Summary

I researched and designed additively manufactured injectors for use on my university’s 3.5kN Nitrous/Ethanol bi-propellant rocket engine. It is designed to be manufactured from aluminum alloy AlSi10Mg using the DMLS printing process. Various injector geometries were considered, but the simplicity of fuel-centric coaxial shear geometry outweighed the potential efficiency gains of more complicated injectors. Each shear element is impinging on another, which increases combustion efficiency. The outer elements have a lower oxidizer/fuel ratio to manage thermal loads on the chamber wall. Film cooling orifices were also included for the same purpose. Injector orifice sizing was done with a custom MATLAB script, which allowed for efficient optimization of the geometry. An injector of this geometry is unable to be made with conventional manufacturing processes.