A Novel Numerical and Experimental Investigation Into Radial Injection for Suspension High Velocity Oxy Fuel (SHVOF) Thermal Spray

In suspension high-velocity oxyfuel (SHVOF) thermal spraying, the suspension is usually injected axially into the combustion chamber. Deposition of oxygen sensitive materials such as graphene can be difficult using this approach as the particles degrade with extended exposure to oxygen at high temperatures. Radial injection outside of the nozzle, however, reduces in-flight particle time thereby accommodating oxygen sensitive nanomaterials. The aim of this study is to investigate how radial injection parameters affect in-flight particle conditions during SHVOF spraying. The models used in this work are shown to accurately predict flame temperature in the combustion chamber for an Al₃O₂ suspension. Experimental observations of the liquid jet obtained using high-speed imaging are compared to numerically predicted values. The results indicate that in-flight particle characteristics can be improved by more than 30% in SHVOF spraying by optimizing the suspension flow rate and radial injection angle.