Numerical study on supersonic combustion with cavity-based fuel injection

Kim, Kyung Moo; Baek, Seung Wook; Han, Cho Young

doi:10.1016/j.ijheatmasstransfer.2003.07.004

Cited by 195 publications

(57 citation statements)

References 21 publications

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“…To solve this problem, some fuel injection techniques have been proposed. The strut [5][6][7][8][9][10][11][12][13][14], the cavity [15][16][17][18], the cantilevered ramp [4], the backward facing step [19][20][21] and the combination [22][23][24][25], whose principle is to generate vorticity in the vicinity of the walls of the combustor. The region forming the vorticity, namely the recirculation zone, has low flow velocity.…”

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confidence: 99%

Parametric effects on the combustion flow field of a typical strut-based scramjet combustor

et al. 2011

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The flame-holding mechanism in hypersonic propulsion technology is the most important factor in prolonging the duration time of hypersonic vehicles. The two-dimensional coupled implicit Reynolds-averaged Navier-Stokes equations, the shear-stress transport k- turbulence model and the finite-rate/eddy-dissipation reaction models were used to simulate the combustion flow field of a typical strut-based scramjet combustor. We investigated the effects of the hydrogen-air reaction mechanism and fuel injection temperature and pressure on the parametric distributions in the combustor. The numerical results show qualitative agreement with the experimental data. The hydrogen-air reaction mechanism makes only a slight difference in parametric distributions along the walls of the combustor, and the expansion waves and shock waves exist in the combustor simultaneously. Furthermore, the expansion wave is formed ahead of the shock wave. A transition occurs from the shock wave to the normal shock wave when the injection pressure or temperature increases, and the reaction zone becomes broader. When the injection pressure and temperature both increase, the waves are pushed out of the combustor with subsonic flows. When the waves are generated ahead of the strut, the separation zone is formed in double near the walls of the combustor because of the interaction of the shock wave and the boundary layer. The separation zone becomes smaller and disappears with the disappearance of the shock wave. Because of the horizontal fuel injection, the vorticity is generated near the base face of the strut, and this region is the main origin for turbulent combustion. , hypersonic propulsion technology has drawn increasing attention from researchers. However, the flame-holding mechanism in the scramjet combustor cannot satisfy the requirement for cruising a long time in near-space [3] because of the short residence time of the mixture remaining in the supersonic flow, which is in the order of milliseconds [4]. This restricts improvement of the aerodynamic performance of hypersonic vehicles. To solve this problem, some fuel injection techniques have been proposed. The strut [5][6][7][8][9][10][11][12][13][14], the cavity [15][16][17][18], the cantilevered ramp [4], the backward facing step [19][20][21] and the combination [22][23][24][25], whose principle is to generate vorticity in the vicinity of the walls of the combustor. The region forming the vorticity, namely the recirculation zone, has low flow velocity. In this region the fuel mixes with the supersonic flow and the mixture can stay in the scramjet combustor for a long time. Zou et al. [6] have used a newly-proposed partiallyresolved numerical simulation procedure to investigate turbulent combustion in a two-dimensional DLR scramjet engine, and the large-scale turbulence was defined by the temporal filtering. Oevermann [7] has used a two-equation k- turbulence model combined with a stretched laminar

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confidence: 99%

Parametric effects on the combustion flow field of a typical strut-based scramjet combustor

et al. 2011

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“…The low incoming Mach number is of benefit to the mixing process in supersonic flows because of the fuel staying in the supersonic flow for only several milliseconds. 18,20) Meanwhile, the descending gradient of the maximum injectant mole fraction is larger for cases with a negative angle of attack, and this implies that the negative angle of attack has a greater impact on the mixing process than a positive one in this typical cantilevered ramp injector.…”

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confidence: 98%

Influences of Angles of Attack and Sideslip on the Flow Field of a Cantilevered Ramp Injector in Supersonic Flows

Huang

Wang

Liu

et al. 2014

Trans. Japan Soc. Aero. S Sci.

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The cantilevered ramp injector has been employed as an effective fuel injection strategy in the shock-induced combustion ramjet engine, and its flow field characteristics have attracted increasing attention. Three-dimensional ReynoldsAveraged Navier-Stokes (RANS) equations coupled with the RNG k-" turbulence model have been employed to investigate the flow field of a cantilevered ramp injector in a freestream with a Mach number of 6.0. The effects of the angles of attack and sideslip on the flow field of a cantilevered ramp injector have been studied, and the predicted axial distribution of the maximum injectant mole fraction shows good agreement with the available experimental data in public literature. The obtained results show that the case with an angle of attack 3 can promote the mixing process between the fuel and air most efficiently in a typical cantilevered ramp injector. However, it cannot prevent the premature ignition of the premixed combustible flow. The mixing process cannot be promoted when the normalized axial distance is larger than 7.55 in cases with different angles of sideslip, and larger angles of sideslip can reduce the effect of premature ignition for the premixed combustible flow.

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“…No-slip conditions (u=v=w =0) were assumed for wall boundaries. At the outflow, all the physical variables were extrapolated from the internal cells based on the flow being supersonic (Kim et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

Supersonic mixing augmentation mechanism induced by a wall-mounted cavity configuration

Huang

Ding

et al. 2016

JZUS-A

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Abstract:An efficient mixing process is very important for the engineering implementation of an airbreathing propulsion system. The air and injectant should be mixed sufficiently before entering the combustor. Two new wall-mounted cavity configurations were proposed to enhance the mixing process in a conventional transverse injection flow field. Their flow field properties were compared with those of a system with only transverse injection ports. Grid independency analysis was used to choose a suitable grid scale, and the mixing efficiencies at four cross-sectional planes (namely x=20, 40, 60, and 80 mm, which are just downstream of the jet orifice) were compared for the configurations considered in this study. The results showed that hydrogen penetrated deeper when a cavity was mounted upstream of the transverse injection ports. This is beneficial to the mixing process in supersonic flows. The mixing efficiency of the configuration with the wall-mounted cavity was better than that of the conventional physical model, and the mixing efficiency of the proposed novel physical model I (98.71% at x=20 mm) was the highest of all. In the case with only transverse injection ports, the vortex was broken up by the strong interaction between the shear layer over the cavity and the jet.

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Numerical study on supersonic combustion with cavity-based fuel injection

Cited by 195 publications

References 21 publications

Parametric effects on the combustion flow field of a typical strut-based scramjet combustor

Parametric effects on the combustion flow field of a typical strut-based scramjet combustor

Influences of Angles of Attack and Sideslip on the Flow Field of a Cantilevered Ramp Injector in Supersonic Flows

Supersonic mixing augmentation mechanism induced by a wall-mounted cavity configuration

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