. The ammonia ratio based on the mole fraction and lower heating value was varied from 0 to 0.2. The results showed that the ratio of the turbulent burning velocity and unstretched laminar burning velocity decreased with an increase in the ammonia ratio. The reason for this variation is that the flame area decreased with an increase in the ammonia ratio as the flame surface density decreased and the fractal inner cutoff increased. The volume fractions in the turbulent flame region were almost the same with ammonia addition, indicating that combustion oscillation can be handled in a manner similar to that for the case of natural gas for CH4/NH3/air flames. •Turbulent combustion characteristics of CH4/NH3/air at 0.5 MPa were experimentally revealed.•The ratios of turbulent and laminar burning velocity decreased with an increase in ammonia ratio.•The flame fronts became blunt with an increase in ammonia ratio.•Volume fractions of the turbulent flame region were similar weather CH4/NH3/air flames or not.