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Full-Text Articles in Mechanical Engineering
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 …
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 …