Experimental and computational analysis of air injection as a mitigation technique for silt erosion in hydro turbines

Hydroelectric power plants play a critical role in renewable energy generation, but sediment-laden water leads to silt erosion in key components such as turbine blades and guide vanes, adversely affecting efficiency and operational longevity. This study introduces a novel air injection technique aimed at mitigating silt erosion on guide vane surfaces. The research involved both computational simulations and experimental testing, employing a specially designed rotating disc apparatus. Erosion tests were conducted on guide vanes both with and without air injections, using NACA 4412 hydrofoil profiles at a 10° angle of attack. The variable parameters in the study included air injection velocity (ranging from 7.5 m/s to 17.5 m/s), silt concentration (2500 ppm), and air injection angles (90°). The measured output includes erosion rate, material loss, and surface erosion patterns. Simulation results indicated an erosion reduction of approximately 40%, while experimental results showed an efficiency of 27% to 38%, with the optimum air injection velocity observed at 12.5 m/s. The novelty of this approach lies in the use of air injection as a protective layer over the guide vanes, creating a buffer zone that shields the surface from silt impact and reduces erosion. This method presents a significant improvement over traditional erosion mitigation techniques, such as material coatings and sediment chambers. <strong>Received: 10 October 2024 </strong> <strong>Accepted: 06 November 2024 </strong> <strong>Published: 20 November 2024</strong>