The droplet pass from a subcritical liquid state to a supercritical fluid state, accompanied by mass transfer. However, current combustion models of such systems describe the transition by subcritical means, along with other simplifications. This research deals with developing and implementing a realistic model for heating, evaporation and combustion of a liquid oxygen droplet in a hot supercritical hydrogen-rich environment. During the combustion process the fuel droplets are subjected to temperatures and pressures beyond their critical point as shown in the phase diagram. This gives rise to a number of interesting phenomena at the critical point.
Many liquid fuels undergo supercritical combustion.
One example of this is the NASA Space Shuttle's main engines which use gaseous hydrogen as fuel and liquid oxygen as the oxidant. A more common example would be your car engine which uses gasoline as fuel and air as the oxidant. By increasing the accuracy of the combustion model, the performance of these engines can be increased. The exact boundary of the liquid-supercritical fluid can be modeled over time as shown in the following figures.