Effects of orifice on pressure difference in pilot-control globe valve by experimental and numerical methods

Pilot-Control Globe Valve (PCGV) can utilize pressure difference caused by fluid flow through the orifice on valve core as its power, for open and close the main valve with a small pilot valve. It has obvious advantages of energy conservation and quick response. Orifice structure on the valve core is the main component to determine the pressure difference, which is used to push the valve core. In this paper, the numerical model with User Defined Functions (UDFs) method is carried out, and the experimental device is arranged. The numerical and experimental results of valve core displacements achieve agreements. Then, analysis of pressure difference under different static pressures, inlet velocities and different orifice diameters are carried out. It shows that pressure difference has no relationship with static pressure, thus PCGV can be adopted in hydrogen pipelines. Meanwhile, higher inlet velocity can turn out larger pressure difference with quicker response of PCGV. In addition, there exits an unbalanced moment, and 15 mm is the extreme diameter of the orifice for DN150 PCGV. Finally, the design method of the orifice structure in PCGV is proposed with design formulas. This work can help the precise design work of PCGV, and it can be referred by other researchers who are also deal with orifice structures in similar valves design work.