数值模拟喷嘴对多级多尺度液柱塔内部流场的影响

Numerical simulation of the influence of nozzles on the flow field inside the multilevel and multiscale liquid-column tower

为了探索不同喷嘴对液柱塔的影响,本文希望以新型的多级多尺度液柱塔为研究对象,利用流体力学软件CFD模拟压力旋转和扇形雾化喷嘴,找出它们影响塔内流场分布的规律。以雷诺时均的奈维-斯托克斯方程(N-S)为基础,采用Lagrange离散相模型,预测喷嘴对气体流场分布的影响。数值模拟与实验结果表明,在压力旋转和扇形喷嘴组合使用条件下,浆液喷淋对烟气具有明显的整合作用,防止气体撞击,避免了雾沫夹带现象。模拟液气比与实验值的误差为4.6%,证明模拟液柱塔的模型比较实用。由于在模拟过程中忽略了内部构件对气液运动轨迹的影响,所以模拟结果存在一定的局限性。尽管模拟结果与实验数据有一定差距,但二者显示了相同的现象。尤其是通过颗粒轨迹的模拟研究之后,可以清楚地看出单级喷嘴存在的缺陷,为液柱塔喷嘴选择提供了重要的参考依据。

In order to explore the influences that nozzle affect the liquid-column tower,the computational fluid dynamics（CFD） is used to simulate the distribution of the flow field in new style of multilevel and multiscale liquid-column tower with different nozzles.It can be predicted that different nozzles could affect the distribution of the gas flow field with Lagrange discrete phase model based on Reynolds time-averaged Navier-Stokes equations.Numerical simulation and experiment results showed that the spray slurry has obviously integration effect on the flue gas with combination of pressure-swirl-atomizer and flat fan atomizer nozzle,they could prevent gas collision and avoid entrainment.The enor between the liquid-gas ratio of the numerical simulation and experimental results was 4.6%and it also proved that the selected model to simulate spray tower was practical.As the simulation process ignored the internals effects for the gas-liquid trajectory,there are some limitations.Although there are some differences between the simulation results and experimental data,both showed the same phenomenon.Especially through the simulation of particle trajectory,we can clearly see defects in a single-stage nozzle,which provides an important reference to the liquid column tower for choose nozzles.