为了研究气液同轴离心式喷嘴缩进室内部非定常流动过程,采用Level Set和VOF(Volume of fluid)相耦合的方法,结合网格自适应技术对缩进长度为8mm的液体中心式气液同轴离心式喷嘴流动过程进行了数值仿真研究,计算得到了较为精细的液膜一...为了研究气液同轴离心式喷嘴缩进室内部非定常流动过程,采用Level Set和VOF(Volume of fluid)相耦合的方法,结合网格自适应技术对缩进长度为8mm的液体中心式气液同轴离心式喷嘴流动过程进行了数值仿真研究,计算得到了较为精细的液膜一次破碎过程、流场结构和压力振荡特性。结果表明:液膜的破碎模式受气液比的影响较大,随气液比的增加,液膜破碎模式由波动破碎逐步转变为湍流破碎。此外,清晰获得了自激振荡过程,分析了缩进室内部压力场及速度场分布特征。研究发现,随着气体压降增加,气体环缝出口会出现膨胀波和激波,形成一个“扇环形”的超声速流场区域;激波后气流分离,出现旋涡,形成局部高压区,旋涡中心随激波面周期性地上下移动,致使局部压力出现周期性振荡。展开更多
As a class of newly emerging functional material, Gallium based liquid metals have attracted increasing attentions in many fields, such as chip cooling, printed electronics and microfiuidics, etc. Particularly, the mo...As a class of newly emerging functional material, Gallium based liquid metals have attracted increasing attentions in many fields, such as chip cooling, printed electronics and microfiuidics, etc. Particularly, the motion control of liquid metal droplet has been recently tried for its importance in microelectromechanical system （MEMS）, microfluidics and potential use in micro-machine or reconfigurable soft robot. This paper is dedicated to explore the motion behavior of liquid metal droplet under AC electric field. The quickly induced oscillation phenomena of liquid metal droplet and surrounding electrolyte solution were observed and the major factors to influence such behaviors are theoretically interpreted and experimentally investigated, including the size of the liquid metal droplet, electrode voltage, electrolyte solution concentration and AC signal frequency etc. Moreover, some typical features to distinguish AC filed actuation with DC field are observed, such as intensive fluid waving induced by the resonance stimulation, and the efficient inhibition of solution electrolysis. Finally, two important applications of adopting AC induced surface oscillation of liquid metal droplet to develop solution mixer as well as fluidic pump were demonstrated which successfully avoid gas generation inside electrolyte environment. The bulk oscillation effects of liquid metal as clarified here could be very useful in a variety of areas such as solution disturbance and mixing, and fluid oscillator or pump etc.展开更多
The liquid membrane oscillation of a novel water （aqueous tetradecyl trimethyl ammoniumbromide, TTAB and alcohol solution）/oil （picric acid in chloroform solution）/water （aqueous glucose solution） system was inv...The liquid membrane oscillation of a novel water （aqueous tetradecyl trimethyl ammoniumbromide, TTAB and alcohol solution）/oil （picric acid in chloroform solution）/water （aqueous glucose solution） system was investigated. By using homemade device, the curves of various liquid membranes oscillation with different concentration of TTAB and picric acid, types of alcohol and other organic solvents at different temperature were measured. The results show that the water （aqueous 7 mmol/L of TTAB and 0.5 mol/L of n-propanol solution）/oil （0.5 mmol/L of picric acid in chloroform solution）/water （aqueous glucose solution） system performed sustained and stable oscillation at 30 ℃. And the novel system can recognise added amino acid.展开更多
The electrical oscillations across a liquid membrane in water/oil/water system was studied with octanol as oil phase by introducing two opposite charged surfactants in oil and aqueous phase, respectively. The sustaine...The electrical oscillations across a liquid membrane in water/oil/water system was studied with octanol as oil phase by introducing two opposite charged surfactants in oil and aqueous phase, respectively. The sustained and rhythmic oscillation was observed. To a certain extent, the features of the oscillation （e.g. induction time, frequency, life time and orientation of the pulse pikes） strongly depend on the property of surfactant, dissolved in octanol. The mechanism may be explained by the formation and destruction of dual-ion surfactant membrane accompanying with emulsification at the interface and considering the coupling effect of diffusion and associated reaction in the vicinity of the interface.展开更多
Theoretical consideration was proposed for the influences of the oscillator phase on the response nature of an electrode-separated piezoelectric sensor (ESPS) to liquid properties and verified experimentally. For the ...Theoretical consideration was proposed for the influences of the oscillator phase on the response nature of an electrode-separated piezoelectric sensor (ESPS) to liquid properties and verified experimentally. For the oscillators with different phases, the oscillation frequency of the ESPS may increase, maintain nearly constant or decrease with increasing conductivity in low conductivity solutions. The sensitivity of response to density and viscosity increases slightly with increasing oscillator phase. The response to permittivity depends hardly on the oscillator phase. In addition, the dependence of the oscillation frequency of the ESPS on the supply voltage of the oscillator was explained. The ESPS was used to determine atropine sulfate with a detection limit of 1.6x10(-7) mol/L.展开更多
The liquid membrane oscillation of a novel water（aqueous tetradecyl trimethyl ammoniumbromide,TTAB and alcohol solution）/oil（picric acid in chloroform solution）/water（aqueous glucose solution） system was investi...The liquid membrane oscillation of a novel water（aqueous tetradecyl trimethyl ammoniumbromide,TTAB and alcohol solution）/oil（picric acid in chloroform solution）/water（aqueous glucose solution） system was investigated by means of a homemade device.The results show that the water（aqueous 7 mmol/L TTAB and 0.5 mol/L n-propanol solution）/oil（0.5 mmol/L icric acid in chloroform solution）/water（0.1 mol/L glucose solution） system performed sustained and stable oscillation at 30℃.The oscillation curve under optimized conditions is considered to be referent.Several oscillation curves were accumulated with the addition of different amino acids.The results showed that the novel system can recognize the added amino acids such as L-tryptophan,L-tyrosine,and D,L-tyrosine.And there is corresponding relationship between the change of curve shape and the quantity of amino acid added.展开更多
The influence of low-frequency sonolysis on the kinetics bimolecular liquid-phase reactions was studied with due regard for the association (dimers and trimers) of starting reagents. The mathematical modeling of chemi...The influence of low-frequency sonolysis on the kinetics bimolecular liquid-phase reactions was studied with due regard for the association (dimers and trimers) of starting reagents. The mathematical modeling of chemical reactions that were described by nonlinear differential equations is performed. The steady states, the singular points characteristics, the nature of concentration oscillations in the reaction system are described. With increasing frequency and amplitude of low-frequency sonic waves (up to some critical value), we observed the cessation of the reaction. This observation offers an additional tool for controlling reaction rate by the external action of low-frequency vibrations. The conclusions of the work are obtained under certain assumptions. The exact determination of the critical conditions for changes in dynamics is beyond the scope of the problem.展开更多
文摘为了研究气液同轴离心式喷嘴缩进室内部非定常流动过程,采用Level Set和VOF(Volume of fluid)相耦合的方法,结合网格自适应技术对缩进长度为8mm的液体中心式气液同轴离心式喷嘴流动过程进行了数值仿真研究,计算得到了较为精细的液膜一次破碎过程、流场结构和压力振荡特性。结果表明:液膜的破碎模式受气液比的影响较大,随气液比的增加,液膜破碎模式由波动破碎逐步转变为湍流破碎。此外,清晰获得了自激振荡过程,分析了缩进室内部压力场及速度场分布特征。研究发现,随着气体压降增加,气体环缝出口会出现膨胀波和激波,形成一个“扇环形”的超声速流场区域;激波后气流分离,出现旋涡,形成局部高压区,旋涡中心随激波面周期性地上下移动,致使局部压力出现周期性振荡。
基金partially supported by the Dean’s Research Funding of the Chinese Academy of Sciences and Beijing Municipal Science and Technology Project(Grant No.Z141100000514005)
文摘As a class of newly emerging functional material, Gallium based liquid metals have attracted increasing attentions in many fields, such as chip cooling, printed electronics and microfiuidics, etc. Particularly, the motion control of liquid metal droplet has been recently tried for its importance in microelectromechanical system （MEMS）, microfluidics and potential use in micro-machine or reconfigurable soft robot. This paper is dedicated to explore the motion behavior of liquid metal droplet under AC electric field. The quickly induced oscillation phenomena of liquid metal droplet and surrounding electrolyte solution were observed and the major factors to influence such behaviors are theoretically interpreted and experimentally investigated, including the size of the liquid metal droplet, electrode voltage, electrolyte solution concentration and AC signal frequency etc. Moreover, some typical features to distinguish AC filed actuation with DC field are observed, such as intensive fluid waving induced by the resonance stimulation, and the efficient inhibition of solution electrolysis. Finally, two important applications of adopting AC induced surface oscillation of liquid metal droplet to develop solution mixer as well as fluidic pump were demonstrated which successfully avoid gas generation inside electrolyte environment. The bulk oscillation effects of liquid metal as clarified here could be very useful in a variety of areas such as solution disturbance and mixing, and fluid oscillator or pump etc.
文摘The liquid membrane oscillation of a novel water （aqueous tetradecyl trimethyl ammoniumbromide, TTAB and alcohol solution）/oil （picric acid in chloroform solution）/water （aqueous glucose solution） system was investigated. By using homemade device, the curves of various liquid membranes oscillation with different concentration of TTAB and picric acid, types of alcohol and other organic solvents at different temperature were measured. The results show that the water （aqueous 7 mmol/L of TTAB and 0.5 mol/L of n-propanol solution）/oil （0.5 mmol/L of picric acid in chloroform solution）/water （aqueous glucose solution） system performed sustained and stable oscillation at 30 ℃. And the novel system can recognise added amino acid.
文摘The electrical oscillations across a liquid membrane in water/oil/water system was studied with octanol as oil phase by introducing two opposite charged surfactants in oil and aqueous phase, respectively. The sustained and rhythmic oscillation was observed. To a certain extent, the features of the oscillation （e.g. induction time, frequency, life time and orientation of the pulse pikes） strongly depend on the property of surfactant, dissolved in octanol. The mechanism may be explained by the formation and destruction of dual-ion surfactant membrane accompanying with emulsification at the interface and considering the coupling effect of diffusion and associated reaction in the vicinity of the interface.
基金Project supported by the National Natural Science Foundation of China.
文摘Theoretical consideration was proposed for the influences of the oscillator phase on the response nature of an electrode-separated piezoelectric sensor (ESPS) to liquid properties and verified experimentally. For the oscillators with different phases, the oscillation frequency of the ESPS may increase, maintain nearly constant or decrease with increasing conductivity in low conductivity solutions. The sensitivity of response to density and viscosity increases slightly with increasing oscillator phase. The response to permittivity depends hardly on the oscillator phase. In addition, the dependence of the oscillation frequency of the ESPS on the supply voltage of the oscillator was explained. The ESPS was used to determine atropine sulfate with a detection limit of 1.6x10(-7) mol/L.
基金Supported by the Open Research Fund of Shenzhen Key Laboratory of Functional Polymer,China
文摘The liquid membrane oscillation of a novel water（aqueous tetradecyl trimethyl ammoniumbromide,TTAB and alcohol solution）/oil（picric acid in chloroform solution）/water（aqueous glucose solution） system was investigated by means of a homemade device.The results show that the water（aqueous 7 mmol/L TTAB and 0.5 mol/L n-propanol solution）/oil（0.5 mmol/L icric acid in chloroform solution）/water（0.1 mol/L glucose solution） system performed sustained and stable oscillation at 30℃.The oscillation curve under optimized conditions is considered to be referent.Several oscillation curves were accumulated with the addition of different amino acids.The results showed that the novel system can recognize the added amino acids such as L-tryptophan,L-tyrosine,and D,L-tyrosine.And there is corresponding relationship between the change of curve shape and the quantity of amino acid added.
文摘The influence of low-frequency sonolysis on the kinetics bimolecular liquid-phase reactions was studied with due regard for the association (dimers and trimers) of starting reagents. The mathematical modeling of chemical reactions that were described by nonlinear differential equations is performed. The steady states, the singular points characteristics, the nature of concentration oscillations in the reaction system are described. With increasing frequency and amplitude of low-frequency sonic waves (up to some critical value), we observed the cessation of the reaction. This observation offers an additional tool for controlling reaction rate by the external action of low-frequency vibrations. The conclusions of the work are obtained under certain assumptions. The exact determination of the critical conditions for changes in dynamics is beyond the scope of the problem.
