Download or read book Temperature Measurements in Gases Using Planar Laser induced Fluorescence Imaging of NO and O2 written by Michael Poliang Lee and published by . This book was released on 1991 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three techniques based on Planar Laser-Induced Fluorescence (PLIF) have been developed for the measurement of 2-D temperature fields in gaseous flows. The methods are applicable to a wide range of aerodynamic and combustion flows.

Download or read book Temperature Measurements in Gases Using Planar Laser induced Fluorescence Imaging of NO and O p2 s written by Michael Poliang Lee and published by . This book was released on 19?? with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three techniques based on Planar Laser-Induced Fluorescence (PLIF) have been developed for the measurement of 2-D temperature fields in gaseous flows. The methods are applicable to a wide range of aerodynamic and combustion flows.

Download or read book Single pulse Gas Thermometry at Low Temperatures Using Two photon Laser induced Fluorescence in NO N2 Mixtures written by and published by . This book was released on 1983 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Temperature Measurement in High temperature Gases Using KrF Laser induced O2 Fluorescence written by Jay Henderson Grinstead and published by . This book was released on 1995 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Induced Fluorescence Measurements and Modeling of Nitric Oxide in High Pressure Premixed Flames written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-25 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced fluorescence (LIF) has been applied to the quantitative measurement of nitric oxide (NO) in premixed, laminar, high-pressure flames. Their chemistry was also studied using three current kinetics schemes to determine the predictive capabilities of each mechanism with respect to NO concentrations. The flames studied were low-temperature (1600 less than T less than 1850K) C2H6/O2/N2 and C2H6/O2/N2 flames, and high temperature (2100 less than T less than 2300K) C2H6/O2/N2 flames. Laser-saturated fluorescence (LSF) was initially used to measure the NO concentrations. However, while the excitation transition was well saturated at atmospheric pressure, the fluorescence behavior was basically linear with respect to laser power at pressures above 6 atm. Measurements and calculations demonstrated that the fluorescence quenching rate variation is negligible for LIF measurements of NO at a given pressure. Therefore, linear LIF was used to perform quantitative measurements of NO concentration in these high-pressure flames. The transportability of a calibration factor from one set of flame conditions to another also was investigated by considering changes in the absorption and quenching environment for different flame conditions. The feasibility of performing LIF measurements of (NO) in turbulent flames was studied; the single-shot detection limit was determined to be 2 ppm. Reisel, John R. and Laurendeau, Normand M. Unspecified Center NASA-CR-195404, E-9248, NAS 1.26:195404 NAG3-1038; RTOP 537-02-20...

Download or read book Temperature measurements in hypersonic air flows using laser induced O2 fluorescence written by Gabriel Laufer and published by . This book was released on 1988 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Induced Fluorescence Measurements and Modeling of Nitric Oxide in Counterflow Diffusion Flames written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-27 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: The feasibility of making quantitative nonintrusive NO concentration ([NO]) measurements in nonpremixed flames has been assessed by obtaining laser-induced fluorescence (LIF) measurements of [NO] in counterflow diffusion flames at atmospheric and higher pressures. Comparisons at atmospheric pressure between laser-saturated fluorescence (LSF) and linear LIF measurements in four diluted ethane-air counterflow diffusion flames with strain rates from 5 to 48/s yielded excellent agreement from fuel-lean to moderately fuel-rich conditions, thus indicating the utility of a model-based quenching correction technique, which was then extended to higher pressures. Quantitative LIF measurements of [NO] in three diluted methane-air counterflow diffusion flames with strain rates from 5 to 35/s were compared with OPPDIF model predictions using the GRI (version 2.11) chemical kinetic mechanism. The comparisons revealed that the GRI mechanism underpredicts prompt-NO by 30-50% at atmospheric pressure. Based on these measurements, a modified reaction rate coefficient for the prompt-NO initiation reaction was proposed which causes the predictions to match experimental data. Temperature measurements using thin filament pyrometry (TFP) in conjunction with a new calibration method utilizing a near-adiabatic H2-air Hencken burner gave very good comparisons with model predictions in these counterflow diffusion flames. Quantitative LIF measurements of [NO] were also obtained in four methane-air counterflow partially-premixed flames with fuel-side equivalence ratios (phi(sub B)) of 1.45, 1.6, 1.8 and 2.0. The measurements were in excellent agreement with model predictions when accounting for radiative heat loss. Spatial separation between regions dominated by the prompt and thermal NO mechanisms was observed in the phi(sub B) = 1.45 flame. The modified rate coefficient proposed earlier for the prompt-NO initiation reaction improved agreement between code predictions and measurements in the re

Download or read book Quantitative Plif Imaging in High Pressure Combustion written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-11-06 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the final report for a research project aimed at developing planar laser-induced fluorescence (PLIF) techniques for quantitative 2-D species imaging in fuel-lean, high-pressure combustion gases, relevant to modem aircraft gas turbine combustors. The program involved both theory and experiment. The theoretical activity led to spectroscopic models that allow calculation of the laser-induced fluorescence produced in OH, NO and 02 for arbitrary excitation wavelength, pressure, temperature, gas mixture and laser linewidth. These spectroscopic models incorporate new information on line- broadening, energy transfer and electronic quench rates. Extensive calculations have been made with these models in order to identify optimum excitation strategies, particularly for detecting low levels (ppm) of NO in the presence of large 02 mole fractions (10% is typical for the fuel-lean combustion of interest). A promising new measurement concept has emerged from these calculations, namely that excitation at specific wavelengths, together with detection of fluorescence in multiple spectral bands, promises to enable simultaneous detection of both NO (at ppm levels) and 02 or possibly NO, 02 and temperature. Calculations have been made to evaluate the expected performance of such a diagnostic for a variety of conditions and choices of excitation and detection wavelengths. The experimental effort began with assembly of a new high-pressure combustor to provide controlled high-temperature and high-pressure combustion products. The non-premixed burner enables access to postflame gases at high temperatures (to 2000 K) and high pressures (to 13 atm), and a range of fuel-air equivalence ratios. The chamber also allowed use of a sampling probe, for chemiluminescent detection of NO/NO2, and thermocouples for measurement of gas temperature. Experiments were conducted to confirm the spectroscopic models for OH, NO and 02. Hanson, R. K. Glenn Research Center...

Download or read book Single pulse Temperature Measurements in a Turbulent Flame Using KrF Laser induced O2 Fluorescence written by Jay H. Grinstead and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Determination of Oxygen and Nitrogen Recombination Coefficients at Elevated Temperature Using Laser induced Fluorescence written by Jochen Marschall and published by . This book was released on 1997 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Low pressure Laser Induced Fluorescence for Measuring Temperature Profiles in a Rarefied Gas written by Thomas Orville Leimkuehler and published by . This book was released on 2000 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a rarefied gas, heat transfer in the transition regime (i.e., Knudsen number range of 0.1 to 10) is affected by molecular as well as gas-surface interactions. Theoretical results for the heat transfer can be obtained through computational solutions of the Boltzmann equation and appropriate intermolecular and gas-surface interaction models. As with all computational and phenomenological models, experimental verification is required. In this work, a low-pressure laser induced fluorescence (LIF) technique is investigated for measuring temperature profiles between parallel flat plates, and the results are compared to theoretical predictions. Iodine vapor is used as the gas medium due to its attractive spectral properties. Two surfaces of a closed, short cylindrical iodine cell are employed as a parallel flat plate geometry and are maintained at different temperatures. Cold and hot plate temperature combinations of (1) 20°C and 70°C, respectively, and (2) 20°C and 115°C, respectively, were used. Calibration measurements were performed at uniform temperatures of 45°C and 70°C, Solid iodine stem temperatures of 0°C and -20°C, corresponding to pressures of 30 mtorr and 3 mtorr, respectively, and Knudsen numbers of 0.05 and 0.5, respectively, were investigated. The data shows the expected trends, indicating observable temperature jumps at the surfaces and matching well with the theoretical predictions in the bulk gas. Deviations from the theory were largest near the surface, possibly a result of the limitations of the theoretical models for this particular experimental case. In addition, problems stemming from fluctuations of the chamber pressure as well as attenuation of the excitation laser beam affected collection of definitive temperature profile measurements. However, much progress with the low-pressure LIF technique has been made, and the technique continues to look promising for obtaining accurate and reliable temperature profile measurements in the transition regime.

Download or read book Measurement of Gas Density and Temperature Profiles in UF6 Using Laser Induced Fluorescence written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser induced fluorescence (LIF) can be used to determine the pressure and temperature of an UF6 gas sample. An external pulsed laser is used to excite the gas and a multichannel fiber optics system simultaneously collects fluorescence signals emanating from a number of points in the gas. The signals are digitized and presented to a minicomputer for data reduction. Both fluorescence intensity and lifetime are used to deduce temperature and pressure. The LIF probe system is described. Analysis of the data is discussed, and representative results are presented.

Download or read book Spectroscopic Gas Temperature Measurement written by Richard H. Tourin and published by . This book was released on 1966 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Induced Fluorescence Gas Puff Density Measurements written by Matthew Thomas Evans and published by . This book was released on 2012 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The double gas puff valve is a device used to inject a supersonic puff of gas to act as a load in z-pinch plasma implosions. The purpose of the annular gas shells is to mimic a cylindrical column along the z-axis in efforts to reduce Rayleigh-Taylor instability. However before integration of the valve into the zpinch pulsed power machine the gas profile needs to be examined. Tuning the density of the gas to fit specific profiles leads to improvement in plasma radiative sources and yields. The axial uniformity of the cylindrical gas column is highly dependent on the nozzle characteristics and shape. Performance is then determined by the density, speed, and symmetry of the gas column. Measurement of the density distribution is performed using a spectroscopic measuring technique called laser-induced fluorescence. LIF is a 1-dimensional imaging technique that maps the concentration of atoms with the aid of a tracer. LIF and the 2-dimensional counterpart planar laser-induced fluorescence (PLIF) examine the gas flow in the r-z plane with sub-millimeter resolution. The tracer molecule fluoresces due to excitation by a laser beam. The fluorescence signal is imaged using a streak camera and a charge-coupled-device (CCD) in combination. The method also allows the study of gas puff reliability. Any differences between gas shells can then be examined and interpreted with reliable certainty. Imaging software is used to determine the density from the intensity of the fluorescence images. A detail account of the process is illustrated in this study. A control system was constructed for operations of the gas puff valve in both LIF and z-pinch experiments. The pressure system is designed to tailor specific profiles as needed. The LIF system is detailed along with any components built for the gas puff valve. Results of these measurements serve to verify the uniformity of flow and determine the density distribution of the gas puff.

Download or read book A Proposal for Measurements of Density and Temperature Distribution in a Rarefied Gas Confined Between Two Parallel Plates of Different Temperature Using Laser indused Fluorescence written by Timothy R. Weinstock and published by . This book was released on 1992 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this proposal is to carry out precise density and temperature measurements for a rarefied gas enclosed between two parallel plates, which are at different temperatures. The experiment will be performed by using a laser-induced fluorescence measurement technique and will be conducted for system Knudsen numbers ranging from 0.1 to 10.0. To accomodate this range, the chamber pressure will be controlled from 10−2 to 10−4 torr and the plate spacing will be 5 cm. A Coherent model 899-29 ring dye laser system will excite two transitions occuring at different wavelengths for pure iodine gas present in the vacuum chamber. The subsequent fluorescent intensities of the gas excited by the laser will be detected by an Oriel photomultiplier tube based light measurement system. The fluorescence line shapes will be anallyzed by the laser system's AUTO SCAN software. We will obtain experimental data on the temperature and density distriubtions from the intensities and lineshapes obtained at a series of points located along a line normal to the plate surfaces. The experimental data will then be compared to the existing theories which describe these distributions for the Knudsen number range being analyzed.

Download or read book Combined Planar Measurements of Velocity and Pressure Fields in Compressible Gas Flows Using Laser induced Iodine Fluorescence written by Bernhard Hiller and published by . This book was released on 1986 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book OH Planar Laser Induced Fluorescence PLIF Measurements for the Study of High Pressure Flames written by Sarah Tedder and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: