Numerical Simulation Of Low Discharge Liquid From Large Natural Ventilation Cooling Tower

For nuclear power plant at home and abroad of low level waste liquid discharge main research results are reasonable put waste water emission limit value,low emission,low waste water in the water,sediment and river sediment diffusion migration on radioactive nuclide adsorption law,low level waste water for water,residents’health and ecological effects and so on.There are few studies on new methods for low-level liquid waste.Is proposed in this paper a new method of low level liquid waste emissions,the use of large natural ventilation cooling tower emissions low level liquid waste concrete is:use of heating boiler into a hot steam,and through the pipe from the cooling tower above the water discharge,low waste steam in the tower under hot and humid air fireball,from the outlet of the cooling tower,eventually dispersion in the atmosphere.By using FLUENT software for large natural ventilation cooling tower,to simulate the low emissions waste liquid method is put analyzed using large natural ventilation cooling tower emissions the feasibility of the low level liquid waste.The main research results are as follows:(1)Effect of ambient wind speed on low level liquid exhaust emissions,through the same four seasons of spring,summer,autumn and winter weather conditions can be obtained after comparing different environmental wind:wind environment have great influence on low level liquid waste gases,when the environment is greater than 3 m/s wind against low level liquid waste gases.Under the condition of no wind,the cooling tower discharges low emission waste liquid gas,and the gas rises vertically.The flow rate,temperature and humidity of low emission waste liquid gas will only affect the air flow field above the exit of the cooling tower,and have no effect on the diffusion of low radioactive waste gas.When the environment less than 3 m/s wind,low waste liquid gas lift is higher,The increase of the velocity of the low level liquid waste gas at the chimney outlet of the cooling tower is conducive to the discharge of the low level liquid waste gas;(2)Under different meteorological conditions,the ambient wind has little effect on the temperature inside the large natural draft cooling tower,and the temperature inside the tower is 15℃higher than that outside the tower;(3)According to the comparative analysis of the four seasons of spring,summer,autumn and winter numerical simulation,it can be seen that:Meteorological condition basic had no effect on low level liquid waste gases,without rain,spring,summer,autumn and winter four seasons all can emissions;Combined with the meteorological conditions of the area where the factory is located,the environmental wind speed is higher in spring,the precipitation is more in summer,the evaporation is minimum in winter,the climate is dry,usually cold and need water distribution in the outer area,there is no air flow in the inner area,it is easy to form condensed water droplets in winter,the water droplets become larger and fall down,the waste liquid can not go up,the best season for discharge is autumn.(4)Through the different scheme design of waste liquid discharge days,waste flow rate,discharge pipe size and boiler power.(5)By controlling the gas emission of low-level liquid waste,when the ambient wind speed is 2 m/s and the pipe flow rate is 3 m/s,the steam dilution ratio of low-level liquid waste gradually increases and the diffusion range gradually increases with the increase of gas emission distance.The minimum dilution ratio of low-level liquid waste gas is 10~3 times,and the maximum dilution ratio is 10~8 times,The optimal dilution ratio of 10~6 times.