交流电场作用下附着在壁面上气泡的动力学研究
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摘要
为了研究交流电场对附壁气泡动力学行为的影响,采用基于FLUENT软件的VOF+LS+SPP方法对余弦交流电场作用下CCl4液体中附着在水平板上的气泡的动力学行为特性进行了模拟研究。利用VOF+LS+SPP方法数值模拟了直流电场作用下附壁气泡的形变过程,并与文献中实验结果对比,验证了该方法适用于附壁气泡的动态特性研究;对比了直流电场和余弦交流电场作用下气泡的脱离时间,研究表明,直流电场作用下,电压需要接近40kV气泡才能脱离壁面;而在余弦交流电场作用下电压为20kV时气泡就可脱离壁面;分析了在余弦交流电场作用下,不同角频率和电压对附壁气泡动态特性的影响规律,结果表明,电压一定时,气泡的脱离时间随着角频率ω的增大而减小,但当角频率ω超过最优角频率时,气泡的脱离时间将增大;当角频率保持不变时,电压越大,气泡脱离时间越短。
The boiling heat transfer performance is closely related to the dynamic behavior of bubbles attached to the wall during boiling.In this paper,a VOF+LS+SPP method,based on FLUENT software,is used to study the effect of cosine AC electric field on the dynamics of an air bubble attached to a horizontal plate and surrounded by liquid CCl4.The VOF+LS+SPP method is utilized to simulate the deformation of the air bubble under the DC electric field.The simulation results are verified by the experimental data in the literature,proving the feasibility of the numerical method.It is found that the bubble will separate from the wall when the voltage reaches 40 kV under the action of the DC electric field.However,for the AC electric field,a lower voltage of 20 kV can make the bubble depart from the wall.The influence of the different angular frequencies and voltages on the bubble dynamic behavior is analyzed numerically under the action of the AC electric field.The results show that when the voltage remains unchanged,the departure time of bubbles is reduced with the increase of the angular frequency.But when the angular frequency exceeds the optimal value,the departure time of bubble will increase with the growing of the angular frequency.When the angular frequency remains constant,the bubble departure time is shortened with the increase of the voltage.
The boiling heat transfer performance is closely related to the dynamic behavior of bubbles attached to the wall during boiling.In this paper,a VOF+LS+SPP method,based on FLUENT software,is used to study the effect of cosine AC electric field on the dynamics of an air bubble attached to a horizontal plate and surrounded by liquid CCl4.The VOF+LS+SPP method is utilized to simulate the deformation of the air bubble under the DC electric field.The simulation results are verified by the experimental data in the literature,proving the feasibility of the numerical method.It is found that the bubble will separate from the wall when the voltage reaches 40 kV under the action of the DC electric field.However,for the AC electric field,a lower voltage of 20 kV can make the bubble depart from the wall.The influence of the different angular frequencies and voltages on the bubble dynamic behavior is analyzed numerically under the action of the AC electric field.The results show that when the voltage remains unchanged,the departure time of bubbles is reduced with the increase of the angular frequency.But when the angular frequency exceeds the optimal value,the departure time of bubble will increase with the growing of the angular frequency.When the angular frequency remains constant,the bubble departure time is shortened with the increase of the voltage.
引文
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[22]Di Marco P,Kurimoto R,Saccone G,et al.Bubble shape under the action of electric forces[J].Experimental Thermal and Fluid Science,2013,49:160-168.
[23]Jalaal M,Khorshidi B,Esmaeilzadeh E,et al.Behavior of a single bubble in a nonuniform DC electric field[J].Chemical Engineering Communications,2010,198(1):19-32.
[24]Chen F,Liu D,Song Y.Visualization of a Single Boiling Bubble in a DC Electric Field[C].ASME 2012Fluids Engineering Division Summer Meeting collocated with the ASME 2012Heat Transfer Summer Conference and the ASME 2012 10th Inter-national Conference on Nanochannels,Microchannels,and Minichannels.American Society of Mechanical Engineers,2012:245-252.
[2]Wang Q,Zhang G,Wang C,et al.The electrically induced bubble behaviors considering different bubble injection directions[J].International Journal of Heat and Mass Transfer,2017,104:729-742.
[3]Kano I.Boiling heat transfer enhancement by utilizing Electrohydrodynamic(EHD)force in micro sized space[C].Industry Applications Society Annual Meeting,IEEE,2013:1-8.
[4]Hristov Y,Zhao D,Kenning D B R,et al.A study of nucleate boiling and critical heat flux with EHD enhancement[J].Heat and Mass Transfer,2009,45(7):999-1017.
[5]Huber G,Tanguy S,Sagan M,et al.Direct numerical simulation of nucleate pool boiling at large microscopic contact angle and moderate Jakob number[J].International Journal of Heat and Mass Transfer,2017,113:662-682.
[6]Siedel S,Cioulachtjian S,Robinson A J,et al.Electric field effects during nucleate boiling from an artificial nucleation site[J].Experimental Thermal and Fluid Science,2011,35(5):762-771.
[7]Wang Z T,Dong Q M,Zhang Y H,et al.Numerical study on deformation and interior flow of a droplet suspended in viscous liquid under steady electric fields[J].Advances in Mechanical Engineering,2014,6(7):1-12.
[8]Sunder S,Tomar G.Numerical simulations of bubble formation from submerged needles under non-uniform direct current electric field[J].Physics of Fluids,2013,25(10):102104-102123.
[9]Marco P D,Kurimoto R,Saccone G,et al.Bubble shape under the action of electric forces[J].Experimental Thermal and Fluid Science,2013,49(49):160-168.
[10]Pan K L,Chen Z J.Simulation of bubble dynamics in a microchannel using a front-tracking method[J].Computers and Mathematics with Applications,2014,67(2):290-306.
[11]Dong W,Li R Y,Yu H L,et al.An investigation of behaviors of a single bubble in a uniform electric field[J].Experimental Thermal and Fluid Science,2006,30(6):579-586.
[12]Zu Y Q,Yan Y Y.A numerical investigation of electrohydrodynamic(EHD)effects on bubble deformation under pseudo-nucleate boiling conditions[J].International Journal of Heat and Fluid Flow,2009,30(4):761-767.
[13]Jalaal M,Khorshidi B,Esmaeilzadeh E,et al.Behavior of a single bubble in a nonuniform DC electric field[J].Chemical Engineering Communications,2010,198(1):19-32.
[14]Marco P D.The use of electric force as a replacement of buoyancy in two-phase flow[J].Microgravity Science and Technology,2012,24(3):215-228.
[15]Wang T,Li H X,Zhang Y F,et al.Numerical simulation of bubble dynamics in a uniform electric field by the adaptive 3D-VOSET method[J].Numerical Heat Transfer,Part A:Applications,2015,67(12):1352-1369.
[16]Wang T,Li H X,Zhao J F.Three-dimensional numerical simulation of bubble dynamics in microgravity under the influence of nonuniform electric fields[J].Microgravity Science and Technology,2016,28(2):133-142.
[17]Mcgranaghan G,Robinson A J.EHD augmented convective boiling:flow regimes and enhanced heat transfer[J].Heat Transfer Engineering,2014,35(5):517-527.
[18]Mcgranaghan G,Robinson A J.The mechanisms of heat transfer during convective boiling under the influence of AC electric fields[J].International Jour-nal of Heat and Mass Transfer,2014,73:376-388.
[19]Zhang A L,Wang Y N,Sun D L,et al.Development of a VOF+LS+SPP method based on FLUENT for simulating bubble behaviors in the electric field[J].Numerical Heat Transfer,Part B:Fundamentals,2017,71:186-201.
[20]Cho H J,Kang I S,Kweon Y C,et al.Study of the behavior of a bubble attached to a wall in a uniform electric field[J].International Journal of Multiphase Flow,1996,22(5):909-922.
[21]Kweon Y C,Kim M H,Cho H J,et al.Study on the deformation and departure of a bubble attached to a wall in dc/ac electric fields[J].International Journal of Multiphase Flow,1998,24(1):145-162.
[22]Di Marco P,Kurimoto R,Saccone G,et al.Bubble shape under the action of electric forces[J].Experimental Thermal and Fluid Science,2013,49:160-168.
[23]Jalaal M,Khorshidi B,Esmaeilzadeh E,et al.Behavior of a single bubble in a nonuniform DC electric field[J].Chemical Engineering Communications,2010,198(1):19-32.
[24]Chen F,Liu D,Song Y.Visualization of a Single Boiling Bubble in a DC Electric Field[C].ASME 2012Fluids Engineering Division Summer Meeting collocated with the ASME 2012Heat Transfer Summer Conference and the ASME 2012 10th Inter-national Conference on Nanochannels,Microchannels,and Minichannels.American Society of Mechanical Engineers,2012:245-252.