• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.393-396
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• 2006

This paper presents the characteristics of the performance parameters of dual mode(ramjet-scramjet combined) engine, inlet and combustor for wide range of flight Mach number, resulted from the analysis of its operating limitations. The transitional-critical flight Mach number from ramjet to scramjet and the performance of two types of combustors, such as constant pressure- and constant area- combustor, are conceptually evaluated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.586-595
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• 2010

An analytical study based on physical understandings and aero-thermodynamic theories was conducted to observe the performance characteristics and to derive the essential design parameters of dual ramjet(dual-combustion/dual-mode) propulsion for wide Mach number. The performances and operating limitations of the engines with two types combustors, such as constant pressure- and constant area- combustor, over various flight Mach numbers was investigated. Finally, the transition Mach number from ramjet to scramjet was carried out to optimize performance load balancing of ramjet and scramjet.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.596-604
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• 2010

In order to investigate the operating conditions and major design parameters of a dual ramjet propulsion system, an theoretical analysis of ramjet and scramjet propulsion systems was performed. The performance characteristics of each engine are delivered by thermo-dynamical cycle analysis, considering loss effects in a real engine. The performance sensitivity analysis is conducted by investigating various performance parameters, such as an intake efficiency, combustor inlet Mach number, configuration of the combustor, fuel flow rate, and exhaust nozzle efficiency. Based on these analysis results, the processes of application to dual ramjet cycle engines are specified.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.330-335
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• 2017

Recently many studies have been made for the development of propulsion system with wide range flight from supersonic to hypersonic. Dual Mode scramjet engine as a hybrid cycle with advantage of ramjet and scramjet has one combustor. It works under the ramjet mode (subsonic combustion) and scramjet mode (supersonic combustion) respectively. In this study, Experimental results of hot firing tests of dual scramjet engine designed on the condition of Mach 3.5~6 as a flight Mach number are discussed. The tests were carried out on a ground test bench under free stream condition of Mach 6 at 27.6km altitude. In the tests, the adopted design and technological solutions were verified and efficient operation of the dual mode ramjet engine with Kerosene combustion during 5 seconds was demonstrated.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.115-128
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• 2006

A technical analysis of current scramjet and combined-cycle engine is presented. Substantial research has been pursued to characterize the operation mechanism of scramjet propulsion, especially in the areas of flame stabilization and system integration, dramatically over the years in support of both military and space access application. Major technology that had significant impact on the maturation of scramjet propulsion technology are dual combustion ramjet, dual mode ramjet, and combined cycle engine to cover a typical wide rage of flight, up to flight Mach number 10. Notable are the fundamental and practical techniques, for instance, scram propulsion itself, thermal relaxation and protection using endothermic fuel and/or CSiC composit materials, and design/manufacture of movable intake and nozzle, to realize high speed propulsion system in near future.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.400-401
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• 2009

Present paper introduces the concepts and R&D activities on the hypersonic vehicles, X-51A by USAF using Dual-Mode Ramjet (DMR) and HyFly by US Navy using Dual-Combustion Ramjet (DCR) both sponsored by DARPA.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.325-329
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• 2017

In this study, the combustion experiment of hydrocarbon-kerosene fueled dual mode ramjet combustor was performed at mach number 3.5~6.0 conditions. Through the experiment, the temperature and the pressure distribution inside the combustion chamber were measured and the combustion characteristics inside the combustion chamber were investigated. In the mach number 3.5~5.0 range, it was able to identify subsonic combustion in the downstream combustion chamber. In the mach number 6.0 condition, the injected fuel from the injectors was naturally fired, and it was possible to confirm that supersonic combustion was successful in the upper chamber.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.45-51
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• 2018

The generation mechanism of NAR is not yet understood. In the present study, an in-depth analysis of the computational results previously obtained by the authors is conducted to investigate the flow mechanism responsible for NAR. A theoretical analysis has also been performed to understand the gas dynamic features during transition from scramjet to ramjet mode. It is known that there exists a critical value of the fuel equivalence ratio at which the flow states at the inlet of isolator remain unchanged. An increase in the equivalence ratio over the critical value leads to a sudden change in the static pressure and the Mach number at the inlet of the isolator, which is responsible for the generation of NAR.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.419-422
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• 2010

An unsteady numerical combustion analysis was performed to investigate the combustion characteristics of A Dual Combustion Ramjet(DCR) engine using a gas generator. According to a variance of the equivalence ratio of the gas generator, the flow pattern in the combustor was analyzed. A typical acoustic frequency in the combustor was observed by detail analysis of pressure fluctuation at each location of the combustor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.289-292
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• 2007

Performance of a dual mode ramjet engine based on the sensitivity analysis of design parameters (the gap between cowl and inlet spike and combustor length) was analyzed from the view points of aerodynamics and thermodynamics. A dual mode engine performing from supersonic to hypersonic (Mach no. 2 to 6) was designed in a proposed flight envelop. The design method and result were comparable to the results of the previous study, Hyperion RLV, and the CFD calculation.