| Popis: |
This report presents the results of a study undertaken to help build a database and modeling capability that will support the design of a laser-based ignition system for a gun-fire simulation (GUFS) platform. In this study, the thermal transport properties of pressed pellets of candidate igniter materials were experimentally investigated in the range 20-100 deg C via (1) the technique developed by Miller and Kotlar ("Technique for Measuring Thermal Diffusivity/Conductivity of Small Thermal Insulator Specimens," Review of Scientific instruments, vol. 64, p. 2954, 1993) and (2) a small modification to their technique that allows it to be used for (slightly) electrically conductive materials. The compounds investigated in this manner include black powder, red powder (with and without 0.5-weight-percent carbon black), B/KNO3, A1A, Zr/KClO4, Ti/KClO4, an ARCO formulation (with 0.5-weight-percent carbon black), and an FeO/Ti/Zr/NC mixture. In addition, the heat capacities of these compounds were determined over the range 20-100 deg C via differential scanning calorimetry. The experimentally derived parameters are employed as input to a simplified model of the heat-transfer process attending the irradiation of a candidate with a relatively low-fluence laser beam. The results indicate that the differences in the thermal transport properties of the materials studied will not lead to significant differences in the irradiance required to ignite them. |
