Innovative approach to correlate heat-transfer data to supecritical carbon dioxide flowing upward in a bare tube

Existing literature on problems of heat transfer to fluids at supercritical pressures distinguishes three heat-transfer regimes: 1) Deteriorated, 2) normal, and 3) enhanced. Conventional approach to correlate forced-convective heat transfer to supercritical fluids is applied to the normal and enhanced heat-transfer regimes. Although, there were recent attempts to correlate data for the deteriorated heat-transfer regime at mixed convection, currently there are no heat transfer correlations for DHT occurring at pure forced convection at high heat fluxes. Thus, an innovative approach was developed to correlate data without distinguishing heat transfer regimes. The approach is discussed in this paper. Using this approach, the heat transfer data to supercritical CO2 in forced convection regime, which were obtained at MR-1 Loop at Chalk River Laboratories, were correlated with an RMS of approximately 10% (corresponds to approximately 20% spread based on the 2σ-level). This result is twice less than that previously obtained at the University of Ontario Institute of Technology. The paper covers the following major topics: thermal properties of supercritical fluids, specifics of heat transfer to fluids at supercritical state, overview of existing types of correlations, conventional methodology for the development of heat transfer correlations, and innovative methodology for the development of heat transfer correlations.