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This Defense Intelligence Reference Document from the Defense Intelligence Agency, dated 21 November 2010, was produced in FY 2010 under the Advanced Aerospace Weapons System Applications (AAWSA) Program. It reviews propulsion concepts that use plasmas and magnetohydrodynamics. It finds the Ajax MHD energy bypass concept meaningless below Mach 12 but calls a reverse energy bypass with a Virtual Cowl potentially practical. It also predicts that electric propulsion will become standard for spacecraft.
“Jet Propulsion Laboratory”4 pages
UNCLASSIFIED//FOR OFFICIO I Yli'F SiUlb¥ thrust (Fth) is produced from each mass unit of propellant. The thrust efficiency (11) is a measure of how much of the power/energy that is available results in directed kinetic energy (thrust power) in the flow. The thrust density is a measure of how much thrust is produced per unit cross-sectional area, Ac (area perpendicular to the flow direction). Although the thrust density is a packaging issue for spacecraft, it is critical for air vehicles where drag is present. The thrust-to-power measures the acceleration efficiency. Traditionally a trade exists between fuel/propellant efficiency and thrust-to-power (speed vs. economy). The final parameter is the specific mass or weight (mass)-to-power ratio. In most cases the efficiencies improve with the size of the system (economy of scale). Measures of performance are fundamentally different between air-breathing and rocket systems due to the inlet on the air-breathing system. Rocket Air-Breathing . Fm = n1" ue + A, (P, - p ) ·"'" = n1" lu, + (P, - P,,n) A, 1m,. = Iii,, U"'I Thrust lbrusl F111-------- = -~- propellant weight Oow rate fuel weight flow rate ml g., = = 111 u ,, ~" fuel mas~ Oow rate m 1 TSFC = ------- = Thrust Above, m" is the mass flow rate of the air, m I is the mass flow rate of the fuel, m" is the exit flow rate, go is the acceleration of gravity (reference point, Earth), Ue is the nozzle exit velocity, u is the flight/vehicle velocity, Ueq is the equivalent exit velocity, Ae is the nozzle exit cross-sectional area, Pe is the nozzle exit 6 UNCLASSIFIED/,6OA O66161,R,b 11165 8HLY
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 32 pages are in the text index: search them above, or from the library's search.