Ramjet propulsion

However, it must be noted that Eq. (1.62) is applicable for ramjet propulsion, as in ducted rockets and solid-fuel ramjets, because in these cases air enters through the inlet and a pressure difference between the inlet and the exit is set up. The mass flow rate from the inlet m plays a significant role in the generation of thmst in the case of ramjet propulsion. 

Kubota, N., and Kuwahara, T., Ramjet Propulsion, Nikkan Kogyo Press, Tokyo, 1997. 

Although several different system configurations have been simulated, the focus of this paper will be on the unsteady, compressible, multiphase flow in an axisymmetric ramjet combustor. After a brief discussion of the details of the geometry and the numerical model in the next section, a series of numerical simulations in which the physical complexity of the problem solved has been systematically increased are presented. For each case, the significance of the results for the combustion of high-energy fuels is elucidated. Finally, the overall accomplishments and the potential impact of the research for the simulation of other advanced chemical propulsion systems are discussed. 

Kailasanath, K., J.H. Gardner, J. P. Boris, and E. S. Oran. 1987. Numerical simulations of acoustic-vortex interactions in a central-dump ramjet combustor. J. Propulsion Power 3 525-33. 

Frolov, S.M., V. Ya. Basevich, and A. A. Belyaev. 1999. Flame stabilization in a ramjet burner. 12th ONR Propulsion Meeting Proceedings. Eds. G.D. Roy and S.L. Anderson. University of Utah, Salt Lake City, UT. 76-81. 

Crump, J. E., K. C. Schadow, V. Yang, and F. E. C. Culick. 1986. Longitudinal combustion instabilities in ramjet engines Identification of acoustic modes. J. Propulsion Power 2 105-9. 

Ducted rockets are intermediate between solid rockets and liquid ramjets in their propulsion characteristics. The propulsive force of soHd rockets is generated by the combustion of propellants composed of oxidizer and fuel components. Thus, no additional fuels or oxidizers need to be introduced from the atmosphere into the rocket motor. The momentum change of the exhaust gas from the nozzle attached to the aft-end of the combustion chamber is converted into the thrust for propulsion. On the other hand, the propulsive force of Hquid ramjets is generated by the combustion of a liquid hydrocarbon fuel with air introduced from the atmo-sphere.Ii] jjjg incoming air is compressed by a shock wave formed at the air-intake attached to the front end of the combustor. The air taken in from the atmosphere serves only as the oxidizer for the ramjets. The thrust is created by the momentum difference between the exhaust gas from the combustor and the air taken in from the atmosphere. 

Technology of Ramjet and Ramrocket Propulsion at Bayern-Chemie, AY75, )an. 1989. 

For propulsion in the atmosphere, where ambient air is available, this air may be induced by the jet engine in order to participate essentially in the chemical transformation of the fuel the engine is then properly called an air flow jet engine (in Fig 1 the Turboprop, Turbojet, Ramjet Pulse Jet are examples of air flow jet engines) in contrast to the rocket, which does not use any air and is the only jet engine which can be used for propulsion in vacuum... 

The inability of the engine to produce a useful propulsive force at zero or low flight speeds necessitates the use of an auxiliary power plant to initially accelerate the vehicle to the required take-over speed of the ramjet. Such auxiliary power is also required for controlled landing of the vehicle. As a consequence the ramjet engine is not well-suited for conventional aircraft applications (with the exception of the helicopter) and the principal application of the engine appears to be further restricted to missiles or other similar vehicles of a one-flight expendable nature ... 

Fuel-rich propellants (FRPs) with high metal content find use in ram-rockets which operate with the combustion of fuel-rich hot gases generated in the primary chamber or combustor and ram air inducted from atmosphere to a secondary chamber or combustor for full combustion. The rocket system where energy for propulsion is derived in such a manner is termed an integrated rocket-ramjet (IRR). The major benefit of a ram-rocket is substantial reduction in the weight of rocket or missile as the oxidizer need not be carried along with the propellant fuel. Fuel-rich propellant formulations for ram-rockets consist of metal fuels, binder... 

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