Studies of Jet A1 Fuel Atomization Through Non Circular Orifices

The performance of the liquid rocket engine depends on the atomization behavior of the fluid being injected into the combustion chamber. Generally, a plain injector with a circular orifice has been used in the injector, but it has the disadvantage of having a low spray cone angle. The breakup length, mean droplet diameter, and Sauter mean diameter is also higher. Thus, to overcome these drawbacks, non-circular orifices have been utilized in the present study. The shapes used for non-circular orifices are semi-circular and plus. The results obtained with the non-circular orifice is compared with the circular orifices of the same area ratio. The working fluid used for the studies is Jet A1 fuel. Studies were also conducted with different L/D ratios by choosing an effective orifice length to reduce the upstream losses. The axis-switching phenomena were observed with the semi-circular as well as with the plus jets. The mean droplet size of the circular jets was more prominent compared to non-circular jets, and the Sauter mean diameter of non-circular jets droplets was smaller than that of the circular jet droplet. The spray cone angle has increased by 290% for plus jets and 30% for semi-circular jets compared to circular jets.