| dc.description.abstract | Abstract. Turbine low-pressure bypass control valves operate under high-pressure differential conditions. Typical single-stage control valve has high flow velocity at the throttle, resulting in severe vibration and noise. The multistage labyrinth channel control valve has demonstrated excellent performance under severe conditions. This paper researched the effect of the six variables on the flow characteristics of the labyrinth channel. The accuracy of the numerical simulations has been validated, and the maximum error relative to the experiment is less than 5%. The results show that increasing the number of stages of the labyrinth channel to control the flow velocity is a feasible way. Meanwhile, the shape coefficient can increase the mass flow rate of the labyrinth channel significantly, but the effect on the energy loss is not significant. Moreover, the Mach number is unevenly distributed along the flow direction due to the inertia during corner flow; thus, excessive width of the labyrinth channel should be avoided. However, the Mach number distribution in the Z direction is uniform, despite the different shape coefficient of the labyrinth channel. In addition, the energy dissipation in the low Mach number region as well as the breakup and growth of vortex structures in the high Mach number region result in increased energy loss. | |
