The Navy needs robust high-speed rotary unions for advanced liquid-cooled and high-temperature-superconducting (HTS) generators. We propose to develop hydrostatic bearing/seal rotary unions (HBSRUs) to meet Navy needs. Hydrostatic bearings can operate at large radii with fast rotational speeds, so our HBSRUs have room for large flow capabilities. The hydrostatic bearings offer the same advantages to our HBSRUs that hydrostatic bearings offer to spindles of high-precision high-speed machine tools (including nano-precision diamond-turning lathes for optics): high-speed capability, long life, durable, reliable, large damping of shocks and vibrations, and dynamically stable. Proprietary designs give our HBSRU for liquid-cooled generators minimal seal leakage and our HBSRU for HTS generators zero seal leakage. Our HBSRU uses materials that give our HBSRU graceful degradation to avoid catastrophic failures. In Phase I, we will develop initial conceptual designs of our HBSRU and establish performance goals and metrics to analyze the feasibility of our HBSRU. In Phase II, we will build and demonstrate prototype HBSRUs. In Phase III, we will transition our HBSRU into Navy systems and other systems in the government and private sector.
Benefit: Future Navy weapon systems and electric-drive propulsion systems will require improvements to component power densities. High-speed advanced liquid-cooled and high-temperature-superconducting generators have the potential to improve the power densities of electrical generators. However, both technologies require rotary unions to transfer the cooling fluid from the stationary equipment skid to the rotating shaft. Our HBSRU has the potential to meet Navy requirements for: large flow capability; high-speed capability; long-life, durable, and reliable; large damping of shocks and vibrations; dynamically stable; zero seal leakage; and graceful degradation. The Air Force is developing More-Electric Aircraft (MEA), which place demanding size and weight constraints on generators and motors. Advanced liquid-cooled and high-temperature-superconducting generators are attractive for Air Force MEA to limit size and weight. Our HBSRU will allow advanced liquid-cooled and high-temperature-superconducting generators and motors on Air Force MEA. Modern machining centers (and live tooling on turning centers) use through-the-tool cooling to direct coolant to the cutting zone. Optimal cutting speeds are continually increasing, and there are currently no through-the-tool cooling systems that can operate with the high rotational speeds of high-speed machining operations. Our HBSRU will allow through-the-tool cooling to be used with high-speed machining operations. Gas turbines in combined-cycle power plants use compressor bleed air to cool high-temperature turbine blades. The use of compressor bleed air reduces the efficiency of the gas turbine. Higher system efficiency could be achieved if water could be used to cool the turbine blades. The heated water could then be used in the Rankine (steam-turbine) bottoming cycle. It is currently challenging to direct the water into the rotating shaft of a gas turbine to the turbine blades. Our HBSRU will allow water-cooling of power-generation gas turbines.
Keywords: Aerostatic Bearings, Aerostatic Bearings, rotary coupling, water-cooled generator, Power Density, High-Temperature Superconducting, electric ship, electric drive, NGIPS
