Mass transfer adjustment of the ionic liquid in the hydrogen compressor through a circular arc top baffle design

The ionic liquid-based compressor for hydrogen pressurisation is a promising technology and facility for hydrogen storage and transport. However, the liquid discharge with the high-pressure gas significantly influences the compression efficiency of this type of hydrogen compressor. Therefore, a circular arc top rectangular baffle structure is proposed and designed in this study, aiming to adjust the mass of the ionic liquid carried over by the hydrogen gas, consequently improving the hydrogen compression performance. The effect of different baffle configurations with varying geometric parameters on the multi-phase flow characteristics inside the compression cavity is investigated through numerical simulations. The simulation model used was validated through visualization experiments using a high-speed camera system. The findings demonstrate that the baffle structure significantly influences gas-liquid interface dynamics, hydraulic jump phenomena, and gas region formation during compression cycles. The case with the design parameter of length at 20 mm and height at 10 mm exhibited the best performance in the tested configuration, achieving the highest isothermal efficiency of 85.35%, the lowest hydrogen discharge temperature of 398.90 K, and the minimum liquid-to-gas mass ratio. Within the 12–45 MPa pressure range and 5 Hz operating frequency, the baffle structure effectively suppresses liquid sloshing, reduces momentum in the vertical direction, and enhances gas discharge while minimising liquid carryover. These results provide critical insights for optimizing ionic liquid compressor design and improving the operational efficiency of hydrogen refuelling infrastructure.