Combustion of HAN-Methanol-Water Monopropellant Droplets Under Reduced-Gravity Conditions

摘要

Experiments were performed to study reduced gravity combustion characteristics of isolated monopropellant droplets composed of hydroxylammonium nitrate (HAN), methanol and water. All experiments were performed in air at 0.1 MPa and about 25 degrees Celsius. Droplets initially in the mm size range were supported on fibers and were ignited using a hot wire. Burning rates, extinction characteristics and internal bubbling characteristics depended significantly on the initial mass fraction of HAN in a droplet. Increasing the initial mass fraction of HAN reduced droplet burning rates and increased the diameter at which flame extinction occurred. As the initial HAN mass fraction increased, conditions were attained where droplets could not be ignited. Internal bubbling was sometimes observed to cause droplet shattering.