旋叶分离器中液滴运动相变特性分析

为研究AP1000核电站蒸汽发生器中初级旋叶分离器的液滴运动相变特性以及液滴相变对汽水分离性能的影响,通过建立液滴运动相变模型,基于AP1000旋叶分离器三维模型,采用欧拉-拉格朗日方法求解气液两相流动模型,计算得到了不同工况下旋叶分离器的汽水分离效率和压降的变化规律,并分析了液滴相变特性对分离效率的影响,获得了不同初始半径液滴的相变特性。计算结果表明:随着蒸汽流速的增加,分离效率和压降快速增加;压降相同时,半径较小的液滴在运动蒸发过程中半径变化百分比较大,相比半径较大的液滴其运动轨迹容易改变,更易逃逸出分离器,造成考虑相变时的分离效率降低;在正常运行工况下,液滴相变对分离效率的影响可忽略。计算结果可为进一步研究汽水分离装置中的汽水分离性能提供理论依据,并用于指导汽水分离装置的设计。

Characteristics Analysis of Droplet Phase Transformation during Moving in Swirl-vane Separator

To investigate the characteristics of the droplet phase transformation during moving in the swirl-vane separator and the influence of the droplet phase transformation on the steam-water separation performance within the steam-water separator of the AP1000 steam generator, a phase transformation model for single moving droplet was developed. The steam-water separation efficiency and the pressure drop were obtained by using the Euler-Lagrange approach based on the three-dimensional geometric model of the swirl-vane separator. The analysis of the influence of the droplet phase transformation on the separation performance and the radius variation of different sizes of droplets was conducted. The results indicate that the separation efficiency and the pressure drop increase rapidly with the steam velocity. In addition, the radius variation percentage of the smaller droplet is greater during the moving and evaporating process in the swirl-vane separator, which leads to the more likely change of the motion trajectories, the increasing probability to escape from the separator, and the smaller separation efficiency. Besides, the influence of the droplet phase transformation on the separation performance can be negligible under the actual operation conditions. The calculation results can provide theoretical basis for the further investigation of the separation performance and guide the design of the steam-water separator.