防冲挡板对液液分离器入口流场影响的数值分析

Numerical Analysis of the Impingement Baffle Effects on Inlet Flow Field of Liquid-Liquid Separator

应用Fluent软件对卧式液液分离器入口处防冲挡板的作用进行数值研究,综合分析不同进液速度、冲击间距和挡板尺寸对分离器内流体在挡板前后流动状态的影响,并提出改进方案.结果表明:随着冲击间距的增大,防冲挡板前部的环形回流区的尺度不断增大,冲击射流中轴线上方的环形回流区中心向后上方移动,轴线下方环形回流区中心向后下方移动,迫使环形回流区之后的顺、逆时针涡流向挡板后移动;冲击间距越小,防冲挡板降低冲击射流速度和湍流强度的效果越好,但冲击间距不可小于进液管直径;随着防冲挡板尺寸的增大,防冲挡板后部的流场稳定性增强,但当挡板尺寸过大时,挡板与分离器内壁之间形成狭缝射流,具有较大的速度和动量的流体冲击后部流场,造成分离器内部流场严重湍动及速度分布不均.

The internal separation zone of liquid liquid-liquid separator needs a stable flow field environment, in this paper, numerical simulation to the influence of the impingement baffle configurations at the entrance of the horizontal liquid-liquid separators is carded out by using Fluent software. It analyzes comprehensively how the impingement baffle configurations affects the liquid distribution in different situations ,with different inlet velocities, different baffle dimensions and different impinging distance in horizontal liquid-liquid separators, and proposed improvement plan. The results show that, with the impinging distance increasing, the annular recirculation zone＇ s scale keeps increasing, above the axis of the impinging jet, the backflow zone center keeps moving back and up constantly, the below vortex center keeps moving back and down, and it makes the clockwise and anticlockwise vortexes moving back to the baffle. The smaller impinging space, the better effect on reducing jet velocity and turbulence intensity, except it is smaller than liquid inlet pipe diameter;as the baffle size increases, the separator interior flow stability will baecome more superior, but when the baffle size is too large, it will form slit jet between the baffle and the inner wall of separator, and the fluid has so great speed and momentum that it will result in serious disturbance and uneven distribution of velocity to the rear of the separation zone.