CFD analysis of flow boiling in the ITER first wall

This paper compares two Computational Fluid Dynamic (CFD) approaches for the analysis of flow boiling inside the first wall (FW) of the International Thermonuclear Experimental Reactor (ITER): (1) the Rohsenow model for nucleate boiling, seamlessly switching to the Volume of Fluid (VOF) approach for film boiling, as available in the commercial CFD code STAR-CCM+, (2) the Bergles–Rohsenow (BR) model, for which we developed a User Defined Function (UDF), implemented in the commercial code FLUENT. The physics of both models is described, and the results with different inlet conditions and heating levels are compared with experimental results obtained at the Efremov Institute, Russia. The performance of both models is compared in terms of accuracy and computational cost.

► Two boiling models, Rohsenow model for nucleate boiling, switching to the Volume of Fluid for film boiling using STAR-CCM+ and Bergles–Rohsenow model, for which we developed a User Defined Function, implemented in FLUENT, are tested and compared on a flat-channel geometry. ► Performance is checked in terms of accuracy and computational cost. ► As a first approximation analysis Bergles–Rohsenow model may be a good choice, if more accurate information on thermal behavior or flow field is required, the other should be preferred.