Optimized initial down-scaled model design of RD-CRPT (ALPHEUS, D2.2)

Report, 2020

This report describes how the optimised initial down-scaled model design of the Rim-Driven Counter-Rotating Pump-Turbine (RD-CRPT) in the ALPHEUS project was derived. A first design was made in prototype scale, according to the expected requirements of the final machines. The design was scaled to an appropriate model scale with respect to requirements from the experimental test facility at TU Braunschweig. In model scale a manual optimisation process was conducted in an iterative manner. The goal with the optimisation procedure was to increase the efficiency for a wide range of operating conditions in both pump and turbine modes. The process has resulted in a design of a down-scaled model with far better performance than the initial design. The RD-CRPT design is ready to be subjected to further numerical sensitivity analysis and multi-objective optimisation. It has been decided that it is the Shaft-Driven Counter-Rotating Pump-Turbine (SD-CRPT) that will be experimentally studied, rather than the RD-CPRT due to the fact that the Rim driven configuration cannot use “off the shelf” motor/generators components.