Design Considerations for Fixed-Cone Valve with Baffled Hood

Abstract

Fixed-cone valves (FCVs) are practical devices used to regulate flow at dams having medium to high heads. These valves are designed to safely reduce the flow energy by redirecting the pipe flow into a free-discharging conical jet and, under certain circumstances, through a hood or another containment structure to control the conical jet. However, the hood concentrates the jet and, consequently, the remaining energy. A relatively new hood design using baffle blocks has been successful in reducing the area required to contain and dissipate the jet energy. Although baffle blocks have previously been used in cylindrical FCV hoods, there is no established design standard for the placement and sizing of the blocks. This paper considers a design not previously documented in the literature for an FCV with a conventional hood that implements baffle blocks. The design analysis uses both computational fluid dynamics and physical modeling and compares the results.