Experimental study of concurrent-flow flame spread over thin solids in confined space in microgravity

Concurrent flow flame spread experiments are conducted over thermally thin solid fuels in microgravity aboard the International Space Station (ISS) under varying levels of confinement. Samples cotton fiberglass blended textile fabric burned air flows a small duct. Baffles placed parallel to sample sheet, one on each side symmetrically. The distance between baffles is varied change confinement burning event. Three different materials used alter radiative boundary conditions space that resides: transparent polycarbonate, black anodized aluminum, and polished aluminum. In all tests, samples ignited at upstream leading edge allowed burn completion. results show low speeds (<17 cm/s), reaches steady state for tested baffle types distances. rates lengths increase first then decrease when decreases, resulting an optimal spread. Furthermore, there exists limiting below which fails It concluded imposed by accelerates during combustion thermal expansion reflect radiation back surface, both intensifying burning. However, also limits oxygen supply introduces conductive heat loss away from flame. At same speed, length rate largest aluminum baffles, lowest polycarbonate baffles. differences most prominent intermediate While feedback expected similar distances as limited reduced supply.