压力变化条件下静止液滴相变模型

Static droplet phase transformation model for variable pressure conditions

汽水分离装置是蒸汽发生器中非常重要的部件,作用是去除蒸汽流中夹带的小液滴,为汽轮机提供品质合格的饱和蒸汽,其性能对核电站运行的安全性和经济性有着十分重要的影响。液滴在汽水分离装置中的运动过程中,阻力和结构的变化会造成压力降低,打破汽液相平衡,造成液滴的蒸发,进而影响汽水分离性能。该文从压力变化条件下静止液滴的物理现象描述和机理解释出发,建立了压力变化条件下静止液滴相变的水动力学—动力学模型,通过了时间步长的网格无关性验证,与实验结果吻合良好,相对误差在±5%以内。该模型可以为进一步研究汽水分离装置中的液滴运动相变过程和改进汽水分离性能提供理论依据。

The steam-water separator is a very important part of steam generators. The steam separator removes small droplets carried by the vapor stream to provide saturated vapor to the steam turbine. The steam-water separator performance then greatly impacts the safety and economy of the nuclear power station. As droplets move through the separator, the pressure decreases due to the flow resistance and structure variation, which may break the liquid-vapor equilibrium, cause the droplets to evaporate and influence the steam-water separator performance. This paper gives a hydrodynamic-kinetic model of static droplet phase transformations when the pressure varies based on physical and mechanist models of droplet evaporation. The model predictions are independent of the time step and the results agree well with existing data with relative errors less than ±5%. This model provides a theoretical reference for further studies of droplet phase transformations to improve the separation performance of steam separators.