Downstream Ramjet-Mode Combustion in a Dual-Mode Scramjet Engine

Kato, Kanenori; Kanda, Takeshi; Kobayashi, Kan; Kudo, Kenji; Murakami, Atsuo

doi:10.2514/1.17547

Cited by 10 publications

(11 citation statements)

References 12 publications

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“…Authors demonstrated the advantages of the downstream combustion ramjet-mode with the dual-mode scramjet engine combustor model [9][10][11] . The advantages of the downstream combustion ramjet-mode were summarized as follows:…”

Section: Downstream Combustion Ramjet-modementioning

confidence: 99%

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Ramjet-Mode Operation in a Combined Cycle Engine Combustor

Kato¹,

Kudo²,

Murakami³

et al. 2009

Trans. JSASS Space Tech. Japan

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A rocket-ramjet combined-cycle engine was tested in ramjet-mode. The combustor model had two rockets in the combustor section. They were used as an igniter in this operation mode. In the preliminary tests, the downstream combustion ramjet-mode was demonstrated with a 1.4-degree of divergent duct condition. In this study, the upstream and downstream combustion ramjet-mode operations were applied to the combined cycle engine model with large angle of divergent duct condition. In the case of upstream combustion ramjet-mode, the combustion condition at the exit of the combustor showed high combustion efficiency.

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Section: Downstream Combustion Ramjet-modementioning

confidence: 99%

“…Authors investigated the downstream combustion ramjet-mode in a scramjet engine combustor [9][10][11] . In the downstream combustion ramjet-mode, the subsonic combustion was attained in the downstream divergent duct.…”

Section: Introductionmentioning

confidence: 99%

Ramjet-Mode Operation in a Combined Cycle Engine Combustor

Kato¹,

Kudo²,

Murakami³

et al. 2009

Trans. JSASS Space Tech. Japan

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“…22 In the dual-mode engine, an isolator is installed between the inlet and the combustor to isolate high pressure in the combustor from the inlet. Supersonic airflow from the inlet is decelerated to subsonic velocity through the pseudo-shock in the isolator in the ramjet mode.…”

Section: E Dual-mode Combustormentioning

confidence: 99%

“…When the step is in the pseudo-shock, a ratio of pressure at the step to that at exit of the pseudoshock is almost unity, differing from the ratio of Eq. (22) in which the step is located upstream of the pseudo-shock. (23) Then, the frictions are related as follows, differing from the relation expressed in Eq.…”

Section: B Effect Of Backward-facing Step On Startingmentioning

confidence: 99%

Momentum Balance Model of Flow Field with Pseudo-Shock

Kanda

Tani

2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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The length of a pseudo-shock was estimated with a new momentum balance model. In this simple model, it is presumed that there is no wall friction in the region of the pseudo-shock. Inflow conditions are specified at a boundary sufficiently upstream of the pseudo-shock. The outflow boundary condition is applied with, for example, specified pressure or choking. The outflow impulse function is balanced with the inflow impulse function, the wall friction upstream of the pseudo-shock, and the reaction force from the wall. The starting position of the pseudo-shock is determined through balance of the forces in this model, and the length of the pseudo-shock is also determined. The model was applied to several kinds of flow fields, for example, straight ducts with and without a backward-facing step, and divergent ducts. The model was also applied to the diffuser of an ejector-jet, in which two gases flowed in parallel. The calculated results reasonably agreed with the experimental results within the scope of preliminary application. The starting position of the pseudo-shock was primarily dominated by the reaction force in the divergent duct. Several features of the pseudo-shock were discussed with the present model. (7) and (17) a = papameter of Eq. (7) B = parameter of Eqs. (7) and (17) 2 JAXA Research and Development Report JAXA-RR-06-037E e = outflow f = friction i = inflow p = pseudo-shock, state at the exit of pseudo-shock r = reaction step = step t = total th = throat w = wall 1 = upstream of pseudo-shock, entrance, primary flow 1b = after bleeding and upstream of pseudoshock 2 = downstream of pseudo-shock, secondary flow

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“…[7][8][9] When a scramjet engine is operated in ramjet mode, supersonic flow is decelerated to subsonic speed through a pseudo shock wave within the isolator, and the subsonic flow is re-accelerated to supersonic speed due to heat release by combustion. Although this conventional ramjet-mode operation assumes fuel injection within the constant-area combustor, Kanda et al 7) and Kato et al 8) attempted fuel injection at the exit of the diverging combustor to form the choking point there in their scramjet component tests. This downstream combustion ramjet-mode operation resulted in a lower peak pressure than in conventional ramjetmode operation without deterioration of thrust performance.…”

Section: Ramjet-mode Operation With Downstream Combustion In a Scramjmentioning

confidence: 99%

Suppression of Combustor-Inlet Interaction in a Scramjet Engine under Mach 4 Flight Conditions

Kobayashi

Kanda

Tomioka

et al. 2007

Trans. Japan Soc. Aero. S Sci.

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A sidewall-compression-type scramjet engine was tested under Mach 4 flight conditions. The tested engine had an inlet, a constant cross-sectional area isolator, a constant cross-sectional area combustor, a diverging combustor, and an internal nozzle. In a previous study under the same flight conditions, the maximum thrust increment using fuel injection within the constant-area combustor was 1,380 N at an equivalence ratio of 0.31, and further fuel injection resulted in combustor-inlet interaction (designated as CII). To suppress the CII in the present study, we attempted (1) two-stage fuel injection within the constant-area combustor and the diverging combustor and (2) a boundary layer bleed on the top wall. The former was to suppress heat release around the first-stage fuel injectors in the constant-area combustor, and the latter was to decrease interaction length by decreasing the boundary layer thickness on the top wall. In the case of two-stage fuel injection, the maximum thrust increment was 2,230 N at an equivalence ratio of 0.63. In the case of the boundary layer bleed, on the other hand, the maximum thrust increment was 2,300 N at an equivalence ratio of 0.66. Thus, twostage fuel injection and boundary layer bleed led to 62% and 67% higher maximum thrust increments than that obtained in the previous study, respectively. Finally, both the two-stage fuel injection and boundary layer bleed were applied simultaneously to obtain the best thrust performance, and the maximum thrust increment was 2,560 N at an equivalence ratio of 0.95. As a result, we obtained an 86% higher maximum thrust increment than that in the previous study. The thrust achievement factor, which was defined as the ratio of the maximum thrusts obtained from experiment and theoretical prediction, under this condition was estimated as 70%.

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Downstream Ramjet-Mode Combustion in a Dual-Mode Scramjet Engine

Cited by 10 publications

References 12 publications

Ramjet-Mode Operation in a Combined Cycle Engine Combustor

Ramjet-Mode Operation in a Combined Cycle Engine Combustor

Momentum Balance Model of Flow Field with Pseudo-Shock

Suppression of Combustor-Inlet Interaction in a Scramjet Engine under Mach 4 Flight Conditions

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