HIGH TEMPERATURE EVAPORATION AND COMBUSTION CHARACTERISTICS OF GELLED KEROSENE DROPLETS

In the field of rocket propulsion, safety and performance are important aspects of any propellant. Gelled propellants are suitable candidates that can cater to both the requirements. In this study, the evaporation and combustion behavior of Jet-A1 and metallized Jet-A1 are investigated and compared to gelled Jet-A1 and metalized gelled Jet-A1 droplets. The study involves analysis of high-speed images of a suspended single droplet undergoing evaporation and combustion. Results show that the evaporation of gelled Jet-A1 droplets is characterized by a slow heat-up period followed by a brief quick evaporation due to the presence of high volatile gellant components. The combustion of gelled Jet-A1 droplets has two stages, initial burning characterized by occasional shape oscillations, and bubble formation and collapse leading to droplet swelling and explosion, while the combustion of metallized gelled Jet-A1 droplets showed a similar two-stage process with explosions that resulted in the formation of multiple children droplets. These disruptive phenomenons change the droplet size and sudden change in area of contact with air resulting in frequent rapid combustion.