Large eddy simulation of turbulent heat transfer at supercritical pressures

•Large eddy simulation.•Heat transfer at super-critical pressures.•Prediction of heat transfer deterioration.•Insight into turbulent statistics.•Useful for improvement of RANS models.

The paper presents results of large eddy simulation of turbulent heat transfer for water at supercritical pressures. Two cases are considered; the downward and the upward flow in an externally heated pipe. The temperature range for both considered cases entails the pseudo-critical region, where physical properties of the working fluid change significantly. The upward case, in particular, features the heat transfer deterioration, characterized by large increase in wall temperature. The numerical framework consists of staggered finite volume method, defined on Cartesian grids, integrated in time with a projection method. Variable physical properties of the working fluid are implemented as look-up tables, based on the NIST database. Turbulent statistics were gathered for a range of 55 large-eddy turn-over times. The results for first and second moment statistics are presented. Wall temperature, in particular, compares favorably with measurements. The authors believe that insight into turbulent statistics presented in this work can be useful to improve Reynolds-averaged Navier–Stokes based models.