Reverse engineering of pump as turbine for CFD analysis

Abstract

Reverse engineering (RE) using 3D scanning is already a relatively technologically simple and cost-effective method. For water turbines, this is particularly true for RE of larger machines. With microturbines, there is a lot of pressure to minimise costs, even at the cost of reduced accuracy. Using an existing micro-PAT (Pump as Turbine) as an example, we showed the approach to assessing these microturbines, starting with scanning the entire internal flow profile of the turbine, reconstructing the surface into a 3D model, and numerically assessing it using CFD (Computational Fluid Dynamics). A different approach is necessary compared to standard large machines, whose dimensions allow troublefree scanning of the flow parts of the turbine. Using CFD, we assessed the reconstructed geometry of the PAT. Two significant findings were made: the importance of high-quality 3D scanning by combining several cheaper 3D scanners and the necessity for reliable in-situ measurements for a successful CFD validation. Our future focus involves optimising PAT runner geometry in turbine mode to enhance energy production at the site and, at the same time, eliminating existing cavitation.