# Effects of Air Injection on the Dynamic Characteristics of Sediment Deposition and Erosion Distribution in Pump-Turbine Runners

## TL;DR

This study examines how air injection affects sediment erosion in pump-turbine runners to improve their efficiency and lifespan.

## Contribution

The novel contribution is the use of aeration short pipes to investigate air injection's impact on erosion distribution in pump-turbine runners.

## Key findings

- Guide vane aeration reduces erosion on the runner crown and blade working surface.
- Main shaft aeration increases erosion and causes expansion of the erosion region at high aeration concentrations.

## Abstract

As the core equipment of pumped storage power stations, the erosion and wear of pump-turbine runner blades have become critical issues affecting the operational efficiency and service life of units. To mitigate particle impact energy and surface wear of the runner blades, this study proposes the installation of aeration short pipes with a diameter of 4 mm and a length of 20 mm at the adjustable guide vanes and the main shaft, aiming to investigate the influence of air injection on erosion characteristics. Numerical simulations demonstrate that air injection significantly alters the flow characteristics in the runner region and establishes a coupling relationship between erosion distribution and different aeration concentrations and injection methods. Guide vane aeration effectively reduces sediment-induced erosion on the runner crown and blade working surface, while simultaneously leading to more localized erosion on the crown and band. In contrast, main shaft aeration increases erosion on the crown and blade working surface, and under high aeration concentrations, the erosion region exhibits a significant expansion trend.