Attempts to reduce cavitation phenomena at the Ciawi Dam inlet conduit using CFD Modeling

The conduit bottom outlet is prone to cavitation damage on its channel surface, and one preventive measure is the installation of air ventilation. This research aims to grasp flow characteristics comprehensively, predict cavitation likelihood at the intake, and assess the impact of a ventilation pipe's installation. Utilizing Computational Fluid Dynamics (CFD), the study modeled flow dynamics, focusing on velocity and pressure variables. The Ciawi bottom outlet intake was meticulously modeled at a 1:1 scale under normal water level conditions, and model accuracy was validated through physical testing by BHGK. The research includes two series: Series 0 (intake without ventilation pipe) and Series 1 (intake with ventilation pipe), with gate opening heights varied at 25%, 50%, 75%, and 100% for both series. Simulation results show that in Series 0, potential cavitation damage is indicated at a 75% gate opening in sections 3 and 4 with a cavitation index of 0.11. Series 1, featuring ventilation pipe installation, demonstrated positive outcomes, eliminating potential cavitation damage in the inlet bottom outlet, with all cavitation indices surpassing 0.2. This study provides crucial insights for preventing cavitation damage in conduit bottom outlets through the strategic deployment of ventilation systems.