A series of combustion tests were performed at the NASA Glenn Research Center with metallized gelled JP-8/aluminum fuels in a pulse detonation engine (PDE). Nanoparticles of aluminum with diameters of 60 to 100 nm were used. Gellants were nanoparticles composed of hydrocarbon alkoxide materials. Using simulated air (a nitrogen-oxygen mixture), researchers investigated the ignition potential of metallized gelled fuels with nanoparticle aluminum. Ignition of the JP-8/aluminum was possible with 23-wt% or less oxygen loading in the simulated air. JP-8 fuel alone was unable to ignite with less than 30-wt% oxygen loading in the simulated air. Single-shot tests of the metallized gelled fuel were used to demonstrate the capability of the fuel to improve fuel detonability. The tests were conducted at ambient temperatures and with maximal detonation pressures of 1340 psia.
During testing, only single-shot firings of the PDE were conducted with the metallized gelled fuel. Multiple shots were not planned as we wished to see if any improvements were possible with the gelled fuel. In many cases, improvements in the detonation velocity were observed. Further testing and analyses will be required to optimize the configuration of the PDE.
Metallized gelled fuels have many applications in aeronautics and space flight. Although the applications of PDEs are in the future, testing should continue to reveal the best operating points for these engines. Increased metal loading testing would allow better packaging of the fuel in the missile or other aerospace vehicle. The combustion efficiency for the higher metal loadings, which has not yet been investigated, is a good area for continued research. The use of a compressor section to improve the PDE seems warranted.
A metallized gelled JP-8/aluminum fuel was created to be combusted in a PDE. The fuel was formulated successfully with JP-8, nanometer-sized aluminum particles, and nanoengineered gellants. A sonicator was used to assure complete mixing of the fuel components for the testing, and the fuel remained stable for the 1- to 2-week time from formulation to engine firing. Metal loadings in the JP-8/aluminum ranged from 4.85 to 25 wt%, and gellant amounts ranged from 1 to 1.2 wt%
Added oxygen (O2) required for a PDE with metallized gelled JP–8/aluminum fuel; 23-wt% O2 baseline.
Long description of figure.
A minimum aluminum loading of 12- to 18-wt% nanometer-sized particles allowed JP-8/aluminum combustion in the PDE without oxygen addition. A PDE with metallized gelled fuels might reduce dependence on added oxygen for ignition and might simplify engine design. Also, by increasing the fuel density, the metallized gelled fuel can make the vehicle more compact. Metallized gelled propellants and propulsion could offer many vehicle advantages and create a bright future for many high-energy aerospace visions.
Palaszewski, B., et al.: Metallized Gelled Propellants Combustion Experiments in Pulse Detonation Engine. AIAA-2004-4191, 2004.
Find out more about fuels and space propellants for reusable launch vehicles: http://sbir.grc.nasa.gov/launch/foctopsb.htm
Glenn contacts:
Bryan A. Palaszewski, 216-977-7493, 216-433-5802 (fax), Bryan.A.Palaszewski@nasa.gov; and Kevin J. Breisacher, 216-977-7475, Kevin.J.Breisacher@nasa.gov
Authors:
Bryan A. Palaszewski, Kevin J. Breisacher, John M. Jurns, and Kimberly A. Kearns
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Last updated: October 16, 2006
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