Entrainment experiments of combined directed valve tray and CFD simulation

doi:10.16085/j.issn.1000-6613.2018-0405

Abstract

Abstract:

Hydraulic experiments were carried out on two types of combined directed valve tray. The entrainment and related hydraulics data of two 1 m diameter trays with different float valve arrangement were measured. The geometric model was established according to the structural and size parameters of experimental trays and the flow field of combined directed valve tray was simulated with Fluent 6.3.26, and the flow pattern characteristics was investigated. The simulation results of clear liquid height and entrainment agreed well with experimental data, which proved the validity of simulation. The entrainment and liquid backflow of two trays were analyzed and the results showed that the entrainment and liquid backflow could be efficiently decreased by properly arranging trapezoidal float valves with stronger oriented ability instead of rectangular float valves on tray. The average entrainment of experimental and simulation results decreased by 13.4% and 10.6%, respectively, while the average of backflow ratio decreased by 12.8%. This research results showed that CFD simulation was expected to provide a guidance for arrangement of two types of float valve and optimization design of the tray.

Key words: combined directed valve tray, hydraulic experiment, entrainment, CFD, float valve arrangement

摘要：

对组合导向浮阀塔板进行了水力学实验，测定了2块直径1m、不同浮阀排布的组合导向浮阀塔板的雾沫夹带和相关水力学数据。根据实验塔板的结构和尺寸参数建立几何模型，采用Fluent 6.3.26软件对板上气液两相流动进行CFD模拟，考察了塔板上的气液两相流动状况。清液层高度和雾沫夹带的模拟结果与实验结果吻合较好，验证了模拟的准确性。对两块不同浮阀排布的组合导向浮阀塔板的雾沫夹带和板上液体反向流进行了分析，结果表明在适当位置用导向能力更强的梯形浮阀代替矩形浮阀可有效降低雾沫夹带率和液体反向流比例，雾沫夹带率的实验值和模拟值分别降低了13.4%和10.6%，液体反向流比例降低了12.8%。研究结果表明，通过CFD模拟可望指导两种浮阀的合理排布和塔板的优化设计。

关键词: 组合导向浮阀塔板, 水力学实验, 雾沫夹带, 计算流体力学, 浮阀排布

CLC Number:

TQ021.1

Xianhe WAN, Jiexu ZHANG, Lijun JI, Jiawen ZHU. Entrainment experiments of combined directed valve tray and CFD simulation[J]. Chemical Industry and Engineering Progress, 2019, 38(04): 1654-1661.

万先河, 张杰旭, 纪利俊, 朱家文. 组合导向浮阀塔板的雾沫夹带实验及CFD模拟[J]. 化工进展, 2019, 38(04): 1654-1661.

Figures/Tables 16

References 25

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网格数	清液层高度/mm	网格数	清液层高度/mm
175875	90	751487	66
306360	81	1357830	65
565610	75

网格数	清液层高度/mm	网格数	清液层高度/mm
175875	90	751487	66
306360	81	1357830	65
565610	75

项目	参数	项目	参数
塔径/m	1	开孔率/%	8.48
板间距/m	0.6	浮阀最大开度/m	0.015
堰高/m	0.03～0.07	导向孔高度/m	0.005
堰长/m	0.732

项目	参数	项目	参数
塔径/m	1	开孔率/%	8.48
板间距/m	0.6	浮阀最大开度/m	0.015
堰高/m	0.03～0.07	导向孔高度/m	0.005
堰长/m	0.732

A _hole	——		孔面积，m²
e _V	——		雾沫夹带率，%
F _s	——		空塔气相动能因子，(m/s)·(kg/m³)^0.5
g	——		重力加速度，g=9.81m/s²
h _cl	——		清液层高度，m
h _w	——		堰高，m
k	——		湍动能，m²/s²
L	——		液体的质量流率，kg/h
L _w	——		液流强度，m³/(m·h)
M _G,L	——		动量源相
N _h	——		孔个数
Q	——		流量，m³/s
T	——		回流体积分数，%
T _av	——		回流体积分数的时均值，%
t	——		时间，s
U _s	——		空塔气速，m/s
u , u	——		速度矢量、速度标量，m/s
V	——		网格总体积，m³
V_x	——		x方向液相速度为负的网格体积，m³
w _a	——		弓形区雾沫夹带占比
w _r	——		矩形区雾沫夹带占比
x,y,z	——		x,y,z坐标轴
α		——		相体积分数
α^a ^verage		——		相平均体积分数
ε		——		湍流耗散率，m²/s²
μ _eff		——		有效动力黏度，Pa·s
ρ		——		相密度，kg/m³
下角标
a		——		弓形区
q		——		指气相或液相
G	——	气相
r	——	矩形区
L	——	液相