| Project/Area Number |
09450368
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Aerospace engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KAJI Shojiro School of Engineering, The University of Tokyo, Professor, 大学院・工学系研究科, 教授 (80013704)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Tetsuya Research Division for Space Propulsion, Institute of Space and Astronautical Science, Research Associate, 宇宙推進研究系, 助手 (80249937)
WATANABE Toshinori School of Engineering, The University of Tokyo, Associate Professor, 大学院・工学系研究科, 助教授 (10201211)
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| Project Period (FY) |
1997 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥13,000,000 (Direct Cost: ¥13,000,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1999: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1998: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1997: ¥7,500,000 (Direct Cost: ¥7,500,000)
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| Keywords | supersonic combustion / SCRAM Jet / thermal choking / compound choking / high enthalpy wind tunnel / space plane / hydrogen combustion |
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| Research Abstract |
The most important problems in supersonic combustion ram jet engines (SCRAM) which are suitable for hypersonic transports and space planes are the phenomena such as thermal choking and compound choking. In the case of integrated SCRAM engines, the boundary layer flow which is developed along the vehicle fuselage is sucked into engines with the main flow. The flow tube of the boundary layer and that of the main flow have the same total temperature but different total pressures and Mach numbers. When they coexist in the engine they behave quite queerly against the cross-sectional area change in the engine and heat addition in each flow tube. The main flow tube is easily choked at supersonic conditions because of the existence of the boundary layer flow, where the static pressure balance is kept between two flow tubes. This phenomenon is called compound choking.
The purpose of the present research is to investigate the details of choking phenomena in SCRAM engines and to find out the control rule which is necessary for stable operation of SCRAM engines.
In order to realize choking in SCRAM engines, an engine module of 30mm×32.6mm frontal cross section was put in the supersonic wind tunnel of 100mm×100mm cross section driven by the vitiated air of temperature 2000K (maximum) at Mach number 2.0. Self-ignition was realized by injecting hydrogen fuel into the engine module. From the pressure signals measured on the engine wall, it was recognized that supersonic combustion was realized while the injection pressure of hydrogen was low. But when the injection pressure was increased the pressure inside the engine increased indicating subsonic combustion. In such circumstances the region of high pressure was observed to extend in sequence from downstream to upstream in the engine and it finally fell into the unstart condition.
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