This study numerically investigates the effect of the edge of a sliding valve with a sill of different widths. The sill is introduced in the labyrinth sliding valve. The simulations were performed using FLOW-3D software. The results showed that the most critical factor affecting the discharge coefficient in constant hydraulic conditions was the shape of the valve edge. In a fixed cross section, a labyrinth valve increases the effective length and the discharge coefficient (by 7.8%) compared to a standard sliding valve. When the height of the edge of the labyrinth valve is fixed, the discharge coefficient in the labyrinth mode was calculated to be 8.3%. With the combined use of a labyrinth sliding valve with a sill in the widths of 5, 15, 20, and 30.5 cm, the discharge coefficient increased by 9.9, 11.8, 13.4, and 20.8%, respectively, compared to the standard sliding valve with an opening of 6 cm. The maximum discharge coefficient was increased 20.8% compared to the standard sliding valve with simultaneous use of the labyrinth sliding valve and the sill with the largest width.
