Numerical and Experimental Characterization of an Aerodynamically Redesigned Disc in a DN350 Double-Eccentric Butterfly Valve in Terms of Flow Coefficient, Pressure Loss and Hydrodynamic Disc Load

Flow control in pressurized water-transmission and irrigation lines relies on large-diameter butterfly valves, whose disc governs both the line pressure loss and the actuation load. This study compares the conventional disc of a DN350 double-flanged double-eccentric butterfly valve with an aerodynamically redesigned disc using a dual-track approach. A three-dimensional steady incompressible RANS solution (Simcenter FLOEFD) sweeps the opening angle from 30 to 90 degrees in 10-degree steps, while flow-coefficient (Kv) values are measured on the manufactured valve per TS EN 1267. The model yields the inlet static pressure, hydrodynamic disc force (Fd) and volumetric flow rate, from which the pressure loss, loss coefficient (zeta), drag coefficient (Cd) and CFD-derived Kv follow. Dimensioned within patented H/D and Y/D rules, the redesigned disc reduces the disc volume by 42.8 percent and the mass from 38.7 to 22.2 kilograms. Across all opening angles it lowers the pressure loss by 49 to 67 percent, the loss coefficient by 46 to 65 percent and the disc force by 34 to 63 percent, while the experimental Kv rises by 20 to 37 percent. The disc force is a comparative proxy for the actuation-torque demand. The absolute torque is not computed.