An Open-Source Framework for the Design and Simulation of Turbomachinery

This thesis presents a comprehensive framework for the design, simulation, and analysis of turbomachinery components, with particular emphasis on air-cycle refrigeration systems. Rising demand for environmentally sustainable and energy-efficient solutions in aviation and industrial applications has renewed interest in air-cycle technology as an alternative to conventional vapour-compression systems. To support this development, an open-source Computer-Aided Engineering (CAE) pipeline has been created that integrates parametric geometry generation, meshing, and numerical simulation. The geometric modelling is built on a modular Python toolchain (pyTurbo, pyNURBS), which provides a Computer-Aided Design (CAD) kernel with implementations of NURBS, intersection, and geometry manipulation algorithms. On this foundation, pyTurbo enables the parametric construction of turbomachinery parts, where blades are defined through meridional and angle curves combined with thickness distributions. This approach offers high flexibility in shaping a wide range of components. The workflow is seamlessly coupled with Open-FOAM, including extensions to the solver environment such as a rothalpy-based energy equation and turbomachinery-specific function objects, thereby improving the accuracy of simulations in rotating reference frames. Validation of the methodology is carried out on the well-documented Sundstrand T-100 auxiliary power unit radial turbine, which serves as a benchmark for geometry reconstruction and Computer Fluid Dynamic (CFD) analysis. The results confirm that the developed workflow can reliably reproduce turbomachinery characteristics such as specific speed, velocity ratio, and flow structures. In addition, the study introduces post-processing strategies for performance evaluation and for the physical interpretation of flow phenomena. The thesis advances the state of knowledge in two main respects: first, by establishing a reproducible and extensible design-to-simulation pipeline for turbomachinery research and development; and second, by examining modelling strategies that reinforce the potential of air-cycle technologies in sustainable energy and refrigeration systems. The outcomes support the future development of efficient turbomachinery while bridging the gap between theoretical design principles, computational modelling, and practical implementation.