Research on the transport performance of servo valve for diaphragm compressor

The oil-gas pressure differential is a key factor determining the operational reliability of diaphragm hydrogen compressors, which are critical equipment for hydrogen energy storage and transportation. This paper presents a CFD study on hydraulic oil flow characteristics in 45 MPa and 90 MPa class diaphragm compressors with fully open servo valve flow channels. The results reveal a linear relationship between inlet mass flow rate and hydraulic oil pressure. The inlet flow velocity is primarily perpendicular to the inlet cross-section, with minimal transverse components. The inlet Reynolds number ranges from 4000 to 8000, corresponding to the transitional flow regime where turbulence effects cannot be neglected. The total inlet pressure also increases linearly with oil pressure, and the 45 MPa compressor achieves the most favorable hydraulic flow dynamic pressure at 47.5 MPa. This work provides valuable theoretical guidance for oil pressure parameter selection and servo valve structural optimization in high-pressure diaphragm hydrogen compressors.