Experimental study of steam turbine control valves

Because of the converging-diverging configuration of the valve passage, venturi valves have been widely used in large turbines to regulate inlet flow as turbine governing valves for about half a century. From the 1960s, a number of valve failure incidents have been reported. Improvement to current designs was strongly demanded but, owing to the complicated nature of the fluid-structure interaction mechanisms, the basic mechanism causing valve failure is still far from being fully understood. Experimental investigations on a half-scale valve were performed here. The study confirmed that asymmetric unstable flow is the root cause of valve problems, such as noise, vibration and failure.