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Articles 1 - 30 of 33
Full-Text Articles in Mechanical Engineering
Narrow-Linewidth Megahertz-Repetition-Rate Optical Parametric Oscillator For High-Speed Flow And Combustion Diagnostics, Naibo Jiang, Walter R. Lempert, Gary L. Switzer, Terrence R. Meyer, James R. Gord
Narrow-Linewidth Megahertz-Repetition-Rate Optical Parametric Oscillator For High-Speed Flow And Combustion Diagnostics, Naibo Jiang, Walter R. Lempert, Gary L. Switzer, Terrence R. Meyer, James R. Gord
Terrence R Meyer
We demonstrate the ability to generate ultra-high-frequency sequences of broadly wavelength-tunable, high-intensity laser pulses using a custom-built optical parametric oscillator pumped by the thirdharmonic output of a "burst-mode" Nd:YAG laser. Burst sequences consisting of 6-10 pulses separated in time by 6-10 Îs are obtained, with average total conversion efficiency from the 355 nm pump to the near-IR signal and idler wavelengths of 33%. Typical individual pulse output energy for the signal and idler beams is in the range of 4-6 mJ, limited by the available pump energy. Line narrowing is demonstrated by means of injection seeding the idler wave using …
Interference-Free Gas-Phase Thermometry At Elevated Pressure Using Hybrid Femtosecond/Picosecond Rotational Coherent Anti- Stokes Raman Scattering, Joseph D. Miller, Chloe Elizabeth Dedic, Sukesh Roy, James R. Gord, Terrence R. Meyer
Interference-Free Gas-Phase Thermometry At Elevated Pressure Using Hybrid Femtosecond/Picosecond Rotational Coherent Anti- Stokes Raman Scattering, Joseph D. Miller, Chloe Elizabeth Dedic, Sukesh Roy, James R. Gord, Terrence R. Meyer
Terrence R Meyer
Rotational-level-dependent dephasing rates and nonresonant background can lead to significant uncertainties in coherent anti-Stokes Raman scattering (CARS) thermometry under high-pressure, lowtemperature conditions if the gas composition is unknown. Hybrid femtosecond/picosecond rotational CARS is employed to minimize or eliminate the influence of collisions and nonresonant background for accurate, frequency-domain thermometry at elevated pressure. The ability to ignore these interferences and achieve thermometric errors of <5% is demonstrated for N2 and O2 at pressures up to 15 atm. Beyond 15 atm, the effects of collisions cannot be ignored but can be minimized using a short probe delay (~6.5 ps) after Raman excitation, …
Comparison Of Line-Peak And Line-Scanning Excitation In Two-Color Laser-Induced-Fluorescence Thermometry Of Oh, Stanislav Kostka, Sukesh Roy, Patrick J. Lakusta, Terrence R. Meyer, Michael W. Renfro, James R. Gord, Richard Branam
Comparison Of Line-Peak And Line-Scanning Excitation In Two-Color Laser-Induced-Fluorescence Thermometry Of Oh, Stanislav Kostka, Sukesh Roy, Patrick J. Lakusta, Terrence R. Meyer, Michael W. Renfro, James R. Gord, Richard Branam
Terrence R Meyer
Two-line laser-induced-fluorescence (LIF) thermometry is commonly employed to generate instantaneous planar maps of temperature in unsteady flames. The use of line scanning to extract the ratio of integrated intensities is less common because it precludes instantaneous measurements. Recent advances in the energy output of high-speed, ultraviolet, optical parameter oscillators have made possible the rapid scanning of molecular rovibrational transitions and, hence, the potential to extract information on gas-phase temperatures. In the current study, two-line OH LIF thermometry is performed in a wellcalibrated reacting flow for the purpose of comparing the relative accuracy of various line-pair selections from the literature and …
Laser Applications To Chemical, Security, And Environmental Analysis: Introduction To The Feature Issue, Terrence R. Meyer, Volker Ebert, Wolfgang Schade
Laser Applications To Chemical, Security, And Environmental Analysis: Introduction To The Feature Issue, Terrence R. Meyer, Volker Ebert, Wolfgang Schade
Terrence R Meyer
This Applied Optics feature issue on Laser Applications to Chemical, Security, and Environmental Analysis (LACSEA) highlights topics and papers presented at the LACSEA 2010 Twelfth Topical Meeting sponsored by the Optical Society of America.
Mhz-Rate Nitric Oxide Planar Laser-Induced Fluorescence Imaging In A Mach 10 Hypersonic Wind Tunnel, Naibo Jiang, Matthew Webster, Walter R. Lempert, Joseph D. Miller, Terrence R. Meyer, Christopher B. Ivey, Paul M. Danehy
Mhz-Rate Nitric Oxide Planar Laser-Induced Fluorescence Imaging In A Mach 10 Hypersonic Wind Tunnel, Naibo Jiang, Matthew Webster, Walter R. Lempert, Joseph D. Miller, Terrence R. Meyer, Christopher B. Ivey, Paul M. Danehy
Terrence R Meyer
Nitric oxide planar laser-induced fluorescence (NO PLIF) imaging at repetition rates as high as 1 MHz is demonstrated in the NASA Langley 31 in. Mach 10 hypersonic wind tunnel. Approximately 200 timecorrelated image sequences of between 10 and 20 individual frames were obtained over eight days of wind tunnel testing spanning two entries in March and September of 2009. The image sequences presented were obtained from the boundary layer of a 20° flat plate model, in which transition was induced using a variety of different shaped protuberances, including a cylinder and a triangle. The high-speed image sequences captured a variety …
Simultaneous High-Speed Measurement Of Temperature And Lifetime-Corrected Oh Laserinduced Fluorescence In Unsteady Flames, Terrence R. Meyer, Galen B. King, Matthew Glusenkamp, James R. Gord
Simultaneous High-Speed Measurement Of Temperature And Lifetime-Corrected Oh Laserinduced Fluorescence In Unsteady Flames, Terrence R. Meyer, Galen B. King, Matthew Glusenkamp, James R. Gord
Terrence R Meyer
A means of performing simultaneous, high-speed measurements of temperature and OH lifetime-corrected laser-induced fluorescence (LIF) for tracking unsteady flames has been developed and demonstrated. The system uses the frequency-doubled and frequency-tripled output beams of an 80 MHz mode-locked Ti:sapphire laser to achieve ultrashort laser pulses (order 2 ps) for Rayleigh-scattering thermometry at 460 nm and lifetime-corrected OH LIF at 306.5 nm, respectively. Simultaneous, high-speed measurements of temperature and OH number density enable studies of flame chemistry, heat release, and flame extinction in unsteady, strained flames where the local fluorescence-quenching environment is unknown.
Hybrid Femtosecond/Picosecond Coherent Anti-Stokes Raman Scattering For High-Speed Gas-Phase Thermometry, Joseph D. Miller, Mikhail N. Slipchenko, Terrence R. Meyer, Hans U. Stauffer, James R. Goird
Hybrid Femtosecond/Picosecond Coherent Anti-Stokes Raman Scattering For High-Speed Gas-Phase Thermometry, Joseph D. Miller, Mikhail N. Slipchenko, Terrence R. Meyer, Hans U. Stauffer, James R. Goird
Terrence R Meyer
We demonstrate hybrid femtosecond/picosecond (fs/ps) coherent anti-Stokes Raman scattering for high-speed thermometry in unsteady high-temperature flames, including successful comparisons with a time- and frequencyresolved theoretical model. After excitation of the N2 vibrational manifold with 100 fs broadband pump and Stokes beams, the Raman coherence is probed using a frequency-narrowed 2:5 ps probe beam that is time delayed to suppress the nonresonant background by 2 orders of magnitude. Experimental spectra were obtained at 500 Hz in steady and pulsed H2–air flames and exhibit a temperature precision of 2.2% and an accuracy of 3.3% up to 2400 K. Strategies for real-time gas-phase …
Probe-Pulse Optimization For Nonresonant Suppression In Hybrid Fs/Ps Coherent Anti-Stokes Raman Scattering At High Temperature, Joseph D. Miller, Mikhail N. Slipchenko, Terrence R. Meyer
Probe-Pulse Optimization For Nonresonant Suppression In Hybrid Fs/Ps Coherent Anti-Stokes Raman Scattering At High Temperature, Joseph D. Miller, Mikhail N. Slipchenko, Terrence R. Meyer
Terrence R Meyer
Hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps CARS) offers accurate thermometry at kHz rates for combustion diagnostics. In high-temperature flames, selection of probe-pulse characteristics is key to simultaneously optimizing signal-to-nonresonant-background ratio, signal strength, and spectral resolution. We demonstrate a simple method for enhancing signal-to-nonresonant-background ratio by using a narrowband Lorentzian filter to generate a time-asymmetric probe pulse with full-width-half-maximum (FWHM) pulse width of only 240 fs. This allows detection within just 310 fs after the Raman excitation for eliminating nonresonant background while retaining 45% of the resonant signal at 2000 K. The narrow linewidth is comparable to that of a …
Single-Shot Gas-Phase Thermometry Using Purerotational Hybrid Femtosecond/Picosecond Coherent Anti-Stokes Raman Scattering, Joseph D. Miller, Sukesh Roy, Mikhail N. Slipchenko, James R. Gord, Terrence R. Meyer
Single-Shot Gas-Phase Thermometry Using Purerotational Hybrid Femtosecond/Picosecond Coherent Anti-Stokes Raman Scattering, Joseph D. Miller, Sukesh Roy, Mikhail N. Slipchenko, James R. Gord, Terrence R. Meyer
Terrence R Meyer
High-repetition-rate, single-laser-shot measurements are important for the investigation of unsteady flows where temperature and species concentrations can vary significantly. Here, we demonstrate singleshot, pure-rotational, hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps RCARS) thermometry based on a kHz-rate fs laser source. Interferences that can affect nanosecond (ns) and ps CARS, such as nonresonant background and collisional dephasing, are eliminated by selecting an appropriate time delay between the 100-fs pump/Stokes pulses and the pulse-shaped 8.4-ps probe. A time- and frequency-domain theoretical model is introduced to account for rotational-level dependent collisional dephasing and indicates that the optimal probe-pulse time delay is 13.5 ps …
Fast-Framing Ballistic Imaging Of Velocity In An Aerated Spray, David Sedarsky, James Gord, Campbell Carter, Terrence R. Meyer, Mark Linne
Fast-Framing Ballistic Imaging Of Velocity In An Aerated Spray, David Sedarsky, James Gord, Campbell Carter, Terrence R. Meyer, Mark Linne
Terrence R Meyer
We describe further development of ballistic imaging adapted for the liquid core of an atomizing spray. To fully understand spray breakup dynamics, one must measure the velocity and acceleration vectors that describe the forces active in primary breakup. This information is inaccessible to most optical diagnostics, as the signal is occluded by strong scattering in the medium. Ballistic imaging mitigates this scattering noise, resolving clean shadowgram-type images of structures within the dense spray region. We demonstrate that velocity data can be extracted from ballistic images of a spray relevant to fuel-injection applications, by implementing a simple, targeted correlation method for …
Quantitative Time-Averaged Gas And Liquid Distributions Using X-Ray Fluorescence And Radiography In Atomizing Sprays, Christopher D. Radke, J. Patrick Mcmanamen, Alan L. Kastengren, Benjamin R. Halls, Terrence R. Meyer
Quantitative Time-Averaged Gas And Liquid Distributions Using X-Ray Fluorescence And Radiography In Atomizing Sprays, Christopher D. Radke, J. Patrick Mcmanamen, Alan L. Kastengren, Benjamin R. Halls, Terrence R. Meyer
Terrence R Meyer
A method for quantitative measurements of gas and liquid distributions is demonstrated using simultaneous x-ray fluorescence and radiography of both phases in an atomizing coaxial spray. Synchrotron radiation at 10.1 keV from the Advanced Photon Source at Argonne National Laboratory is used for x-ray fluorescence of argon gas and two tracer elements seeded into the liquid stream. Simultaneous time-resolved x-ray radiography combined with timeaveraged dual-tracer fluorescence measurements enabled corrections for reabsorption of x-ray fluorescence photons for accurate, line-of-sight averaged measurements of the distribution of the gas and liquid phases originating from the atomizing nozzle.
100-Ps-Pulse-Duration, 100-J Burst-Mode Laser For Khz–Mhz Flow Diagnostics, Sukesh Roy, Joseph D. Miller, Mikhail N. Slipchenko, Paul S. Hsu, Jason G. Mance, Terrence R. Meyer, James R. Gord
100-Ps-Pulse-Duration, 100-J Burst-Mode Laser For Khz–Mhz Flow Diagnostics, Sukesh Roy, Joseph D. Miller, Mikhail N. Slipchenko, Paul S. Hsu, Jason G. Mance, Terrence R. Meyer, James R. Gord
Terrence R Meyer
A high-speed, master-oscillator power-amplifier burst-mode laser with ∼100 ps pulse duration is demonstrated with output energy up to 110 J per burst at 1064 nm and second-harmonic conversion efficiency up to 67% in a KD*P crystal. The output energy is distributed across 100 to 10,000 sequential laser pulses, with 10 kHz to 1 MHz repetition rate, respectively, over 10 ms burst duration. The performance of the 100 ps burst-mode laser is evaluated and been found to compare favorably with that of a similar design that employs a conventional ∼8 ns pulse duration. The nearly transform-limited spectral bandwidth of 0.15 cm−1 …
Femtosecond Coherent Anti-Stokes Raman Scattering Measurement Of Gas Temperatures From Frequency-Spread Dephasing Of The Raman Coherence, Robert P. Lucht, Sukesh Roy, Terrence R. Meyer, James R. Gord
Femtosecond Coherent Anti-Stokes Raman Scattering Measurement Of Gas Temperatures From Frequency-Spread Dephasing Of The Raman Coherence, Robert P. Lucht, Sukesh Roy, Terrence R. Meyer, James R. Gord
Terrence R Meyer
Gas-phase temperatures and concentrations are measured from the magnitude and decay of the initial Raman coherence in femtosecond coherent anti-Stokes Raman scattering (CARS). A time-delayed probe beam is scattered from the Raman polarization induced by pump and Stokes beams to generate CARS signal; the dephasing rate of this initial coherence is determined by the temperature-sensitive frequency spread of the Raman transitions. Temperature is measured from the CARS signal decrease with increasing probe delay. Concentration is found from the ratio of the CARS and nonresonant background signals. Collision rates do not affect the determination of these quantities.
Effects Of Repetitive Pulsing On Multi-Khz Planar Laser-Induced Incandescence Imaging In Laminar And Turbulent Flames, James Bennett Michael, Prabhakar Venkateswaran, Christopher R. Shaddix, Terrence R. Meyer
Effects Of Repetitive Pulsing On Multi-Khz Planar Laser-Induced Incandescence Imaging In Laminar And Turbulent Flames, James Bennett Michael, Prabhakar Venkateswaran, Christopher R. Shaddix, Terrence R. Meyer
Terrence R Meyer
Planar laser-induced incandescence (LII) imaging is reported at repetition rates up to 100 kHz using a burst-mode laser system to enable studies of soot formation dynamics in highly turbulent flames. To quantify the accuracy and uncertainty of relative soot volume fraction measurements, the temporal evolution of the LII field in laminar and turbulent flames is examined at various laser operating conditions. Under high-speed repetitive probing, it is found that LII signals are sensitive to changes in soot physical characteristics when operating at high laser fluences within the soot vaporization regime. For these laser conditions, strong planar LII signals are observed …
Dual-Pump Vibrational/Rotational Femtosecond/ Picosecond Coherent Anti-Stokes Raman Scattering Temperature And Species Measurements, Chloe Elizabeth Dedic, Joseph D. Miller, Terrence R. Meyer
Dual-Pump Vibrational/Rotational Femtosecond/ Picosecond Coherent Anti-Stokes Raman Scattering Temperature And Species Measurements, Chloe Elizabeth Dedic, Joseph D. Miller, Terrence R. Meyer
Terrence R Meyer
A method for simultaneous ro-vibrational and pure-rotational hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps CARS) is presented for multi-species detection and improved temperature sensitivity from room temperature to flame conditions. N2∕CH4 vibrational and N2∕O2∕H2 rotational Raman coherences are excited simultaneously using fs pump pulses at 660 and 798 nm, respectively, and a common fs Stokes pulse at 798 nm. A fourth narrowband 798 nm ps pulse probes all coherence states at a time delay that minimizes nonresonant background and the effects of collisions. The transition strength is concentration dependent, while the distribution among observed transitions is related to temperature through …
Micro-Optical Initiation Of Nanoenergetic Materials Using A Temporally Tailored Variable-Pulse-Width Laser, Mikhail N. Slipchenko, Clint E. Moody, Joseph D. Miller, Sukesh Roy, James R. Gord, Terrence R. Meyer
Micro-Optical Initiation Of Nanoenergetic Materials Using A Temporally Tailored Variable-Pulse-Width Laser, Mikhail N. Slipchenko, Clint E. Moody, Joseph D. Miller, Sukesh Roy, James R. Gord, Terrence R. Meyer
Terrence R Meyer
Nanoenergetic materials can provide a significant enhancement in the rate of energy release as compared with microscale materials. The energy-release rate is strongly dependent not only on the primary particle size but also on the level of agglomeration, which is of particular interest for the inclusion of nanoenergetics in practical systems where agglomeration is desired or difficult to avoid. Unlike studies of nanoparticles or nanometer-size aggregates, which can be conducted with ultrafast or nanosecond lasers assuming uniform heating, microscale aggregates of nanoparticles are more sensitive to the thermophysical time scale of the heating process. To allow control over the rate …
Quantitative Measurement Of Binary Liquid Distributions Using Multiple-Tracer X-Ray Fluorescence And Radiography, Benjamin R. Halls, Terrence R. Meyer, Alan L. Kastengren
Quantitative Measurement Of Binary Liquid Distributions Using Multiple-Tracer X-Ray Fluorescence And Radiography, Benjamin R. Halls, Terrence R. Meyer, Alan L. Kastengren
Terrence R Meyer
The complex geometry and large index-of-refraction gradients that occur near the point of impingement of binary liquid jets present a challenging environment for optical interrogation. A simultaneous quadruple-tracer x-ray fluorescence and line-of-sight radiography technique is proposed as a means of distinguishing and quantifying individual liquid component distributions prior to, during, and after jet impact. Two different pairs of fluorescence tracers are seeded into each liquid stream to maximize their attenuation ratio for reabsorption correction and differentiation of the two fluids during mixing. This approach for instantaneous correction of xray fluorescence reabsorption is compared with a more time-intensive approach of using …
100 Khz Thousand-Frame Burst-Mode Planar Imaging In Turbulent Flames, James B. Michael, Prabhakar Venkateswaran, Joseph D. Miller, Mikhail N. Slipchenko, James R. Gord, Sukesh Roy, Terrence R. Meyer
100 Khz Thousand-Frame Burst-Mode Planar Imaging In Turbulent Flames, James B. Michael, Prabhakar Venkateswaran, Joseph D. Miller, Mikhail N. Slipchenko, James R. Gord, Sukesh Roy, Terrence R. Meyer
Terrence R Meyer
High-repetition-rate, burst-mode lasers can achieve higher energies per pulse compared with continuously pulsed systems, but the relatively few number of laser pulses in each burst has limited the temporal dynamic range of measurements in unsteady flames. A fivefold increase in the range of timescales that can be resolved by burst-mode laser-based imaging systems is reported in this work by extending a hybrid diode- and flashlamp-pumped Nd:YAGbased amplifier system to nearly 1000 pulses at 100 kHz during a 10 ms burst. This enables an unprecedented burstmode temporal dynamic range to capture turbulent fluctuations from 0.1 to 50 kHz in flames of …
Spatially And Temporally Resolved Temperature And Shock-Speed Measurements Behind A Laser-Induced Blast Wave Of Energetic Nanoparticles, Sukesh Roy, Naibo Jiang, Han U. Stauffer, Jacob B. Schmidt, Waruna D. Kulatilaka, Terrence R. Meyer, Christopher E. Bunker, James R. Gord
Spatially And Temporally Resolved Temperature And Shock-Speed Measurements Behind A Laser-Induced Blast Wave Of Energetic Nanoparticles, Sukesh Roy, Naibo Jiang, Han U. Stauffer, Jacob B. Schmidt, Waruna D. Kulatilaka, Terrence R. Meyer, Christopher E. Bunker, James R. Gord
Terrence R Meyer
Spatially and temporally resolved temperature measurements behind an expanding blast wave are made using picosecond (ps) N2 coherent anti-Stokes Raman scattering (CARS) following laser flash heating of mixtures containing aluminum nanoparticles embedded in ammonium-nitrate oxidant. Production-front ps-CARS temperatures as high as 3600 ± 180 K-obtained for 50-nm-diameter commercially produced aluminum-nanoparticle samples-are observed. Time-resolved shadowgraph images of the evolving blast waves are also obtained to determine the shock-wave position and corresponding velocity. These results are compared with near-field blast-wave theory to extract relative rates of energy release for various particle diameters and passivating-layer compositions.
A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel
A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel
Terrence R Meyer
The opaque nature of many multiphase flows has long posed a significant challenge to the visualization and measurement of desired characteristics. To overcome this difficulty, X-ray imaging, both in the form of radiography and computed tomography, has been used successfully to quantify various multiphase flow phenomena. However, the relatively low temporal resolution of typical X-ray systems limit their use to moderately slow flows and time-average values. This paper discusses the development of an X-ray detection system capable of high-speed radiographic imaging that can be used to visualize multiphase flows. Details of the hardware will be given and then applied to …
Developing Inquiry-Based Laboratory Exercises For A Mechanical Engineering Curriculum, Sriram Sundararajan, Leann E. Faidley, Terrence R. Meyer
Developing Inquiry-Based Laboratory Exercises For A Mechanical Engineering Curriculum, Sriram Sundararajan, Leann E. Faidley, Terrence R. Meyer
Terrence R Meyer
This paper describes the development of two inquiry-based experiments in a mechanical engineering curriculum at a land grant research-intensive university, aimed at providing students with the opportunity to design and perform experiments. One experiment in engineering measurements (system behavior) and one experiment in fluid dynamics were developed. In each case, students working on teams were posed with a scenario and question to answer. For example, in the system dynamics experiment, students were asked to verify that a thermal system and electrical system were mechanically equivalent systems. In the fluid dynamics experiment, students were asked to investigate drag coefficients for flow …
Quantitative Measurement Of Binary Liquid Distributions Using Multiple-Tracer X-Ray Fluorescence And Radiography, Terrence R. Meyer
Quantitative Measurement Of Binary Liquid Distributions Using Multiple-Tracer X-Ray Fluorescence And Radiography, Terrence R. Meyer
Terrence R Meyer
No abstract provided.
100-Ps-Pulse-Duration, 100-Joule Burst-Mode Laser For Khz–Mhz Flow Diagnostics, Terrence R. Meyer
100-Ps-Pulse-Duration, 100-Joule Burst-Mode Laser For Khz–Mhz Flow Diagnostics, Terrence R. Meyer
Terrence R Meyer
No abstract provided.
Single-Shot Gas-Phase Thermometry Using Pure-Rotational Hybrid Femtosecond/Picosecond Coherent Anti-Stokes Raman Scattering, Terrence R. Meyer
Single-Shot Gas-Phase Thermometry Using Pure-Rotational Hybrid Femtosecond/Picosecond Coherent Anti-Stokes Raman Scattering, Terrence R. Meyer
Terrence R Meyer
© 2011 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited
Velocity Imaging For The Liquid–Gas Interface In The Near Field Of An Atomizing Spray: Proof Of Concept, David L. Sedarsky, Megan E. Paciaroni, Mark A. Linne, James R. Gord, Terrence R. Meyer
Velocity Imaging For The Liquid–Gas Interface In The Near Field Of An Atomizing Spray: Proof Of Concept, David L. Sedarsky, Megan E. Paciaroni, Mark A. Linne, James R. Gord, Terrence R. Meyer
Terrence R Meyer
We describe adaptation of ballistic imaging for the liquid core of an atomizing spray. To describe unambiguously the forces that act to break apart the liquid core in a spray, one must directly measure the force vectors themselves. It would be invaluable, therefore, to obtain velocity and acceleration data at the liquid-gas interface. We employ double-image ballistic imaging to extract velocity information through the application of image analysis algorithms. This method is shown to be effective for liquid phase droplet features within the resolution limit of the imaging system. In light of these results, it is clear that a three- …
Broadband Coherent Anti-Stokes Raman Scattering Spectroscopy Of Nitrogen Using A Picosecond Modeless Dye Laser, Sukesh Roy, Terrence R. Meyer, James R. Gord
Broadband Coherent Anti-Stokes Raman Scattering Spectroscopy Of Nitrogen Using A Picosecond Modeless Dye Laser, Sukesh Roy, Terrence R. Meyer, James R. Gord
Terrence R Meyer
Broadband picosecond coherent anti-Stokes Raman scattering (CARS) spectroscopy of nitrogen is demonstrated using 145-ps pump and probe beams and a 115-ps Stokes beam with a spectral bandwidth of 5 nm. This is, to our knowledge, the first demonstration of broadband CARS using subnanosecond lasers. The short temporal envelope of the laser pulses and the broadband spectral nature of the Stokes beam will enable nonresonant-background-free, single-shot, or time-dependent spectroscopy in high-pressure or hydrocarbon-rich environments. Successful correlation of room-temperature broadband picosecond N2 CARS with a theoretical spectrum is presented.
Measurements Of Oh Mole Fraction And Temperature Up To 20 Khz By Using A Diode-Laser-Based Uv Absorption Sensor, Terrence Meyer, Sukesh Roy, Thomas Anderson, Joseph Miller, Vlswanath Katta, Robert Lucht, James Gord
Measurements Of Oh Mole Fraction And Temperature Up To 20 Khz By Using A Diode-Laser-Based Uv Absorption Sensor, Terrence Meyer, Sukesh Roy, Thomas Anderson, Joseph Miller, Vlswanath Katta, Robert Lucht, James Gord
Terrence R Meyer
Diode-laser-based sum-frequency generation of ultraviolet (UV) radiation at 313.5 nm was utilized for high-speed absorption measurements of OH mole fraction and temperature at rates up to 20 kHz. Sensor performance was characterized over a wide range of operating conditions in a 25.4 mm path-length, steady, C2H4-air diffusion flame through comparisons with coherent anti-Stokes Raman spectroscopy (CARS), planar laser-induced fluorescence (PLIF), and a two-dimensional numerical simulation with detailed chemical kinetics. Experimental uncertainties of 5% and 11% were achieved for measured temperatures and OH mole fractions, respectively, with standard deviations of <3% at 20 kHz and an OH detection limit of <1 part per million in a l m path length. After validation in a steady flame, high-speed diode-laser-based measurements of OH mole fraction and temperature were demonstrated for the first time in the unsteady exhaust of a liquid-fueled, swirl-stabilized combustor. Typical agreement of 5% was achieved with CARS temperature measurements at various fuel/air ratios, and sensor precision was sufficient to capture oscillations of temperature and OH mole fraction for potential use with multiparameter control strategies in combustors of practical interest.
Ballistic Imaging Of The Liquid Core For A Steady Jet In Crossflow, Mark A. Linne, Megan Paciaroni, James R. Gord, Terrence R. Meyer
Ballistic Imaging Of The Liquid Core For A Steady Jet In Crossflow, Mark A. Linne, Megan Paciaroni, James R. Gord, Terrence R. Meyer
Terrence R Meyer
A time-gated ballistic imaging instrument is used to obtain high-spatial-resolution, single-shot images of the liquid core in a water spray issuing into a gaseous crossflow. We describe further development of the diagnostic technique to improve spatial resolution and present images and statistics for various jets under crossflow experimental conditions (different Weber numbers). Series of these images reveal a near-nozzle flow field undergoing breakup and subsequent droplet formation by stripping. One can also detect signatures of spatially periodic behavior in the liquid core and formation of small voids during breakup.
10 Khz Detection Of Co2 At 4.5 Um By Using Tunable Diode-Laser-Based Difference-Frequency Generation, Terrence R. Meyer, Sukesh Roy, Thomas N. Anderson, Robert P. Lucht, Rodolfo Barron-Jimenez, James R. Gord
10 Khz Detection Of Co2 At 4.5 Um By Using Tunable Diode-Laser-Based Difference-Frequency Generation, Terrence R. Meyer, Sukesh Roy, Thomas N. Anderson, Robert P. Lucht, Rodolfo Barron-Jimenez, James R. Gord
Terrence R Meyer
A compact, high-speed tunable, diode-laser-based mid-infrared (MIR) laser source has been developed for absorption spectroscopy of CO2 at rates up to 10 kHz. Radiation at 4.5 um with a mode-hop-free tuning range of 80 GHz is generated by difference-frequency mixing the 860 nm output of a distributed-feedback diode laser with the 1064 nm output of a diode-pumped Nd:YAG laser in a periodically poled lithium niobate crystal. MIR absorption spectroscopy of CO2 with a detection limit of 44 ppm m at 10 kHz is demonstrated in a C2H4-air laminar diffusion flame and in the exhaust of a liquid-fueled model gas-turbine combustor.
Diode-Laser-Based Ultraviolet-Absorption Sensor For High-Speed Detection Of The Hydroxyl Radical, Thomas N. Anderson, Robert P. Lucht, Terrence R. Meyer, Sukesh Roy, James R. Gord
Diode-Laser-Based Ultraviolet-Absorption Sensor For High-Speed Detection Of The Hydroxyl Radical, Thomas N. Anderson, Robert P. Lucht, Terrence R. Meyer, Sukesh Roy, James R. Gord
Terrence R Meyer
A new diode-laser-based UV-absorption sensor for high-speed detection of the hydroxyl radical (OH) is described. The sensor is based on sum-frequency generation of UV radiation at 313.5 nm by mixing the output of a 763-nm distributed-feedback diode laser with that of a 532-nm high-power, diode-pumped, frequency-doubled Nd:YVO4 laser in a B-barium borate crystal.