Effect of Gas Composition on Aerodynamic Performance and Internal Flow of Ethane Oxidation Dehydrogenation Centrifugal Compressor

Effect of gas composition on aerodynamic performance and internal flow in ethane oxidation dehydrogenation (ODH) centrifugal compressors is investigated. Although inert gases are widely used to reduce explosion risk in ODH processes, the effects of multi-component inert gases on compression thermodynamics and internal flow structures are not fully understood. The novelty of this work lies in a systematic quantification of how different inert-gas compositions change the evolution of internal flow, thereby influencing the loss mechanisms and isentropic efficiency in a high-pressure ODH environment. Three gas mixtures are evaluated: Mixture ۱ (C۲H۶ ۵۵%, O۲ ۱۵%, CO۲ ۱۵%, ۱۰%, H۲ ۵%), Mixture ۲ (C۲H۶ ۵۵%, O۲ ۱۸%, CO۲ ۱۰%, ۷%, He ۵%, N۲ ۵%), and Mixture ۳ (C۲H۶ ۵۳%, O۲ ۱۸%, CO۲ ۸%, N۲ ۱۵%, ۶%). Numerical simulations are conducted using a steady-state mean streamline model coupled with the SST turbulence model. The isentropic efficiency varies non-monotonically with mass flow rate, staying nearly constant from ۶.۵ to ۷.۱ kg/s and then decreasing markedly. Detailed flow analysis shows that low-density gases such as H۲ and He promote leakage flow and flow separation, increasing energy dissipation; in contrast, N۲ reduces separation-related losses. Compared with Mixture ۱, the isentropic efficiency increases by ۲۱.۶۵% for Mixture ۲ and further improves by ۳۰.۲۵% for Mixture ۳ (a cumulative increase of ۸.۶% over Mixture ۲). Overall, the results provide quantitative trends and mechanistic understanding of multi-component inert-gas effects on compressor performance, which can help researchers evaluate and design safer ODH compression systems and motivate further studies under other inert-gas combinations and operating conditions.

کلیدواژه ها:

Ethane oxidative dehydrogenation (ODH) ، Centrifugal compressor ، Numerical simulation ، Gas component