Research on influnence of orifice parameteers on fluid resistance variations

The fluid resistance of the orifice to the fluid inside the hydraulic system is the key factor affecting the adjustment of partial pressure and flow, while discharge coefficient determines the magnitude of such resistance. In this paper, a theoretical model of discharge coefficient is established to address calculation accuracy of discharge coefficient in orifice fluid resistance analysis based on computational fluid dynamics and orifice structure. CFD simulation analysis is conducted to compare and validate accuracy of the empirical formula. Furthermore, the influences of orifice parameters on discharge coefficient are analyzed. The results show that discharge coefficient is a variable subject to the influence of flow and orifice length-diameter ratio. For most orifices, as flow increases, discharge coefficient increases first and then stabilize at a certain value; as length-diameter ratio increases, amplitude of variation of discharge coefficient decreases and stabilize around 0.8.