## 1 Introduction  
Hydrogen energy, recognized as a clean secondary energy carrier, offers distinct advantages, including high energy density, zero pollution, and zero carbon emissions [1, 2]. China's hydrogen production capacity has expanded rapidly, rising from 22 million tons in 2019 to 35.5 million tons in 2023, with projections indicating a potential 60 million tons by 2050 [3]. However, widespread hydrogen utilization faces critical safety and technical barriers due to its inherent flammability, explosivity, and property of causing material embrittlement [4], which demands deeper investigations and creative innovations across the entire production-storage-transportation chain [5]. The diaphragm compressor serves as a pivotal device in hydrogen transportation, enabling leakage-free and contamination-free pressurization with a high-pressure ratio. It is indispensable for hydrogen refueling stations and distributed supply systems, where the compressor provides essential pressure elevation to meet operational requirements [6; 7]. Nevertheless, the diaphragm compressor presents two main challenges: the diaphragm's lifespan directly impacts its reliability, while its volumetric efficiency limits the flow capacity and energy efficiency [8]. Addressing these technical bottlenecks requires advanced material processing, structural design, and integrated system optimization to balance performance, reliability, and cost-effectiveness [9]. Recent studies on the cavity profile of diaphragm compressors have been conducted. [PERSON] et al. [10; 11] proposed innovative cavity generatrix designs (two-exponential and three-exponential cavity profiles) validated through computational simulations and experimental tests, achieving a 10% increase in cavity volume and a 19.6% reduction in radial stress levels. Building on this work, [PERSON] et al. [12] further investigated the flow-stress interaction, revealing that while these optimized profiles reduced radial stresses by 8.2 to 13.9% compared to conventional designs, they increased clearance volumes and decreased flowrates, highlighting trade-offs between stress mitigation and volumetric efficiency. [PERSON] et al. [13] refined generatrix configurations to minimize radial stresses and reduce clearance volumes through the diaphragm deflection analysis. Moreover, several investigations into diaphragm compressor reliability have also focused on assessing diaphragm operational lifespan and analyzing thermal stress distributions within compressor head components. Thermal-structural analyses conducted by [PERSON] et al. [14; 15] on high-pressure hydrogen compressor cylinder heads demonstrated that geometric modifications effectively mitigated stress concentrations and enhanced operational reliability under extreme thermal conditions. [PERSON] et al. [16] improved the reliability of the GH4169 alloy diaphragm through material hardening and surface processing optimization. [PERSON] et al. [17] investigated critical maintenance factors by analyzing the diaphragm compressor failures, identifying valve performance degradation and oil pressure fluctuations as primary contributions to operational instability. Moreover, several studies focused on the diaphragm compressor's flowrate optimization. [PERSON] et al. [18; 19; 20] examined the influence of hydraulic oil compressibility and operating temperature on the volumetric efficiency in hydrogen refueling systems, proposing a self-adjusting oil piston mechanism to optimize cavity volume utilization. [PERSON] et al. [21; 22] developed a fluid-structure interaction (FSI) model to simulate compressor dynamics, experimentally quantifying the effects of the suction pressure, compression ratio, and rotational speed on the volumetric efficiency. [PERSON] et al. [23] evaluated an innovative wrap-around cooled diaphragm compressor design for hydrogen refueling stations, demonstrating improved energy efficiency and thermal management compared to conventional configurations.