Development of a cross-flow-turbine by using 3D-CFD-calculations

This work presents a different approach of developing and optimizing a two chamber-cross-flow turbine by using numerical investigations. The development process starts with the preliminary 1D-calculation of the velocity components to determine the main turbine geometry. Based on the preliminary design a broad-based numerical investigation was conducted by using complex, 2-phase flow calculations with moving surfaces. These investigations implied the whole geometry components of the hydraulic machine (e.g. runner blades, nozzle, guide vane) to determine their influence on the maximum reachable turbine performance. With a simplified CFD-turbine-model, a considerable number of different turbine designs were analyzed. The CFD-calculations clearly show that the major impact on the turbine performance is caused by the runner blades and the interaction between the nozzle and the runner blades. Following the CFD-calculations, the most promising design was then investigated on a test rig in the laboratory of the Institute for Hydraulic Fluid Machinery.
The final step of the development process represents the field measurement of the prototype turbine.