Development And Application Of Non Linear Mid Infrared Laser Spectroscopy For Combustion Diagnostics
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Author | : |
Publisher | : |
Total Pages | : 84 |
Release | : 2012 |
Genre | : |
ISBN | : 9789174733563 |
Download Development and Application of Non-linear Mid-infrared Laser Spectroscopy for Combustion Diagnostics Book in PDF, Epub and Kindle
Author | : Jagdish P. Singh |
Publisher | : Elsevier |
Total Pages | : 455 |
Release | : 2007-10-03 |
Genre | : Science |
ISBN | : 0080551017 |
Download Laser-Induced Breakdown Spectroscopy Book in PDF, Epub and Kindle
Laser induced breakdown spectroscopy (LIBS) is basically an emission spectroscopy technique where atoms and ions are primarily formed in their excited states as a result of interaction between a tightly focused laser beam and the material sample. The interaction between matter and high-density photons generates a plasma plume, which evolves with time and may eventually acquire thermodynamic equilibrium. One of the important features of this technique is that it does not require any sample preparation, unlike conventional spectroscopic analytical techniques. Samples in the form of solids, liquids, gels, gases, plasmas and biological materials (like teeth, leaf or blood) can be studied with almost equal ease. LIBS has rapidly developed into a major analytical technology with the capability of detecting all chemical elements in a sample, of real- time response, and of close-contact or stand-off analysis of targets. The present book has been written by active specialists in this field, it includes the basic principles, the latest developments in instrumentation and the applications of LIBS . It will be useful to analytical chemists and spectroscopists as an important source of information and also to graduate students and researchers engaged in the fields of combustion, environmental science, and planetary and space exploration. * Recent research work* Possible future applications* LIBS Principles
Author | : Timothy Robert Brewer |
Publisher | : |
Total Pages | : 352 |
Release | : 1996 |
Genre | : |
ISBN | : |
Download Ultrafast Spectroscopy: I. Combustion and Molecular Dynamics II. Development of Tunable Mid-infared Laser System to Study Vibrational Dynamics Book in PDF, Epub and Kindle
Author | : Katherine Louise Richard |
Publisher | : |
Total Pages | : 484 |
Release | : 2007 |
Genre | : High resolution spectroscopy |
ISBN | : |
Download Development of a Laser System for High Resolution Non-linear Infrared Spectroscopy Book in PDF, Epub and Kindle
Author | : Alan C. Eckbreth |
Publisher | : CRC Press |
Total Pages | : 630 |
Release | : 2022-01-27 |
Genre | : Technology & Engineering |
ISBN | : 1000124622 |
Download Laser Diagnostics for Combustion Temperature and Species Book in PDF, Epub and Kindle
This book examines the variety of potential laser diagnostic techniques and presents a considerable theoretical foundation elucidating physics relevant to the laser diagnostics. It explains the Raman-based approaches for major species and temperature measurements.
Author | : M. J. New |
Publisher | : |
Total Pages | : 466 |
Release | : 1996 |
Genre | : Combustion engineering |
ISBN | : |
Download Laser Development and Novel Applications of Polarization Spectroscopy for Combustion Diagnostics Book in PDF, Epub and Kindle
Author | : Stefan Welzel |
Publisher | : Logos Verlag Berlin GmbH |
Total Pages | : 198 |
Release | : 2009 |
Genre | : Science |
ISBN | : 3832523456 |
Download New Enhanced Sensitivity Infrared Laser Spectroscopy Techniques Applied to Reactive Plasmas and Trace Gas Detection Book in PDF, Epub and Kindle
Infrared laser absorption spectroscopy (IRLAS) employing both tuneable diode and quantum cascade lasers (TDLs, QCLs) has been applied with both high sensitivity and high time resolution to plasma diagnostics and trace gas measurements. TDLAS combined with a conventional White type multiple pass cell was used to detect up to 13 constituent molecular species in low pressure Ar/H2/N2/O2 and Ar/CH4/N2/O2 microwave discharges, among them the main products such as H2O, NH3, NO and CO, HCN respectively. The hydroxyl radical has been measured in the mid infrared (MIR) spectral range in-situ in both plasmas yielding number densities of between 1011 ... 1012 cm-3. Strong indications of surface dominated formation of either NH3 or N2O and NO were found in the H2-N2-O2 system. In methane containing plasmas a transition between deposition and etching conditions and generally an incomplete oxidation of the precursor were observed. The application of QCLs for IRLAS under low pressure conditions employing the most common tuning approaches has been investigated in detail. A new method of analysing absorption features quantitatively when the rapid passage effect is present is proposed. If power saturation is negligible, integrating the undisturbed half of the line profile yields accurate number densities without calibrating the system. By means of a time resolved analysis of individual chirped QCL pulses the main reasons for increased effective laser line widths could be identified. Apart from the well-known frequency down chirp non-linear absorption phenomena and bandwidth limitations of the detection system may significantly degrade the performance and accuracy of inter pulse spectrometers. The minimum analogue bandwidth of the entire system should normally not fall below 250 MHz. QCLAS using pulsed lasers has been used for highly time resolved measurements in reactive plasmas for the first time enabling a time resolution down to about 100 ns to be achieved. A temperature increase of typically less than 50 K has been established for pulsed DC discharges containing Ar/N2 and traces of NO. The main NO production and depletion reactions have been identified from a comparison of model calculations and time resolved measurements in plasma pulses of up to 100 ms. Considerable NO struction is observed after 5 ... 10 ms due to the impact of N atoms. Finally, thermoelectrically cooled pulsed and continuous wave (cw) QCLs have been employed for high finesse cavity absorption spectroscopy in the MIR. Cavity ring down spectroscopy (CRDS) has been performed with pulsed QCLs and was found to be limited by the intrinsic frequency chirp of the laser suppressing an efficient intensity build-up inside the cavity. Consequently the accuracy and advantage of an absolute internal absorption calibration is not achievable. A room temperature cw QCL was used in a complementary cavity enhanced absorption spectroscopy (CEAS) configuration which was equipped with different cavities of up to 1.3 m length. This spectrometer yielded path lengths of up to 4 km and a noise equivalent absorption down to 4 x 10-8 cm-1Hz-1/2. The corresponding molecular concentration detection limit (e.g. for CH4, N2O and C2H2 at 1303 cm-1/7.66 Aem) was generally below 1 x 1010 cm-3 for 1 s integration times and one order of magnitude less for 30 s integration times. The main limiting factor for achieving even higher sensitivity is the residual mode noise of the cavity. Employing a 0.5 m long cavity the achieved sensitivity was good enough for the selective measurement of trace atmospheric constituents at 2.2 mbar.
Author | : Kaj Nyholm |
Publisher | : |
Total Pages | : 41 |
Release | : 1995 |
Genre | : Combustion |
ISBN | : 9789512224937 |
Download Nonlinear Laser Techniques for Combustion Diagnostics Book in PDF, Epub and Kindle
This thesis is a review of the author's work in the field of laser diagnostics of combustion processes.
Author | : Wei Ren |
Publisher | : |
Total Pages | : |
Release | : 2013 |
Genre | : |
ISBN | : |
Download Mid-infrared Laser Diagnostics for Chemical Kinetics Study of Oxygenates Book in PDF, Epub and Kindle
Biofuels are classified as renewable because the carbon present in the vegetable oil or animal fat feedstocks originates from carbon dioxide already present in the atmosphere. One of the current focuses on biofuel-based combustion research is the design of advanced energy conversion devices using complex reaction mechanisms. The development of these mechanisms requires a large experimental database to ensure accuracy of computational predictions. Infrared laser-absorption diagnostics are widely used in combustion research for fast, sensitive, and non-intrusive measurements of species concentration, temperature, and pressure. This thesis explores three new areas of laser diagnostic research: (a) mid-infrared diagnostics, (b) sensing in multiphase flows, and (c) applications to shock tube chemical kinetics. A novel distributed-feedback quantum-cascade laser (DFB-QCL) near 4.7 um was investigated to develop a new mid-infrared absorption sensor for in situ measurements of carbon monoxide (CO) and temperature in combustion gases. The laser provides convenient access to the stronger vibrational bands of CO than was possible previously, enabling ppm-level detectivity with an optical path length of 10 cm at high temperatures between 1000-2000 K. Wavelength modulation spectroscopy with 1f-normalized 2f detection (WMS-2f/1f) of CO2 was developed for accurate temperature sensing in multiphase combustion flows. In this method, two tunable diode lasers with wavelengths near 2.7 um were used to measure time-varying gas temperature during the evaporation of shock-heated fuel aerosols. These recently developed mid-IR laser absorption diagnostics were then applied in studying the thermal decomposition of oxygenates (biofuel surrogates) by measuring species concentration time-histories behind reflected shock waves. In a particular study of methyl formate (the simplest biodiesel surrogate), the reaction rate constants of methyl formate unimolecular decomposition were measured using the mid-IR CO absorption behind reflected shock waves. Detailed comparisons of the measured methanol and CO time-histories with the model predictions were made. Sensitivity and reaction pathway analyses for these oxygenated fuel components were performed, leading to rate recommendations with improved model performance.
Author | : Kevin Schwarm |
Publisher | : |
Total Pages | : 0 |
Release | : 2023 |
Genre | : |
ISBN | : |
Download Real-time Laser Absorption Spectroscopy for Polyfuel Combustion Engines Book in PDF, Epub and Kindle
This dissertation details the development and application of mid-infrared laser absorption spectroscopy sensing methods towards advancing low-carbon reciprocating engines for high-efficiency and low-emission power generation in a decarbonized energy sector. The scope of this work includes advancement in methods for fundamental spectroscopic studies, integration of advanced sensors into production reciprocating engines for characterization of combustion of low-carbon fuel blends, and computational methods advancement for high-speed real-time signal processing. A high-temperature, high-pressure optical gas cell is designed to enable controlled studies of molecular absorption spectra at high temperatures (>1200 K) and high pressures (>200 atm) to validate spectroscopic parameters at the elevated conditions in combustion engines. A novel optical approach provides access to the mid-wave infrared wherein lies the fundamental rovibrational absorption bands of combustion species critical to characterization of combustion process and emissions formation. Laser absorption sensors are developed and utilized for experimental measurements in the exhaust of a production Honda single-cylinder spark-ignition engine through design of an in-line exhaust sensor module to gain optical access to exhaust gases close-coupled to the exhaust valve. High-temperature opto-mechanical design and laser fiber-coupling assist in achieving robust measurements of cycle-resolved temperature and species (CO and NO) concentration at a rate of 10 kHz. The exhaust sensor is demonstrated by capturing cycle-to-cycle and intra-cycle emissions dynamics and characterizing emissions response to low-carbon fuel blends incorporating natural gas, hydrogen, and ammonia. To enable real-time measurement output at 10 kHz, computational time of the sensor data processing is reduced to sub-ms scales through the use of machine learning algorithms on an embedded processing platform. Compact neural network and ridge regression models are developed to calculate species concentration and temperature directly from transmitted laser signals, removing the need for computationally-intensive nonlinear fitting methods. The machine learning algorithms are deployed to a field-programmable gate array (FPGA) for further acceleration. Hardware-in-the-loop demonstration yields computational time and latency below 100 μs to expand use of the 10 kHz exhaust sensor for real-time sensing applications. Complementary to the sensor development work, a time-resolved chemical-kinetic model is constructed within Cantera to evaluate reciprocating engine performance and emissions during fueling with low- and non-carbon blends. The simulation model provides insights into strategies for optimization of low-carbon combustion and serves as a foundation for sensor interpretation and future work in engine optimization. Discussion of ongoing work includes the design and development of an electro-hydraulic camless valvetrain for future integration into a reciprocating engine architecture to enhance adaptability for fuel-flexible operation.