LaserDiagnosticsReactingFlowsLect23ME501F2011

LaserDiagnosticsReactingFlowsLect23ME501F2011 - Purdue...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Purdue University ME 501: Statistical Thermodynamics Lecture 23: Laser Diagnostic Measurement of Gas Phase Properties in Reacting and Nonreacting Flows Prof. Robert P. Lucht Room 2204, Mechanical Engineering Building School of Mechanical Engineering Purdue University West Lafayette, Indiana Lucht@purdue.edu, 765-494-5623 (Phone) Patterned Border Template 1 November 2, 2011 School of Mechanical Engineering Purdue University ME 687 Course Overview Course Objective: Develop working knowledge of laser techniques for species concentration, temperature, and velocity measurements in complex reacting media. Working Knowledge of Laser Techniques? • • • • • Laser systems Optical elements for laser diagnostic systems Species spectroscopy Interaction of laser radiation with the molecule or atom Calculation of signal levels, estimates of accuracy, precision Complex Reacting Media? • Laminar or turbulent flames, steep gradients in species concentration and temp, need high spatial, temporal resolution • Collisional environment of molecule or atom is drastically different in different parts of the flame Template 2 Patterned Border • Collisional environment can significantly affect signal levels from laser techniques School of Mechanical Engineering Purdue University Issues in Combustion Science: Why Use Laser Diagnostics? • Flame Chemistry - complex reaction mechanisms, importance of free radicals that are difficult to measure by other techniques, lasers do not perturb the flow and temperature fields nearly as much as physical probes Example: H2/O2/N2 Chemistry Initiation Reaction (1) H 2 O2 HO2 H Initiation Chain-Branching Reactions (2) H O2 O OH Chain Branching (3) O H 2 H OH P HO H (4) H 2 OH atterned Border Template 3 for (4) Except 2 (5) O H 2O OH OH School of Mechanical Engineering Purdue University Issues in Combustion Science: Why Use Laser Diagnostics? Chain Termination, 3-Body Recombination (6) H H M H 2 M (7) H OH M H 2O M Chain Termination 3 Body Recombination NO Formation: Zeldovich Thermal NOx Mechanism (8) O N 2 NO N Very Temperature Sensitive (9) N O2 NO O High Activation Energy (10) N OH NO H Lasers can be used to measure all T, all major species, O, H, OH, and NO. Temperature measurement by thermocouple compromised by Template 4 perturbs flow Patterned Border radiation, and flame chemistry. Physical probes perturb flow. School of Mechanical Engineering Purdue University Issues in Combustion Science: Why Use Laser Diagnostics? Patterned Border Template 5 School of Mechanical Engineering Purdue University Issues in Combustion Science: Why Use Laser Diagnostics? Patterned Border Template 6 School of Mechanical Engineering Purdue University Spectroscopic Spectroscopic Laser Techniques • Development of commercialized tunable lasers about 25 years ago has led to routine use of laser techniques for probing flames and plasmas. • Laser technology continues to advance, sometimes with dramatic impact on “old” laser techniques. • Recent advances with actual or potential impact on flame and/or plasma diagnostics: blue diode lasers, DFB diode lasers, injection-seeded Nd:YAG lasers with > 1 J Patterned Border Template 7 per pulse, picosecond laser systems, femtosecond laser systems, BBO crystals School of Mechanical Engineering Purdue University Rayleigh Scattering – Filtered Rayleigh Scattering Flame or Nonreacting Flow Beam Dump Single-Frequency Laser Excited Electronic Level Iodine Cell Virtual Level CCD Array Ground Electronic Level Patterned Border Template 8 Strong signal, spatially resolved, not species-specific School of Mechanical Engineering Purdue University Tunable Laser Absorption Flame or Plasma Tunable Laser System Photomultiplier or Photodiode Excited Electronic Or Vibrational Level Ground Electronic Or Vibrational Level Trans Laser Intensity Laser Frequency Patterned Border Template 9 Species-specific, quantitative, path-averaged School of Mechanical Engineering Purdue University NO Sensor System Patterned Border Template 10 School of Mechanical Engineering Purdue University Field Demonstration: Honeywell Gas Turbine Engine Patterned Border Template 11 School of Mechanical Engineering Purdue University Gas Turbine Measurements: High Load Condition Absorption 1 0.12 Absorption 2 Theory Absorption 0.1 Absorption Results x = 56ppm NO T = 750 K 2 0.08 -1 coll = 0.598 cm Scaling Factor = 1.26 0.06 0.04 Sampling Probe Results x =55-65 ppm 0.02 NO 0 -20 -15 -10 T = 712-751 K Patterned Border Template 12 -5 0 5 10 15 20 Frequency Detuning (GHz) School of Mechanical Engineering Purdue University Sensors for Detection of Trace Chemical Species Haley Molly Patterned Border Template 13 School of Mechanical Engineering Purdue University Absorption Spectroscopy with an Arc Lamp Patterned Border Template 14 Lucht, M.S. Thesis, 1979. School of Mechanical Engineering Purdue University Absorption Spectroscopy: Flat Flame Burner Measurements of OH concentration and temperature were performed as a function of height above the burner surface. Conditions along the horizontal beam path were approximately uniform within the flame. Patterned Border Template 15 Lucht, M.S. Thesis, 1979. School of Mechanical Engineering Purdue University Absorption Spectroscopy: OH Spectrum Patterned Border Template 16 Lucht, M.S. Thesis, 1979. School of Mechanical Engineering Purdue University Absorption Spectroscopy: OH Rotational Temperature Temperature was determined from a Boltzmann plot for different rotational transitions. Lucht, M.S. Thesis, 1979. Patterned Border Template 17 School of Mechanical Engineering Purdue University Laser-Induced Fluorescence (LIF) Excited Electronic Level Nonradiative Decay Frequency-Doubling Crystal Dye Laser Nd:YAG Laser Q-switched, 10-nsec pulse, 500 mJ 545 nm to 800 nm 532 nm 272 nm to 400 nm Flame Ground Electronic Level Lens Focusing Lens Beam Dump or Power Meter Collecting Lens Photomultiplier or Digital Camera Spectrometer or Filter Computer Species-selective, spatially resolved, strong signals, Patterned Border Template 18 complicated by nonradiative decay, not all species fluoresce School of Mechanical Engineering Purdue University Laser-Induced Fluorescence Spectroscopy: Two-Level Model 2 0 n1 W12 1 n2 W21 n2 A21 n1 Q12 Patterned Border Template 19 School of Mechanical Engineering n2 Q21 Purdue University Temperature Measurement from Linear LIF Excitation Scans Excited Transition a Excited Transition b W12,b W12,a T21,a T21,b A34,a Patterned Border Template 20 School of Mechanical Engineering A34,b Purdue University Temperature Measurement from Excitation Scans Patterned Border Template 21 Bechtel, Applied Optics, Vol. 18, 2100-2106 (1979) School of Mechanical Engineering Purdue University Temperature Measurement from Excitation Scans Bechtel, Applied Optics, 1979 Patterned Border Template 22 School of Mechanical Engineering Purdue University Temperature Measurement from Excitation Scans Bechtel, Applied Optics, 1979 Patterned Border Template 23 School of Mechanical Engineering Purdue University Two-Line Linear LIF Temperature Measurements Patterned Border Template 24 J. E. Dec. and J. O. Keller, 21st Symposium (International) on Combustion, 1986. School of Mechanical Engineering Purdue University Two-Line Linear LIF Temperature Measurements Patterned Border Template 25 J. E. Dec. and J. O. Keller, 21st Symposium (International) on Combustion, 1986. School of Mechanical Engineering Purdue University Two-Line Linear LIF Temperature Measurements J. E. Dec. and J. O. Keller, 21st Symposium (International) on Combustion, 1986. Patterned Border Template 26 School of Mechanical Engineering Purdue University Spontaneous Spontaneous Raman Scattering Flame or Plasma Beam Dump Fixed Frequency Laser Excited Electronic Level Virtual Level v+1, J v, J Photomultiplier or CCD Array Spectrometer Species-specific, spatially resolved, Patterned Border Template 27 quantitative, weak signal School of Mechanical Engineering Purdue University Selection Rules for Vibrational Raman Scattering v = ±1, J = 0 or ±2 Vibrational Stokes O-branch J = -2 O(3) O(2) S(1) Raman S(0) Laser Q(2) Laser Raman Laser Q(0) Q(1) Q(3) Raman Vibrational Stokes Q-branch J = 0 Vibrational Stokes S-branch J = +2 Je 3 ve=1 2 1 0 Jg 3 vg=0 Patterned Border Template 28 School of Mechanical Engineering 2 1 0 Purdue University Vibrational Raman Scattering Spectrum- Low Temperature vg = 0 ve = 1 Vibrational Stokes Q-branch J = 0 Vibrational Stokes O-branch J = -2 L Vibrational Stokes S-branch J = +2 Patterned Border Template 29 School of Mechanical Engineering Purdue University Vibrational Raman Scattering: Anti-Stokes Transitions v = -1, J = 0 or ±2 Q(3) Q(2) Q(1) Raman Vibrational Anti-Stokes Q-branch J = 0 Laser Q(0) Je 3 ve=1 2 1 0 Jg 3 vg=0 Patterned Border Template 30 School of Mechanical Engineering 2 1 0 Purdue University Vibrational Q-Branch Raman Scattering SpectrumHigh Temperature Vibrational Stokes Q-branch J = 0 Vibrational Anti-Stokes Q-branch J = 0 ve - 1 ve 1 vg + 1 vg 0 0 2 1 1 3 2 2 3 3 4 Patterned Border Template 31 L School of Mechanical Engineering 2 1 Purdue University Intensities of Raman Transitions Marshall Lapp, Raman Short Course, Sandia National Labs, Livermore, CA, 1980. Patterned Border Template 32 School of Mechanical Engineering Purdue University Raman Temperature, Multispecies Concentration Measurements Marshall Lapp, Raman Short Course, Sandia National Labs, Livermore, CA, 1980. Patterned Border Template 33 School of Mechanical Engineering Purdue University Raman Temperature, Multispecies Concentration Measurements Patterned Border Template 34 Marshall Lapp, Raman Short Course, Sandia National Labs, Livermore, CA, 1980. School of Mechanical Engineering Purdue University Triple-Pump CARS Experiments Triple-pump CARS measurements performed in laminar hydrogen/air diffusion flame. Simultaneous acquisition of single-shot H2/N2 and H2/O2 spectra demonstrated. Patterned Border Template 35 School of Mechanical Engineering Purdue University Coherent Anti-Stokes Raman Scattering (CARS) • Conventional pump “Single-Pump” CARS Stokes • Noninvasive pump • Coherent Laser-Like V Signal • Spatially and Temporally Resolved • Excellent Gas Temperature Data (especially at higher temperatures) Patterned Border Template 36 Stokes Pump1 Pump1 School of Mechanical Engineering CARS CARS Purdue University Energy Level Diagram for CARS n' n' n n 1 0 2 1 3 e 2 0 3 g or e g CARS Patterned BorderNonresonant 37 Template Four-Wave Mixing CARS 3 0 1 2 School of Mechanical Engineering NR 3 CARS Purdue University CARS Temperature Measurements Nitrogen CARS is widely used for temperature measurements in flames, sophisticated models of the nitrogen CARS spectrum have been developed. Patterned Border Template 38 School of Mechanical Engineering Purdue University CARS Temperature Measurements Patterned Border Template 39 School of Mechanical Engineering Purdue University N2 CARS Temperature Measurements in Near-Adiabatic H2/Air Flames Patterned Border Template 40 School of Mechanical Engineering Purdue University CARS Concentration Measurements: ThreeLaser CARS CARS Spectrum Frequen cy CARS Energy Level Diagram Grou nd E lectronic Level v" = 2 Patterned Border Template 41 v" = 1, J v" = 0, J School of Mechanical Engineering Purdue University Three-Laser CARS of N2/CO2 0 2 N2 CARS 1 3=0-2+1 v=1,J 2300 cm-1 v=0,J CO2 CARS 1 2 0 3=1-2+0 Patterned Border Template 42 1300 cm-1 School of Mechanical Engineering v=1,J v=0,J Purdue University Three-Laser CARS of N2/CO2 Patterned Border Template 43 School of Mechanical Engineering Purdue University Three-Laser CARS of N2/CO2 Patterned Border Template 44 School of Mechanical Engineering Purdue University Three-Laser CARS of N2/CO2 in JP8-Fueled CFM56 Combustor Patterned Border Template 45 Lucht, et al., AIAA J., Vol. 41, 679-686 (2003) School of Mechanical Engineering Purdue University Three-Laser CARS of N2/CO2 in JP8-Fueled CFM56 Combustor Patterned Border Template 46 School of Mechanical Engineering Purdue University CARS in Diamond-Forming Flames Patterned Border Template 47 Bertagnolli et al., J. Appl. Phys., Vol. 83, 2315 (1998). School of Mechanical Engineering Purdue University CARS in Diamond-Forming Flames Patterned Border Template 48 School of Mechanical Engineering Purdue University CARS in Diamond-Forming Flames Patterned Border Template 49 School of Mechanical Engineering Purdue University CARS in Diamond-Forming Flames Patterned Border Template 50 School of Mechanical Engineering Purdue University CARS in Diamond-Forming Flames H2 CARS spectrum 60 m below deposition substrate. Boltzmann plot, T = 1774 K. Patterned Border Template 51 School of Mechanical Engineering Purdue University CARS in Diamond-Forming Flames H2 CARS spectrum 530 m below deposition substrate. Boltzmann plot, T = 3185 K. Patterned Border Template 52 School of Mechanical Engineering Purdue University CARS in Diamond-Forming Flames Patterned Border Template 53 School of Mechanical Engineering Purdue University Other Laser Diagnostic Techniques • Particle Imaging Velocimetry • Resonant Four-Wave Mixing, Degenerate Four-Wave Mixing (DFWM) • Photoacoustic Spectroscopy • Resonant Photoionization Spectroscopy, Resonant Multi-Photon Photoionization Spectroscopy (REMPI) • Laser-Induced Incandescence (LII) Patterned Border Template 54 School of Mechanical Engineering ...
View Full Document

This note was uploaded on 12/26/2011 for the course ME 501 taught by Professor Na during the Fall '10 term at Purdue University-West Lafayette.

Ask a homework question - tutors are online