A novel constant interfacial area cell for determining the extraction kinetics of Er(Ⅲ) from chloride medium

A novel constant interfacial area cell(NCIAC),by spatially separating the agitation from liquid flow circulation of organic and aqueous two phases,was suggested to obtain detailed kinetic data for Er(Ⅲ) extraction from chloride medium by 2-ethyl-hexyl-phosphonic acid mono-(2-ethylhexyl) ester(EHEHPA).Different from the traditional Lewis cell and the constant interfacial area cell with laminar flow,the concentrations of Er(Ⅲ) in organic and aqueous two phases were uniform,and the stability of the interfacial area between the two phases could be controlled effectively.Therefore,the special requirements for the design of agitators in the traditional Lewis cell and the constant interfacial area cell for minimizing the influence of diffusion resistance could be avoided.Experimental results indicated that the extraction kinetics was mainly affected by the aqueous flow rate,interfacial area between organic and aqueous two phases,and the aqueous p H values.An extraction kinetic equation was suggested based on the experimental data.

Degradation of Microcystin-LR by Gas-Liquid Interfacial Discharge Plasma

In this study, we report on the degradation of microcystin-LR （MC-LR） by gas- liquid interracial discharge plasma. The influences of operation parameters such as average input voltage, electrode distance and gas flow rate are investigated. Experimental results indicate that the input voltage and gas flow rate have positive influences on MC-LR degradation, while the electrode distance has a negative one. After 6 min discharge with 25 kV average input voltage and 60 L/h air aerati by discharge both in on, the degradation rate of MC-LR achieves 75.3%. distilled water and MC-LR solution are measured H202 and 03 generated Moreover, an emission spectroscopy is used as an indicator of the processes that take place on the gas-liquid boundary and inside plasma. Varied types of radicals （O, .OH, CO, 03, etc.） are proved to be present in the gas phase during gas-liquid interfacial discharge.

Measurement and Prediction of Interfacial Area on a DistiIlation Tray

In this paper the modern electron optical equipment is used to translate the clear image of speed moving bubbles in bubbling liquid on a sieve tray into the digital information stored in computer, and the computer aided image processing technique is utilized to measure the bubble size distributions and interfacial areas under various operating conditions. And the dynamic behavior of bubbles in turbulent liquid is analyzed theoretically; the mechanism of bubble deformation and breakage is explored on the basis of Kolmogoroff′s isotropic turbulence hypothesis; the mathematical model for predicting the gas liquid interfacial area is proposed. The comparison between the simulated results and the experimental data shows that the model is higher in accuracy, simple in form and convenient in use.

Numerical investigation on characteristics of interfacial wave of liquid film in gas-liquid two-phase flow using OpenFOAM

Liquid film cooling as an advanced cooling technology is widely used in space vehicles.Stable operation of liquid film along the rocket combustion inner wall is crucial for thermal protection of rocket engines.The stability of liquid film is mainly determined by the characteristics of interfacial wave,which is rarely investigated right now.How to improve the stability of thin film has become a hot spot.In view of this,an advanced model based on the conventional Volume of Fluid(VOF)model is adopted to investigate the characteristics of interfacial wave in gas-liquid flow by using OpenFOAM,and the mechanism of formation and development of wave is revealed intuitively through numerical study.The effects from gas velocity,surface tension and dynamic viscosity of liquid(three factors)on the wave are studied respectively.It can be found that the gas velocity is critical to the formation and development of wave,and four modes of droplets generation are illustrated in this paper.Besides,a gas vortex near the gas-liquid interface can induce formation of wave easily,so changing the gas vortex state can regulate formation and development of wave.What’s more,the change rules of three factors influencing on the interfacial wave are obtained,and the surface tension has a negative effect on the formation and development of wave only when the surface tension coefficient is above the critical value,whereas the dynamic viscosity has a positive effect in this process.Lastly,the maximum height and maximum slope angle of wave will level off as the gas velocity increases.Meanwhile,the maximum slope angle of wave is usually no more than 38°,no matter what happens to the three factors.

Measurements of the effective mass transfer areas for the gas–liquid rotating packed bed

Rotating packed bed(RPB) is one of the most effective gas–liquid mass transfer enhancement reactors, its effective specific mass transfer area(ae) is critical to understand the mass transfer process. By using the NaOH–CO_(2) chemical absorption method, the aevalues of three RPB reactors with different rotor sizes were measured under different operation conditions. The results showed that the high gravity factor and liquid flow rate were major affecting factors, while the gas flow rate exhibited minor influence.The radius of packing is the dominant equipment factor to affect aevalue. The results indicated that the contact area depends on the dispersion of the liquid phase, thus the centrifugal force of rotating packed bed greatly influenced the aevalue. Moreover, the measured ae/ap(effective specific mass transfer area/specific surface area of packing) values were fitted with dimensionless correlation formulas. The unified correlation formula with dimensionless bed size parameter can well predict the experimental data and the prediction errors were within 15%.

基于可解释性神经网络的界面面积浓度预测

界面面积浓度(Interfacial Area Concentration,IAC)是两相流动的封闭两流体模型中界面传递项的关键参数,用于表征气液界面传输能力的强弱。对界面面积浓度的建模预测通常有经验关联式和界面面积输运方程等方法,但这些方法都有较大的数据依赖性。而对神经网络模型增添可解释性可以为模型修正提供方向,严谨提升预测精度。为更好地预测两相流动的IAC,基于神经网络建立了IAC的预测模型,结合不同气泡行为、物理关系及统计分布并利用事后可解释性方法,对比分析了不同输入特征组合的神经网络模型预测能力;并通过神经网络每层的结构参数大小,分析输出比重挑选合适的数据预处理方法。通过事后可解释性分析得到空泡份额是IAC预测的重要因素,而对训练数据进行对数变换预处理能够显著提高模型对真实数据的预测能力。

棒束子通道空泡份额及相界面浓度分布特性实验研究

棒束通道相态分布特性对反应堆内传热传质及流动阻力具有重要影响。本文对5×5棒束通道空气水两相流开展实验研究,采用四头电导探针测量了子通道内部的空泡份额、相界面浓度、气泡直径、气泡速度等相界面参数的局部分布。结果表明,气泡受横向作用力的影响,在子通道内会形成两种典型分布,随液相流速升高和气相流速降低,轴峰分布逐渐转变为壁峰分布;不同类型子通道空泡分布不均匀,中心子通道受壁面影响较小,气泡数量最多,边通道和角通道几乎被液相占据;本实验工况下,现有的空泡份额和相界面浓度计算关系式预测性能良好,平均最小误差分别为±18.2%与±12.2%。

Stability of Stratified Gas-Liquid Flow in Horizontal and Near Horizontal Pipes

A viscous Kelvin-Helmholtz criterion of the interfacial wave instability is proposed in this paper based on the linear stability analysis of a transient one-dimensional two-fluid model. In thismodel, the pressure is evaluated using the local momentum balance rather than the hydrostatic approximation. The criterion predicts well the stability limit of stratified flow in horizontal and nearly horizontal pipes. The experimental and theoretical investigation on the effect of pipe inclination on the interfacial instability are carded out. It is found that the critical liquid height at the onset of interfacial wave instability is insensitive to the pipe inclination. However, the pipe inclination significantly affects critical superficial liquid velocity and wave velocity especially lor low gas velocities.

A Hydrodynamic Modei for Slug Frequency in Horizontal Gas-Liquid Two-Phase Flow

The prediction of slug frequency has important significance on gas-liquid two-phase flow. A hydrody-namic modei 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 modei 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 30m long and its inner diameter is 24 mm. It is observed experimentally that the interfacial wave frequency at the inlet is about l to 3 times the frequency of stable slug. The slug frequencies predicted by the modei fit well with Tronconi (1990) modei and the experimental data. The combination of the hydrodynamic modei and the experimental data results in a conclusion that the frequency of equilibrium liquid slug is approximately half the miniraum frequency of interfacial wave.

主被动耦合防/除冰技术及能耗控制研究进展

随着航空工业的不断发展,对于飞机表面防/除冰技术提出了更高效、更低能耗、更大面积的需求。从现有主动防/除冰技术和被动防/除冰技术出发,主要具体介绍了电热除冰、压电除冰、超疏水表面和低界面韧性涂层等技术。简要介绍了不同技术的除冰机理,总结了各项技术的研究现状,并对比分析了各类防/除冰技术的优势与不足。虽然各项技术均有良好的防/除冰效果,但仍然受到能耗高、效率低、除冰不彻底等问题的限制。而主被动耦合除冰技术能有效地综合各自的技术优势,同时补足各自的劣势,表现出更加优异的除冰效果,近年来相关研究受到广泛关注,其中重点介绍了超疏水表面耦合电热除冰技术。面对飞机大面积、高效、快速、低能的表面防除冰需求,考虑到压电除冰的低能耗和低界面韧性涂层在大面积积冰条件下的优势,提出低界面韧性涂层耦合压电材料除冰技术具有重要的研究意义。

竖直管道内闪蒸界面传播现象的数值研究

闪蒸界面传播是一种特殊的闪蒸现象,广泛存在于航天器真空环境下的排液过程中.闪蒸界面传播规律的深入研究是完善闪蒸机制,预测真空排液过程,提升航天活动可控性、安全性的重要前提.闪蒸界面传播现象研究目前主要依赖于实验观测,缺乏适合的数值方法.为了避免跨尺度模拟带来的庞大计算量,文章对计算域进行分区,在各分区内建立面密度模型,实现了单一工况下的闪蒸界面传播二维数值模拟.在此基础上,还提出闪蒸界面面密度的气相Weber数修正模型.该模型对不同温度压力条件下的界面微观形态特征进行代数表征,从而令数值模拟能够计算预测不同温度和压力工况条件下的闪蒸界面传播表观速度.最后,模拟了相同出口压力、不同名义过热度条件下的闪蒸界面传播现象,以及相同名义过热度、不同出口压力条件下的传播现象.计算结果表明,当出口压力恒定时,闪蒸界面处的真实过热度以及界面传播表观速度都随名义过热度的增加而增加.且在过热度较小时,真实过热度以及名义过热度都与闪蒸界面传播表观速度之间近似呈线性关系.当名义过热度恒定时,闪蒸界面传播表观速度会随出口压力的增加而增加.

Micro-interface enhanced mass transfer sodium carbonate absorption carbon dioxide reaction

Micro-interface intensified reactor(MIR)can be applied in series/parallel in the absorption of CO_(2)in industrial gases by Na_(2)CO_(3)due to the ability to produce large numbers of stable microbubbles.This work focuses on the variation pattern of mass transfer characteristics parameters of the reaction gas in Na_(2)CO_(3) solution under the influence of different solution properties and operating parameters in the reaction of CO_(2)absorption by Na2CO3.The mass transfer characteristics parameters include bubble Sauter mean diameter,gas holdup,interfacial area,liquid side mass transfer coefficient,and liquid side volume mass transfer coefficient kLa.The solution properties and operating parameters include Na2CO3 concentration(0.05–2.0 mol·L^(-1)),superficial gas velocity(0.00221–0.01989 m·s^(-1)),superficial liquid velocity(0.00332–0.02984 m·s^(-1)),and ionic strength(1.42456–1.59588 mol·kg^(-1)).And volumetric mass transfer coeffi-cients kLa and superficial reaction rates r of the MIR and the bubble column reactor are compared in the reaction of sodium carbonate absorption of carbon dioxide,and the former shows a greater improvement under different solution properties and operating parameters.The enhanced role of MIR in mass transfer in non-homogeneous reactions is verified and the feasibility of industrial practical applications of MIR is demonstrated.

CuSn预合金粉芯复合银钎料的润湿铺展机理

研究了添加质量分数为30%~70%CuSn预合金粉复合银钎料在T2紫铜基体上的润湿铺展过程,并讨论了CuSn预合金粉复合银钎料在紫铜基体上的润湿铺展机理.结果表明,在与紫铜基体的润湿铺展过程中,初始接触角由30%CuSn的119°降低到70%CuSn的94°.最终接触角由30%CuSn的15°下降到70%CuSn的7°.当粉芯中CuSn合金粉含量为60%时,钎料在铜板上的润湿面积达到530.04 mm^(2),相比于未添加CuSn合金粉时提高了约66%.由于低熔点CuSn预合金粉的前驱润湿作用使复合银钎料表面张力降低,初始接触角和最终接触角随着CuSn预合金粉含量的增加而减小.CuSn预合金粉在钎焊过程中先于BAg30CuZnSn钎料外皮熔化,形成熔融的铜锡液态合金薄层,降低了固液界面张力.随后,熔化的BAg30CuZnSn箔带在先期熔化的铜锡液态薄层上铺展,并与其发生溶质原子的扩散反应,最终形成液态复合钎料.低熔点CuSn预合金粉的加入,使复合银钎料在铜上的润湿性能显著改善.添加40%CuSn预合金粉复合银钎料与铜基体的反应润湿界面均匀致密,其中白色富Ag相互连接,Sn元素主要分布于富Ag相和周围的锡青铜相中.

Simulation of interfacial Marangoni convection in gas-liquid mass transfer by lattice Boltzmann method

Interfacial Marangoni convection has signifi-cant effect on gas-liquid and/or liquid-liquid mass transfer processes.In this paper,an approach based on lattice Boltzmann method is established and two perturbation models,fixed perturbation model and self-renewable interface model,are proposed for the simulation of interfacial Marangoni convection in gas-liquid mass transfer process.The simulation results show that the concentration contours are well consistent with the typical roll cell convection patterns obtained experimentally in previous studies.

Efficient organic-inorganic hybrid cathode interfacial layer enabled by polymeric dopant and its application in large-area polymer solar cells

An organic-inorganic hybrid cathode interfacial layer(CIL) was developed by doping ZnO with the naphthalene-diimide based derivative NDI-PFNBr. It was found the resulting organic-inorganic hybrid CIL showed apparently improved conductivity and could act as an effective cathode interlayer to modify indium tin oxide(ITO) transparent electrodes. As a result, by employing the blend of PTB7-Th:PC71BM as the photoactive layer, the inverted polymer solar cells(PSCs) exhibited a remarkable enhancement of power conversion efficiency(PCE) from 8.52% for the control device to 10.04% for the device fabricated with the hybrid CIL. Moreover, all device parameters were simultaneously improved by using this hybrid CIL. The improved open-circuit voltage(VOC) was attributed to the reduced work function of the ITO cathode, whereas the enhancements in fill factor(FF) and short-circuit current density(JSC) were assigned to the increased conductivity and more effective charge extraction and collection at interface. Encouragingly, when the thickness of the hybrid CIL was increased to 80 nm, the resulting device could still keep a PCE of 8.81%, exhibiting less thickness dependence. Considering these advantages, 16 and 93 cm2large-area PSCs modules were successfully fabricated from the hybrid CIL by using doctor-blade coating techniques and yielded a remarkable PCE of8.05% and 4.49%, respectively. These results indicated that the hybrid CIL could be a promising candidate to serve as the cathode interlayer for high-performance large-area inverted PSCs.

The Behavior and Characteristics of the InterfacialWaves in Gas-Liquid Two-Phase Separated FlowThrough Downward Inclined Rectangular Channel

An experimental investigation on the behavior and characteristics of interfacial waves in downward inclined rectangular channel was conducted. The interfacial waves were traced and measured by us-ing conductance technique. The wav patterns were distinguished and defined. The characteristics of the interfacial waves, such as time-averaged film thickness, wave height, wave propagation speed,wavlength and wave frequency, were systematically examined in terms of gas and liquid superficial volumetric fiuxes. The effect of the inclination and flow channel geometry of the test section on the interfacial wav was also investigated.

Kinetics of cerium(Ⅳ) and fluoride extraction from sulfuric solutions using bifunctional ionic liquid extractant(Bif-ILE)[A336][P204]

The extraction kinetics of Ce（Ⅳ） and Ce（Ⅳ）-F^- mixture systems from sulfuric solutions to n-heptane solution containing Bif-ILE[A336][P204]（[trialkylmethylammonium][di-2-ethylhewanxylphosphinate]） with a constant interfacial area cell with laminar flow were studied,just to elucidate the extraction mechanism and the mass transfer models.The data were analyzed in terms of pseudo-first-order constants.The effects of stirring speed,specific interfacial area and temperature on the extraction rate in both systems were discussed,suggesting that the extractions were mixed bulk phases-interfacial control process.Supported by the experimental data,the corresponding rate equations for Ce（Ⅳ） extraction system and Ce（Ⅳ）-F^- mixture extraction system were obtained.The experimental results indicated the rate-controlling step.The kinetics model was deduced from the rate-controlling step and consistent with the rate equation.

相间交界面对非饱和土应力状态的影响

非饱和土是一种三相多孔介质,不同相之间的交界面尤其是气液交界面的存在直接影响了非饱和土的宏观行为.首先对土中交界面的形式和作用进行了探讨,指出气液交界面对非饱和土的行为有重要影响,并给出了界面功和气液比表面积的表达式.在已有的非饱和土变形功表达式基础上,引入界面能影响,得到了考虑交界面影响的非饱和土自由能方程.利用所得的自由能方程,给出了考虑交界面影响的非饱和土固相和液相相应的应力变量.对考虑交界面面积的液相流动方程进行了探讨,给出了非平衡条件下的土水特征曲线表达式,指出在平衡条件下土水特征曲线中应当考虑交界面面积的影响,传统土水特征曲线是三维关系在吸力-饱和度平面上的投影.将比表面积与土水特征曲线的关系,利用已有试验数据验证了该表达式的合理性.利用界面面积的表达式计算有效应力,将其与已有试验结果进行对比,表明给出的比表面积表达式可很好地反映实际情况.不同于已有现象学研究,本文推导具有严格的理论基础,研究表明完整的有效应力表达式中应考虑土体内部作用力的影响,其不仅包含基质吸力,同时还包含其他形式的作用力,其大小与界面比表面积有关.该表达式为下一步研究界面效应对土体变形、强度和流动特性的研究提供了基础.

水力喷射-空气旋流器用于湿法烟气脱硫及其传质机理

在一种新型高效的气液传质设备——水力喷射-空气旋流器（WSA）中,以Ca（OH）2料浆为吸收剂进行了模拟烟气湿法脱硫的实验研究。结果表明：脱硫率随进口气速增加而增加;随液体喷射速度增加先增加,增加到一定程度后几乎不变;随烟气中SO2的进口浓度增加而减小,存在一适宜的Ca（OH）2浓度和回流比。在气体流量24～72 m3·h-1、循环液体量0.4～0.8 m3·h-1、料浆中Ca（OH）2浓度7500 g·m-3时,对SO2浓度为1891～6373 mg·m-3的烟气进行湿法脱硫,脱硫率达88.9%～97.7%,且WSA的旋流气体和喷射液体在湿法脱硫中具有自清洁能力,未发现内部结垢和喷孔堵塞现象。总体积传质系数KGa、有效相界面积a均随进口气速uG增大而增大,而总传质系数KG随uG增加变化较小;当液体喷射速度 uL≤0.26 m·s-1时,KGa和KG随uL增加快速增大,之后增加缓慢,而a随uL几乎线性增加,KGa和KG随吸收剂中Ca（OH）2浓度cL增加有一最大值。结合实验数据拟合得到了相关的经验公式,这些关联式能较好地预测WSA的湿法脱硫传质性能。气体旋流场强度对总体积传质系数KGa和有效相界面积a起支配作用,脱硫传质过程同时受气膜和液膜阻力控制,但以液膜控制为主。

化学吸收法测定旋转填料床有效相界面积

用化学吸收法测量了同心环波纹碟片旋转填料床在气液两相沿径向逆流条件下有效相界表面积及有效比相界表面积．实验结果表明，同心环波纹碟片旋转填料床不仅可１００％地有效利用填料自身的表面积，而且可起到良好的雾化扩展相界面积的作用，使相界面积增加２～３．５倍．