Numerical Simulation Of Effect Of Temperature On Flow Accelerated Corrosion In Orifice Pipeline

In the operation of the steam and water pipe in the power plant,FAC is ubiquitous and threatens the pipeline system.It is a mechanism that causes the dissolution and thinning of carbon steel under the combination of physical and chemical factors.The process of FAC is complicated,it will invalidate the pipeline system of the power plant,causing security threats and property damage,therefore,it is necessary to research the FAC.Experiments to study FAC not only require equipment with excellent performance,but also strict environmental conditions.Compare with the complicated and time-consuming on experiment.The use of computational fluid dynamics to combine simulation results with experimental data has become an effective method for studying FAC.Based on the research results of flow accelerated corrosion mechanism,influencing factors,numerical simulation and prediction models by scholars at home and abroad,it is found that the research on the influence factors of temperature in the numerical simulation is lacking,and the physical properties are neglected.The important phenomenon that the parameter changes with temperature.In order to predict the location and rate of flow accelerated corrosion of power plant pipelines,based on the actual working conditions of power plant pipelines,the fluid dynamics software is used to adjust the physical property parameters of the working fluid according to the temperature change,and simulate under other conditions.The flow field under the orifice tube,the observation velocity and the distribution of the turbulent flow energy in the whole and vertical direction downstream of the orifice.The simulations show the changes of solubility,velocity,turbulent flow energy,wall shear force and mass transfer coefficient at different temperatures.And combined with the flow accelerated corrosion prediction model to more accurately analyze the effect of temperature on flow accelerated corrosion.The results show that the velocity of the central axis of the orifice plate and the static pressure distribution are consistent with the previous experimental results.The velocity in the vertical direction and the turning point of the turbulent flow energy with the distance from the orifice are the same.The closer to the axis,the higher the velocity,turbulent flow energy,wall shear force,mass transfer coefficient,and flow accelerated corrosion on the central axis approach the orifice as the temperature increases;the simulated velocity,turbulent flow energy and wall surface The wall shearing force,mass transfer coefficient and flow accelerated corrosion rate are the same at the first and second peaks and the minimum value with temperature change.The flow accelerated corrosion rate reaches between 0.7-1.0D(D is the inner diameter of the pipe)downstream of the orifice plate.Peak,the second peak appears between 3.8-4.3D,which is the high-risk corrosion zone of the orifice pipe;mass transfer coefficient Both the solubility and the solubility are affected by the temperature.Below 150°C,the effect of temperature on the accelerated corrosion rate of the flow is significant and is mainly achieved by the mass transfer coefficient.