共查询到20条相似文献,搜索用时 109 毫秒
1.
采用CFD-PBM耦合方法对Kenics型静态混合器内分散相油滴破碎及聚并行为进行数值模拟研究,分析了雷诺数、混合元件数、元件长径比等参数对分散相液滴粒径的影响,揭示了分散相在Kenics静态混合器内流动过程中液滴粒径的演化规律.结果表明,随雷诺数增大,分散相液滴出口粒径不断减小,并出现临界趋势;静态混合器的前几个元件... 相似文献
2.
3.
以水-煤油为介质,在不同的流速下,通过高速照相的方法,研究了15种不同的苏尔士静态混合器(SV型)的分散性能,分析了苏尔士静态混合器结构参数对分散性能的影响,得出液滴直径-流速关系曲线,并拟合成数学关系式。 相似文献
4.
5.
静态混合器广泛应用于溶剂萃取,改造静态混合器的入口结构可以提升混合效果。为探究不同入口结构对液液分散的影响,以传统SK型静态混合器、非对流入口静态混合器、Roughton静态混合器、Y-静态混合器4种不同入口结构的静态混合器为研究对象,通过计算流体力学-种群平衡模型(CFD-PBM)数值模拟方法,考察了不同入口结构对静态混合器中液体流速、混合效果和Sauter平均直径(d32)的影响。模拟结果表明:不同入口结构的静态混合器具有显著差异的流体流动状态、混合效果和液液分散效果。混合效果和液液分散效果从好到差依次为Y-静态混合器、Roughton静态混合器、非对流入口静态混合器和传统SK型静态混合器。在混合元件区,4种入口类型的静态混合器的流速相同,但是混合元件发挥混合和分散的作用不同。Y-静态混合器和Roughton静态混合器作为液液分散设备,可以以较少的混合元件数实现高分散效果。 相似文献
6.
7.
8.
9.
F.Streiff的研究结果表明,在雷诺数Re=200~20000和界面张力σ=24.7~46达因/厘米的实验范围之内,苏尔士SMV型静态混合器的分散性能可以用D_s/d_h=0.21We~(-0.5)Re~(0.15)来表示,本文的实验结果与之相符。 本文还用加入乳化剂的方法使界面张力分别减小到12.6、4.75和2.12达因/厘米,实验结果证明F.Streiff导出的公式仍然相对地适用。 本文通过不同体系液滴直径随静态混合器长度变化的不同规律,进一步指出,对于层流和加乳化剂的情况下,液滴直径随累计长度增加而减小。 相似文献
10.
静态混合器因具有结构紧凑、强化性能优异和连续性生产等优点被广泛应用于过程工业中,但Q型静态混合器(QSM)内多相流分散混合强化机理不完善制约了其在精细化工和原料药绿色生产中的应用。采用计算流体力学(CFD)耦合群体平衡方程对QSM内相含率α≤5%时液滴分散特性进行数值模拟,分析液液界面张力、动力黏度和相含率对液滴群d32的分散行为的影响。标准旋流静态混合器内的d32数值预测结果与实验结果有良好的一致性。模拟结果表明,在z/l=11.5处不同分散相d32减小73%~96%,RL-90-QSM对不同物性介质的分散混合具有高效性和普适性;在高雷诺数和低相含率下,不同分散相流过z/l=0~2时d32破碎速率最大,在z/l=2.5处d32减小51%~90%,d32随混合时间的增加逐渐减小且在z/l=10后趋于稳定;界面张力对混合结果的影响大于动力黏度。 相似文献
11.
以饱和硫酸钙为介质,在安装Kenics静态混合器的水平液固两相流化床换热管上进行实验研究,考察介质流速、Kenics静态混合器扭率、颗粒体积分数及颗粒尺寸对压降的影响,并与冷态实验条件下的压降变化规律进行比较。结果表明:同等操作条件,安装Kenics静态混合器后压降比安装前提高20%~140%;压降随雷诺数的增大而增大,随Kenics静态混合器扭率的增大而减小;颗粒体积分数对压降也有影响。根据实验数据,得出了稳定操作条件下压降与上述影响因素之间的经验关联式,为带有Kenics静态混合器的水平液固两相流化床换热器的设计提供计算依据。 相似文献
12.
13.
14.
为了解决水平液固循环流化床中颗粒分布不均匀问题,在内径29 mm、长4 m的水平有机玻璃管流化床内放入Kenics静态混合器,采用CCD图像测量与数据处理系统考察静态混合器的结构、个数、安装位置对液固二相流中颗粒分布的影响;同时,利用U型管压差计考察不同条件下静态混合器的压降。实验结果表明:Kenics静态混合器能明显地改善管内颗粒分布情况;单个扭率Y=3.5的Kenics静态混合器压降最小;2个扭率Y=3.5的Kenics静态混合器间距为40 mm时对颗粒分布影响长度是最长的。 相似文献
15.
改进型Ross静态混合器牛顿流体流动的实验与数值模拟 总被引:2,自引:0,他引:2
在改进型Ross静态混合器中对牛顿流体的流动进行了实验研究,并对空管和5单元的改进型Ross静态混合器的流动进行了数值模拟,将实验与数值模拟结果进行了比较,证实二者的结果一致. 结果表明,在改进型Ross静态混合器中,牛顿流体流动的压力降与雷诺数和静态混合器长径比的关系为Dp=14.7231Re-0.156(L/D)0.446ru2/2;在Re=20000时,z因子有最大值;整个静态混合器的压力降(流动阻力)主要集中在混合单元区域. 相似文献
16.
The mechanism of drop breakup inside SMX static mixers in the laminar flow regime was studied using experimental observations and computational fluid dynamics (CFD). The deformation and breakup of a single drop was simulated using the volume of fluid (VOF) model. It was observed that drops break up after collision with the leading edges and cross‐points of the bars in the SMX static mixer. It was found that drop collision with the bar cross‐points of the SMX static mixer elements is most effective for drop breakup. Elongation and folding result in drop breakup at the cross‐points. 相似文献
17.
Laminar mixing of shear thinning fluids in a SMX static mixer 总被引:1,自引:0,他引:1
Flow and mixing of power-law fluids in a standard SMX static mixer were simulated using computational fluid dynamics (CFD). Results showed that shear thinning reduces the ratio of pressure drop in the static mixer to pressure drop in empty tube as compared to Newtonian fluids. The correlations for pressure drop and friction factor were obtained at ReMR?100. The friction factor is a function of both Reynolds number and power-law index. A proper apparent strain rate, area-weighted average strain rate on the solid surface in mixing section, was proposed to calculate pressure drop for a non-Newtonian fluid. Particle tracking showed that shear thinning fluids exhibit better mixing quality, lower pressure drop and higher mixing efficiency as compared to a Newtonian fluid in the SMX static mixer. 相似文献
18.
19.
A general correlation for pressure drop in a Kenics static mixer 总被引:3,自引:0,他引:3
A new pressure drop correlation in a Kenics static mixer has been developed. Pressure drop data were generated from computational fluid dynamics (CFD) calculations, avoiding the experimental limitations in obtaining comprehensive data enough for developing a reliable pressure drop correlation. Dimensional analysis reveals that the pressure drop characteristic of the Kenics static mixer can be described by three dimensionless groups, i.e., the friction factor, Reynolds number (Re), and aspect ratio of a mixing element (AR). A systematic graphical analysis led to a single master curve governing the pressure drop behavior of the Kenics static mixer, which had never been achieved before. We derived a pressure drop correlation fitting well with the obtained master curve in a general form into which the AR effect on the pressure drop is directly incorporated. Unlike the already existing correlations available in the literature, the correlation proposed in this study can cover the whole range of Re from laminar to turbulence. The reliability of the proposed correlation was validated by the comparison with various pressure drop data reported in the literature. 相似文献
20.
The objective of this study was to characterize the two-phase flow hydrodynamic behaviour and mass transfer in a static mixer in a horizontal pipe. Different arrangements of elements of the static mixer were tested and their performances compared. The pressure drop, bubble diameters and mass transfer coefficient were measured. The influence of operating conditions was also studied. A different correlations are proposed and compared with other correlations found in the literature. 相似文献