Flow field characteristics in sinusoidal corrugated baffle settler

doi:10.16085/j.issn.1000-6613.2019-1228

Abstract

Abstract:

The volume of fluid (VOF) model was used to simulate the flow field in the sinusoidal corrugated baffle settler. The average flow field for the corrugated baffle and flat baffle were compared. The time evolution characteristics of axial velocity uniformity (λ₁) were analyzed, and the spatial distribution characteristics of λ₁ and area weighted average turbulence intensity (I_a) in the baffle settler were explored. Flow field uniform & steady criteria (USC)wasintroduced. The impact of distanc (L_b/D) on USC was studied. The results showed that corrugated baffle can reduce back mixing effectively. Within 0.84＜L_b/D＜2.17, the λ₁ in the corrugated plate settler was higher than that of the plane baffle. With the decrease of L_b/D, the λ₁ of the flat baffle settler was unchanged, but the λ₁ of the corrugated baffle settler decreased without any obvious influence on I_a. Compared with the flat baffle, the corrugated baffle can effectively reduce the gradient of velocity, reduce the back mixing area and improve the stability of the flow field. When L_b/D=2.17, USC of corrugated plate settler reached 14.68, which was 93.67% higher than that of the flat baffle.

Key words: numerical simulation, separator, sinusoidal corrugated baffle, multiphase flow, particle image velocimetry (PIV)

摘要：

采用VOF模型对正弦波纹式入口挡板的重力非均相沉降器内流场进行数值模拟研究。对比了正弦波纹挡板与平挡板的平均流场分布情况，分析了沉降器的轴向流速均一程度（λ₁）随时间演化特性，探究了λ₁和面积加权平均湍流强度（I_a）在沉降器内空间分布特性；引入流场均稳指标USC，研究了冲击间距（L_b/D）对USC的影响。结果表明：正弦波纹挡板作为入口构件可以有效降低返混。在0.84＜L_b/D＜2.17范围内，正弦波纹板沉降器内流场的均一程度整体高于平面挡板；随着L_b/D减小，平挡板沉降器内流场的λ₁基本不变，但正弦波纹挡板沉降器内流场的λ₁降低，且对I_a的影响不明显。对比平挡板，正弦波纹挡板可以有效降低轴向速度的梯度，使返混区面积减小，流场稳定性提高。随着L_b/D增加，USC值呈现多峰值趋势，L_b/D=2.17时正弦波纹板沉降器的USC取得极大值为14.68，较平挡板提高了93.67%。

关键词: 数值模拟, 沉降器, 正弦波纹挡板, 多相流, 粒子图像测速

CLC Number:

TQ051.8

Yuhui ZHANG,Bin GONG,Xueping WANG,Jing ZHANG,Jianhua WU. Flow field characteristics in sinusoidal corrugated baffle settler[J]. Chemical Industry and Engineering Progress, 2020, 39(4): 1273-1281.

张玉辉,龚斌,王学平,张静,吴剑华. 正弦波纹挡板式沉降器内流动特性[J]. 化工进展, 2020, 39(4): 1273-1281.

Figures/Tables 12

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网格方案	网格体积×10^-9/m³		网格总数	平均偏差/%
网格方案	最小值	最大值	网格总数	平均偏差/%
1^#	3.02	19.77	644278	17.02
2^#	2.48	14.99	819495	13.86
3^#	1.09	10.58	1083770	2.698
4^#	0.70	6.073	1887723	—

网格方案	网格体积×10^-9/m³		网格总数	平均偏差/%
网格方案	最小值	最大值	网格总数	平均偏差/%
1^#	3.02	19.77	644278	17.02
2^#	2.48	14.99	819495	13.86
3^#	1.09	10.58	1083770	2.698
4^#	0.70	6.073	1887723	—

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