Numerical analysis of inorganic fouling with multi-physics turbulent models

The occurrence of inorganic fouling (gypsum, CaSO4.2H(2)O) is investigated numerically by considering a 2-D, fully discrete and fully coupled multi-physics turbulence models. The novelty of the study is associated with the fact that all transfer rates, which are simultaneously evaluated, are determined based on calculated gradients and not based explicitly on wall correlations, as often done, especially for mass transfer. The fluid flow simulations consider two low-Re turbulence models (k-omega and SST k-omega), which are assisted by two models for the turbulent Prandtl number and three models for the turbulent Schmidt number. The implemented 2-D models are fully validated against classical laws of the wall for momentum, heat and mass transfer. After validation, the multi-physics results are compared with existing experimental fouling data and the commonly employed KernSeaton model. The results show that the proposed models are fully capable of predicting fouling. More specifically, the present 2-D results show that the relation between the deposition rate constant and temperature, through the Arrhenius equation, shows an R-squared agreement of 0.68, which can be considered good when compared with the agreement returned by the 0-D model (R-2 = 0.18). Furthermore, the experimental deposition mass flux reported in the literature shows a better agreement with the presently proposed 2-D approach than the available 0-D model.

Automated summary

The occurrence of inorganic fouling was numerically investigated using 2-D fully discrete and fully coupled multi-physics turbulence models. The study introduced a novel approach for determining transfer rates based on calculated gradients instead of wall correlations. The results of the study showed that the proposed models were capable of predicting fouling accurately, with better agreement compared to existing models.