Grant: NSERC/NRCan/AECL Generation IV Energy Technologies Program

The proposed research consists of a systematic study of the heat-transfer, pressure-loss and turbulence mixing characteristics of Supercritical Water Reactor (SCWR) fuel-bundle subassemblies through experimentation complemented by direct numerical simulations, and culminates in the development of semi-analytical prediction models that can be incorporated in SCWR design tools. The experiments are to be performed on two existing test setups configured for thermal-hydraulic studies using R134a and water at supercritical pressure and temperature, and the focus is to be on upward-flow and downward-flow bundle subassembly configurations. Tests will be performed for both steady and transient conditions. The complementary direct numerical simulations are intended to shed light on the dominant physical mechanisms responsible for the unique momentum and heat transfer characteristics observed in channel flows when the working fluid is at a supercritical state. Specifically, the focus of the computational effort will be on the coherent flow structures of turbulence and sensitivity of these structures and their mutual interactions to the thermodynamic state of the working fluid near the pseudo-critical point. The outcomes of the proposed work are: identification of the dominant physical mechanisms responsible for the forced-convection heat-transfer and pressure-loss characteristics of supercritical fluid flow in fuel-bundle subassemblies for upward-flow and downward-flow configurations, and physically-realistic convective-heat transfer and pressure-loss prediction models applicable to such conditions.