Flammability maps for microgravity burning of a small flat material in a quiescent ambient.

A gas fuel supplied burner (BRE) was used to emulate burning of real solid and liquid fuels in microgravity to address the fire safety concerns of spacecrafts. The analytical solution of these flames was utilized to predict the steady flame temperature, and a critical temperature range of 1100–1200 K, was chosen to distinguish between self-extinguished and steady flames. Steady flames are examined on a flammability diagram composed of the emulated heat of combustion and heat of gasification. It is shown that for a given heat of combustion, there is an upper and a lower limit value of heat of gasification that will allow steady burning. The theory and the boundary of extinction experimental data support the limits. The upper limit is classed as radiation extinction with the lower like the fire-point in Earth gravity and is called small flame extinction limit. A theoretical prediction for steady burning is demonstrated to within 10% for a given atmospheric condition of pressure and oxygen, material diameter, and external radiative heat flux. The material properties of Δ h c , heat of combustion; L, heat of gasification; and T b , burning temperature allow for the prediction of burning in microgravity, and can serve as a method to evaluate fire safety of spacecrafts. [ABSTRACT FROM AUTHOR]