Rocket Nozzle Design and Validation with FEATool Multiphysics

Small sugar-propellant rocket motors, often called R-Candy motors, provide an accessible platform for studying propulsion and nozzle design. Their relatively simple construction makes them suitable for educational and experimental rocketry, but predicting how combustion pressure, temperature, and exhaust flow interact inside a small motor can still require considerable trial and error. In particular, the nozzle must accelerate the combustion gases while maintaining stable chamber pressure, manageable thermal loads, and consistent thrust.



Researchers at the Instituto Politécnico Nacional combined a systems-based design process with Computational Fluid Dynamics (CFD) to connect simulation, physical measurements, and design refinement. A preliminary motor and convergent-divergent nozzle were developed in SolidWorks and transferred to FEATool Multiphysics, where the internal flow and thermal fields were simulated. The FEATool results were then compared with static-firing measurements and fed back into the design process. The study found that the CFD model reproduced the main observed propulsion behavior and provided flow and temperature information that could be used to improve the nozzle geometry and simulation setup.

Visit https://www.featool.com/model-showcase/2026-08-21-Rocket-Nozzle-CFD-Optimization/ for more details and CFD toolbox download!