Analysis of Computational Fluid Dynamics Code FLUENT Capabilities for Supercritical Water Heat Transfer Applications in Vertical Bare Tubes

Abstract

In this paper, the computational fluid dynamics (CFD) code FLUENT was used to predict walltemperature profiles inside vertical bare tubes with supercritical water (SCW) as the cooling medium, to assess the capabilities of FLUENT for SCW heattransfer applications. Numerical results are compared to experimental data and current onedimensional (1D) models represented by existing heattransfer empirical correlations. Walltemperature and heattransfer coefficients were analyzed to select the best model to describe the fluid flow before, at, and after the pseudocritical region. k−دµ and k−د‰ turbulent models were evaluated in the process, with variations in the submodel parameters such as viscous heating, thermal effects, and lowReynoldsnumber correction. Results of the analysis show a fit of آ±10% for wall temperatures using the SST k−د‰ model within the deteriorated heattransfer regime and less than آ±5% within the normal heattransfer regime. The accuracy of the model is higher than any empirical correlation tested in the mentioned regimes and provides additional information about the multidimensional effects between the bulkfluid and wall temperatures.