THE CHARACTERISTICS OF WATER FLOW DISPLACED BY GAS IN NANO ARRAYS
SongFuquan1,*,, HuXiao1, ZhuGenmin1, ZhuWeiyao2 1 School of Petrochemical and Energy Engineering, Zhejiang Ocean University, Zhoushan 316022, Zhejiang, China2 School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China 中图分类号:TE312 文献标识码:A
关键词:纳米阵列;气驱水流动;微纳米流动;毛细管力 Abstract The two-phase flow characteristics of water flow displaced by gas at nanometer scale have a wide application in the development of nano-fluidic chips and shale gas. In this paper, experiments of water flow displaced by gas and single-phase flow was carried out to study the flow characteristics of water flow displaced by gas at nanoscale of alumina membranes with diameters of 292.8 nm, 206.2 nm, 89.2 nm, 67.0 nm and 26.1 nm. The experiments show that there are three flow stages for water flow displaced by gas at nanoscale: firstly, the flow rate increases slowly with increasing the driving pressure in the first stage, and the gas flux is decreased about one order of magnitude when compared with gas single-phase flow; secondly, gas flux increases rapidly with increasing the driving pressure as water in nano arrays are largely driven out in the second stage; thirdly, gas flow characteristics are consistent with the single-phase flow when water in nano arrays are all displaced out in the third stage. The analysis results show that due to the “pinning" effect of capillary pressure at the gas-liquid interface and the interaction of solid-liquid interface, gas flux increase slowly in the first stage of water flow displaced by gas. And the larger driving pressure is required to increase the gas flux in nano arrays, which is the main reason of the nonlinear flow characteristics. Once the “pinning" effect is destroyed, the gas will enter the pipeline to promote the movement of the interface, which will change the capillary curvature between capillary column and liquid column. As a result, the capillary force reduces rapidly with the increase of displacing pressure and gas flux will increase sharply, which is the main reason of the sudden change of water flow displaced by gas in the second stage.
显示原图|下载原图ZIP|生成PPT 图3氧化铝膜接触角测量结果 -->Fig. 3Results of contact angle on alumina film -->
2 实验结果
2.1 气体流量随压力梯度的变化关系
按照上述实验方法和步骤,对饱和水后的纳米阵列进行气驱水实验,计量出口处气体的流量变化. 为更清楚地比较不同规格纳米 阵列中的气体流量,防止小管径的实验数据被重叠,将管径相近的实验结果绘制在同一张图中. 从图4看出,每种规格管径下重复实验的重复性较好,基本说明实验数据是可靠性的. 从图4 可以看出, 每种规格管径纳米阵列的气驱水流动都存在三个阶段:第一阶段,气体流量缓慢增大,该过程所有规格管径下的气体 流量值太小,曲线重叠在一起,紧贴横坐标;第二阶段,气体流量急剧增大,此时气体流量随驱替压力变化的曲线开始分离; 第三阶段,气体流量保持稳定较快增长,该阶段不同管径规格的实验曲线基本完全分离,表现出管径越大,气体流量越大的实验现象. 显示原图|下载原图ZIP|生成PPT 图4不同纳米阵列规格下的气驱水流动结果比较 -->Fig. 4Comparison results of water flow displaced by gas in nano arrays -->
利用上述实验装置,进行单相气体流动实验,比较单相气体与气驱水流过纳米阵列完整的3个变化过程,结果如图5所示. 显示原图|下载原图ZIP|生成PPT 图5气驱水与单相流动的气体流量对比 -->Fig. 5Comparison of gas flux between water flow displaced by gas and single-phase flow -->
在整个气驱水过程中,相比较于第三阶段的流量而言,初期的气体流量值非常小,导致这部分实验曲线被重叠在一起. 为了分析气驱 水第一阶段的流动特征,截取流量急剧增加A转折点前的流量随驱替压力的实验数据,如图6所示. 显示原图|下载原图ZIP|生成PPT 图6气驱水第一阶段流动特征 -->Fig. 6First stage flow characteristics of water flow displaced by gas -->
通过开展纳米尺度下气驱水流动与单相气体流动实验,从实验结果可以得出以下结论: (1)单相气体与气驱水时气相流动实验结果表明:纳米尺度下,气驱水时气体流量变化存在三个阶段:第一阶段气体流量缓慢增大,比单相气体流量降低约一个数量级;第二阶段纳米阵列中的水被大量驱替出,流量迅速增大;第三阶段纳米阵列中的水全部被驱替出,气体流动特征与单相气体流动保持一致. (2)气驱水第一阶段过程中,存在气液界面毛细压的“钉扎”效应,使得在气驱水初期,气体流量先缓慢增大. 毛细管力是气驱水产生非线性流动的主要原因. (3)在气驱水过程中,当气驱压力继续增大,“钉扎”作用破坏,气体流量迅速增大. 毛细管力对气驱水流动的影响,是造成第二阶段气体流量突变的主要原因. 本文实验采用氧化铝膜作为纳米阵列通道,并非单根纳米管. 纳米阵列通道内的几何尺寸不确定度及膜材料的均匀性有可能影响流 量特性,特别对流量转折点A的发生;但由于目前实验条件限制,尚无法进行纳米通道内的流动显示,因此文章中对流动图像的解释, 特别是第一和第二阶段的分析结论还有待进一步实验验证. The authors have declared that no competing interests exist.
(ZhaoCuilin.Study on gas-solid flow in 300 MW tangential fired boilers. [PhD Thesis] . Harbin: Harbin Institute of Technology, 2007 (in Chinese)) [本文引用: 1]
(YuanBo.Development of three-dimensional thermal-hydraulic analysis code for stream generator with two-phase flow model and porous media approach. [PhD Thesis] . Beijing: North China Electric Power University, 2016 (in Chinese)) [本文引用: 1]
[3]
PetersenFJ, WørtsO, SchaeferT, et al.Effervescent atomization of aqueous polymer solutions and dispersions . Pharmaceutical Development & Technology, 2001, 6(2): 201 [本文引用: 1]
(ZhuHongwei.Droplets manipulation and graphene transistor sensor research in microfluidic chip. [PhD Thesis] . Wuhan: Wuhan University, 2013 (in Chinese)) [本文引用: 1]
[5]
HuY, DevegowdaD, StrioloA, et al.Microscopic dynamics of water and hydrocarbon in shale-kerogen pores of potentially mixed-wettability . SPE Journal, 2014, 20(1): 112-124 [本文引用: 1]
(DongDazhong, WangYuman, LiXinjing, et al.Breakthrough and prospect of shale gas exploration and development in China . J Nature Gas Industry, 2016, 36: 19-25 (in Chinese)) [本文引用: 1]
(WangHongjun, MaFeng, TongXiaoguang, et al.Assessment of global unconventional oil and gas resources . Petroleum Exploration and Development, 2016, 43: 1-10 (in Chinese)) [本文引用: 1]
(SunKeming, ZhangShucui.Hydraulic fracture propagation in shale gas bedding reservoir analytical analysis . Chinese Journal of Theoretical and Applied Mechanics, 2016, 48(5): 1229-1237 (in Chinese)) [本文引用: 1]
(LiJing, LiXiangfang, LiYingying, et al.Model for gas transport in nanopores of shale and tight formation under reservoir condition . Chinese Journal of Theoretical and Applied Mechanics, 2015, 47(6): 932-944 (in Chinese)) [本文引用: 2]
(FangXinhui.Fabrication of superdrophobic film and study of gas liquid two phase flow. [PhD Thesis] . Dalian: Dalian University of Technology, 2009 (in Chinese)) [本文引用: 1]
(SongFuquan, ZuoJiachuan.The Characteristics of drag reduction of liquid flowing in micro-channels . Chinese Journal of Applied Mechanics, 2009, 26(4): 633-637 (in Chinese)) [本文引用: 3]
[12]
YuanQZ, ZhaoYP.Multiscale dynamic wetting of a droplet on a lyophilic pillar-arrayed surface . Journal of Fluid Mechanics, 2013, 716: 171-188 [本文引用: 1]
[13]
WuQ, BaiB, MaY, et al.Optic imaging of two-phase-flow behavior in 1D nanoscale channels . SPE Journal, 2014, 19(5): 793 [本文引用: 1]
(LiuZhaomiao, LiuLikun, ShenFeng.Two-phase flow characteristics in Y-junction microchannel . Chinese Journal of Theoretical and Applied Mechanics, 2014, 46(2): 209-216 (in Chinese)) [本文引用: 1]
[15]
AlfiM, NasrabadiH, BanerjeeD.Experimental investigation of confinement effect on phase behavior of hexane, heptane and octane using lab-on-a-chip technology . Fluid Phase Equilibria, 2016, 423: 25-33 [本文引用: 1]
[16]
FalkK, CoasneB, PellenqR, et al.subcontinuum mass transport of condensed hydrocarbons in nanoporous media . Nature Communications, 2015, 6: 6949 [本文引用: 1]
[17]
QinX, YuanQ, ZhaoY, et al.Measurement of the rate of water translocation through carbon nanotubes . Nano Letters, 2011, 11(5): 2173-2177 [本文引用: 1]
[18]
HoltJK, ParkHG, WangY, et al.Fast mass transport through sub-2-nanometer carbon nanotubes . Science, 2006, 312(5776): 1034-1037 [本文引用: 1]
[19]
KumarVA, StevenS, LeeW, et al.Observation of extreme phase transition temperatures of water confined inside isolated carbon nanotubes . Nature Nanotechnology, 2016, 12: 267-273 [本文引用: 1]
[20]
JiangRJ, SongFQ, LiHM.Flow characteristics of deionized water in microtubes . Chinese Physics Letters, 2006, 23(12): 3305-3308 [本文引用: 1]
[21]
WuQ, OkJT, SunY, et al.Optic imaging of single and two-phase pressure-driven flows in nano-scale channels . Lab on A Chip, 2013, 13(6): 1165 [本文引用: 1]
(HuRan, ChenYifeng, WanJiamin, et al.Supercritical CO2 water displacements and CO2 capillary trapping: micromodel experiment and numerical simulation . Chinese Journal of Theoretical and Applied Mechanics, 2017, 49(3): 638-648 (in Chinese)) [本文引用: 1]
(LiuZhaomiao, LiuJia, ShenFeng.Simulation on flow patterns and characteristics of two-phase gas-liquid flow in a 90° bend under different gravity . Chinese Journal of Theoretical and Applied Mechanics, 2015, 47(2): 223-230 (in Chinese))
(OuyangWeiping, ZhangMian, SunHu.Effect of wellbore gas-liquid two-phase flowon well test of fractured horizontal wells in tight gas reservoir . Chinese Journal of Theoretical and Applied Mechanics, 2016, 48(2): 464-472 (in Chinese)) [本文引用: 1]
[25]
SecchiE, MarbachS, NiguèsA, et al.Massive radius-dependent flow slippage in carbon nanotubes . Nature, 2016, 537(7619): 210 [本文引用: 1]
[26]
SparreboomW, BergAVD, EijkelJCT.Principles and applications of nanofluidic transport . Nature Nanotechnology, 2009, 4(11): 713 [本文引用: 1]
[27]
MonteiroPJ, RycroftCH, BarenblattGI.A mathematical model of fluid and gas flow in nanoporous media . Proc Natl Acad Sci USA, 2012, 109(50): 20309-13 [本文引用: 1]
[28]
MajumderM, ChopraN, AndrewsR, et al.Nanoscale hydrodynamics: Enhanced flow in carbon nanotubes . Nature, 2005, 438(7064): 44 [本文引用: 1]
[29]
WhitbyM, CagnonL, ThanouM, et al.Enhanced fluid flow through nanoscale carbon pipes . Nano Letters, 2008, 8(9): 2632-2637 [本文引用: 1]
[30]
MattiaD, GogotsiY.Review: static and dynamic behavior of liquids inside carbon nanotubes . Microfluidics & Nanofluidics, 2008, 5(3): 289-305 [本文引用: 1]
(ChangJin, GaoShusheng, HuZhimin, et al.Flow mechanism of high pressure gas in microtubes . Acta Petrolei Sinica, 2015, 36(12): 1559-1570 (in Chinese)) [本文引用: 1]
(ZhaoQingmin, YueXiangan, WangFei, et al.Flow characteristicss of high pressure real gas in microtubes . Journal of China University of Petroleum ( Edition of Natural Science), 2012, 36(4): 129-133 (in Chinese)) [本文引用: 2]
(LiZhanhua, ZhengXu.The problems and progress in the experimental study of micro/nano-scale flow . Journal of Experiments in Fluid Mechanics, 2014, 28(3): 1-9 (in Chinese)) [本文引用: 2]
(HuHaibao, BaoLuyao, HuangSuhe.Simulation of the liquid couette flow in a nano-channel with different wettability . Chinese Journal of Theoretical and Applied Mechanics, 2013, 45(4): 507-514 (in Chinese)) [本文引用: 1]