Numerical Simulation of Gas-liquid Two-phase Separation in Vortex Separator
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摘要: 对于气液两相分离，传统分离器或体积过大，或旋流强度低，因此考虑提出一种新式的涡流式分离器。利用涡流二极管逆向流动形成强度较高旋流的特点，在旋流腔上方加入一根支管，从切向入口进入的两相流由于密度差和旋流的作用，气相会聚集在中心由于浮力作用从上支管流出分离器，液相会分布在四周由于重力作用从下支管流出分离器，从而实现两相分离。采用数值模拟的方式分别对不同旋流腔尺寸以及出口形状的分离器进行计算，模拟结果表明，在进口流量为0.5 t/h、入口含气率1%~5%工况下，控制底流口压力和入口相同，溢流口与入口压差在80~90 kPa范围内，分离器对粒径在50~100 μm的气泡分离效率可以达到90%以上。Abstract: For gas-liquid two-phase separation, traditional separators are either too large in volume or low in swirling intensity. So a new type of cyclone separator is proposed. Utilizing the reverse flow of vortex diode to form a high-strength swirling flow, a branch pipe is added above the swirling chamber. For the two-phase flow entering from the tangential inlet, due to the density difference and swirling flow, the gas phase will gather in the center and flow out of the separator from the upper branch pipe due to buoyancy, and the liquid phase will be distributed around the separator from the lower branch pipe due to gravity, thus realizing the separation of the two phases. The separators with different swirling chamber sizes and outlet shapes are calculated by numerical simulation. The simulation results show that under the working condition that the inlet flow is 0.5 t/h and the inlet air content is 1%~5%, the pressure at the control underflow port is the same as that at the inlet, the pressure difference between the overflow port and the inlet is 80~90 kPa, and the separation efficiency of the separator for bubbles with a diameter of 50 μm and 100 μm can be above 90%.
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Key words:
- Gas removal /
- Cyclone separator /
- Vortex diode /
- Numerical simulation
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图 1 涡流式分离器流体域模型图
a—切向入口；b—圆盘形旋流腔；c—上支管；d—下支管
Figure 1. Fluid Domain Model Diagram of Vortex Separator
图 4 模型A和模型B在0.5 t/h进口流量下的压力分布云图
Figure 4. Cloud Chart of Pressure Distribution of Model A and Model B at 0.5 t/h Inlet Velocity
图 5 不同溢流口背压下模型B气相体积分数分布云图
Figure 5. Cloud Chart of Model B Gas Volume Fraction Distribution under Different Back Pressures
图 6 下出口含气率及上出口夹带率随溢流口背压变化
Figure 6. Lower Outlet Air Content and Upper Outlet Entrainment Rate Varying with Back Pressure of Overflow Port
图 7 不同气泡直径下模型B气相体积分数分布云图
Figure 7. Cloud Chart of Model B Gas Volume Fraction Distribution under Different Bubble Diameters
图 9 不同气泡直径下模型C气相体积分数分布云图
Figure 9. Cloud Chart of Model C Gas Volume Fraction Distribution under Different Bubble Diameters
表 1 网格无关性验证设置
Table 1. Set of Grid Independence Verification
网格编号 网格尺寸/mm 网格数量 1 2.60 534160 2 1.90 1003211 3 1.55 1540675 4 1.35 2044809 5 1.19 2520578 
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表 2 涡流式分离器模型尺寸参数
Table 2. Dimension Parameters of Vortex Separator
参数 模型A 模型B 旋流腔直径/mm 150 200 旋流腔高度/mm 30 20 切向入口直径/mm 30 20
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表 3 中心压降随背压变化
Table 3. Center Pressure Drop Varying with Back Pressure
溢流口背压/MPa 中心压力/MPa 中心压降/kPa 14.95 14.955 45 14.94 14.954 46 14.93 14.953 47 14.92 14.952 48 14.91 14.951 49
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表 4 出口质量流量随溢流口背压变化
Table 4. Mass Flow Rate at Outlet Varying with Back Pressure
溢流口
背压/MPa底流口质量流量/
(10−3 kg·s−1)溢流口质量流量/
(10−3 kg·s−1)分离效率/% 液体 气体 液体 气体 14.95 1314.00 8.09 4.45 2.40 22.62 14.94 1304.29 4.60 14.27 5.95 56.47 14.93 1297.10 2.46 21.57 8.12 77.20 14.92 1289.94 1.19 28.09 9.52 90.03 14.91 1282.16 0.59 34.92 10.30 96.69
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表 5 不同模型分离效率比较
Table 5. Comparison of Separation Efficiencies of Different Models
计算模型 模型B 模型C 入口含气率/% 5 5 气泡直径/μm 100 50 100 50 下出口含气率/% 0.32 1.60 0.00004 0.68 分离效率/% 96.7 65.5 ＞99 89.7
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表 6 出口质量流量随含气率的变化
Table 6. Outlet Mass Flow Varying with Air Content
入口含气率/% 底流口质量流量/
(10−3 kg·s−1)溢流口质量流量/
(10−3 kg·s−1)分离效率/% 液体 气体 液体 气体 1 1258.18 5.69×10−6 120.82 2.03 97 3 1245.39 2.30×10−5 105.23 6.31 ＞99 5 1231.42 5.36×10−5 90.82 10.58 ＞99
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表 7 不同分离器性能比较
Table 7. Performance Comparison of Different Separators
性能 旋叶式分离器 离心式柱状分离器 新式涡流分离器 是否依赖背压 是 否 是 鲁棒性能 差 优 中等 压降大小 中等 小 大 体积大小 中等 大 小 分离性能 优 良 优
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