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arXiv · 1706.02931

A wall-function approach for direct precipitation/crystallization fouling in cfd modelling

Sverre Gullikstad Johnsen·Stein Tore Johansen·Bernd Wittgens
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Abstract

The main objective of this paper is to present a generic modelling framework, for the diffusive mass transport through the turbulent, reactive boundary layer of multi-component fluid mixtures that precipitate on the wall. The modelling is based on Maxwell-Stefan diffusion in multi-component mixtures, the relaxation to chemical equilibrium model, and the single-phase Navier-Stokes equations. Final-ly, turbulence is introduced by Reynolds-averaging. The governing equations are simplified in accordance with common assumptions of computational fluid dynamics (CFD), and based on the assumption that the over-all bulk flow is parallel to the wall, 1-dimensional equations for the species and heat transport perpendicular to the wall have been formulated. The equations are solved on a fine grid in order to fully resolve the boundary layer, and the effect of allowing/disallowing deposition and chemical reactions was investigated for a simplified test-case (4-component ideal mixture of perfect gasses capable of chemical reaction and sublimation fouling). The developed framework can be employed as a sub-grid model for direct precipitation/crystallization/solidifica-tion fouling in coarse grid CFD models.

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Sverre Gullikstad Johnsen, Stein Tore Johansen, Bernd Wittgens. 2017-06-09. A wall-function approach for direct precipitation/crystallization fouling in cfd modelling. https://arxiv.org/abs/1706.02931

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