Combustion Enhancement of Liquid Fuels via Nanoparticle Additions: Screening, Dispersion, and Characterization

• Main Authors: Boyer,J E, Bushman,Zachary, Adair,James H, Kuo,Kenneth K, Billingsley,Matthew C
• Format: Report
• Language: English
• Subjects: COMBUSTIBLE PARTICLES; combustion; COMBUSTION STABILIZERS; fuel additives; liquid rocket FUELS; nanoparticles; PERFORMANCE ENHANCERS; TEST AND EVALUATION

Addition of nano-sized combustible particles to liquid propulsion fuel (e.g., RP-2) offers the possibility of generating an enhanced fuel with increased energy density, while maintaining or improving ignition characteristics of the bulk fuel. The culmination of increases in widespread availability/affordability of a large variety of nano-sized particles, understanding of nano-sized particle ignition and combustion, and advances in colloidal science of nano-sized metal particle/liquid suspensions, now allow for the development of enhanced nano-fluid fuels. To evaluate the suitability of various nanoparticles for use in an enhanced fuel, it is necessary to evaluate the both physical requirements for creating a stable suspension and the compliance of readily and economically available nanopowder materials with these criteria. In addition, a suitable dispersant must be found to ensure the suspension remains stable. In this program, an initial particle and dispersant screening process was developed and reduced to a standard procedure with evaluation criteria. Multiple dispersants and particles were assessed as dilute suspensions, and the most promising dispersant compounds and concentrations identified and used for further investigation with higher particle loading fractions. Although the manufacturers' advertised specifications fell within the size criterion for forming a stable suspension, all commercially available nano-sized aluminum particles examined were found to be unsuitable in the as-delivered state. A high fraction of the particles were determined to be in the form of undispersable permanent agglomerates made up of many primary particles, represented as an Average Agglomeration Number (AAN) significantly greater than 10. After removal of the oversized agglomerates through settling and filtration, only an unacceptably small percentage of material remained in the dispersed state (often 90% loss). 62nd JPM / 10th MSS / 8th LPS / 7th SPS Joint Subcommittee Meeting, 01 Jun 2015, 04 Jun 2015, For presentation at 62nd JPM / 10th MSS / 8th LPS / 7th SPS Joint Subcommittee Meeting in Nashville, TN (June 2015)PA Case Number: #15287; Clearance Date: 28 May 2015