Research On Simulation And Modeling Of Steam-water Separator

Between high pressure cylinder and low pressure cylinder, steam-water separator is an important part of moisture separator reheater system in nuclear power plant. As exhaust wetness from high pressure cylinder is relatively large, if the steam gets into low pressure cylinder without dehumidification and heating, the internal efficiency of steam turbine would reduce and blade erosion would be caused, so steam-water separator is rather important.Corrugated steam separator is a kind of steam-water separator which works by using the difference of density, inertia force, adhesion between Steam and water. In steam water separation process,many factors,such as secondary droplets,structural parameters,velocity and diameter of droplets,and density can affect separation efficiency.This paper, taking steam water separator for 900MW nuclear power plant as research object and using CFD numerical simulation technique, firstly the SolidWorks software is used to establish a geometric model and mesh it with ICEM; then use Fluent to solve. the flow field.Using discrete phase model, the droplets and steam in corrugated steam separator are considered separately,firstly,analysis the steam-phase flow field,explore the relationship between structural parameters of corrugated plates and pressure drop in the flow field, and current velocity in the same way. Then discuss the impact of structural parameters, velocity,density and diameter of droplets on separation efficiency, according to the relevant literature,determine the diameter of droplets, considering turbulent effect and secondary droplets, get relationships between various factors and separation efficiency and show the accuracy of this calculation by comparison with known experimental results. At last modeling and simulation it by equilibrium equations considering inertia of volume and thermal. Using Fortran to program the model and completing steady state and dynamic calculation to research and verification model. The accuracy of the model is proved by comparison with the parameter of steam water separator for 900MW nuclear power plant. Then study the operation performances of the system by falling the load and changing diameter of the droplets.