A numerical simulation of premixed methane-air gas at equivalence ratio 0.7 was conducted to investigate the flame stability of the low swirl combustion under the conditions of different bulk velocity from 10.12 m/s to 40.00 m/s
inlet temperature from 300 K to 500 K and inlet pressure from 101.325 kPa to 8×101.325 kPa. Mechanism of the combustion stability was revealed by analysis of flow field structure and flame characteristics of the low swirl injector. The results show that the bulk velocity
inlet temperature and inlet pressure exert small influences on the flow field structure
so the self-similar characteristics of the low swirl combustion remain. The mean axial aerodynamic stretch rate
the mean radial aerodynamic stretch rate and the virtual origin are almost not affected by the inlet conditions
which facilitates protecting the stability of flame front. The possibility of backfiring reduces with the increasing bulk velocity or the inlet pressure
while the possibility of backfiring increases with the increasing inlet temperature. The flame front of low swirl combustion retains its stability under wider inlet conditions.
关键词
Keywords
references
CHENG R K, FABLE S A, SCHMIDT D, et al. Development of a low swirl injector concept for gas turbines [C]∥Proceedings of 2001 International Joint Power Conference. New York, USA: ASME, 2001: 95-101.
CHAN C K, LAU K S, CHIN W K, et al. Freely propagating open premixed turbulent flames stabilized by swirl [C]∥ International Symposium on Combustion. Amsterdam, Netherlands: Elsevier Inc., 1992: 511-518.
JOHNSON M R, LITTLEJOHN D, NAZEER W A, et al. A comparison of the flowfields and emissions of high-swirl injectors and low-swirl injectors for lean premixed gas turbines [J]. Proceedings of the Combustion Institute, 2005, 30(2): 2867-2874
CHENG R K, LITTLEJOHN D, NAZEER W A, et al. Laboratory studies of the flow field characteristics of low-swirl injectors for adaptation to fuel-flexible turbines [J]. Journal of Engineering for Gas Turbines Power, 2006, 130(2): 277-285.
LITTLEJOHN D, CHENG R K. Fuel effects on a low-swirl injector for lean premixed gas turbines [J]. Proceedings of the Combustion Institute, 2007, 31(6): 3155-3162.
CHENG R K, LITTLEJOHN D. Effects of combustor geometry on the flowfields and flame properties of a low-swirl injector [C]∥ASME Turbo Expo 2008: Power for Land, Sea, and Air. New York, USA: ASME, 2008: 393-407.
NEUMAYER M. RANS simulation of methane combustion in a low swirl burner [D]. München, Germany: Technische Universitaet München, 2013.
YIN Hang, ZHONG Shili, DAI Ren, et al. Design of low swirl syngas burner and analysis on the flow pattern [J]. Journal of Chinese Society of Power Engineering, 2011, 31(2): 131-136.
LIU Weijie, GE Bing, TIAN Yinshen, et al. Equivalence ratio effects on low swirl combustion for premixed methane-air gas [J]. Combustion Science and Technology, 2014(1): 65-69.
KAZAKOV A, FRENKLACH M. Reduced reaction sets based on GRI-Mech 1.2 [DB/OL]. [2015-03-16]. http: ∥combustion.berkeley.edu/drm/ 1994.
LIU W, GE B, TIAN Y, et al. Experimental and numerical investigations of low-swirl multi-nozzle combustion in a lean premixed combustor [C]∥ASME Turbo Expo 2014. New York, USA: ASME, 2014: V04AT04A045.
DAY M, TACHIBANA S, BELL J, et al. A combined computational and experimental characterization of lean premixed turbulent low swirl laboratory flames: Ⅰ Methane flames [J]. Combustion and Flame, 2012, 159(1): 275-290.