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Robert Pitz

Chair, Department of Mechanical Engineering
Professor of Mechanical Engineering


Mechanical Engineering


Intellectual Neighborhoods

Research Focus

Laser diagnostics, laminar & turbulent combustion, turbulence-chemistry interaction, pollutant formation, supersonic combustion, gas turbine combustion, rocket propulsion, Raman scattering, laser-induced fluorescence, molecular-tagging velocimetry.

Current Projects

Laser Diagnostics of Combustion Laboratory 
Professor R. W. Pitz 
Using advanced laser diagnostics, chemical reactions and pollutant generation are studied in flames that simulate combustion in gas turbines, direct injection spark ignition engines, and natural gas appliances. Chemical species and temperature are measured in laminar and turbulent flames with laser-induced Raman scattering and fluorescence. The velocity flow fields are determined with advanced molecular methods such as hydroxyl tagging velocimetry. The laser measurements are combined with computer simulations to determine the effect of aerodynamics on combustion chemistry and mixing. New laser methods are developed for imaging of chemical species, fluid mixing, and fluid velocity. Extensive experimental facilities are available including burners (laminar, turbulent), electronic cameras, lasers (excimer, dye, YAG), computers, and spectrometers.

Publications

C. A. Hall, W. D. Kulatilaka, N. Jiang, J. R. Gord, and R. W. Pitz, “Minor Species Structure of Premixed Cellular Tubular Flames, Proceedings of the Combustion Institute, 35, pp. 1107-1114, 2015

N. Grady and R. W. Pitz, “Vibrationally Excited Hydroxyl Tagging Velocimetry,” Applied Optics, 53, pp. 7182-7188, 2014

C. A. Hall, W. D. Kulatilaka, S. Roy, J. R. Gord, and R. W. Pitz, “Quantitative Atomic Hydrogen Measurements in Premixed Hydrogen Tubular Flames, Combustion and Flame161, pp. 2924-2932, 2014.

R. W. Pitz, S. T. Hu, and P. Y. Wang, “Tubular Premixed and Diffusion Flames: Effect of Stretch and Curvature,” Progress in Energy and Combustion Science, 42, pp.1-34, 2014.

M. C. Ramsey and R. W. Pitz, “Energetic Cavitation Collapse Drives Megabar Plasma,” Physical Review Letters, 110, 154301 (5 pages), 2013. 

C. A. Hall, R. W. Pitz, and P. Y. Wang, "Structural Study of Premixed Hydrogen-Air Cellular Tubular Flames," Proceedings of the Combustion Institute, vol. 34, 2013.

N. R. Grady, R. W. Pitz, C. D. Carter, K.-Y. Hsu, C. Ghodke, and S. Menon, "Supersonic Flow over a Ramped-Wall Cavity Flameholder with an Upstream Strut," Journal of Propulsion and Power, 28, 982-990, 2012.

M. C. Ramsey, R. W. Pitz, T P. Jenkins, Y. Matsutomi, C. Yoon and W. E. Anderson, "Planar 2D Velocity Measurements in the Cap Shock Pattern of a Thrust Optimized Rocket Nozzle,"  Shock Waves, 22, 39-46, 2012.

A. M. ElBaz and R. W. Pitz, "N2O Molecular Tagging Velocimetry in Experimental Air Flows," Applied Physics B, 106, 961-969, 2012.

T. S. Cheng, S. R. March, R. W. Pitz, J. A. Wehrmeyer, and J.-Y. Chen, "Laser Raman Measurements of Temperature and Species Concentration in Swirling Lifted Hydrogen Jet Diffusion Flames," International Journal of Hydrogen Energy, 37, 7900-7911, 2012.

S. W. Shopoff, P. Wang, and R. W. Pitz, "The Effect of Stretch on Cellular Formation in Non-Premixed Opposed-Flow Tubular Flames," Combustion and Flame, 158, pp. 876–884, 2011.

M. C. Ramsey and R. W. Pitz, "Template Matching for Improved Accuracy in Molecular Tagging Velocimetry," Experiments in Fluids, 51, pp. 811-819, 2011.

S. W. Shopoff, P. Wang, and R. W. Pitz, "Experimental Study of Cellular Instability and Extinction of Non-Premixed Opposed-Flow Tubular Flames," Combustion and Flame, 158, 2165-2177, 2011.

M. D. Lahr, R. W. Pitz, Z. W. Douglas, and C. D. Carter, "Hydroxyl-Tagging-Velocimetry Measurements in a Supersonic Flow over a Cavity," Journal of Propulsion and Power, 26, No. 4, pp. 790-798, 2010.

S. T. Hu and R. W. Pitz "Structural Study of Non-Premixed Tubular Hydrocarbon Flames," Combustion and Flame, 156,pp. 51-61, 2009.

S. T. Hu, R. W. Pitz, and Y. Wang "Extinction and Near-Extinction Instability of Non-Premixed Tubular Flames," Combustion and Flame, 156,pp. 90-98, 2009.

S. T. Hu, P. Y. Wang, and R. W. Pitz, "A Structural Study of Premixed Tubular Flames," Proceedings of the Combustion Institute, 32, pp.1133-1140, 2009.

Y. Wang, S. T. Hu, and R. W. Pitz, "Extinction and Cellular Instability of Premixed Tubular Flames," Proceedings of the Combustion Institute, 32, pp. 1141-1147, 2009.

B. K. Choi, W. P. Kang, I. L. Davis, J. L. Davidson, S. T. Hu and R. W. Pitz, "Thermionic electron emission from chemical vapor deposition diamond by nanosecond laser heating," Journal of Vacuum Science and Technology B, 27, pp. 557-561, 2009.

B. A. V. Bennett, Z. Cheng, R. W. Pitz, and M. D. Smooke, "Computational and Experimental Study of Oxygen-Enhanced Axisymmetric Laminar Methane Flames," Combustion Theory and Modelling, 12, pp. 497-527, 2008.

P. Y. Wang, S. T. Hu, and R. W. Pitz, "Numerical Investigation of the Curvature Effects on Diffusion Flames," Proceedings of the Combustion Institute, 31, pp. 989-996, 2007.

S. T. Hu, P. Y. Wang, R. W. Pitz, and M. D. Smooke, "Experimental and Numerical Investigation of Non-Premixed Tubular Flames," Proceedings of the Combustion Institute, 31, pp. 1093-1099, 2007.

V. R. Katta, S. Hu, P. Wang, R. W. Pitz, W. M. Roquemore and J. R. Gord, "Investigations on Double-State Behavior of the Counterflow Premixed Flame System," Proceedings of the Combustion Institute, 31, pp. 1055-1066, 2007.

T. S. Cheng, J. A. Wehrmeyer, and R. W. Pitz, "Conditional Analysis of Lifted Hydrogen Jet Diffusion Flame Experimental Data and Comparison to Laminar Flamelets," Combustion and Flame, 150, pp. 340-354, 2007.

P. Wang, J. A. Wehrmeyer, and R. W. Pitz, "Stretch Rate of Tubular Premixed Flames," Combustion and Flame, 145, pp. 401-414, 2006.

Z. Cheng, R. W. Pitz, and J. A. Wehrmeyer, "Lean and Ultralean Stretched Propane-Air Counterflow Flames," Combustion and Flame, 145, pp. 647-662, 2006.

Z. Cheng, J. A. Wehrmeyer, and R. W. Pitz, "Experimental and Numerical Studies of Opposed Jet Oxygen-Enhanced Methane Diffusion Flames," Combustion, Science and Technology, 178, pp. 2145-2163, 2006.

Z. Cheng, J. A. Wehrmeyer, and R. W. Pitz, "Lean or Ultra-Lean Stretched Planar Methane/Air Flames," Proceedings of the Combustion Institute, 30, pp. 285-293, 2005.

R. W. Pitz, M. D. Lahr , Z. W. Douglas, J. A. Wehrmeyer, S. Hu, C. D. Carter, K.-Y. Hsu, C. Lum, and M. M. Koochesfahani, "Hydroxyl Tagging Velocimetry in a Supersonic Flow over a Cavity," Applied Optics, 31, pp. 6692-6700, 2005.

L. A. Ribarov, S. Hu, J. A. Wehrmeyer, and R. W. Pitz, "Hydroxyl Tagging Velocimetry Method Optimization: Signal Intensity and Spectroscopy," Applied Optics, 31, pp. 6616-6626, 2005.

L. A. Ribarov, J. A. Wehrmeyer, S. Hu, and R. W. Pitz, "Multiline Hydroxyl Tagging Velocimetry Measurements in Reacting and Nonreacting Experimental Flows," Experiments in Fluids, 37, pp. 65-74, 2004.

D. M. Mosbacher, J. A. Wehrmeyer, R. W. Pitz, C. J. Sung, and J. L. Byrd, “Experimental and Numerical Investigation of Premixed Tubular Flames, Proceedings of the Combustion Institute, 29, pp. 1479-1486, 2002.

H. S. Xue, S. K. Aggarwal, R. J. Osborne, T. M. Brown, and R. W. Pitz, “On the Comparison of Predicted and Measured Counterflow Partially Premixed Flame Structures: Assessment of Reaction Mechanisms,” AIAA J., 40, 1236-1238, 2002.

T. C. Cole, W. A. Cole, T. M. Brown, and R. W. Pitz, “Measurement of Smoke Concentration using Degenerate Four-Wave Mixing,” Measurement, Science and Technology, 13, 464-470, 2002.

J. A. Wehrmeyer, Z. Cheng, D. M. Mosbacher, R. W. Pitz, and R. J. Osborne, “Opposed Jet Flames of Near-Limit Premixed Propane-Air Reactants vs. Hot Products, Combustion and Flame, 128, 232-241, 2002.

L. A. Ribarov, J. A. Wehrmeyer, R. W. Pitz, and R. A. Yetter, “Hydroxyl Tagging Velocimetry (HTV) in Experimental Air Flows,” Applied Physics B, 74, 175-183, 2002.

R. W. Pitz, J. A. Wehrmeyer, L. A. Ribarov, D. A. Oguss, F. Batliwala, P. A. DeBarber, S. Deusch, and P. E. Dimotakis, “Unseeded Molecular Flow Tagging in Cold and Hot Flows Using Ozone and Hydroxyl Tagging Velocimetry, Measurement, Science and Technology, 11, 1259-1271, 2000.

J. A. Wehrmeyer, L. A. Ribarov, D. A. Oguss, and R. W. Pitz, “High Temperature Flow Tagging Velocimetry with 193 nm H2O Photodissociation,” Applied Optics, 38, pp. 6912-6917, 1999.

L. A. Ribarov, J. A. Wehrmeyer, F. Batliwala, R. W. Pitz, and P. A. DeBarber, “Ozone Tagging Velocimetry using Narrowband Excimer Lasers,” AIAA Journal, 37, pp. 708-714, 1999.

T. M. Brown, R. W. Pitz, and C. J. Sung, "Oscillating Stretch Effects on the Structure and Extinction of Counterflow Diffusion Flames" Proceedings of the Combustion Institute, 27, pp. 703-710, 1998.

T. M. Brown, M. A. Tanoff, R. J. Osborne, R. W. Pitz, and M. D. Smooke, "Experimental and Numerical Investigation of Laminar Hydrogen-Air Counterflow Diffusion Flames," Combustion, Science and Technology, 129, pp. 71-88, 1997.

M. A. Tanoff, M. D. Smooke, R. J. Osborne, T. M. Brown, and R. W. Pitz, "The Sensitive Structure of Partially Premixed Methane-Air vs. Air Counterflow," Proceedings of the Combustion Institute, 26, pp. 1121-1128, Combustion Institute, Pittsburgh, 1996.

R. W. Pitz, T. M. Brown, S. P. Nandula, P. A. Skaggs, P. A. DeBarber, M. S. Brown, and J. Segall, "Unseeded Velocity Measurement by Ozone Tagging Velocimetry," Optics Letters, 21, pp. 755-757, 1996. Best Paper in Engineering Award, Vanderbilt University, 1997.

D. Trees, T. M. Brown, M. D. Smooke, K. Seshadri, G. Balakrishnan, R. W. Pitz, V. Giovangigli, and S. P. Nandula, "The Structure of Nonpremixed H2/Air Flames," Combustion, Science and Technology, 104, pp. 427-439, 1995.

T. S. Cheng and R. W. Pitz, "Simultaneous Measurements of Conserved and Reactive Scalars in Turbulent Diffusion Flames for Assessment of PDF Models," Proceedings of the Combustion Institute, 25, pp. 1133-1139, 1994.

S. P. Nandula, T. M. Brown, and R. W. Pitz, "Measurements of Scalar Dissipation in the Reaction Zones of Turbulent Nonpremixed H2-Air Flames," Combustion and Flame, 99, pp. 775-783, 1994.

T. M. Brown, R. W. Pitz, C. F. Hess, and C. P. Wood, "Pulsed Photothermal Laser Deflection for Low-Level Smoke Measurements in Jet Engine Exhausts,” Applied Physics B, 59, pp. 351-356, 1994.

T. S. Cheng, J. A. Wehrmeyer, R. W. Pitz, O. Jarrett, Jr., and G. B. Northam, "Raman Measurement of Mixing and Finite-Rate Chemistry in a Supersonic Hydrogen-Air Diffusion Flame," Combustion and Flame, 99, pp. 157-173, 1994.

S. P. Nandula, T. M. Brown, R. W. Pitz, and P. A. DeBarber, "Single-Pulse, Simultaneous Multipoint Multispecies Raman Measurements in Turbulent Nonpremixed Jet Flames," Optics Letters, 19, pp. 414-416, 1994.

R. W. Pitz, T. S. Cheng, J. A. Wehrmeyer, and C. F. Hess, "Two-Photon Predissociative Fluorescence of H2O by a KrF Laser for Concentration and Temperature Measurement," Applied Physics B, 56, pp. 94-100, 1993.

T. S. Cheng, J. A. Wehrmeyer, and R. W. Pitz, "Simultaneous Temperature and Multi-Species Measurement in a Lifted Hydrogen Diffusion Flame," Combustion and Flame, 91, pp. 323-345, 1992.

R. Villaseñor, J.-Y. Chen and R. W. Pitz, "Interaction between Chemical Reaction and Turbulence in Supersonic Nonpremixed H2-Air Combustion,” AIAA Journal, 30, pp. 2552-2554, 1992.

J. A. Wehrmeyer, T. S. Cheng, and R. W. Pitz, "Temperature Measurement in Turbulent Flames by KrF Excimer-Induced Raman Scattering," Temperature, Its Measurement and Control in Science and Industry, vol. 6, J. F. Schooley, ed., American Institute of Physics, New York, pp. 695-700, 1992.

J. A. Wehrmeyer, T. S. Cheng, and R. W. Pitz, "Raman Scattering Measurements in Flames Using a Tunable KrF Laser," Applied Optics, 31, pp. 1495-1504, 1992.

R. Villaseñor, J.-Y. Chen, and R. W. Pitz, "Modeling Ideally Expanded Supersonic Turbulent Jet Flows with Nonpremixed H2-Air Combustion," AIAA Journal, 30, pp. 395-402, 1992.

R. W. Pitz, "Low-Level Smoke Emission Measurements from a Flame by Photothermal Deflection Spectroscopy," Applied Optics, 29, pp. 2418-2423, 1990.

R. W. Pitz, J. A. Wehrmeyer, J. M. Bowling, and T. S. Cheng, "Single-Pulse Vibrational Raman Scattering by a Broadband KrF Excimer Laser in a Hydrogen-Air Flame," Applied Optics, 29, pp. 2325-2332, 1990.

M. Lapp, M. C. Drake, C. M. Penney, R. W. Pitz, "Flame Images from Pointwise Raman Data," J. Quantitative Spectroscopy & Radiative Transfer, 40, pp. 363-368, 1988.

J. O. Keller, J. L. Ellzey, R. W. Pitz, I. G. Shepherd, and J. W. Daily, "The Structure and Dynamics of Reacting Plane Mixing Layers," Experiments in Fluids, 6, pp. 33-43, 1988.

R. W. Pitz, C. M. Penney, and M. Lapp, "Acoustically Modulated Optical Transmission For Low Level Gaseous Species Measurement," Applied Optics, 26, pp. 5272-5275, 1987.

M. C. Drake, S. M. Correa, R. W. Pitz, W. Shyy and C. P. Fenimore, "Superequilibrium and Thermal Nitric Oxide Formation in Turbulent Diffusion Flames," Combustion and Flame, 69, pp. 347-365, 1987.

M. C. Drake, R. W. Pitz and W. Shyy, "Conserved Scalar Probability Density Functions in a Turbulent Jet Diffusion Flame," Journal of Fluid Mechanics, 171, pp. 27-51, 1986.

M. C. Drake, R. W. Pitz and M. Lapp, "Laser Measurements on Nonpremixed H2-Air Flames for Assessment of Turbulent Combustion Models," AIAA Journal, 24, pp. 905-917, 1986.

R. W. Pitz and M. C. Drake, "Intermittency and Conditional Averaging in a Turbulent Nonpremixed Flame by Raman Scattering," AIAA J., 24, pp. 815-822, 1986.

M. C. Drake and R. W. Pitz, "Comparison of Turbulent Diffusion Flame Measurements of OH by Planar Fluorescence and Saturated Fluorescence," Experiments in Fluids, 3, pp. 283-292, 1985.

R. P. Lucht, D. W. Sweeney, N. M. Laurendeau, M. C. Drake, M. Lapp and R. W. Pitz, "Single Pulse, Laser-Saturated Fluorescence Measurements of OH in Turbulent Nonpremixed Flames," Optics Letters, 9, pp. 90-92, 1984.

M. C. Drake, R. W. Pitz, M. Lapp, C. P. Fenimore, R. P. Lucht, D. W. Sweeney and N. M. Laurendeau, "Measurements of Superequilibrium Hydroxyl Concentrations in Turbulent Nonpremixed Flames Using Saturated Fluorescence," Proceedings of the Combustion Institute, 20, pp. 327-335, 1984.

M. C. Drake, R. W. Pitz, S. M. Correa and M. Lapp, "Nitric Oxide Formation from Thermal and Fuel-Bound Nitrogen Sources in a Turbulent Nonpremixed Syngas Flame," Proceedings of the Combustion Institute, 20, pp. 1983-1990, 1984.

S. M. Correa, M. C. Drake, R. W. Pitz and W. Shyy, "Prediction and Measurement of a Non- Equilibrium Turbulent Diffusion Flame," Proceedings of the Combustion Institute, 20, pp. 337-343, 1984.

G. Kychakoff, R. D. Howe, R. K. Hanson, M. C. Drake, R. W. Pitz, M. Lapp and C. M. Penney, "Visualization of Turbulent Flame Fronts with Planar Laser-Induced Fluorescence," Cover Article, Science, 224, pp.382-384, 1984.

R. W. Pitz and J. W. Daily, "Combustion in a Turbulent Mixing Layer Formed at a Rearward-Facing Step," AIAA Journal, 21, pp. 1565-1570, 1983.

R. W. Pitz, R. Cattolica, F. Robben, and L. Talbot, "Temperature and Density in a Hydrogen-Air Flame From Rayleigh Scattering," Combustion and Flame, 27, pp. 313-320, 1976.