Computational Fluid Dynamics Simulation of Fouling of Plate Heat Exchanger by Phosphate Calcium
Ulla Ojaniemi, Timo Pättikangas, Ari Jäsberg, Eini Puhakka, Antti Koponen
Abstract
A computational fluid dynamics (CFD) model was developed for fouling of calcium phosphate in heat exchangers which can consider the tendency of fluid components to precipitate and the surface properties of the materials. In the CFD model the precipitation of inversely soluble mineral due to the temperature increase in the near-surface region of the heated wall was modeled based on the saturation ratio. The precipitates form small, spherical particles that can adhere on the wall surface. The wall function model developed for adherence was modified to consider the turbulent viscosity modeled by CFD. The model was tested against experiments made with simulated milk ultrafiltrate, which is an aqueous solution simulating the mineral composition of milk. This preliminary adhesion CFD model paves the route to build a more comprehensive model for predicting the likely profile of milk deposition in heat exchangers.