Mechanical property and sealing performance analysis of the diaphragm compressor cylinder head for the hydrogen refueling station under the mutation impact load

Abstract: Under the combined action of structure-process -load, the stiffness and stress distribution at the sealing interface of the ultra-high pressure diaphragm compressor cylinder head exhibit significant nonlinear and uncertain characteristics, resulting in damage to the sealing interface, diaphragm and sealing ring. This paper first establishes a finite element numerical model considering assembly process parameters based on sudden impact load conditions, and analyzes the dynamic characteristics under different assembly process parameters. It is found that some modal frequencies transition with bolt loosening. Then, the mechanical characteristics of the assembly interface of the compressor sealing system under sudden impact load were studied. The maximum equivalent stress at the assembly interface was 298.9 MPa, and the maximum deformation at the top of the air chamber was 0.167mm. Finally, the nonlinear effects of sealing ring compression rate, sealing ring diameter, and sealing groove structure on contact stress and sealing performance were obtained. The results show that as the compression ratio increases by 20% and 25%, the contact pressure at the sealing interface increases by 42.0% and 77.5%, respectively; When the compression rate is 25%, the width of the sealing groove increases by 0.5mm, and the maximum contact pressure decreases by 8.1%. The research on the dynamic characteristics and sealing performance of diaphragm compressors provides technical support for the structural optimization design of diaphragm compressors cylinder head.