Mark Rodarte M.S. Graduate Student Mechanical Engineering Thesis: Development of a Semi-Empirical Model to gauge S-CO2 Seal Leakage in Turbomachinery

Motivation for Research S-CO2 presents itself well as a potential working fluid in Gen IV nuclear power plants. The high densities found in this region can be used to reduce compressor work and increase efficiency. Further research of seal leakage operating under such extreme pressure gradients is required.

Goals and Potential Problems To construct a blowdown test facility which can be used to test leakage rates of S-CO2 under high pressure gradients. To develop a semi-empirical model which can be used to determine seal leakage rates for various seals (labyrinth, brush, hybrid-brush, etc). Potential Problems: The system will be subject to both choked and unchoked conditions during each blowdown test. The fluid proceeds below the vapor dome as the pressure is reduced and is converted to a two-phase mixture.

Testing Apparatus Proposed The HP blowdown tank is heated to inlet conditions in order to exhaust S-CO2 through the shafts seals. Mass flow rate, pressure, and temperature measurements are recorded during the process.