Flame speed enhancement of a nitrocellulose monopropellant using graphene microstructures

The control and enhancement of thecombustion wave propagation velocities of solid monopropellants are very important for the development of low cost and efficient micro power systems such as microthrusters and thermal-to-electrical energy conversion devices. In this work, theflame speed enhancement of a nitrocellulose (NC) solid monopropellant using highlyconductivegraphene structures was demonstrated. Two differentgraphene structures, namely,graphenefoam (GF) andgraphene nano-pellets (GNPs), were studied. For the GNP-doped NC films, fuel layers 500  ± 30 μm thick were deposited and the doping concentrations were varied from 1% to 5% by mass. For the GF, the fuel loading ratio (%) and thefoam density were varied to study their effect on theflame speed propagation behavior. Self-propagatingcombustion waves were observed, with averageflame speed enhancements up to 8 times the bulk value. Theflame speed enhancement, for both the GNPs and the GF, showed a parabolic trend as a function of their concentrations, and an optimum value for each case was determined. However, theflame speed enhancement, as a function of the GF density (for a fixed fuel loading ratio), showed a monotonic decreasing trend. Moreover, the reusability of the GF structures was also tested by re-depositing them with fuel aftercombustion. Similarflame speed enhancement was obtained using the fresh and the re-used GF structures.
Source: Journal of Applied Physics - Category: Physics Authors: Source Type: research