Bulletin of the American Physical Society
65th Annual Gaseous Electronics Conference
Volume 57, Number 8
Monday–Friday, October 22–26, 2012; Austin, Texas
Session DT3: Green Plasma Technologies |
Hide Abstracts |
Chair: Walter Lempert, Ohio State University Room: Classroom 202 |
Tuesday, October 23, 2012 10:00AM - 10:30AM |
DT3.00001: Modeling of Plasma Assisted Combustion Invited Speaker: Haruaki Akashi Recently, many experimental study of plasma-assisted combustion has been done. However, numerous complex reactions in combustion of hydrocarbons are preventing from theoritical study for clarifying inside the plasma-assisted combustion, and the effect of plasma-assist is still not understood. Shinohara and Sasaki [1,2] have reported that the shortening of flame length by irradiating microwave without increase of gas temperature. And they also reported that the same phenomena would occur when applying dielectric barrier discharges to the flame using simple hydrocarbon, methane. It is suggested that these phenomena may result by the electron heating. To clarify this phenomena, electron behavior under microwave and DBD was examined. For the first step of DBD plasma-assisted combustion simulation, electron Monte Carlo simulation in methane, oxygen and argon mixture gas(0.05:0.14:0.81) [2] has been done. Electron swarm parameters are sampled and electron energy distribution function (EEDF)s are also determined. In the combustion, gas temperature is higher($>$1700K), so reduced electric field $E/N$ becomes relatively high($>$10V/cm/Torr). The electrons are accelerated to around 14 eV. This result agree with the optical emission from argon obtained by the experiment of reference [2]. Dissociation frequency of methane and oxygens are obtained in high. This might be one of the effect of plasma-assist. And it is suggested that the electrons should be high enough to dissociate methane, but plasma is not needed.\\[4pt] [1] K. Shinohara et al, J. Phys. D:Appl. Phys., 42, 182008 (1-7) (2009).\\[0pt] [2] K. Sasaki, 64th Annual Gaseous Electronic Conference, 56, 15 CT3.00001(2011). [Preview Abstract] |
Tuesday, October 23, 2012 10:30AM - 10:45AM |
DT3.00002: A novel microwave plasma combustor toward understanding plasma assisted ignition and plasma assisted combustion of methane/air mixtures Chuji Wang, Wei Wu A novel microwave plasma combustor has been developed to study mechanisms of plasma-assisted ignition (PAI) and plasma-assisted combustion (PAC). The system allows us to inject a 2.45 MHz atmospheric argon microwave plasma jet directly into a combustion reaction zone to investigate effects of PAI and PAC. Three distinct zones: a pure plasma zone, a plasma-combustion hybrid zone, and a combustion zone are investigated by optical emission spectroscopy (OES) and cavity ringdown spectroscopy (CRDS) of OH, etc. plasma and combustion intermediates. The experimental results allow us to understand the formation of OH radicals and roles of OH in PAI and PAC of methane-air mixtures in a wide range of fuel equivalence ratios ranging from rich to lean burn. A U-curve of plasma power versus fuel equivalence ratio in the PAI of methane-air mixtures is observed. The roles of OH in PAI and PAC of premixed methane-air flames around the flammability limit are discussed. [Preview Abstract] |
Tuesday, October 23, 2012 10:45AM - 11:00AM |
DT3.00003: Measurement of OH radical density in dielectric barrier discharge enhanced premixed burner flame Kazunori Zaima, Koichi Sasaki In this work, we examined temporal variation of OH radical density in a premixed burner flame assisted by dielectric barrier discharge (DBD)using cavity-ringdown absorption spectroscopy. We attached a premixed burner to a dielectric base plate, and the upper part of the premixed burner flame with CH$_4$/O$_2$/Ar gas mixture was covered with a quartz tube. An aluminum electrode was attached on the outside of the quartz tube, and it was connected to a high-voltage power supply. DBD inside the quartz tube was obtained between the aluminum electrode and the electrically-grounded burner nozzle. To measure the temporal variation of OH radical density, we constructed a system of cavity-ringdown absorption spectroscopy using a cw diode laser. We obtained the absorbance of OH radicals with and without DBD by comparing the ringdown signals observed at an absorption wavelength of OH radicals (6900.690 cm$^{-1}$) and an off-tuned wavelength (6900.900 cm$^{-1}$). As a result, it was observed that the density of OH radicals in the presence of DBD was lower than that in the absence of DBD at almost all the discharge phases. It is suggested from the result that the consumption of OH radicals is enhanced due to the change in combustion reactions in the flame in the presence of DBD. [Preview Abstract] |
Tuesday, October 23, 2012 11:00AM - 11:15AM |
DT3.00004: Surface treatment of dye-sensitized solar cell using dielectric barrier discharge Ryo Ono, Shungo Zen, Yoshiyuki Teramoto, Keisuke Hanawa, Soichi Kobayashi, Tetsuji Oda We have developed surface treatment of dye-sensitized solar cell (DSSC) using dielectric barrier discharge (DBD). The DSSC consists of TiO$_2$ nanoporous photoelectrode sensitized with dye. The photoelectrode is a 10-$\mu$m thick film made by sintering TiO$_2$ paste on a conductive glass substrate at 450 C. After the sintering, the TiO$_2$ film is dipped into dye solution for sensitization. The DBD treatment is applied to the TiO$_2$ film after the sintering. The DBD treatment improves the energy conversion efficiency, $\eta$, by a factor of 1.05 to 1.15 depending on humidity and O$_2$ concentration. It can be deduced that radicals such as O, O$_3$, and OH contribute to the DBD treatment. The DBD treatment also has an effect of reducing the sintering temperature of TiO$_2$ paste. If the TiO$_2$ paste is sintered at much lower than 450 C (i.e. $\le 300$ C), a solar cell cannot be produced, that is, $\eta = 0\%$. However, if the DBD treatment is applied after the low temperature sintering, a solar cell can be produced. This is important because the low-temperature sintering enables us to use materials that cannot resist high temperature. The DBD treatment is also applied to a plastic substrate DSSC. But the DBD causes damage on the TiO$_2$ film and at present it is not suceeded. [Preview Abstract] |
Tuesday, October 23, 2012 11:15AM - 11:30AM |
DT3.00005: CO$_{2}$ Dissociation by Low Current Gliding Discharge in the Reverse Vortex Flow Alexander Gutsol If performed with high energy efficiency, plasma-chemical dissociation of carbon dioxide can be a way of converting and storing energy when there is an excess of electric energy, for example generated by solar elements of wind turbines. CO$_{2}$ dissociation with efficiency of up to 90{\%} was reported earlier for low pressure microwave discharge in supersonic flow. A new plasma-chemical system uses a low current gliding discharge in the reverse vortex flow of plasma gas. The system is a development of the Gliding Arc in Tornado reactor. The system was used to study dissociation of CO$_{2}$ in wide ranges of the following experimental parameters: reactor pressure (15-150 kPa), discharge current (50-500 mA), gas flow rate (3-30 liters per minute), and electrode gap length (1-10 cm). Additionally, the effect of thermal energy recuperation on CO$_{2}$ dissociation efficiency was tested. Plasma chemical efficiency of CO$_{2}$ dissociation is very low (about 3{\%}) in a short discharge at low pressures (about 15 kPa) when it is defined by electronic excitation. The highest efficiency (above 40{\%}) was reached at pressures 50-70 kPa in a long discharge with thermal energy recuperation. It means that the process is controlled by thermal dissociation with subsequent effective quenching. Plasma chemical efficiency was determined from the data of chromatographic analysis and oscilloscope electric power integration, and also was checked calorimetrically by the thermal balance of the system. [Preview Abstract] |
Tuesday, October 23, 2012 11:30AM - 11:45AM |
DT3.00006: Numerical simulations for plasma-based dry reforming Ramses Snoeckx, Robby Aerts, Annemie Bogaerts The conversion of greenhouse gases (CO2 and CH4) to more valuable chemicals is one of the challenges of the 21st century. The aim of this study is to describe the plasma chemistry occurring in a DBD for the dry reforming of CO2/CH4 mixtures, via numerical simulations. For this purpose we apply the 0D simulation code ``Global{\_}kin,'' developed by Kushner, in order to simulate the reaction chemistry and the actual reaction conditions for a DBD, including the occurrence of streamers. For the chemistry part, we include a chemistry set consisting of 62 species taking part in 530 reactions. First we describe the reaction chemistry during one streamer, by simulating one discharge pulse and its afterglow, to obtain a better understanding of the reaction kinetics. Subsequently, we expand these results to real time scale simulations, i.e., 1 to 10 seconds, where we analyze the effects of the multiple discharges (streamers) and input energy on the conversion and the selectivity of the reaction products, as well as on the energy efficiency of the process. The model is validated based on experimental data from literature. [Preview Abstract] |
Tuesday, October 23, 2012 11:45AM - 12:00PM |
DT3.00007: Atmospheric Pressure Glow Discharge for Point-of-Use Water Treatment Alexander Lindsay, Brandon Byrns, Steven Shannon, Detlef Knappe Treatment of biological and chemical contaminants is an area of growing global interest where atmospheric pressure plasmas can make a significant contribution. Addressing key challenges of volume processing and operational cost, a large volume 162 MHz coaxial air-plasma source has been developed.\footnote{Byrns (2012) J. Phys. D: Appl. Phys. 45 (2012) 195204} Because of VHF ballasting effects, the electric discharge is maintained at a steady glow, allowing formation of critical non-equilibrium chemistry. High densities, n$_{e }$ = 10$^{11}$-10$^{12}$, have been recorded. The atmospheric nature of the device permits straightforward and efficient treatment of water samples. [H$^{+}$] concentrations in 150 milliliter tap water samples have been shown to increase by 10$^{5}$ after five minutes of discharge exposure. Recent literature has demonstrated that increasing acidity is strongly correlated with a solution's ability to deactivate microbial contaminants.\footnote{Traylor (2011) J. Phys. D: Appl. Phys. 44 (2011) 472001} The work presented here will explore the impact of treatment gas, system configuration, and power density on water disinfection and PFC abatement. An array of plasma diagnostics, including OES and electrical measurements, are combined with post-process water analysis, including GC-MS and QT analysis of coliform and E.coli bacteria. Development of volume processing atmospheric plasma disinfection methods offers promise for point-of-use treatments in developing areas of the world, potentially supplementing or replacing supply and weather-dependent disinfection methods. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700