Investigation of the number of flow passages in the self-acting valve applied in the hydrogen ionic liquid compressor

Abstract

The ionic liquid compressor is a newly proposed hydrogen compression technology, which has irreplaceable advantages in the application of high-pressure hydrogen refueling stations. In the gas compression chamber, the suction and discharge of the hydrogen are controlled by the self-acting valve, however, the existence of the ionic liquid piston brings challenges to the design of the self-acting valves. In this paper, a three-dimensional two-phase model was established for the compression chamber in the ionic liquid compressor, in which the motion of the valve plate is controlled by the fluid-structure interaction (FSI) model. The accuracy of the model was verified by experiment. Based on this model, the valve plate motion and the two-phase flow characteristics in the compressor chamber were investigated, with a focus on the influence of the number of flow passages (1, 2, 4, 6, 8, 10) in the valve. When taking the gas-liquid heat-transfer performance and fluid discharge characteristics as the primary evaluation factors and ignoring the delayed closure of the discharge valve. The results indicated that 4 or 6 flow passages optimized fluid discharge characteristics and gas-liquid heat transfer performance. In these two cases, the liquid discharge rates were 8.35 % and 8.90 %, respectively, while the hydrogen temperatures remained within the optimal control range of a small increment of 4.7 % (14 K) and 2.3 % (7 K) in temperature after one cycle.