Numerical Simulation Of Micron Magnesia Oxide Particles Fouling Characteristics In Tube

The tubular heat exchanger is a heat exchange equipment with a pipe wall as a heat exchange partition,and has been widely studied and applied.With its wide application,the enhanced heat transfer technology has also received great attention and development.However,once the fouling is generated in the heat exchanger,the heat exchange efficiency is greatly reduced.The purpose of this paper is to establish a fouling model of micron particles deposition in water in the tube by Euler-Eulerian method and to study the fouling characteristics of the particles inside the tube,and analyze the influence of different working conditions on the particle fouling characteristics.Firstly,the fouling model for the deposition of micron particles in the water in the tube is established.the fouling model includes sedimentary model,denudation model,and fouling thermal resistance model,and the experimental verification is completed with reference to the relevant literature to prove the feasibility of the mathematical model.Then the fouling model is transformed into a programming language.Through the user-defined function(UDF)plug-in program,the paper simulated the effects of different working fluid concentrations,fluid flow rates and inlet temperatures on fouling deposition rate,denudation rate and fouling thermal resistance in pipe using CFD software,and theoretical analysis is carried out.The simulation results show that the influence of working fluid concentration and int flow rate on the fouling characteristics is obvious,and the inlet temperature has little effect on the fouling characteristics.The deposition rate,erosion rate and fouling thermal resistance all increase in proportion with the increase of working medium concentration.The deposition rate and erosion rate increase with the increase of the flow rate,but the thermal resistance of the fouling decreases gradually.The deposition rate,the denudation rate and the thermal resistance of the fouling are basically unchanged with the increase of the inlet temperature.Secondly,the above mathematical model is still used to compare the scale inhibition performance of three common strengthening tubes.The scaling tube with the best scale inhibition effect is selected to study the fouling characteristics of micron particles under different working conditions,and compared with the round tube.The simulation results show that the scale inhibition performance is from strong to weak: zoom tube,bellows,horizontal tube,round tube.And under the conditions of other working conditions,changing the working medium concentration,the inlet fluid flow rate and the inlet temperature,the fouling characteristics of the micron magnesia particles in the scaling tube are similar to those of the round tube,and the deposition rate of the scaling tube and the asymptotic value of the scale thermal resistance are both Less than a round tube.