Life Analysis and Structural Optimization of the Oil Distribution Plate in Ultra-High Pressure Diaphragm Compressors

Abstract Diaphragm compressors are widely used in the field of high-pressure gas compression. The oil distribution plate, as a critical component, is responsible for ensuring the uniform distribution of the hydraulic oil flow field near the diaphragm, thereby guaranteeing the consistency of diaphragm deformation. However, under ultra-high pressure (UHP, pressures exceeding 100 MPa) conditions, the distribution plate is prone to crack-induced failure, leading to the malfunction of the compressor. Therefore, this study employs a fluid-structure interaction (FSI) approach to analyze the characteristics of the hydraulic oil flow field and the transient stress of the oil distribution plate. The fatigue life of the oil distribution plate is calculated using nCode software, and its failure mechanism is elucidated. Furthermore, the influence of the structural parameters of the distribution plate on its life is discussed, and effective methods to extend its service life are proposed. The results indicate that under UHP conditions, the maximum average oil pressure within the oil chamber exceeds the discharge pressure, and the pressure distribution is uneven. The stress at the edge of the oil hole on the underside of the oil distribution plate is the highest, and the life is the shortest. Increasing the oil hole diameter initially elevates and then decreases the life of the oil distribution plate, with the maximum life achieved at a hole diameter of 4 mm. Reducing the depth of the oil guide channel can effectively enhance the service life of the oil distribution plate. This study provides a basis and guidance for the design of the oil distribution plate.