A Modified Turbulent Model for the Supercritical Water Flows in the Vertical Upward Channels

Abstract

The supercritical water undergoes drastic changes in the thermal physical properties near the pseudo-critical point. It is necessary to evaluate whether the conventional turbulent models could successfully capture the wall temperature variations. In this study, the heat transfer of the supercritical water in the vertical tube and multiple fuel rods channel is numerically investigated using different turbulent models. The numerical results are compared with the experimental data. The comparisons indicate that the realisable k - ɛ model, k – ω SST model, and the Reynolds stress model generally give a better agreement with the experimental data on the predictions of the wall temperatures. A new variable turbulent Prandtl model is proposed. Selected better performance turbulent models coupled with the proposed turbulent Prandtl model are assessed. The modified turbulent model shows a great improvement in the prediction of the wall temperatures, especially for the condition in a multiple fuel rods channel.