DESIGN OF INJECTOR PLATES FOR HYBRID ROCKET MOTORS TEST BENCH WITH GASEOUS OXYGEN

Resumo

Hybrid rocket motors have been intensively studied in universities because of their many advantages
compared to other chemical rocket motors. They are safe, simple to handle, present low cost, environmental
cleanliness, and throttling features. Because of these reasons, hybrid motors injection plate is a primary item. There
is a lot of available experimental data about the atomization of particles for liquid injection. However, for laboratory
applications, in which liquid oxygen is more expensive and challenging gaseous oxygen is desirable. From this
point of view, the present study is motivated by the lack of literature about injection plates for compressible fluids.
This paper presents an analytical and numerical design of injectors for gaseous oxygen. In the analytical study
section, continuity, ideal gas, and atomization equations present in literature have been used to design a showerhead
injection plate for the desired pressure drop. The numerical study made it possible to model a viscous flow through
the designed injection plate, resulting in slightly higher pressure drops than isentropic analytical results since the
theoretical results do not account for viscous losses. This numerical model validation enabled the design of more
complex injection plates, such as hollow-cone, pressure-swirl, and vortex ones.