Publications

Flash ignition tests at the national solar thermal test facility

Ricks, Allen J.; Brown, Alexander B.; Christian, Joshua M.

Nuclear weapon airbursts can create extreme radiative heat fluxes for a short duration. The radiative heat transfer from the fireball can damage and ignite materials in a region that extends beyond the zone damaged by the blast wave itself. Directed energy weapons also create extreme radiative heat fluxes. These scenarios involve radiative fluxes much greater than the environments typically studied in flammability and ignition tests. Furthermore, the vast majority of controlled experiments designed to obtain material response and flammability data at high radiative fluxes have been performed at relatively small scales (order 10 cm2 area). A recent series of tests performed on the Solar Tower at the National Solar Thermal Test Facility exposed objects and materials to fluxes of 100 – 2,400 kW/m2 at a much larger scale (≈1 m2 area). This paper provides an overview of testing performed at the Solar Tower for a variety of materials including aluminum, fabric, and two types of plastics. Tests with meter-scale objects such as tires and chairs are also reported, highlighting some potential effects of geometry that are difficult to capture in small-scale tests. The aluminum sheet melted at the highest heat flux tested. At the same flux, the tire ignited but the flames were not sustained when the external heat flux was removed; the damage appeared to be limited to the outer portion of the tire, and internal pressure was maintained.