Modelling the conjugate heat transfer during the fast-filling of high-pressure hydrogen vessels for vehicular transport

Compressed gas in cylinders is currently the preferred solution for storing hydrogen on board vehicles. Fast-filling combined with high storage pressures is required to meet competitive targets of long driving ranges and short refuelling times. Experiments and CFD models have shown that the fast-filling leads to significant rise in temperature within the hydrogen cylinder, which can lead to its structural failure. Thus, controlling the rise in temperature is vital during the refuelling process. This paper describes the implementation of a universal thermodynamic model that determines the gas and structural temperature during the fast-filling of hydrogen cylinders. It includes the computation of conjugate heat transfer from the gas to the cylinder structure. The thermodynamic model requires negligible computational time without compromising accuracy and can used to implement different fast-filling scenarios on a laptop or personal computer. The flexibility and robustness of the model is shown as it is capable of modelling the fast-filling of cylinders while varying different key parameters such as fill time, structural material, cylinder volume, final pressure, filling rate, initial temperatures and pressures.