Structural optimization study of anti-water hammer air valves

This study addresses the limitations of traditional air valves used in water hammer protection, such as low exhaust efficiency, poor anti-water hammer performance, and the difficulty in accurately modeling dynamic air intake and exhaust behaviors. The research focuses on the anti-water hammer air valve and proposes innovative dynamic air intake and exhaust coefficient models (Cin(p), Cout(p)) based on differential pressure variation. The research examines the structural characteristics of the throttle plug, considering different positions, shapes, and center orifice diameters. Fluent simulations were performed to evaluate the impact of these parameters on the valve's air intake and exhaust performance, identifying the optimal throttle plug design. The results demonstrate that optimizing the throttle plug position to h = 80%, improves the minimum negative pressure by 6.48% to 46.01% compared to the original design. A funnel-shaped throttle plug improves the minimum negative pressure by 11.20% to 29.03%, and an orifice ratio between 10% and 16% enhances the minimum negative pressure by 3.65% to 27.35%. The dynamic air intake and exhaust models, supported by high-precision numerical simulations (R2 = 0.99), overcome the limitations of traditional fixed coefficient models, significantly enhancing transient pressure prediction accuracy. The optimized structure was validated using the mathematical model of an actual AL water conveyance project in Xinjiang, effectively reducing the risk of negative pressure. This study provides a framework for optimizing the structural design of anti-water hammer air valves and a solid theoretical basis for the safe operation of long-distance water conveyance systems.