Study on Combustion Oscillation of Premixed Flame with Pilot Fuel at Elevated Pressures

• Published in: Journal of Thermal Science and Technology Vol. 4; no. 1; pp. 74 - 85
• Main Authors: OHTSUKA, Masaya, YOSHIDA, Shohei, HIRATA, Yoshitaka, KOBAYASHI, Nariyoshi
• Format: Journal Article
• Language: English
• Published: Tokyo The Japan Society of Mechanical Engineers and The Heat Transfer Society of Japan 01.01.2009; Japan Science and Technology Agency; The Japan Society of Mechanical Engineers
• Subjects: Combustion Oscillation; Elevated Pressure; Flame Length; Pilot Fuel; Premixed Flame; Premixed Fuel Rate
• ISSN: 1880-5566; 1880-5566
• DOI: 10.1299/jtst.4.74

Acoustically-coupled combustion oscillation is studied for premixed flame with pilot fuel to be used in gas turbine combustors. Premixed gas is passed through swirl vanes and burnt with the centrally injected pilot fuel. The dependencies of pressure, fuel to air ratio, premixed fuel rate, inlet velocity and air temperature on the combustion oscillation are investigated. Two kinds of oscillation modes of ∼100Hz and ∼350Hz are activated according to inlet velocities. Fluctuating pressures are amplified when the premixed fuel rate is over ∼80% at elevated pressures. The fluctuating pressure peak moves to a higher premixed fuel ratio region with increased pressure or fuel to air ratio for the Helmholz type mode. Combustion oscillation occurs when the pilot fuel velocity is changed proportionally with the flame length.