This paper presents the results of reverse-engineering (RE) strategies, surface roughness and computational fluiddynamics (CFD) modelling for a Wren100 micro gas turbine (MGT). Utilising silicone moulds and resin tooling,precise blade geometry capture was achieved for 3D reconstruction allowing for discrete and parametric geometricmodels to be created. Using these geometries, CFD simulations employing both Reynolds-averaged Navier-Stokes(RANS) and large eddy simulation (LES) models, alongside experimental wind tunnel cascade tests, were used toevaluate these reverse engineering strategies. The results show that while the parametric model captures overallMGT performance with fewer parameters, the discrete model provides enhanced accuracy, highlighting its suit-ability for detailed aerodynamic analyses. Contrary to initial expectations, surface roughness exhibited a noticeableimpact on performance despite the lower Reynolds numbers (40,000), as demonstrated by the CFD model and windtunnel experiments. The results indicate that surface roughness can reduce laminar separation bubbles on the bladeleading edge, delay the onset of transition, and mitigate secondary flow losses. Overall, this study contributes toknowledge advancement in turbine blade reverse engineering and aerodynamics by detailing the impact of surfaceroughness on performance.
