Study on the influence of spring characteristics in the gas valves on the performance of the ionic liquid hydrogen compressor

As a promising ultra-high pressure hydrogen compression technology for hydrogen refuelling stations, ionic liquid compressors have attracted extensive attention in recent years. The self-acting valve is a critical component in the reciprocating compressor, which directly impacts the operational performance of the compressor. However, most of the existing analyses of the two-phase flow and heat transfer characteristics in the cylinder of the ionic liquid compressor do not consider the actual working process of the self-acting valve, which may lead to a large deviation from the actual results. In this study, a three-dimensional two-phase computational fluid dynamics model was established with the motion law of the valve disc coupled, and the reliability of the simulation model is verified by experiments. It was found that when considering the real action of the valve disc, the gas–liquid interface became more stable. The influence of the spring characteristics on the movement of the valve disc and the two-phase flow was studied then by altering the spring stiffness and preload amount, and their impact on the performance of the ionic liquid compressor was analyzed. Based on the analysis of the energy conversion characteristics, a mathematical correlation between the increased value of hydrogen energy and the spring stiffness and the preload amount was established. When the inlet pressure is around 3.991 MPa, while the outlet pressure is about 11.2755 MPa, the spring stiffness of 250 N/m and the preload amount of 2 mm were determined to be the optimal parameters for the self-acting valve in the ionic liquid compressor.