Modelling And Simulation Of Milk Fouling Process:Importance Of The Fouling Layer Structure

Advanced CFD models have been developed to characterize the fouling process of milk.The development of 2D or 3D models can help us to explain experimental observations and demonstrates potential for process analysis and optimization.However,due to the lack of consideration of the fouling layer structure and its evolution,predictive results by those models may be questionable.It should be noted that the importance of deposit structure evaluation in modeling crystallization fouling has been demonstrated in our previous publications.In this work,aiming at a more reliable predictive tool,we modelled milk fouling in a simplified micro-size 2D heat exchanger.It was a fully-coupled multi-domain multi-physics model.A unique feature of this model is that the dynamic change of fouling layer structure was explicitly taken into account while bulk and surface reaction kinetics for ?-lactoglobulin(?-Lg)were coupled with momentum,mass and heat transfer.The structural evolution of the deposit was expressed via a continuously varying geometry of the fouling layer domain.In this way,the intricate interactions between the structure of fouling layer,fouling kinetics,hydrodynamics and heat transfer performance of the heat exchanger could be quantitatively analyzed.The simulation results showed that the structure of the fouling layer does have an important effect on the fouling process of milk.Moreover,the significant difference between this model and the conventional prediction model without considering the fouling layer structure further proved this effect.This indicated that it is necessary to promote the development of milk fouling model involving fouling layer structure evolution.