Parameter Characteristic Analysis of Refueling & Venting Simulation for Group-parallel Fuel Cell Hydrogen Supply System

Safe and stable operation of hydrogen supply systems is a core performance indicator for hydrogen energy vehicles and distributed hydrogen power generation systems. During high-pressure gaseous hydrogen refueling, different series-parallel cylinder group configurations cause uneven refueling flow distribution, inducing internal temperature variations in cylinders. Excessive temperature fluctuations lead to irreversible deterioration of the cylinder material's mechanical properties, while differences in structural parameters cause significant discrepancies in venting rates. Taking three 8-cylinder hydrogen supply system layouts as research objects, this paper examines the time-series evolution of flow rates during refueling and venting. Computational Fluid Dynamics (CFD) simulations are conducted to obtain temperature and pressure distribution under rated operating conditions. Results show the 2-series 4-parallel structure optimally balances charging efficiency and temperature distribution: its refueling time is 2 seconds longer than the 8-parallel structure, but 12.3 seconds shorter than the 4-series 2-parallel structure. After refueling, its cylinder temperature is 4 K lower than the 8-parallel configuration and 2 K higher than the 4-series 2-parallel configuration. Under venting conditions, increasing the flow-passage diameter of TPRD can markedly increase the system venting rate. A 6.2 mm diameter TPRD reduces system pressure to 2.5 MPa within one minute. As the TPRD flow passage diameter increases, the main discharge pipeline diameter will replace the TPRD diameter as the primary bottleneck limiting the venting rate. This study provides a theoretical basis and simulation data for optimizing multi-cylinder hydrogen supply systems, offering technical references for high-power fuel cell heavy-duty trucks and large-scale distributed hydrogen power generation equipment.