The development of reliable, efficient and low-cost liquid-propellant rocket engines is essential for promoting space exploration and satellite deployment. Achieving this relies heavily on a understanding the dynamic processes taking place within the engine.With the rise of modern computing, mathematical modelling has become fundamental inreducing risks and costs during development.

This thesis focuses on developing a fully transient, open-sourced Python-based model of an oxidizer-rich staged-combustion rocket engine, developed in collaboration with Rocket Factory Augsburg. The model moves away from other proprietary software, providing full control over the equations and solvers. It integrates mathematical models for hydraulic lines, combustion processes, pumps, and turbines, forming a comprehensivemodel of a staged-combustion rocket engine.

The model has been validated using real test data from cold-flow and hot-fire tests, successfully demonstrating its ability to replicate the real engine behaviour during start-up and steady-state transients. A sensitivity analysis was also performed to identify key parameters impacting performance during these transient phases.

This work offers valuable insights into the engine’s dynamics, helping to improve design, optimise the start-up sequence, and develop control and health monitoring algorithms. Future work will focus on enhancing accuracy, reducing fine-tuning, and expanding the model’s applicability across a wider range of conditions.