Nicholas Gilhaus, “SRM Submergent Nozzle Particle Breakup Analysis”
Mentor: Ryoichi Amano, Mechanical Engineering
Solid rocket motors primarily use aluminized composite propellants as fuel. As the propellant combusts, it forms aluminum oxide (Al3O3). At high temperatures and pressures, the aluminum oxide tends to agglomerate into molten droplets which cover the nozzle walls and flow from the throat to the exit. By eroding the nozzle walls (specifically in the throat), the aluminum oxide conglomerate negatively affects the ballistic performance of the rocket. Proper investigation of this phenomenon is crucial to developing solutions to the solid rocket motor erosion problem. Previously, our group has conducted research to investigate the particle breakup tendencies in the convergent-divergent (CD) nozzle of a solid rocket motor. Currently, we are investigating the breakup tendencies in the submergent nozzle, a common nozzle used in SRMs that has “pockets” that alter the breakup of aluminum oxide. In the investigation of the CD nozzle, we were able to conclude that, as air and water velocity increase, the breakup phenomenon increases in number and moves down the throat toward the exit. The results of the study will reveal whether a submergent nozzle reduces the erosive effect of the aluminum oxide droplets when compared to the commonly used convergent-divergent nozzle. In addition to the nozzle selection, a proper understanding of how different velocities of air and water effect the breakup tendencies within the nozzle is crucial to develop solutions to the erosion problem. Space exploration is becoming a much more accessible industry and is on the verge of becoming commercial. A solution to erosion from aluminum oxide in solid rocket motors would cut immense costs because boosters have the capability to be reused for numerous trips. This study aims to develop a solution that will drive the space industry further into the (much more affordable) future.