Liquid jets in crossflows are regularly used in the aerospace industry because they are lightweight and effective ways to disperse fuel into air streams. The behavior of the injected liquid is universally dependent on the conditions into which the fuel is injected, which is then dependent on the operating conditions of the engine. Variation in the behavior of the liquid jet can cause variation in fuel mixing, which can affect downstream combustion efficiency. To minimize such variation, this work introduces a solid obstruction into the jet flow path. A variety of solid obstructions (pintiles) are evaluated to determine the effects of geometric parameters on flow independence. These design parameters include penetration into the liquid jet, the vertical distance of the pintile above the injection orifice, and the angle of the pintile relative to the injection surface. The pintiles were examined over a wide variety of flow conditions using high speed Mie scattering, varying Weber numbers (20-80) and momentum flux ratio (4-45). The trajectories of the liquid jets were then evaluated and compared across flow cases to determine the flow independence of each injector. The imaging was also used to ascertain the causes of the higher flow independence to inform future designs. The results demonstrate that pintiles with high orifice coverage, a large height above the injection surface, and an angle of 45° produced the most effective fuel injection. Droplet size distributions were also analyzed using a PDPA at the outlet the system to ensure that the flow independence of the injector did not impact the droplet sizes, and it was determined that the benefit of the pintile did not come at the cost of droplet size, which is an important fueling parameter. Information gathered from this research helps inform future design strategies to improve current and future injection schemes.


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Graduation Date





Ahmed, Kareem


Master of Science in Aerospace Engineering (M.S.A.E.)


College of Engineering and Computer Science


Mechanical and Aerospace Engineering

Degree Program

Aerospace Engineering; Thermofluid Aerodynamic Systems




CFE0008809; DP0026088





Release Date

December 2026

Length of Campus-only Access

5 years

Access Status

Masters Thesis (Campus-only Access)

Restricted to the UCF community until December 2026; it will then be open access.