Composite Ingredients/Mixtures and

Transcription

1 Integration of Nanoenergetic Composite Ingredients/Mixtures and their Reactive Characterization Travis Sippel (Iowa State U. now), Sarah Isert (NSF Fll Fellow), )David idreese, Lori ig Groven (SDSM&T now), Bob Lucht and Steve Son Purdue University West Lafayette, Indiana

2 Condensed phase agglomerates can contribute to twophase flow losses Two-phase flow losses can reduce motor performance by as much as 10% [a] Inclusion modified fuels or other composites can lead to smaller product particles, and potentially lower 2- phase flow loss Motivation [a] H. Cheung, N. S. Cohen, Performance of solid propellants containing metal additives, 1965, 3, Image: Y. M. Timnat, Advanced Chemical Rocket Propulsion, Academic Press, Orlando, FL 1987.

3 Motivation Catalysts and burning rate modifiers are used to tailor burning rates and pressure dependence This is especially important for advanced propellants where burning rate is not a strong function of size o Such as minimum smoke propellants, including SMX [a] that offers ~10% improved importance o Higher surface area is desirable for catalysts However, ultra high surface area catalysts can lead to higher mix viscosity and brittle propellants Catalysts include graphene-based materials Metal alloys are another way to bring in materials such as Li Potential to improve Isp, decrease HCl products Baseline Propellant 3 nm (Encapsulated) [a] Reese, Son and Groven, Composite Propellant Based on a New Nitrate Ester, PEP 2014.

4 Approach: Nanoscale Inclusions or Encapsulation Objectives: Fabricate micron- scale particles with nanoscale features and characterize the combustion of these materials inpropellants p Approach: Use rapid crystallization with nano-catalysts as nucleation sites or mechanical activation (MA) to incorporate nanoscale inclusions in aluminum Progress: 1) Encapsulated graphene oxide and decorated FGO in AP, 2) Characterized Fe 2 O 3 encapsulated AP in a propellant, 3) Characterized Al/LDPE inclusion material in a propellant, 4) Inclusion particles show microexplosion at higher heating rates, and 5) 3D OH PLIF imaging of AP composites achieved AP Crystals with inclusions of nanoscale catalysts Fuel rich Al+ PTFE Powder Mixture Al (black) PTFE (red) EDS map ofal/ptfe particle high energy milled (60 min) indicating uniform distribution of PTFE within particles. Aluminum = red, fluorine = green, carbon = blue.

5 Encapsulated Nanocatalysts in a Propellant Encapsulated nanoscale catalysts are MORE effective than catalyst powders added to propellants p Yields less viscous propellants -> less binder could be used to improve performance! Details of the effect of the flame structure and microscale combustion dynamics characterized using high-speed h PLIF and visible imaging Coarse particle ejection can be seen at lower pressures for catalyzed propellants Other composite particles, such as FGS & UMD could be considered now also 02%C 0.2% Catalyst 90% increase over baseline 44% increase over micron 15% increase over nano Isert, Groven, Lucht, and Son, The Effect of Encapsulated Nanosized Catalysts on the Combustion of Composite Solid Propellants, Combustion and Flame, doi: /j.combustflame

6 OH PLIF Shows Catalyst Effect on Flames a b c d e f 4.8 atm Micron catalyst added a b c d e f 4.8 atm Nano catalyst added a b c d e f 4.8 atm Nano catalyst ENCAPSULATED in fine AP Isert, Groven, Lucht, and Son, The Effect of Encapsulated Nanosized Catalysts on the Combustion of Composite Solid Propellants, Combustion and Flame, doi: /j.combustflame

7 Al with Nano-Inclusions in a Propellant Al/LDPE inclusion particles characterized in a propellant Results similar to Al/PTFE suggesting gas production and microexplosion of particles is the key and not the Al/PTFE reaction Plateau burning observed with Al/LDPE based propellants Sippel et al., Exploring Mechanisms for Agglomerate Reduction in Composite Solid Propellants with Polyethylene y Incluson Modified Aluminum, Combustion and Flame, doi: /j.combustflame

8 LiAl Alloy Replacing Al in an AP Composite Patent disclosure submitted. Additive Max I SP Density I SP Temperature Molecular Weight Cl HCl Cl MCl M MCl [sec] [g cm -3 -s -1 ] [K] [kg kmol -1 ] [%] [%] [%] Neat Al Neat Li /20 Al-Li NaNO