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dc.contributor.authorJohnsen, Sverre Gullikstad
dc.contributor.authorPääkkönen, Tiina
dc.contributor.authorJohansen, Stein Tore
dc.contributor.authorKeiski, Riitta
dc.contributor.authorWittgens, Bernd
dc.date.accessioned2017-06-13T10:51:08Z
dc.date.available2017-06-13T10:51:08Z
dc.date.created2017-04-27T15:41:25Z
dc.date.issued2017
dc.identifier.urihttp://hdl.handle.net/11250/2445920
dc.description.abstractIn a previous paper (Johnsen et al., 2015) and presentation (Johnsen et al., 2016), we developed and demonstrated a generic modelling framework for the modelling of direct precipitation fouling from multi-component fluid mixtures that become super-saturated at the wall. The modelling concept involves the 1-dimensional transport of the fluid species through the turbulent boundary layer close to the wall. The governing equations include the Reynolds-averaged (RANS) advection-diffusion equations for each fluid species, and the axial momentum and energy equations for the fluid mixture. The driving force for the diffusive transport is the local gradient in the species’ chemical potential. Adsorption mechanisms are not modelled per se, but the time-scale of adsorption is reflected in the choice of Dirichlet boundary conditions for the depositing species, at the fluid-solid interface. In this paper, the modelling framework is implemented as a userdefined function (UDF) for the CFD software ANSYS Fluent, to act as a wall boundary condition for mass-transfer to the wall. The subgrid, 1-dimensional formulation of the model reduces the computational cost associated with resolving the fine length-scales at which the boundary-layer mass transfer is determined, and allows for efficient modelling of industry-scale heat exchangers suffering from fouling. The current paper describes the modelling framework, and demonstrates and validates its applicability in a simplified 2D heat exchanger geometry (experimental and detailed CFD modelling data by Pääkkönen et al. (2012, 2016)). By tuning the diffusivity, only, good agreement with the experimental data and the detailed CFD model was obtained, in terms of area-averaged deposition rates.nb_NO
dc.language.isoengnb_NO
dc.titleImplementation, Demonstration and Validation of a User-Defined Wall Function for Direct Precipitation Fouling in Ansys Fluentnb_NO
dc.typeConference objectnb_NO
dc.typeLecturenb_NO
dc.description.versionacceptedVersionnb_NO
dc.identifier.cristin1467012
dc.relation.projectNorges forskningsråd: 226210nb_NO
cristin.unitcode194,64,25,0
cristin.unitnameInstitutt for energi- og prosessteknikk
cristin.ispublishedtrue
cristin.fulltextpostprint


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