Design, Manufacturing and Cold Flow Testing of a Liquid Rocket Engine 3D Printed Pintle Injector

Rocket engine design has a long heritage, however, only recently has it become accessible beyond private industry with modern manufacturing techniques like additive metal manufacturing. The following paper outlines the design process of an additively manufactured rocket engine pintle injector system. The methodology followed an initial design analysis, injector sizing, 1D thermal analysis of the pintle injector plate, Finite Element Method (FEM) analyses of the pintle orifices discharge coefficients, temperature differences and pintle mechanical stresses. These analyses informed the CAD model which was 3D printed with single and double row pintle arrangements, which were cold flow tested and discharge coefficients found to be 0.65 and 0.4 respectively, with annular flow proving a discharge coefficient of 0.47. The pintle tests were affected by manufacturing errors resulting in the hole sizes reduction, as well as pressure error and unavoidable contamination. These results indicated that the CFD simulations overestimated the discharge coefficients.