共查询到18条相似文献,搜索用时 78 毫秒
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彩和光导纤维探针和美国柯达公司生产的EKTAPRO1000型高速动态分析仪研究了生趣直上升管内气液两相弹状流中含气率分布,获得了有关弹状流入口区及充分发展区相分布的实验数据。 相似文献
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In order to investigate the influence of the entrance effect on the spatial distribution of phases, the experiments on gas-liquid two-phase slug flow in a vertical pipe of 0.03m ID were carried out by using optical probes and an EKTAPRO 1000 high speed motion analyzer. It demonstrates that the radial profile of slug flow void fraction is parabolic. Influenced by the falling liquid film, the radial profile curve of liquid slug void fraction in the wake region is also parabolic. Since fully turbulent velocity distribution is built up in the developed region,the void fraction profile in this region is the saddle type. At given superficial liquid velocity, the liquid slug void fraction increases with gas velocity. The radial profiles of liquid slug void fraction at different axial locations are all saddle curves, but void fraction is obviously high around the centerline in the entrance region. The nearer the measuring station is from the entrance, the farther the peak location is away from the wall. 相似文献
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应用电导探针测量技术,对矩形截面螺旋通道内气液两相流局部含气率进行实验研究。在不同的气相折算速度下,应用电导探针测量了弹状流弹单元的长度,并与可视化方法进行对比,验证了电导探针的可靠性,并为信号处理选择合适的阈值。分别在泡状流、弹状流及环状流三种流型的条件下,分析了气相与液相折算速度对局部含气率分布的影响。实验结果发现,螺旋通道气液两相局部含气率呈非对称的抛物线形分布,这种非对称性受流型和液相折算速度的影响。 相似文献
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垂直管内气液两相弹状流压力降 总被引:1,自引:0,他引:1
把空隙率和气相密度沿管子高度的变化当作连续过程,并以微分单元压力降出发,然后在全管范围内积分,从而导出了气液两相在弹状流情况下的总压力降计算式:△P= ln(1+ )+Zc该计算式用于计算弹状流压力降时,简便且准确度高。 相似文献
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水平管气液两相弹状流液弹频率的水动力学新模型 总被引:2,自引:0,他引:2
The prediction of slug frequency has important significance on gas-liquid two-phase flow. A hydrodynamic model was put forward to evaluate slug frequency for horizontal two-phase flow, based on the dependence of slug frequency on the frequency of unstable interfacial wave. Using air and water, experimental verification of the model was carried out in a large range of flow parameters. Six electrical probes were installed at different positions of a horizontal plexiglass pipe to detect slug frequency development. The pipe is 30 m long and its inner diameter is 24 ram. It is observed experimentally that the interracial wave frequency at the inlet is about i to 3 times the frequency of stable slug. The slug frequencies predicted by the model fit well with Tronconi (1990) model and the experimental data. The combination of the hydrodynamic model and the experimental data results in a conclusion that the frequency of equilibrium liquid slug is approximately half the minimum frequency of interfacial wave. 相似文献
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微小三通管内的流量分配及相分配特性对微型工程设备的正常运行至关重要.为了研究微三通管流体分配器的相分配特性,采用计算流体动力学(CFD)方法,对微小三通管道模型进行了数值模拟.计算了jG=0.1m/s,jL=0.05 m/s的两相流不同时刻的相分布图,得到了气泡流经三通管时,气泡分离经历的过程.以空气和水为介质,研究了在不同气相速度和不同液相速度下,采出分率与质量分离效率的关系.气体速度不变,液体速度越大,质量分离效率越高,相的重新分配越不均匀.液体速度不变,气体速度越大,质量分离效率变化不大,总体为气体比液体更容易从侧支管采出. 相似文献
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Interfacial area was measured in cocurrent, gas-liquid upward flow through a vertical, 2.54 cm I.D. and 2.67 m long tube by absorption of CO2 diluted in air into aqueous sodium hydroxide solution. Void fraction and pressure drop were also measured for superficial liquid velocities up to 1.3 m/s. Although the interfacial area exhibited a maximum and minimum with increasing superficial gas velocities at relatively high liquid flow rates as in previous experiments, several significant differences were found. Since the dissipation parameters proposed in the past to correlate interfacial area were found to be less than satisfactory, a new empirical relation is proposed, which can correlate most of the present data within ± 20%. 相似文献
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微通道内气液二相流的空隙率对管路内热质传递具有重要影响。利用高速摄像仪对4种不同深宽比的矩形截面微通道内空气-水二相流的流型进行实时观测和记录,对二相流型图进行了分析和计算,得到了不同流型时的空隙率。4种微通道尺寸(深度×宽度)分别为100μm×200μm,100μm×400μm,100μm×800μm,100μm×2 000μm。结果表明:对于弹状流,空隙率随着微通道截面深宽比的减小而降低,当流型为液环流时,空隙率随着微通道截面深宽比的减小而增加。在实验基础上,将截面深宽比作为参数提出了一个新的空隙率预测模型,计算结果显示:模型能对矩形截面微通道内气液二相流动空隙率进行很好的预测。 相似文献
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垂直上升管中的液弹长度分布 总被引:1,自引:0,他引:1
根据气液相不同的电导性质,通过实验测得了气液二相弹状流中气液弹的长度及速度。利用统计方法研究了在垂直上升管内不同位置以及不同气液表观速度下的液弹长度分布。结果表明该分布能够与对数正态分布关系式符合得很好,气液表观速度对液弹长度影响并不显著。同时还研究了气泡上升速度与前方液弹长度的关系,该关系可以用R.van Hout得到的经验关系式来描绘。 相似文献
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正方形小通道内气液两相流垂直向上流动特性 总被引:2,自引:1,他引:1
辅助高速摄影仪对正方形小通道内氮气-水两相流向上流动进行可视化观察,对流动特性进行了实验研究,获得了典型的流型图像。采用数字图像处理技术对流型图像进行了处理,检测得到气相的周长、面积,并通过提出的假想圆柱体模型计算和统计得到了截面含气率。将压降实验数据分析结果与典型的分相流、均相流压降模型预测值比较,结果表明,Chisholm关系式能较好地预测两相流的压降变化,Lee & Lee关系式和Dukler关系式可较好地预测低表观速度时的两相流压降。 相似文献
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对窄矩形通道(3.25 mm×43 mm)和常规圆管(i.d.50 mm)内泡状流空泡份额分布特性进行了实验研究,探究倾斜对气泡和气液界面分布的影响。实验以空气和纯净水为工质,倾斜角度为5°、10°和15°。结果表明窄矩形通道内空泡份额主要呈壁峰型分布,未观察到核峰型分布;常规圆管内存在核峰型和壁峰型两种分布类型。倾斜对窄矩形通道和常规圆管内壁峰型分布影响相似,即随着倾斜角度的增加,靠近上壁面的峰值被加强,靠近下壁面的峰值被削弱直至消失。对于圆管内核峰型分布,倾斜导致中间宽峰向通道上部倾斜,且峰值随倾斜角度增加而增大。此外,竖直和倾斜条件下壁峰型分布的峰值较常规圆管更加接近通道中心位置。 相似文献
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为了研究气液两相流差压波动信号与空隙率之间的关系,建立了差压波动信号均方根与空隙率的关系式.针对油气两相流和气水两相流,在管径分别为40 mm和50 mm管道上进行实验,分析了文丘里管差压波动信号与空隙率、流量、压力以及流体密度等参数的关系,得到了差压波动信号与空隙率的量纲1关系式.此关系式不仅反应了差压波动信号与空隙率的关系,而且提供了一种间接测量空隙率的方法.该方法只需要测量文丘里管前的压力和前后的差压波动信号,计算出该差压信号的时均值、瞬时值就可以计算得到空隙率的值.实验结果表明在空隙率小于85%的范围内,油气两相流和气水两相流空隙率的测量误差分别为10.9%和11.3%.如果与利用空隙率和差压测量气液两相流流量的方法相结合,则仅利用一个文丘里管就可以实现两相流流量测量. 相似文献
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Mukhtar Abdulkadir Abolore Abdulahi Carol N. Eastwick Barry J. Azzopardi Ivar E. Smith Tor E. Unander 《American Institute of Chemical Engineers》2020,66(4):e16860
This article presents void fraction and pressure gradient data for sulfur hexafluoride (SF6) with gas densities of 28 and 45 kg/m3 and oil (with viscosity 35 times that for water) in a 127 mm diameter pipe. The superficial velocities of gas ranged from 0.1 to 3 m/s and those for liquid from 0.1 to 1 m/s, respectively. Measurements of void fraction data were recorded using a capacitance wire mesh sensor (WMS) system, which permits the 3D visualization of the flow patterns. All the data were obtained with a data acquisition frequency of 1,000 Hz. A differential pressure transducer was used to measure the pressure drops along the length of the pipe. The WMS provide time and cross-sectionally resolved data on void fraction and from an analysis of its output, flow patterns were identified using the characteristic signatures of probability density function (PDF) plot of time series of void fraction. The PDF plots showed the single peak shapes associated with bubbly and churn flows but not the twin-peaked shape usually seen in slug flows. This confirms previous work in larger diameter pipes but with less viscous liquids. For the bubble and churn flows investigated, the pressure gradient was observed to decrease with an increase in gas superficial velocity. Nevertheless, there was an insignificant observed effect of pressure on void fraction below certain transitional flow rates, the effect however became significant beyond these values. In the present work, wisps appear to be smaller, which might be due to the different fluid properties of the working fluids employed. In addition, wisps are easily revealed as long as there is a transition between churn and annular flows regardless of the pressure. Experimental data on void fraction and pressure gradient are compared against existing data. Reasonably good agreements were observed from the results of the comparison. 相似文献