Study On The Kinetic Characteristic Of Fine Particle In Different Water Phases

Water is widely used in power station as coolant, moderator or lubricating material. During the operation of power station, particulate matter will be produced. It causes wide concern to the behavior and deposition rule of particles in different phase of the water and how to relieve the damage of the particles. The different behaviors of particles in different diameters (0.01μm～50μm) in water of different phases in learnt via the ANSYS Fluent and the program WATER 1.0.The behavior of particles in water of different phases is similar. The axial velocity of particles is as U-type, which is the same as the axial fluid velocity. The radial velocity of particles is as M-type, which is the same as the particle concentration. The particles diffusion, the thermophoretic diffusion, the turbulent diffusion and the secondary flow leads to the radial behavior of particles. The secondary flow is unique in the rectangular channel, which lead to the secondary particle flow. In the channel, the liquid film condensed from the vapor or the big-density film from the super-critical water will keep the particles from depositing on the wall.The properties of water in different phases have great influence on the water-laden particles. The dimensionless deposition velocity of particles varies as V-type with the dimensionless residence time. For particles diameter less than 1 micrometers, the diffusion effect becomes the most important deposition mechanism. For particles diameter large than 5 micrometers, the particle inertia mechanism becomes the most important. For other particles, the diffusion effect and the turbulent eddy-impaction are the most important.In the presence of temperature gradient, the dimensionless velocity of small particles will increase while that of the big particles will never change.A coolant channel of SCWR is built to study the behavior and deposition rule of corrosion products. Different conditions are considered and the influence of temperature of the inlet and the heated power of the fuel on the behavior of corrosion products is analyzed. The increasing inlet temperature and the increasing heated power of the fuel will decrease the residence time of the corrosion product and decrease the deposition of the corrosion product.At last, the mechanism of particle movement and deposition is learnt via the analysis of water molecule spacing, the water properties change, the water flow field, and the force on particles. Water properties vary greatly in different phases, and there is a dramatic change in the phase transform region, which lead to different forces on particles. The thermophoretic force, the drag force and the lift force on particle are analyzed. Water in different phases lead to different force on particle. In water liquid, the drag force and the lift fore become the most important while in water-vapor the thermophoretic force become the most important. The particle behavior is the result of collision of particle and water molecular. The stronger the collision, the more velocity of paticles will gain from the water molecular, however the more resistence will be encountered.