Scramjet

Another major computational effort is in the area of metals and their chemistry, which comprises the subject of this manuscript. The studies are directed towards both catalysis and the development of improved materials, such as stronger matrix composites. The materials and gas phase work have some overlap. For example, surface recombination affects the heating on the AOTV heat shield and on the walls of the scramjet. In addition, desorption of these molecules from the walls of the scramjet could impact the chemistry in the flow. 

Tests were conducted using a scramjet combustor and the hypersonic facility of MAI equipped with kerosene-fueled preheater (vitiated air). Oxygen mass fraction T°02 in the vitiated air was slightly lower than in the atmospheric air. y°02 values for each test run can be found in Table 23.1. With an oxygen mass fraction in atmospheric air of 0.232, the kerosene equivalence ratio (ER) in vitiated air is determined by the following relation ... 

Kopchenov, V. I., and K. Lomkov. 1992. The enhancement of the mixing and combustion processes applied to scramjet-engine. AIAA Paper No. 92-3428. 

Kay, I.W., W. T. Peschke, and R. N. Guile. 1990. Hydrocarbon-fuelled scramjet combustor investigation. AIAA Paper No. 90-2337. 

Stouffer, S. D., U. Vandsburger, and G.B. Northam. 1994. Comparison of wall mixing concepts for scramjet combustors. AIAA Paper No. 94-0587. 

Figure 30.5 Comparison of specific impulse and flight Mach number for hydrogen (1) and hydrocarbons (2). PDE performance estimated using ASI Performance deck turbojet, ramjet, and scramjet performance levels reflect well-designed systems for man-rated thrust classes. TJ — turbojets RJ — ramjets SJ — scramjets PDE — pulse detonation engines PIL — preignition hmit [12]...

Shirley, J. A. Eckbreth, A. C. Hall, R. J.,"Investigation of the Feasibility of CARS Measurements in Scramjet Combustion" presented at the 16th JANNAF Combustion Meeting, Monterey,Ca.,... 

Combustion instability that leads to performance deterioration and excessive mechanical loads, which could result in reduced life and premature failure, is an important issue with modern gas turbine engines and ramjet and scramjet combustors. Various techniques of passive and active control to reduce combustion instabilities and improve performance are addressed. Since extensive, promising research is being carried out to develop sensors and actuators, these techniques can be used in practical combustors in the near future. The topics covered in Section 3 provide the required chemical, kinetic, and fluid dynamic understanding to help the designer who is involved in active feedback control for combustion systems. 

NASP was to be used as an experimental vehicle to test high-risk technologies for Reagan s Strategic Defense Initiative, but also to ferry men and equipment to future space stations more economically than could be done with the Space Shuttle. It would take off like a conventional airplane. Hydrogen-fueled, air-breathing scramjet (supersonic combustion ram jet) engines would push it at speeds of up to Mach 25 to the almost-vac-uum of near space, where rocket power would provide the final push needed to reach a space station. 

Figure 16.1 Existing experimental facilities (a) University of Maryland (UMD) liquid-fueled dump combustor (6) UMD supersonic mixing rig (c) Naval Air Warfare Center (NAWC) heated inlet rig and (d) NAW C dual-mode scramjet rig.

Ken Yu s group at the University of Maryland extended the previously reported work [3] to include four sets of experimental and analytical studies to identify key physical mechanisms for controlling mixing and combustion processes in ramjet and scramjet combustors (Chapter 16). In a supersonic mixing-enhancement experiment, the practicality of utilizing passive acoustic excitation as a means to enhance mixing in scramjets is assessed. 

Fig. 7-8 Schematic of a model combustion chamber of a scramjet, from [DLR]... 

The aviation company Aerospatiale in France has tested for several seconds the operation of a slush hydrogen fueled scramjet engine. Ignition in the combustion chamber called statoreactor (there are no moving parts) is to provide the thrust to reach Mach 6 speed [103]. 

I 1.2.13. Energy Efficiency of Plasma-Assisted Combustion in Ram/Scramjet Engines... 

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