Flow force regulation of the main poppet in a large flow load control valve

This paper presents the regulation methods of flow forces acting on the main poppet in a large flow load control valve. The negative flow forces working on the originally designed main poppet, which is as high as 10% of the control force, act as a big disturbance to the main poppet position control, resulting in poor lowering speed control performance of the load control valve or even instability of the main poppet. Firstly, by introducing a damping tail structure to the main poppet, the direction of the flow forces can be regulated to positive and best stability of the main poppet can be achieved with the calculated best parameter combination. Secondly, by introducing a damping tail with holes to the main poppet, the positive flow forces of all main poppet positions can be reduced to minimum, which results in minimum disturbance for the control of main poppet. Computational fluid dynamics calculations were conducted to analyze how the damping tail parameters affect the flow forces and obtain the best parameter combinations. A test rig was set up to validate the effect of above methods. Good agreement of the computational fluid dynamics calculations and experiment results indicates that the proposed methods can provide guidance for the flow force regulation of other valve poppets.