Abstract

The primary cause of mechanical-related fish injury and mortality in turbomachinery is blade strike. Fish contained in the flow may strike with the rotor blades and the fixed diffuser vanes, the latter being a non-negligible factor causing fish damage in pump system. In this study, an experiment-based correlation of fish mutilation ratio acts as critical strike velocity. The relation between strike damage in a vaned diffuser and the theoretical pump head is presented as a function of specific speed. As an example, a vaned diffuser is designed for a single-bladed, mixed-flow impeller with the purpose of improving fish friendliness. This pump can be scaled to operate with a head up to 14 m at peak efficiency, without fish damage in the diffuser. Subsequently, experiments are conducted to show the retained pump performance as well as the great improvement of fish friendliness.

This content is only available via PDF.
You do not currently have access to this content.