Effect of continuous Mach number variation of incoming flow on ram–scram transition in a dual-mode combustor

Abstract Experimental and numerical investigation for a strut dual-mode combustor has been conducted in this paper. A Laval nozzle of alterable throat area is developed to change the incoming flow Mach number in isolator entrance. The Mach number of isolator entrance could be altered from 2.5 Ma to 2.0 Ma. By changing incoming flow Mach number, we obtained different pressure distribution variation at constant equivalence ratio. At 0.53 equivalence ratio, the pressure distribution in isolator and combustor has a different variation trend comparing with equivalence ratio 0.4. With incoming flow Mach number decreasing, the length of the shock train is shortened and pressure peak elevates. During the Mach number variation, the combustion heat release zone has a shift to strut. There is a balance for the combustion velocity and airflow velocity. The higher static temperature is also benefit for promoting combustion speed. The combustion zone shift makes more pressure increment act on the expansion segment to produce extra thrust under low incoming flow Mach number. Meanwhile, a ram–scram transition has taken place when the incoming flow Mach number variation. Further a subsonic discontinuity gap appears at constant segment and the thermal throat is chocked. The mass flow rate reaches up limits and leads to a two-stage pressure variation. The location of pressure variation would affect the combustor thrust.

[1]  Li Yan,et al.  Numerical exploration of mixing and combustion in a dual-mode combustor with backward-facing steps , 2016 .

[2]  Matthew Fotia,et al.  Isolator-Combustor Interactions in a Direct-Connect Ramjet-Scramjet Experiment , 2012 .

[3]  M. Sun,et al.  Flame Flashback in a Supersonic Combustor Fueled by Ethylene with Cavity Flameholder , 2015 .

[4]  Nickolay Smirnov,et al.  Detonation engine fed by acetylene–oxygen mixture , 2014 .

[5]  Wei Huang,et al.  Molecular weight and injector configuration effects on the transverse injection flow field properties in supersonic flows , 2014 .

[6]  Daren Yu,et al.  Effect of Mach number and equivalence ratio on the pressure rising variation during combustion mode transition in a dual-mode combustor , 2018 .

[7]  Jinglei Xu,et al.  Design of an Asymmetric Scramjet Nozzle with Circular to Rectangular Shape Transition , 2014 .

[8]  Li Yan,et al.  Numerical investigation on the ram–scram transition mechanism in a strut-based dual-mode scramjet combustor , 2016 .

[9]  Rui Xue,et al.  Combustion oscillation study in a kerosene fueled rocket-based combined-cycle engine combustor , 2016 .

[10]  Jun Liu,et al.  Effect of cavity location on combustion flow field of integrated hypersonic vehicle in near space , 2011, J. Vis..

[11]  Nickolay Smirnov,et al.  Deflagration-to-detonation transition in gases in tubes with cavities , 2010 .

[12]  Xianggeng Wei,et al.  Large eddy simulation of combustion characteristics in a kerosene fueled rocket-based combined-cycle engine combustor , 2016 .

[13]  Wen Bao,et al.  Flow field characteristics analysis and combustion modes classification for a strut/cavity dual-mode combustor , 2017 .

[14]  Jun-tao Chang,et al.  Experimental and numerical investigation on hysteresis characteristics and formation mechanism for a variable geometry dual-mode combustor , 2017 .

[15]  Wen Bao,et al.  Numerical and experimental investigation of improving combustion performance of variable geometry dual-mode combustor , 2017 .

[16]  Ye Tian,et al.  Experimental and numerical investigations of combustion mode transition in a direct–connect scramjet combustor , 2015 .

[17]  Christopher P. Goyne,et al.  Experimental Study of Vitiation Effects on Scramjet Mode Transition , 2011 .

[18]  Haiyan Wu,et al.  Combustion modes of hydrogen jet combustion in a cavity-based supersonic combustor , 2013 .

[19]  Kuo-Cheng Lin,et al.  Penetration heights of liquid jets in high-speed crossflows , 2002 .

[20]  Sadatake Tomioka,et al.  Experimental Study on Effect of Boundary Layer on Combustion Modes in a Supersonic Combustor , 2010 .

[21]  S. Sujith,et al.  Effect of Trailing Ramp Angles in Strut-Based Injection in Supersonic Flow , 2013 .

[22]  Matthew Fotia,et al.  Mechanics of Combustion Mode Transition in a Direct-Connect Ramjet–Scramjet Experiment , 2015 .

[23]  Jun-tao Chang,et al.  Numerical studies for performance improvement of a variable geometry dual mode combustor by optimizing deflection angle , 2017 .

[24]  J. Driscoll,et al.  Combustion characteristics of a dual-mode scramjet combustor with cavity flameholder , 2009 .

[25]  Daren Yu,et al.  Numerical investigation of the impact of asymmetric fuel injection on shock train characteristics , 2014 .

[26]  V. Babu,et al.  Numerical investigation of the supersonic combustion of kerosene in a strut-based combustor , 2010 .

[27]  Ronald S. Fry,et al.  A Century of Ramjet Propulsion Technology Evolution , 2004 .

[28]  Jun-tao Chang,et al.  Pressure rising slope variation accompanying with combustion mode transition in a dual-mode combustor , 2017 .

[29]  Matthew Fotia,et al.  Ram-Scram Transition and Flame/Shock-Train Interactions in a Model Scramjet Experiment , 2013 .

[30]  Jens von Wolfersdorf,et al.  Experimental Study on Combustion Mode Transition in a Scramjet with Parallel Injection , 2006 .

[31]  Daniel B. Le,et al.  Experimental Study of a Dual-Mode Scramjet Isolator , 2005 .

[32]  Takeshi Kanda,et al.  Dual-Mode Operations in a Scramjet Combustor , 2004 .