Grant: Engage Grants Program

SuperCritical Fluids (SCFs) have been used for some time in various industries, but still up till now their wide application is limited due to incomplete knowledge of specifics of thermophysical properties and heat transfer of these fluids. The most widely used SCFs are water and carbon dioxide. Supercritical water is proposed as a coolant in Generation IV nuclear-reactor concept - a SuperCritical Water-cooled Reactor (SCWR) and as a working fluid in supercritical-pressure Rankine steam cycle in other Gen IV concepts. However, water is not compatible with sodium, molten salts and due to that for reactors with these coolants SuperCritical (SC) carbon dioxide is proposed as a working fluid in the power cycle - Brayton gas-turbine cycle. Therefore, knowledge of specifics of thermophysical properties and heat transfer to SC carbon dioxide is very important for development of power cycles for Sodium Fast Reactor (SFR) and Molten Salt Reactor (MSR). Unfortunately,Computer Fluid Dynamics (CFD) software cannot predict heat transfer in SC carbon dioxide, because heat transfer in SCFs is very complicated phenomena. Also, thermophysical properties of SCFs change very significantly within critical and pseudocritical regions, which creates significant problems in using standard CFD models. Therefore, development of an accurate heat-transfer empirical correlation for SC carbon dioxide to be implemented in modern CFD software is an important task. Experimental datasets for SC carbon dioxide flowing upward in circular vertical bare tubes within specified ranges will be collected and analyzed. Experimental data will be verified and processed. Based on these datasets an empirical heat-transfer correlation will be developed within the designated range of operating conditions and, later on, will be implemented in the PHOENICS CFD software. The Company, Applied Computational Fluid Dynamics Analysis (ACFDA), will be introduced to a new area of research as a short goal and will be able to use the developed correlation in various heat-exchangers calculations for Generation IV nuclear-reactor-concepts power cycles as a longer-term goal.