Multi-objective optimization of the gas valve and liquid piston in the ionic liquid hydrogen compressor

This paper presents a multi-objective optimization for the self-acting valve of the ionic liquid hydrogen compressor. A Taguchi method was employed to investigate the effects of four design parameters on the performance indicators of energy storage (E) and isothermal efficiency (η). The signal-to-noise ratio (SNR) and mean signal-to-noise ratio (MSNR), along with analysis of variance (ANOVA), were used to identify the critical design parameters and their contribution rates to the compressor's performance. A bi-objective optimization of E and η was conducted with grey relational analysis (GRA) employed to obtain the parameter combination closest to the optimal setting. The results indicated that the Mach number had the greatest impact on E and η, with contribution rates of 61.59 % and 81.85 %, respectively. The optimal design parameters were identified as spring stiffness of 100 N/m, Mach number of 0.015, valve disc density of 8.9 g/cm³, and initial liquid piston height of 50 mm.