Anti-wear and anti-cavitation structure optimization of V-type regulating ball valve in the coal chemical industry

Abstract

Aiming at the erosion wear-cavitation phenomenon of the V-type regulating ball valves in the coal chemical industry during the transportation of black water medium, which leads to sealing failures and induces flow-induced vibration issues. It is proposed to add diffusion baffles inside the sphere to transfer the erosion, while the rear valve seat adopts staggered diffusion holes to reduce the throttling cavitation effect, and the optimization scheme is verified through numerical simulations and experimental testing. The research indicates that the optimization model can cause the local jet at the throttling section to diffuse and decelerate, weakening the formation of high-speed jet flow within the sphere's flow channel. Additionally, the optimization model transfers the erosion in the sphere's upstream area to the baffle, and reduces the kinetic energy of particle collisions through the baffle's diffusion effect, thereby reducing the erosion wear on the rear valve seat and the valve sealing pair. Through quantitative analysis, the average wear rate of the optimization model's components is 30 % of the original model. Additionally, the optimization model effectively suppresses the vapor-liquid phase change within the valve, thereby weakening the flow cavitation phenomenon in the valve, and the vapor volume fraction and cavitation distribution range in the fluid domain are significantly reduced. Furthermore, the pressure pulsation coefficient in the fluid domain of the optimization model significantly decreases and exhibits periodic fluctuations, with reduced amplitude and frequency range of large-amplitude pressure pulsations, which helps to avoid the flow-induced resonance phenomenon between the valve and the liquid flow system. Experimental verification shows that the quality loss and erosion rate of the optimization model are both lower than the original model, indicating that the optimization scheme can reduce wear and suppress cavitation, thereby prolonging the valve service life.