Thermal-fluid-structure coupling simulation of filling process of storage tanks with ultra-low temperature and high-flow-rate

To investigate the tank deformation behavior under ultra-low temperature and high-flow-rate filling conditions, a thermal-fluid-structure coupling numerical model for liquid hydrogen (LH2) filling into the storage tank was established. The temperature variation and corresponding structural deformation of the tank during the ultra-low temperature high-flow-rate LH2 filling process were systematically analyzed. The research findings reveal that at a filling flow rate of 8 m3/min and a pressure difference of 0 MPa, 84.1% of the tank volume was filled with fuel within 960 s, resulting in a deformation of 30.418 mm. When the outlet pressure difference increased from 0 to 0.1 MPa, the fuel filling ratio reached 78.5% in 500 s, with a corresponding deformation of 28.907 mm. As the outlet pressure difference further increased from 0.1 to 0.2 MPa, the filling ratio decreased to 45% with a filling duration of 576 s, and the deformation was reduced to 24.527 mm. When the filling flow rate was increased to 15 m3/min, 44% of the tank volume was filled in 250 s, with a deformation of 27.043 mm. Comparative analysis demonstrates that high-flow-rate LH2 filling achieves significantly higher efficiency than low-flow-rate filling, while the structural deformation induced by high-flow-rate filling is larger than that by low-flow-rate filling. When pre-cooling measures were adopted, the tank deformation after switching to high-flow-rate filling was notably smaller than that without pre-cooling. It is therefore concluded that pre-cooling measures are essential for ultra-low temperature high-flow-rate LH2 filling, as they can significantly improve the LH₂ filling efficiency while effectively reducing the thermal deformation of the tank structure.