Single-phase heat transfer prediction in helical coiled tubes in turbulent regime

Abstract

The accurate estimation of thermal–hydraulic parameters is crucial for the design of Small Modular Reactor steam generators, particularly in the case of complex geometries such as helical coiled tubes (HCTs). Reliable design tools are therefore essential for successful design. In this study, we compiled a database of 706 experiments to evaluate the predictive performance of commonly used correlations for heat transfer estimation in turbulent regime HCTs. Despite ranking the correlations according to their predictive performance, none of the existing correlations were able to accurately predict the broad range of experimental data. Therefore, a new correlation called FAMA was derived, which is simple to use, robust and significantly more accurate than any other correlation. Based on the Colburn Analogy, the FAMA correlation achieved a mean absolute difference of 6.21% compared to the experimental database, which represents a 25.7% improvement over the best existing correlation. Furthermore, the FAMA correlation exhibits good asymptotic behavior in straight tubes and is recommended for single-phase flow in HCTs for turbulent Reynolds numbers up to 135,000, curvatures from 0.00963 to 0.2035, and torsions up to 0.81. The Schmidt́s criterion is adopted for determining the critical Reynolds number. Due to its superior performance and wide range of applicability, the FAMA correlation is recommended for modeling and studying helically coiled steam generators as found in novel integral reactors.