Lean blowout characteristics of spray flame in a multi-swirl staged combustor under different fuel decreasing rates
), Abstract
Lean Blow Out (LBO) poses a significant safety hazard when occurring in aero-engines. Understanding the lower stability limits of gas turbine combustors and the characteristics of spray flame close to LBO are imperative for safe operation. The objective of this work is to evaluate the effects of fuel decreasing rates and pressure drops of the injector on LBO performances in a multi-swirl staged combustor equipped with an airblast injector. A set of hardware and control system was developed to realize a user-defined fuel supply law. High-speed imaging was applied to record complete LBO processes under the conditions of linear fuel reduction and stable airflow. Partical Image Velocimetry (PIV) and Planar Mie (PMie) scattering were used to acquire the flow fields and spray fields under non-reacting conditions. Experimental results have shown that LBO limits extend to leaner conditions as the pressure drop of the injector increases. With an increase of the fuel decreasing rate, the exhaust temperature before flame extinction increases, and the LBO Fuel-to-Air-Ratio (FAR) decreases. The time evolution of the integral CH* intensity conforms to a linear function during the LBO process. Proper Orthogonal Decomposition (POD) was used to analyze the dynamic characteristics of lean-burn flames. Under different fuel decreasing rates and pressure drops of the injector, flames close to LBO present similar modal spatial distributions, alternately appearing axial, radial, high-order axial, and high-order radial oscillations.
References
Liu YZ, Sun XX, Sethi V, et al. Review of modern low emissions combustion technologies for aero gas turbine engines. Prog Aerosp Sci 2017;94:12–45.
Huang Y, Yang V. Dynamics and stability of lean-premixed swirl-stabilized combustion. Prog Energy Combust Sci 2009;35(4):293–364.
Stöhr M, Boxx I, Carter C, et al. Dynamics of lean blowout of a swirl-stabilized flame in a gas turbine model combustor. Proc Combust Inst 2011;33(2):2953–60.
Esclapez L, Ma PC, Mayhew E, et al. Fuel effects on lean blow-out in a realistic gas turbine combustor. Combust Flame 2017;181:82–99.
Bhattacharya C, De S, Mukhopadhyay A, et al. Detection and classification of lean blow-out and thermoacoustic instability in turbulent combustors. Appl Therm Eng 2020;180:115808.
Chang LY, Cao Z, Fu B, et al. Lean blowout detection for bluff-body stabilized flame. Fuel 2020;266:117008.
Zubrilin IA, Gurakov NI, Matveev SG. Lean blowout limit prediction in a combustor with the pilot flame. Energy Procedia 2017;141:273–81.
Wang ZH, Hu B, Deng AM, et al. Predicting lean blow-off of bluffbody stabilized flames based on Damköhler number. Chin J Aeronaut 2019;32(2):308–23.
Rao ZM, Li RC, Zhang B, et al. Experimental investigations of equivalence ratio effect on nonlinear dynamics features in premixed swirl-stabilized combustor. Aerosp Sci Technol 2021;112:106601.
De Giorgi MG, Fontanarosa D, Ficarella A, et al. Effects on performance, combustion and pollutants of water emulsified fuel in an aeroengine combustor. Appl Energy 2020;260:114263.
Yin ZY, Boxx I, Meier W. Influence of self-sustained jet oscillation on a confined turbulent flame near lean blow-out. Proc Combust Inst 2017;36(3):3773–81.
Huang Y, Yang V. Bifurcation of flame structure in a lean-premixed swirl-stabilized combustor: transition from stable to unstable flame. Combust Flame 2004;136(3):383–9.
Liu FQ, Zhang KY, Mu Y, et al. Experimental investigation on ignition and lean blow-out performance of a multi-sector centrally staged combustor. J Therm Sci 2014;23(5):480–5.
Colborn JG, Heyne JS, Stouffer SD, et al. Chemical and physical effects on lean blowout in a swirl-stabilized single-cup combustor. Proc Combust Inst 2021;38(4):6309–16.
Yang JH, Liu CX, Liu FQ, et al. Experimental and numerical study of the effect of main stage stratifier length on lean blow-out performance for a stratified partially premixed injector. Proc Inst Mech Eng A J Power Energy 2018;232(7):812–25.
Lefebvre AH, Ballal DR. Gas turbine combustion. New York: CRC Press; 2010.
Ma HA, Xie MZ, Zeng W, et al. Experimental study on combustion characteristics of Chinese RP-3 kerosene. Chin J Aeronaut 2016;29(2):375–85.
Gal PL, Farrugia N, Greenhalgh DA. Laser sheet dropsizing of dense sprays. Opt Laser Technol 1999;31(1):75–83.
Yang SH, Zhang C, Lin YZ, et al. Experimental investigation of the ignition process in a separated dual-swirl spray flame. Combust Flame 2020;219:161–77.
Lin BX, Wu Y, Xu MX, et al. Experimental investigation on spark ignition and flame propagation of swirling kerosene spray flames. Fuel 2021;303:121254.
Liu CX, Liu FQ, Yang JH, et al. Investigations of the effects of spray characteristics on the flame pattern and combustion stability of a swirl-cup combustor. Fuel 2015;139:529–36.
Peiffer EE, Heyne JS, Colket M. Sustainable aviation fuels approval streamlining: auxiliary power unit lean blowout testing. AIAA J 2019;57(11):4854–62.
Chatterjee A. An introduction to the proper orthogonal decomposition. Curr Sci 2000;78(7):808–17.
Iudiciani P, Duwig C, Husseini SM, et al. Proper orthogonal decomposition for experimental investigation of flame instabilities. AIAA J 2012;50(9):1843–54.
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