The destruction of gaseous styrene was studied using a low-temperature plasma induced by tubular multilayer dielectric barrier discharge(DBD).The results indicate that the applied voltage,gas flow rate,inlet styrene c...The destruction of gaseous styrene was studied using a low-temperature plasma induced by tubular multilayer dielectric barrier discharge(DBD).The results indicate that the applied voltage,gas flow rate,inlet styrene concentration and reactor configuration play important roles in styrene removal efficiency(η_(styrene)) and energy yield(EY).Values of η_(styrene) and EY reached 96%and 15567 mg/kWh when the applied voltage,gas flow rate,inlet styrene concentration and layers of quartz tubes were set at 10.8 kV,5.0 m/s,229 mg/m^3 and 5 layers,respectively.A qualitative analysis of the byproducts and a detailed discussion of the reaction mechanism are also presented.The results could facilitate industrial applications of the new DBD reactor for waste gas treatment.展开更多
In this study,two regeneration methods(dielectric barrier discharge(DBD)plasma and ozone(O3)regeneration)of saturated granular activated carbon(GAC)with pentachlorophenol(PCP)were compared.The results show that the tw...In this study,two regeneration methods(dielectric barrier discharge(DBD)plasma and ozone(O3)regeneration)of saturated granular activated carbon(GAC)with pentachlorophenol(PCP)were compared.The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent.Comparing the DBD plasma with O3regeneration,the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O3regeneration.O3regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC,which causes a decrease in PCP on GAC uptake.With increasing regeneration cycles,the regeneration efficiencies of the two methods decrease,but the decrease in the regeneration efficiencies of GAC after O3regeneration is very obvious compared with that after DBD plasma regeneration.Furthermore,the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique,and all the adsorption equilibrium isotherms fit the Langmuir model fairly well,which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process,but to shift the equilibrium towards lower adsorption concentrations.Analyses of the weight loss of GAC show that O3regeneration has a lower weight loss than DBD plasma regeneration.展开更多
Based on the theory of EHD (electronhydrodynamic),a simplified volume forcemodel is applied to simulation to analyze the traits of plasma flow control in flow field,in whichthe cold plasma is generated by a DDD (diele...Based on the theory of EHD (electronhydrodynamic),a simplified volume forcemodel is applied to simulation to analyze the traits of plasma flow control in flow field,in whichthe cold plasma is generated by a DDD (dielectric-barrier-discharge) actuator.With the paraelectricaction of volume force in electric field,acceleration characteristics of the plasma flow areinvestigated for different excitation intensities of RF (radio frequency) power for the actuator.Furthermore,the plasma acceleration leads to an asymmetric distribution of flow field,and henceinduces the deflection of jet plume,then results in a significant deflection angle of 6.26° thrustvectoringeffect.It appears that the plasma flow control technology is a new tentative method forthe thrust-vectoring control of a space vehicle.展开更多
Atmospheric pressure non-thermal plasma is of interest for industrial applications.In this study,polypropylene (PP) films are modified by a dielectric barrier discharge (DBD) with a non-uniform magnetic field in air a...Atmospheric pressure non-thermal plasma is of interest for industrial applications.In this study,polypropylene (PP) films are modified by a dielectric barrier discharge (DBD) with a non-uniform magnetic field in air at atmospheric pressure.The surface properties of the PP films before and after a DBD treatment are studied by using contact angle measurement,atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS).The effect of treatment time on the surface modification with and without a magnetic field is investigated.It is found that the hydrophilic improvement depends on the treatment time and magnetic field.It is also found that surface roughness and oxygen-containing groups are introduced onto the PP film surface after the DBD treatment.Surface roughness and oxygen-containing polar functional groups of the PP films increase with the magnetic induction density.The functional groups are identified as C-O,C=O and O-C=O by using XPS analysis.It is concluded that the hydrophilic improvement of PP films treated with a magnetic field is due to a greater surface roughness and more oxygen-containing groups.展开更多
A numerical simulation method is employed to investigate the effects of the unsteady plasma body force over the stalled NACA 0015 airfoil at low Reynolds number flow conditions.The plasma body force created by a diele...A numerical simulation method is employed to investigate the effects of the unsteady plasma body force over the stalled NACA 0015 airfoil at low Reynolds number flow conditions.The plasma body force created by a dielectric barrier discharge actuator is modeled with a phenomenological method for plasma simulation coupled with the compressible Navier-Stokes equations.The governing equations are solved using an efficient implicit finitevolume method.The responses of the separated flow field to the effects of an unsteady body force in various interpulses and duty cycles as well as different locations and magnitudes are studied.It is shown that the duty cycle and inter-pulse are key parameters for flow separation control.Additionally,it is concluded that the body force is able to attach the flow and can affect boundary layer grow that Mach number 0.1 and Reynolds number of 45000.展开更多
The dielectric barrier discharge(DBD) in the glow regime in neon has been investigated by experiment and two-dimensional(2D) fluid modeling.The discharge was carried out in a planar DBD system with segmented-electrode...The dielectric barrier discharge(DBD) in the glow regime in neon has been investigated by experiment and two-dimensional(2D) fluid modeling.The discharge was carried out in a planar DBD system with segmented-electrodes driven by square-wave voltage.The results show that the glow DBD originates in the center of the electrode and expands outward to the electrode edge during each half cycle of the voltage,forming a radial structure.The discharge decays firstly in the inner area but sustains longer in the edge area,showing a reversed discharge area.The discharge cannot completely cover the entire electrode surface,but remains a border of non- or weak discharge.The fluid modeling shows a similar result in agreement with the experiments.The simulations indicate that the electric field in the edge area is distorted due to the boundary effect so that the electric field and charge distribution are different from that in the inner part.The distorted field reduces the longitudinal component near the edge and causes the local field to be lower than that in the center,and hence makes the discharge behindhand.It also induces a transverse field that makes the discharge extend radially outward to the edge.The boundary effect plays an important role in the glow DBD structure.展开更多
Characteristics of toluene decomposition and formation of nitrogen oxide(NOx) by-products were investigated in a dielectric barrier discharge(DBD) reactor with/without catalyst at room temperature and atmospheric pres...Characteristics of toluene decomposition and formation of nitrogen oxide(NOx) by-products were investigated in a dielectric barrier discharge(DBD) reactor with/without catalyst at room temperature and atmospheric pressure. Four kinds of metal oxides, i.e., manganese oxide(Mn Ox), iron oxide(Fe Ox), cobalt oxide(Co Ox) and copper oxide(Cu O), supported on Al2O3/nickel foam, were used as catalysts. It was found that introducing catalysts could improve toluene removal efficiency, promote decomposition of by-product ozone and enhance CO2 selectivity. In addition, NOx was suppressed with the decrease of specific energy density(SED) and the increase of humidity, gas flow rate and toluene concentration, or catalyst introduction. Among the four kinds of catalysts, the Cu O catalyst showed the best performance in NOx suppression. The Mn Ox catalyst exhibited the lowest concentration of O3 and highest CO2 selectivity but the highest concentration of NOx. A possible pathway for NOx production in DBD was discussed. The contributions of oxygen active species and hydroxyl radicals are dominant in NOx suppression.展开更多
Dielectric barrier discharges(DBD) have been used in the degradation of dioxins due to the large number of excimers and free radicals produced in discharge process. In this article,the density functional theory(DFT) i...Dielectric barrier discharges(DBD) have been used in the degradation of dioxins due to the large number of excimers and free radicals produced in discharge process. In this article,the density functional theory(DFT) is used to study the degradation mechanism of octachlorinated dibenzo-p-dioxin(OCDD) with the atomic oxygen O(3P) in DBD reactor. The reactants, intermediates, transition states and products are optimized at the MPWB1K/6 –31 + G(d,p) level. The vibrational frequencies have been calculated at the same level. The reaction pathways and mechanisms are analyzed in detail. The effect of removing the chlorine atom on environment also has been discussed.展开更多
基金supported by Key Project of Science and Technology Commission of Shanghai Municipality(No.13231201903)National Key Technology R&D Program of China(No.2011BAJ07B04)
文摘The destruction of gaseous styrene was studied using a low-temperature plasma induced by tubular multilayer dielectric barrier discharge(DBD).The results indicate that the applied voltage,gas flow rate,inlet styrene concentration and reactor configuration play important roles in styrene removal efficiency(η_(styrene)) and energy yield(EY).Values of η_(styrene) and EY reached 96%and 15567 mg/kWh when the applied voltage,gas flow rate,inlet styrene concentration and layers of quartz tubes were set at 10.8 kV,5.0 m/s,229 mg/m^3 and 5 layers,respectively.A qualitative analysis of the byproducts and a detailed discussion of the reaction mechanism are also presented.The results could facilitate industrial applications of the new DBD reactor for waste gas treatment.
基金supported by National Natural Science Foundation of China(No.21107085)National High Technology Research and Development Program of China(No.2008AA06Z308)
文摘In this study,two regeneration methods(dielectric barrier discharge(DBD)plasma and ozone(O3)regeneration)of saturated granular activated carbon(GAC)with pentachlorophenol(PCP)were compared.The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent.Comparing the DBD plasma with O3regeneration,the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O3regeneration.O3regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC,which causes a decrease in PCP on GAC uptake.With increasing regeneration cycles,the regeneration efficiencies of the two methods decrease,but the decrease in the regeneration efficiencies of GAC after O3regeneration is very obvious compared with that after DBD plasma regeneration.Furthermore,the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique,and all the adsorption equilibrium isotherms fit the Langmuir model fairly well,which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process,but to shift the equilibrium towards lower adsorption concentrations.Analyses of the weight loss of GAC show that O3regeneration has a lower weight loss than DBD plasma regeneration.
基金supported by National Natural Science Foundation of China (No.90716025)
文摘Based on the theory of EHD (electronhydrodynamic),a simplified volume forcemodel is applied to simulation to analyze the traits of plasma flow control in flow field,in whichthe cold plasma is generated by a DDD (dielectric-barrier-discharge) actuator.With the paraelectricaction of volume force in electric field,acceleration characteristics of the plasma flow areinvestigated for different excitation intensities of RF (radio frequency) power for the actuator.Furthermore,the plasma acceleration leads to an asymmetric distribution of flow field,and henceinduces the deflection of jet plume,then results in a significant deflection angle of 6.26° thrustvectoringeffect.It appears that the plasma flow control technology is a new tentative method forthe thrust-vectoring control of a space vehicle.
基金supported by China Postdoctoral Science Foundation(No.20100480255)the Scientific Research Starting Foundation for Talent Introduction(Nanjing University of Information Science&Technology)
文摘Atmospheric pressure non-thermal plasma is of interest for industrial applications.In this study,polypropylene (PP) films are modified by a dielectric barrier discharge (DBD) with a non-uniform magnetic field in air at atmospheric pressure.The surface properties of the PP films before and after a DBD treatment are studied by using contact angle measurement,atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS).The effect of treatment time on the surface modification with and without a magnetic field is investigated.It is found that the hydrophilic improvement depends on the treatment time and magnetic field.It is also found that surface roughness and oxygen-containing groups are introduced onto the PP film surface after the DBD treatment.Surface roughness and oxygen-containing polar functional groups of the PP films increase with the magnetic induction density.The functional groups are identified as C-O,C=O and O-C=O by using XPS analysis.It is concluded that the hydrophilic improvement of PP films treated with a magnetic field is due to a greater surface roughness and more oxygen-containing groups.
文摘A numerical simulation method is employed to investigate the effects of the unsteady plasma body force over the stalled NACA 0015 airfoil at low Reynolds number flow conditions.The plasma body force created by a dielectric barrier discharge actuator is modeled with a phenomenological method for plasma simulation coupled with the compressible Navier-Stokes equations.The governing equations are solved using an efficient implicit finitevolume method.The responses of the separated flow field to the effects of an unsteady body force in various interpulses and duty cycles as well as different locations and magnitudes are studied.It is shown that the duty cycle and inter-pulse are key parameters for flow separation control.Additionally,it is concluded that the body force is able to attach the flow and can affect boundary layer grow that Mach number 0.1 and Reynolds number of 45000.
基金supported by National Natural Science Foundation of China(No.11175017)
文摘The dielectric barrier discharge(DBD) in the glow regime in neon has been investigated by experiment and two-dimensional(2D) fluid modeling.The discharge was carried out in a planar DBD system with segmented-electrodes driven by square-wave voltage.The results show that the glow DBD originates in the center of the electrode and expands outward to the electrode edge during each half cycle of the voltage,forming a radial structure.The discharge decays firstly in the inner area but sustains longer in the edge area,showing a reversed discharge area.The discharge cannot completely cover the entire electrode surface,but remains a border of non- or weak discharge.The fluid modeling shows a similar result in agreement with the experiments.The simulations indicate that the electric field in the edge area is distorted due to the boundary effect so that the electric field and charge distribution are different from that in the inner part.The distorted field reduces the longitudinal component near the edge and causes the local field to be lower than that in the center,and hence makes the discharge behindhand.It also induces a transverse field that makes the discharge extend radially outward to the edge.The boundary effect plays an important role in the glow DBD structure.
基金funded by the National Natural Science Foundation of China (Nos. 50708021, 51108187)the Research Fund Program of Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University, No. 2013K0007)Guangdong Provincial Key Laboratory of Atmospheric environment and Pollution Control (No. 2011A060901011)
文摘Characteristics of toluene decomposition and formation of nitrogen oxide(NOx) by-products were investigated in a dielectric barrier discharge(DBD) reactor with/without catalyst at room temperature and atmospheric pressure. Four kinds of metal oxides, i.e., manganese oxide(Mn Ox), iron oxide(Fe Ox), cobalt oxide(Co Ox) and copper oxide(Cu O), supported on Al2O3/nickel foam, were used as catalysts. It was found that introducing catalysts could improve toluene removal efficiency, promote decomposition of by-product ozone and enhance CO2 selectivity. In addition, NOx was suppressed with the decrease of specific energy density(SED) and the increase of humidity, gas flow rate and toluene concentration, or catalyst introduction. Among the four kinds of catalysts, the Cu O catalyst showed the best performance in NOx suppression. The Mn Ox catalyst exhibited the lowest concentration of O3 and highest CO2 selectivity but the highest concentration of NOx. A possible pathway for NOx production in DBD was discussed. The contributions of oxygen active species and hydroxyl radicals are dominant in NOx suppression.
基金supported by the National Natural Science Foundation of China (No. 21277082, 21177076, 71201093)the Promotive Research Fund for Excellent Young and Middleaged Scientists of Shandong Province (Nos. BS2012HZ009, BS2012SF012)+2 种基金Graduate Independent Innovation Foundation of Shandong University (No. yzc12120)Program for New Century Excellent Talents in University (NCET-13-0349)Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Community Framework Program (No. 295132)
文摘Dielectric barrier discharges(DBD) have been used in the degradation of dioxins due to the large number of excimers and free radicals produced in discharge process. In this article,the density functional theory(DFT) is used to study the degradation mechanism of octachlorinated dibenzo-p-dioxin(OCDD) with the atomic oxygen O(3P) in DBD reactor. The reactants, intermediates, transition states and products are optimized at the MPWB1K/6 –31 + G(d,p) level. The vibrational frequencies have been calculated at the same level. The reaction pathways and mechanisms are analyzed in detail. The effect of removing the chlorine atom on environment also has been discussed.
