An innovative elasto-hydrodynamic seal concept for supercritical CO₂power cycles

Supercritical CO₂(sCO₂) power cycles are promising next generation power technologies, holding a great potential in fossil fuel power plants, nuclear power production, solar power, geothermal power, and ship propulsion. To unlock the potential of sCO₂power cycles, technology readiness must be demonstrated on the scale of 10 600 MWe and at sCO₂temperatures and pressures of 350 700 °C and 20 30 MPa for nuclear industries. Amongst many challenges at the component level, the lack of suitable shaft seals for sCO₂operating conditions needs to be addressed for the next generation nuclear turbine and compressor development. In this study, we propose a novel Elasto-Hydrodynamic (EHD) highpressure, high temperature, and scalable shaft seal for sCO₂turbomachinery that offers low leakage, minimal wear, low cost, and no stress concentration. The focus in this paper was to conduct a proof-of-concept study with the help of physics-based computer simulations. The results showed that the proof-ofconcept study was successfully demonstrated, warranting further investigation. Particularly, it was interesting to note the quadratic form of the leakage rate, making its peak of = 0.075 kg/s at Pin = 15 MPa and then decaying to less than = 0.040 kg/s at Pin = 30 MPa, suggesting that the proposed seal design could be tailored further to become a potential candidate for the shaft seal problems in sCO₂turbomachinery.