3-D Milk Fouling Modeling of Plate Heat Exchangers with Different Surface Finishes Using Computational Fluid Dynamics Codes

摘要

Milk fouling and self-cleanability of the heat exchanger surface during the pasteurizationnprocess has gained attention from industries as well as academia. In particular,nthe antifouling mechanism associatedwith plate corrugation profiles causing thenextreme turbulent flow scheme and surface coatings to reduce the surface energy isnuncertain. This study was aimed to develop a computational fluid dynamics (CFDs)nmodel in three-dimensional (3-D) environment, which could estimate antifoulingnperformances of plate heat exchangers (PHEs) during milk pasteurization process. Itnwas the first attempt to simulate the fouling and temperature distribution patternsnon realistic corrugated surfaces of PHE unit with different surface treatments. Thenconventional stainless steel surface and stainless steel plates coated with Lectrofluorn641 and graded Ni-P-polytetrafluoroethylene were compared for their antifoulingnperformances.A transient 3-D fouling model was developed based on heat and massntransfer equations, and fouling kinetics involving diffusion and protein adhesionnmechanisms.Pattern and size of corrugations of actual PHEwere measured and subsequentlynused to build 3-D solid geometry using AutoCAD (Autodesk, San Rafael,nCA). The geometry file was meshed using Gambit software (Fluent Inc., Lebanon,nNH) and further transferred to CFD codes. Fouling predictions based on chemicalnkinetics and the temperature-dependent parameters accounting for different surfacenenergy valueswere close to experimental datawithin a maximumprediction error ofn7%. The developed 3-D fouling model is expected to meet the demand of foodnindustries to correlate the surface energy with the self-cleanability of food thermalnprocess equipments and seek the theoretical solution.