Stability of oblique detonations in RAM accelerators

Li, C.; Kailasanath, K.; Oran, Elaine S.

doi:10.2514/6.1992-89

Cited by 11 publications

(3 citation statements)

References 2 publications

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“…As a general way, recent modellings on oblique detonations don't take into account this phenomenon (Li et al 1992;Singh et al 1992). As the experiment of Lehr (1972) has shown, the combustion can strenghten the OSW and then shorten the delay of onset of oblique detonation.…”

Section: Discussionmentioning

confidence: 99%

Supersonic H2-air combustions behind oblique shock waves

1995

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Abstract. In order to study the mechanisms of initiation and stabilization of H2-Air combustions (stoechiometric mixture initially at To = 293 K and P0 = 0.5 bar) in supersonic flow conditions behind an oblique shock wave (OSW), an original technique is used where OSW is generated in this mixture by the lateral expansion of the burnt gas behind a normal CJ gaseous detonation propagating into a bounding reactive mixture. Four Mach number M of propagation of OSW are considered in the study, namely M = 7.7-6.1--4.4 and 3. Depending on the Mach number M and inclinaison angle 0 of OSW different regimes of combustion may occur in the driven mixture. For high values of M (6.1 and 7.7) delayed steady overdriven oblique detonation waves (SODW) were obtained with a near CJ detonation wave as the critical regime. It was found that SODW obtained correspond quite well to prediction of the polar method. When thermal conditions behind the OSW are lower, either for high Mach number 6.1 and 7.7 for smaller angle 0 than the previous case, or for lower Mach number, 4.4 and 3, the flame initiated at the apex is stabilized as a turbulent oblique flame behind the OSW. With much lower conditions, no combustion appears in the H2-Air mixture.

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Section: Discussionmentioning

confidence: 99%

Supersonic H2-air combustions behind oblique shock waves

1995

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“…first used the morphology of standing oblique detonation wave to make a theoretical analysis of the stationarity of ODW, they proposed the Mach number condition and geometric conditions of oblique wedge to achieve the stationarity of oblique wedge. Li [11] etc. found that to avoid ODW from separating from the leading edge of oblique wedge and propagating to the upstream, it needs to be ensured that the angle of oblique chopping is less than a critical value, and this critical value is related to the sound velocity after oblique shock…”

Section: Figure 2 the Structure Of The Transition Zone Of The Abrupt ...mentioning

confidence: 99%

Study of Direct-link Test of Oblique Detonation Engine

Chen

2022

J. Phys.: Conf. Ser.

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Based on the shock tube wind tunnel driven by detonation, simulating the flight altitude of 30km and the incoming flow conditions of flight Mach number 9, this paper conducts a study of direct-link test of the oblique detonation engine with an oblique wedge angle of 30 degrees. The detonation process and stationing characteristics of the oblique detonation wave are analysed in detail by the engine wall pressure measurement combined with the high-speed camera for simultaneous shooting. During the test, the oblique detonation wave successfully detonates on the oblique wedge and is validly stationed. Under the collision effect of the shock waves system downstream the oblique wedge, the oblique detonation wave successfully detonates, and the oblique detonation wave spreads and develops upstream direction after the detonation, and finally, the oblique detonation wave is successfully stationed. Using shadow-graph method to observe the wave system in the combustion chamber, the typical flow field structure such as non-reactive shock wave, oblique detonation wave, transverse wave and triple point is clearly observed, and the angle of oblique detonation wave in the oblique detonation engine tested in this paper is greater than 80 degrees. The successful detonation and stationarity of oblique detonation wave in direct-link test proves the feasibility of oblique detonation wave to be applied to hypersonic propulsion.

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“…In the past, we have performed comprehensive studies of the structure and stability of oblique detonations generated by wedge-induced shocks in supersonic, reactive flows (Li et al 1991;Li et al 1992a;Li et al, 1993a;Li et al 1993b;). The simulations have identified the basic multidimensional structure of oblique detonations and have shown that this structure is stable and resilient to disturbances in the flow in a wide range of flow and mixture conditions.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of oblique detonations in ram accelerators

Kailasanath

Oran

et al. 1995

Shock Waves

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Abstract. Time-accurate numerical simulations are used to study the dynamic development of oblique detonations on accelerating projectiles in ram accelerators. These simulations show that the oblique detonation can be stabilized on the projectile. The high pressure generated behind the detonation can result in accelerations up to 106G and propel the projectile to velocities higher than 4.0 km/s. The detonation structure on the projectile is sensitive to the projectile geometry. A small change in the projectile shape is sufficient to alter the overall detonation structure and significantly affect the pressure distribution on the projectile. In order to maximize the thrust, an appropriate projectile shape has to be chosen to generate the detonation structure just behind the widest part of the projectile body. The projectile acceleration also has strong effects on the flow field and the detonation structure. During the acceleration, the location of the oblique detonation moves upstream from one reflected shock to another. However, once the detonation is stabilized behind the upstream shock, it remains at the new location until the transition to the next upstream shock occurs. In the simulations, the Non-Inertial-Source (NIS) technique was used to accurately represent of the projectile acceleration. Also, the Virtual-Cell-Embedding (VCE) method was employed to efficiently treat the complex projectile geometry on cartesian grids.

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Stability of oblique detonations in RAM accelerators

Cited by 11 publications

References 2 publications

Supersonic H2-air combustions behind oblique shock waves

Supersonic H2-air combustions behind oblique shock waves

Study of Direct-link Test of Oblique Detonation Engine

Dynamics of oblique detonations in ram accelerators

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