Transient heat transfer properties in a pulse detonation combustor

The heat transfer along the axis of a pulse detonation combustor has been characterized for various frequencies and fill fractions at 2.5 atmospheres of pressure for chamber refresh conditions. In a pulse detonation combustor, a supersonic detonation wave is the method for transforming chemical energy into mechanical energy and the wave propagates much faster than the subsonic flames in devices such as rockets and ramjets. The flow field inside a pulse detonation combustor is highly turbulent, unsteady, and varies largely during each combustion cycle. By determining the heat transfer properties at multiple axial locations and the associated combustor wall temperatures, proper combustor material selection can ensure the material properties will not deteriorate and therefore allow for practical operational lifetimes. Experimental testing measured the axial heat transfer characteristics in a pulse detonation combustor at various operating conditions and multiple cooling jacket locations. Computer simulations were used to model the heat transfer inside the pulse detonation combustor and correlate those predications with empirical data. The acquired data from the comparison of the computer simulations and the experimental results was correlated and demonstrated good agreement. The determined values should allow designers the ability to consider regenerative fueling strategies for future systems.http://archive.org/details/transientheattra109455767Approved for public release; distribution is unlimited

An integrated command and control architecture concept for unmanned systems in the year 2030

U.S. Forces require an integrated Command and Control Architecture that enables operations of a dynamic mix of manned and unmanned systems. The level of autonomous behavior correlates to: 1) the amount of trust with the reporting vehicles, and 2) the multi-spectral perspective of the observations. The intent to illuminate the architectural issues for force protection in 2030 was based on a multi-phased analytical model of High Value Unit (HVU) defense. The results showed that autonomous unmanned aerial vehicles are required to defeat high-speed incoming missiles. To evaluate the level of autonomous behavior required for an integrated combat architecture, geometric distributions were modeled to determine force positioning, based on a scenario driven Detect-to-Engage timeline. Discrete event simulation was used to schedule operations, and a datalink budget assessment of communications to determine the critical failure paths in the the integrated combat architecture. The command and control principles used in the integrated combat architecture were based on Boyd's OODA (Obseve, Orient, Decide, and Act) Loop. A conservative fleet size estimate, given the uncertainties of the coverage overlap and radar detection range, a fleet size of 35 should be anticipated given an UAV detection range of 20km and radar coverage overlap of 4 seconds.http://archive.org/details/anintegratedcomm109455244US Navy (USN) authorsApproved for public release; distribution is unlimited