Numerical simulation of the thermal-hydraulic characteristics of the liquid metal flow across the single-start helical coiled tube bundles

The helical-coiled-tube steam generator (HCTSG) has found application in certain liquid Lead-cooled Fast Reactors (LFRs) due to its compact design, ability to mitigate thermal stress, and superior heat transfer capabilities. In order to better understand its performance, research has been conducted on the flow dynamics and convective heat transfer within single-start helical coiled tube bundle of HCTSG, specifically focusing on the liquid lead-bismuth eutectic (LBE) mixture, using numerical simulations. The accuracy of the simulations was verified by comparing the results with experimental data obtained from studies on liquid NaK. Turbulent models and turbulent Prandtl number models were utilized in the simulations and validated against experimental results for liquid NaK. Various parameters such as the pitch-to-diameter ratio and flow conditions were scrutinized to evaluate their impact on flow patterns and heat transfer characteristics. Transition criteria have been determined for the laminar and turbulent flow for LBE. Empirical correlations were developed to predict the friction factor and convective heat transfer coefficients within a Reynolds number range from 30 to 4.0 × 105 and a Peclet number range from 1 to 10000, respectively.