Analysis of Nitrous Oxide Flow and Thermodynamic Behavior in Additively Manufactured Hybrid Rocket Motors

Hybrid propulsion has become established in the contemporary aerospace industry as a disruptive alternative, combining the intrinsic safety of solid fuel rocket motors with the controllability and restart capability characteristic of liquid propellant systems. In this context, the use of nitrous oxide (N2O) as an oxidizer stands out as a strategic solution due to its self pressurizing nature and low toxicity, which significantly simplifies feed system architectures. In parallel, additive manufacturing has revolutionized the field by enabling the production of components with complex internal geometries, such as integrated injector systems and optimized fuel grains, which would be unfeasible using conventional manufacturing methods.

The present research focuses on a hybrid rocket motor with a nominal thrust of 1 kN, fully designed and tested at the Chemical Propulsion Laboratory (CPL) of the University of Brasília. The study investigates the overall performance and thermodynamic behavior of N2O, addressing its complexity as a two-phase fluid through precise instrumentation of pressure, temperature, and mass flow rate on a vertical test stand.

The research methodology comprises the evaluation of the oxidizer’s effects on propulsive performance, as well as a detailed investigation of its dynamic behavior within the system feed lines. The research results not only validate the technical feasibility of this configuration for small-scale missions, but also establish safety protocols and operational procedures that are essential for the advancement of chemical propulsion research in Brazil. Consequently, the convergence of high-performance oxidizers and advanced manufacturing is positioned as a fundamental pillar for the next generation of low-cost, high efficiency launch systems.