The project "Design and Optimisation of a Novel MEMS Microcombustor", delivered for AVS in 2021, addressed a practical process and manufacturing challenge through computational fluid dynamics (CFD) and process modelling. Rather than producing simulation images in isolation, the study was organised around the client's design questions: what controlled performance, where the principal risks or losses occurred, and how the design or operating strategy could be improved.

The Iridium Catalysed Electrolysis CubeSat Thruster (ICE-Cube Thruster) is a novel micro-scale rocket engine which is being developed by URA Thrusters. The thruster utilises the propellants of hydrogen and oxygen produced by the electrolysis of water and is designed to produce a thrust of only 4.5mN. Designing a Micro-Electrical Mechanical Systems (MEMS) thruster to function at this scale is a unique challenge and requires a very different approach compared to the typical rocket engines. Our team conducted a series of parametric studies consisting of geometrical and operational parameters using high-fidelity simulations and obtained critical design data including temperature, pressure and velocity in different parts of the combustion chamber, which enabled the company to successfully improve the design of the thruster. In addition, a bespoke combustion efficiency was developed and a series of reaction equations were implemented by our team in order to enhance the design and obtain the main combustion species.

The methodology centred on a reacting-flow CFD and process model of the MEMS-scale hydrogen-oxygen microcombustor. The representation retained the catalyst or reaction region, microchannels, combustion chamber, walls and nozzle where heat loss and small-scale transport dominate performance. Boundary and operating conditions covered geometric and operational parameters, reactant flow rates, pressure, wall thermal conditions and the implemented reaction mechanism, with material, fluid and equipment properties assigned from the available design information. Resolution was concentrated in regions where steep velocity, thermal, concentration or phase gradients were expected, while the overall model remained efficient enough to compare several credible configurations. This balance allowed system-level performance to be linked to the local mechanisms responsible for it.

The assessment compared combustor dimensions, inlet arrangement and operating points within the microthruster constraints. Performance was judged using temperature, pressure, velocity, species distribution, wall heat load, combustion efficiency and the conditions delivered to the nozzle. Results were reviewed through quantitative summaries and engineering visualisations, such as contours, vectors, streamlines, sections and time histories, selected to suit the physics. Important assumptions and operating uncertainties were considered so that the recommendations relied on repeatable comparative trends rather than a single nominal case.

For AVS, the principal value was critical design data for improving a viable microthruster while protecting materials and efficiency. The final evidence linked each recommendation to the relevant model or process output, making it suitable for internal design reviews, supplier or contractor discussions and, where applicable, planning, safety or regulatory dialogue. The work also created a reusable baseline that can be updated as geometry, operating data or test results become available, reducing the cost and risk of later design iterations.