The labyrinth control valve is one of the important components of the feedwater bypass system of oncethrough boiler in the supercritical(ultra-supercritical) unit. The type and structural parameters of the labyrinth runner are the key to designing the labyrinth control valves

which directly affect the flow field distribution in the valve. On the basis of flow characteristics of the conventional divided-flow and hedge-type runner

a new disc structure is proposed in this paper. In addition

through numerical simulation by the CFX software

the flow field distribution characteristics of the valve with new disc structure and different structural parameters are studied. The results show that

the new disc structure has good flow characteristics

flow resistance characteristics and flow capacity

which can meet the requirements of the valve. In the disc structure parameters

with the increase of the runner depth

the average outlet pressure decreases

and the flow rate and the average outlet velocity increase. With the increase of the runner chamfer

the flow rate and the average outlet velocity increases

while the average outlet pressure decreases and the cavitation occurs in some areas. Furthermore

with the increase of the width of the hedgetype runner and the width of inlet runners and outlet runners

the flow rate increases

and the average outlet pressure and speed show a downward trend. The depth and the chamfer of the runner have a great influence on the flow field

while the effect of the width of the hedge-type runner

the width of the inlet runners

and the width of the outlet runners on the flow field of the valve is limit.