To study the effect of microwave enhanced gliding arc plasma on supersonic combustion, an experiment is carried out on a direct-connected scramjet facility that has installed microwave and gliding arc structures. A single-stage cavity is used as flame stabilizer. The inlet Mach number of combustor is 2.5. The room temperature ethylene is injected perpendicular from the combustor wall, the gliding arc electrode is set in front of fuel jet point, and 2.45 GHz microwave is fed into scramjet in the opposite side of the cavity. The results show that the gliding arc in the scramjet combustor also follows the periodic characteristics of discharge and expansion. Due to the extremely high airflow rate, the gliding arc period is approximately 125 kHz. The plasma causes the pre-combustion shock train of the combustor to move forward, and the initial and stable position of the flame is transferred from the cavity shear layer to the front of the fuel jet, and the supersonic flame rate is increased. Compared with a single microwave or the gliding arc plasma method, the combination of microwave and gliding arc can achieve high power microwave equivalent effect at a lower energy consumption. The study concludes that the microwave enhanced gliding arc plasma can stabilize the supersonic combustion.
[1] BILLIG F S. Research on supersonic combustion[J]. Journal of Propulsion and Power, 1993, 9(4):499-514.
[2] JU Y G, SUN W T. Plasma assisted combustion:Dynamics and chemistry[J]. Progress in Energy and Combustion Science, 2015, 48:21-83.
[3] DOOLEY S, WON S H, HEYNE J, et al. The experimental evaluation of a methodology for surrogate fuel formulation to emulate gas phase combustion kinetic phenomena[J]. Combustion and Flame, 2012, 159(4):1444-1466.
[4] ZHU S H, XU X, JI P F. Flame stabilization and propagation in dual-mode scramjet with staged-strut injectors[J]. AIAA Journal, 2017, 55(1):171-179.
[5] ZHANG Y, ZHU S H, CHEN B, et al. Hysteresis of mode transition in a dual-struts based scramjet[J]. Acta Astronautica, 2016, 128:147-159.
[6] ZHU S H, XU X, YANG Q C, et al. Intermittent back-flash phenomenon of supersonic combustion in the staged-strut scramjet engine[J]. Aerospace Science and Technology, 2018, 79:70-74.
[7] ZHANG J L, CHANG J T, MA J C, et al. Investigation of flame establishment and stabilization mechanism in a kerosene fueled supersonic combustor equipped with a thin strut[J]. Aerospace Science and Technology, 2017, 70:152-160.
[8] MASUMOTO R, TOMIOKA S, KUDO K, et al. Experimental study on combustion modes in a supersonic combustor[J]. Journal of Propulsion and Power, 2011, 27(2):346-355.
[9] JU Y G, SUN W T. Plasma assisted combustion:Progress, challenges, and opportunities[J]. Combustion and Flame, 2015, 162(3):529-532.
[10] LI F, YU X L, TONG Y G, et al. Plasma-assisted ignition for a kerosene fueled scramjet at Mach 1.8[J]. Aerospace Science and Technology, 2013, 28(1):72-78.
[11] CAI Z, ZHU J J, SUN M B, et al. Spark-enhanced ignition and flame stabilization in an ethylene-fueled scramjet combustor with a rear-wall-expansion geometry[J]. Experimental Thermal and Fluid Science, 2018, 92:306-313.
[12] FENG R, LI J, WU Y, et al. Experimental investigation on gliding arc discharge plasma ignition and flame stabilization in scramjet combustor[J]. Aerospace Science and Technology, 2018, 79:145-153.
[13] LI X H, YANG L C, PENG J B, et al. Cavity ignition of liquid kerosene in supersonic flow with a laser-induced plasma[J]. Optics Express, 2016, 24(22):25362.
[14] AN B, WANG Z G, YANG L C, et al. Experimental investigation on the impacts of ignition energy and position on ignition processes in supersonic flows by laser induced plasma[J]. Acta Astronautica, 2017, 137:444-449.
[15] KHODATAEV K V. Microwave discharges and possible applications in aerospace technologies[J]. Journal of Propulsion and Power, 2008, 24(5):962-972.
[16] BAUROV A Y, SHIBKOVA L V, SHIBKOV V M, et al. External combustion of high-speed multicomponent hydrocarbon-air flow under conditions of low-temperature plasma[J]. Moscow University Physics Bulletin, 2013, 68(4):293-298.
[17] SHIBKOV V M, SHIBKOVA L V, KARACHEV A A, et al. The spatial-temporal evolution of combustion under conditions of low temperature discharge plasma of liquid alcohol injected into an air stream[J]. Moscow University Physics Bulletin, 2012, 67(1):138-142.
[18] SHIBKOV V M, SHIBKOVA L V, GROMOV V G, et al. Influence of surface microwave discharge on ignition of high-speed propane-air flows[J]. High Temperature, 2011, 49(2):155-167.
[19] SHIBKOV V M, SHIBKOVA L V. Parameters of the flame due to surface-microwave discharge-initiated inflammation of thin alcohol films[J]. Technical Physics, 2010, 55(1):58-65.
[20] BABUSHOK V I, DELUCIA F C, GOTTFRIED J L, et al. Double pulse laser ablation and plasma:Laser induced breakdown spectroscopy signal enhancement[J]. Spectrochimica Acta Part B:Atomic Spectroscopy, 2006, 61(9):999-1014.
[21] MICHAEL J B, DOGARIU A, SHNEIDER M N, et al. Subcritical microwave coupling to femtosecond and picosecond laser ionization for localized, multipoint ignition of methane/air mixtures[J]. Journal of Applied Physics, 2010, 108(9):093308.
[22] WOLK B, DEFILIPPO A, CHEN J Y, et al. Enhancement of flame development by microwave-assisted spark ignition in constant volume combustion chamber[J]. Combustion and Flame, 2013, 160(7):1225-1234.
[23] IKEDA Y, NISHIYAMA A, KANEKO M. Microwave enhanced ignition process for fuel mixture at elevated pressure of 1 MPa:AIAA-2009-0223[R]. Reston, VA:AIAA, 2009.
[24] ELSABBAGH M, KADO S, IKEDA Y, et al. Measurements of rotational temperature and density of molecular nitrogen in spark-plug assisted atmospheric-pressure microwave discharges by rotational Raman scattering[J]. Japanese Journal of Applied Physics, 2011, 50(7):076101.
[25] FRIDMAN A, NESTER S, KENNEDY L A, et al. Gliding arc gas discharge[J]. Progress in Energy and Combustion Science, 1999, 25(2):211-231.
[26] 孟宇,顾洪斌,张新宇. 微波对超声速燃烧火焰结构的影响[J]. 航空学报, 2019, 40(12):123224. MENG Y, GU H B, ZHANG X Y. Influence of microwave on structure of supersonic combustion flame[J]. Acta Aeronautica et Astronautica Sinica, 2019, 40(12):123224(in Chinese).
[27] WANG Z P, GU H B, CHENG L W, et al. CH* luminance distribution application and a one-dimensional model of the supersonic combustor heat release quantization[J]. International Journal of Turbo & Jet-Engines, 2019, 36(1):45-50.
[28] RAO X, HEMAWAN K, WICHMAN I, et al. Combustion dynamics for energetically enhanced flames using direct microwave energy coupling[J]. Proceedings of the Combustion Institute, 2011, 33(2):3233-3240.
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