Refinement of Cross‐Flow Turbine Design Parameters

Abstract

This paper discusses experiments that were conducted to refine some of the key cross‐flow turbine runner parameters for better performance. The parameters studied were identified by previous studies as key design parameters. The research included narrowing the range of the number of blades, the determination of the impact of the first‐stage exit angle, and the effect of flow stream spreading on the performance of the cross‐flow turbine. The results indicate an optimum number of blades that would produce maximum efficiency of the turbine, and a clear trend of the effect of the first‐stage exit angle and flow stream spreading on the efficiency. For the best nozzle‐runner combination, the maximum efficiency closest to the discharge averaged maximum efficiency is determined to be 92%, with an uncertainty of ±2.4%. This result is an improvement over the reported maximum efficiency of any cross‐flow turbine.