Author: M. FeiglPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Investigation of Nitric Oxide in High Enthalpy Air Plasma Flow Using Laser-induced Fluorescence
Author: M. Feigl31st AIAA Plasmadynamics and Lasers Conference
Author: Nitric Oxide Studies in Low Temperature Plasmas Generated with a Nanosecond Pulse Sphere Gap Electrical Discharge
Author: David Dean BurnettePublisher:
ISBN:
Category :
Languages : en
Pages : 167
Book Description
This dissertation presents studies of NO kinetics in a plasma afterglow using various nanosecond pulse discharges across a sphere gap. The discharge platform is developed to produce a diffuse plasma volume large enough to allow for laser diagnostics in a plasma that is rich in vibrationally-excited molecules. This plasma is characterized by current and voltage traces as well as ICCD and NO PLIF images that are used to monitor the plasma dimensions and uniformity. Temperature and vibrational loading measurements are performed via coherent anti-Stokes Raman spectroscopy (CARS). Absolute NO concentrations are obtained by laser-induce fluorescence (LIF) measurements, and N and O densities are found using two photon absorption laser-induced fluorescence (TALIF). For all dry air conditions studied, the NO behavior is characterized by a rapid rate of formation consistent with an enhanced Zeldovich process involving electronically-excited nitrogen species that are generated within the plasma. After several microseconds, the NO evolution is entirely controlled by the reverse Zeldovich process. These results show that under the chosen range of conditions and even in extreme instances of vibrational loading, there is no formation channel beyond ~2 [mu]sec. Both the NO formation and consumption mechanisms are strongly affected by the addition of fuel species, producing much greater NO concentrations in the afterglow.
Laser-Induced Fluorescence Measurements and Modeling of Nitric Oxide in Counterflow Diffusion Flames
Author: International Aerospace Abstracts
Author: New Trends in Instrumentation for Hypersonic Research
Author: A. BoutierPublisher: Springer Science & Business Media
ISBN: 9401118280
Category : Science
Languages : en
Pages : 612
Book Description
Because of the growing interest in hypersonic flows, the AGARD Fluid Dynamics Panel initiated a sub-working group on instrumentation for hypersonics in 1989. This sub-group, chaired by J. WENDT (VKI -Belgium), was composed of: A. BOUTIER (ONERA -France), K. BUTEFISCH (DLR -Germany), R. CATTOLICA (SANDIA Lab. -USA), V. CLINE (AEDC -USA), A. GIRARD (ONERA -France), R. McKENZIE (NASA Ames -USA), S. OCHELTREE (NASA Langley -USA) and G. SMEETS (ISL -Franco-German Inst.). As a result of several meetings, the idea came to organize this workshop, 27th April - 1st May 1992, on "New Trends in Instrumentation for Hypersonic Research", at Le Fauga-Mauzac ONERA center, in France, where the new hot-shot arc-heated facility F4, as well as a new conference building, were recently completed. This workshop has been organized in close connection with the AGARD FDP Symposium to be held in Torino 4 - 8 May 1992 on "Theoretical and Experimental Methods in Hypersonic Flows": the main conclusions and ideas expressed by the papers and during the discussions of this workshop are reported in session 7 and have been presented in Torino in a special Instrumentation session. As chairman of this workshop, I express many thanks to the Organizing Committee composed of Karl BUTEFISCH, Andre GIRARD, Stewart OCHELTREE and John WENDT for their very constructive help, leading to a meeting that was recognized to be very fruitful for all the participants.
Reactive Oxygen and Nitrogen Species Detection Produced by an Atmospheric Pressure Plasma Jet
Author: Louis FreePublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
This thesis presents a novel, asymmetrical atmospheric pressure plasma jet, that uses air as its working gas, operating in the kilohertz range. The plasma system is designed to be mobile, easily set-up in many environments and has variable controllability, such as voltage, airflow and electrode position. The initial body of work presented in the thesis relates to the design and development of the atmospheric pressure plasma jet used throughout the bulk of the thesis. The key components of the atmospheric plasma jet are introduced. Electrical measurements of the plasma were also preformed and showed that the plasma operated electrically in two modes, the so called noisy and quiet modes. Optical emission spectroscopy was preformed on the plasma jet and showed that the emission spectrum of the jet was complex, containing emissions from many species, both molecular and atomic. These species included but were not limited to atomic species of nitrogen, oxygen and hydrogen and molecular emissions from N2, O2 and OH. In addition to this, it is possible to control the emission intensities from these species by varying the control parameters of the plasma jet such as voltage, airflow and electrode distance. The observed emission spectra were noticed to be lacking in any optical features due to emissions from nitric oxide, while it was believed to be the case that the plasma jet should produce nitric oxide. To test this hypothesis the experimental method laser induced fluorescence was chosen as a means to probe or nitric oxide in the plume region of the plasma. Experimentally it was found that nitric oxide was present within the plume. In addition by again varying the control parameters of the plasma jet the absolute number density of nitric oxide within the plume of the plasma could be varied. Finally, two-photon absorption laser induced fluorescence is used to probe for atomic oxygen in the plume region of the atmospheric pressure plasma jet. Two photon absorption differs from the single photon method in that two photons are simultaneously absorbed by and used to excite the species under investigation, opening up the possibility to probe species with excitation energies that are difficult to reach using conventional lasers systems. Like, the case for nitric oxide, atomic oxygen was confirmed to be present within the plume, although it was not possible to determine an absolute number density. Likewise, by varying the control parameters a change in the trend in the intensity of the fluorescence was observed.
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