Pub Date : 2008-09-01DOI: 10.1080/10519990902958029
H. Shindo, Y. Kimura, N. Sato, M. Suzuki
Long line-shaped plasmas are inevitable in material processing in manufacturing industries, such as flat panel displays (FPDs) and surface modification of large-area thin films. In this work, we studied a newly proposed method of large-scaled line plasma generation. In this method, microwave power of frequency of 2.45 GHz in a narrowed and flattened rectangular waveguide is employed to produce a long uniform line plasma. Since the width of waveguide is very close to the cutoff condition, the wavelength of microwave inside the guide is very much lengthened, providing a condition of long uniform line plasma generation. The narrowed rectangular waveguides of 1.0 and 1.5 m in length and 5 mm in height were examined. The width of the waveguide could be varied from 59 to 61 mm. The waveguide has a long slot of 5 mm width on the top surface to launch the microwave into the discharge plasma chamber. The plasmas of Ar nad He at the pressures of 100 mTorr were generated by employing an extremely long microwave wavelength. It was observed that the microwave electric field became more uniform as the wave guide width was narrowed, indicating that the plasma production is due to the mechanism expected. The optical emission line measurements in Ar and He plasmas also confirmed that the uniform plasma was produced in the entire region of 1 m and 1.5 m. Thus we conclude that the present method of plasma production is quite advantageous for large area processing. Plasma extraction was also successfully tested and further long line plasma of 2 meter is now under consideration.
{"title":"Large-scaled line plasma production by evanescent microwave in a narrowed rectangular waveguide","authors":"H. Shindo, Y. Kimura, N. Sato, M. Suzuki","doi":"10.1080/10519990902958029","DOIUrl":"https://doi.org/10.1080/10519990902958029","url":null,"abstract":"Long line-shaped plasmas are inevitable in material processing in manufacturing industries, such as flat panel displays (FPDs) and surface modification of large-area thin films. In this work, we studied a newly proposed method of large-scaled line plasma generation. In this method, microwave power of frequency of 2.45 GHz in a narrowed and flattened rectangular waveguide is employed to produce a long uniform line plasma. Since the width of waveguide is very close to the cutoff condition, the wavelength of microwave inside the guide is very much lengthened, providing a condition of long uniform line plasma generation. The narrowed rectangular waveguides of 1.0 and 1.5 m in length and 5 mm in height were examined. The width of the waveguide could be varied from 59 to 61 mm. The waveguide has a long slot of 5 mm width on the top surface to launch the microwave into the discharge plasma chamber. The plasmas of Ar nad He at the pressures of 100 mTorr were generated by employing an extremely long microwave wavelength. It was observed that the microwave electric field became more uniform as the wave guide width was narrowed, indicating that the plasma production is due to the mechanism expected. The optical emission line measurements in Ar and He plasmas also confirmed that the uniform plasma was produced in the entire region of 1 m and 1.5 m. Thus we conclude that the present method of plasma production is quite advantageous for large area processing. Plasma extraction was also successfully tested and further long line plasma of 2 meter is now under consideration.","PeriodicalId":343034,"journal":{"name":"2008 17th International Conference on Gas Discharges and Their Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130658477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-09-01DOI: 10.1108/02602280910986638
J. Benech, P. Freton, J. Gonzalez, M. Masquère
3D models developed for improving industrial applications and characterizing plasma medium, need to be validated by experimental developments. Nevertheless, spectroscopic measurements on 3D plasmas are very complex and consequently, until now, there is a lack of experimental results. We developed an experimental 3D plasma characterization based on tomographic method. The principle of this method is presented in this paper with the corresponding experimental setup that we performed. We also give some preliminary results.
{"title":"Spectroscopic measurements on 3D objects in thermal plasmas","authors":"J. Benech, P. Freton, J. Gonzalez, M. Masquère","doi":"10.1108/02602280910986638","DOIUrl":"https://doi.org/10.1108/02602280910986638","url":null,"abstract":"3D models developed for improving industrial applications and characterizing plasma medium, need to be validated by experimental developments. Nevertheless, spectroscopic measurements on 3D plasmas are very complex and consequently, until now, there is a lack of experimental results. We developed an experimental 3D plasma characterization based on tomographic method. The principle of this method is presented in this paper with the corresponding experimental setup that we performed. We also give some preliminary results.","PeriodicalId":343034,"journal":{"name":"2008 17th International Conference on Gas Discharges and Their Applications","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127395207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A two-dimensional numerical model of a laminar premixed methane-air flame affected by weak direct-current electric field has been built based on the ANSYS CFX hydrodynamic solver. The chemical transformations in the model are described by the GRI-Mech scheme and are solved within the CHEMKIN package. Both packages exchange data during the runtime via ANSYS CFX programming interface. The steady-state simulations of flame without electric fields show a good agreement between measured and modeled flame parameters such as maximal temperature, normal flame propagation speed and the height of the flame. The model allows the qualitative physical interpretation of the electric field effects on the flame by the action of the volume force arising due to the charges separation in the external electric field. The model reproduces the experimentally observed increase in combustion completeness and the decrease in carbon monoxide concentration in the exhaust gas that both result from application of an electric field.
{"title":"Influence of weak electric fields on the flame structure","authors":"A. Starikowskii, M. Skoblin, T. Hammer","doi":"10.2514/6.2008-995","DOIUrl":"https://doi.org/10.2514/6.2008-995","url":null,"abstract":"A two-dimensional numerical model of a laminar premixed methane-air flame affected by weak direct-current electric field has been built based on the ANSYS CFX hydrodynamic solver. The chemical transformations in the model are described by the GRI-Mech scheme and are solved within the CHEMKIN package. Both packages exchange data during the runtime via ANSYS CFX programming interface. The steady-state simulations of flame without electric fields show a good agreement between measured and modeled flame parameters such as maximal temperature, normal flame propagation speed and the height of the flame. The model allows the qualitative physical interpretation of the electric field effects on the flame by the action of the volume force arising due to the charges separation in the external electric field. The model reproduces the experimentally observed increase in combustion completeness and the decrease in carbon monoxide concentration in the exhaust gas that both result from application of an electric field.","PeriodicalId":343034,"journal":{"name":"2008 17th International Conference on Gas Discharges and Their Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129401544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Roupassov, A. Nikipelov, M. Nudnova, A. Starikovskii
Currently, the problem of flow active control by low-temperature plasma is considered to be one of the most booming realms of aerodynamics . The paper presents a results on controlling boundary layer attachment by plasma actuator withhighvoltage pulsed periodic nanosecond excitation. Actuator-induced gas velocities show near-zero values for nanosecond pulses. The measurements performed show overheating in the discharge region at fast (τ ≃ 1μs) thermalization of the plasma inputed energy. The mean values of such heating of the plasma layer can reach 70, 200, and even 400 K for 7-, 12-, and 50-ns pulse durations, respectively. The emerging shock wave together with the secondary vortex flows disturbs the main flow. The resulting pulsed-periodic disturbance causes an efficient transversal momentum transfer into the boundary layer and further flow attachment to the airfoil surface. Thus, for periodic pulsed nanosecond dielectric barrier discharge DBD, the main mechanism of impact is the energy transfer to and heating of the near-surface gas layer. The following pulse-periodic vortex movement stimulates redistribution of the main flow momentum. The experiments performed here have shown high efficiency of the given mechanism to control boundary layer separation, lift and drag force coefficients, and acoustic noise reduction in the Mach number range of 0.05 to 0.85. The design of the SDBD was typical asymmetric plasma actuator with one exposed and one covered electrodes . In our experiments, the exposed electrode was a cathode. The lower covered electrode was an anode. The experiments were carried out on the generator with a pulse length of 12 ns. Two regimes of the generator's operation were used. One was periodic, with a constant frequency of pulses fed onto the discharge gap. The other was burst mode, with impulses fed in bursts. The number of pulses in a burst varied from 1 to 100 with a repetition frequency of 100 kHz, and the time between the bursts being 1-100 ms. The number of pulses in the burst varied to produce constant averaged discharge power for various experimental conditions. The mean power in all burst regimes was equal to 25 W.The electrodes were made of 50 ?m aluminum foil. Their length was 90 cm and their widths were 15 and 10 mm for the lower and upper electrodes, respectively. The dielectric layer consisted of three PVC-films with a total thickness of 240 ?m.
{"title":"Flow separation control by plasma actuator with nanosecond pulse periodic discharge","authors":"D. Roupassov, A. Nikipelov, M. Nudnova, A. Starikovskii","doi":"10.2514/6.2008-1367","DOIUrl":"https://doi.org/10.2514/6.2008-1367","url":null,"abstract":"Currently, the problem of flow active control by low-temperature plasma is considered to be one of the most booming realms of aerodynamics . The paper presents a results on controlling boundary layer attachment by plasma actuator withhighvoltage pulsed periodic nanosecond excitation. Actuator-induced gas velocities show near-zero values for nanosecond pulses. The measurements performed show overheating in the discharge region at fast (τ ≃ 1μs) thermalization of the plasma inputed energy. The mean values of such heating of the plasma layer can reach 70, 200, and even 400 K for 7-, 12-, and 50-ns pulse durations, respectively. The emerging shock wave together with the secondary vortex flows disturbs the main flow. The resulting pulsed-periodic disturbance causes an efficient transversal momentum transfer into the boundary layer and further flow attachment to the airfoil surface. Thus, for periodic pulsed nanosecond dielectric barrier discharge DBD, the main mechanism of impact is the energy transfer to and heating of the near-surface gas layer. The following pulse-periodic vortex movement stimulates redistribution of the main flow momentum. The experiments performed here have shown high efficiency of the given mechanism to control boundary layer separation, lift and drag force coefficients, and acoustic noise reduction in the Mach number range of 0.05 to 0.85. The design of the SDBD was typical asymmetric plasma actuator with one exposed and one covered electrodes . In our experiments, the exposed electrode was a cathode. The lower covered electrode was an anode. The experiments were carried out on the generator with a pulse length of 12 ns. Two regimes of the generator's operation were used. One was periodic, with a constant frequency of pulses fed onto the discharge gap. The other was burst mode, with impulses fed in bursts. The number of pulses in a burst varied from 1 to 100 with a repetition frequency of 100 kHz, and the time between the bursts being 1-100 ms. The number of pulses in the burst varied to produce constant averaged discharge power for various experimental conditions. The mean power in all burst regimes was equal to 25 W.The electrodes were made of 50 ?m aluminum foil. Their length was 90 cm and their widths were 15 and 10 mm for the lower and upper electrodes, respectively. The dielectric layer consisted of three PVC-films with a total thickness of 240 ?m.","PeriodicalId":343034,"journal":{"name":"2008 17th International Conference on Gas Discharges and Their Applications","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122353839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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