High-Speed Impeller Design for the First Stage of a Hydrogen Compressor System.

Hydrogen compressors are key components of emerging hydrogen infrastructure. They are needed to meet the growing demand for hydrogen as an energy carrier. One of the challenges in their design is selecting a material and geometry for the impeller that ensures safe operation at high rotational speeds. This paper presents a numerical and structural analysis of a high-speed impeller designed for the first stage of a hydrogen compressor intended for pipeline transmission. The impeller geometry was developed using a 0D design algorithm and verified with CFD simulations. Stress and deformation were assessed using finite element method tools. The operating conditions considered were 28,356 rpm and a compression ratio of 1.25 at an isentropic efficiency of 75%. Four materials were analysed: aluminium 7075-T6, aluminium 2024 T851, stainless steel AISI 420, and titanium alloy Ti-6Al-2Sn-2Zr-2Mo. Equivalent stresses obtained from simulations were compared to the yield strengths of the materials. This study showed that aluminium 7075-T6 is the most suitable material due to its strength, machinability, and availability. It showed an equivalent stress of 398 MPa at a yield strength of 460-530 MPa. The results support the development of safe and efficient impellers for hydrogen compressors that can operate in future energy systems.