H. Xu
Ultool, LLC, Georgia, United States
Keywords: High Efficiency, Supercritical CO2 Power Cycles, Robust sCO2 Turbomachinery, Seal, Bearing, Small Module Reactor, Aircraft Engines, Tesla Turbine.
Supercritical CO2 (sCO2) power cycles are superior to conventional counterparts in terms of efficiency and size. They hold great potential in power generation, ship propulsion and Aircraft engines. Significant progress has been achieved in recent years, especially in DOE’s 1MW Recompression Closed Brayton Cycle project for nuclear power and 10MW Supercritical Transformational Electric Power (STEP) project. To unlock the potential of sCO2 power cycles, technology readiness must be demonstrated at sCO2 temperatures and pressures of 350 – 700 ºC and 20 – 35 MPa. Amongst the many subcomponent challenges of sCO2 turbomachinery, the lack of sCO2 seals and bearings is outstanding. It is well-known that traditional seals (brush seals, compliant foil seals, mechanical seals) and bearings (film bearings, magnetic bearings, and foil bearings) cannot operate under sCO2 conditions. With the support of DOE SBIR Program, Ultool, LLC has conducted multiple projects to develop enabling technologies for sCO2 turbomachinery: 1. Elasto-hydrodynamic (EHD) seal: It is a simple cylindrical structure that reduces sCO2 leakage as pressure increases. We developed several candidate EHD seal prototypes and demonstrated EHD sealing at the SNL sCO2 seal test facility. 2. Elasto-hydrostatic (EHS) Bearing: EHS bearing can be directly placed in sCO2 and provide heavy loading capacity.