| Description |
JP-10 is a synthetic fuel with high volumetric energy content. One problem with JP-10, is that its combustion kinetics can be too slow for efficient combustion in hypersonic flight applications. Chapter 2 presents a study on the thermal breakdown and catalytic combustion of JP-10 fuel using CeO 2 (ceria) nanoparticles, in a flow tube reactor. In-situ mass spectrometry was used to analyze decomposition products. In the absence of O2, CeO2 efficiently oxidizes JP-10, reducing decomposition onset temperatures by 300 K over that in a clean flow tube. Under conditions with O2 and CeO2 present, oxidation of JP-10 was found to be catalytic; i.e., oxidation is initiated by reaction of JP-10 with CeO2, which is then reoxidized by O2. Boron is of interest as a high energy density fuel as it has one of the highest volumetric heats of combustion known. A major difficulty in getting boron to burn efficiently is that boron surfaces are protected by a native oxide layer. Chapter 3 presents a simple, scalable, one-step, one-pot synthesis method for producing ∼50 nm boron nanoparticles that are largely unoxidized, made soluble in hydrocarbons through oleic acid functionalization, and optionally coated with ceria. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used to investigate size distributions, with X-ray photoelectron spectroscopy (XPS) to probe the surface chemistry. Cryogenic methane has been proposed as a fuel for use in hypersonic engines, due to its relatively high energy content; however its poor ignition performance needs to be addressed through use of catalysts. Chapters 4 and 5 investigate the composition, structure, and surface chemistry of several types of Pd/PdO based nano-catalysts designed to be fuel soluble. A combination of high resolution transmission electron microscopy (HRTEM), electron diffraction, scanning transmission electron microscopy/energy dispersive x-ray spectroscopy (STEM/EDX), and XPS were used. In-situ generated particles were found to be primarily crystalline, metallic Pd, in a narrow size distribution around 8 nm. The ignition temperature was lowered ∼150 K by the catalyst, and evidence is presented showing that ignition is correlated with formation of a subnanometer oxidized Pd surface layer at higher temperatures. |
