Development and Application of a Time and Space Resolved Optical Diagnostic for Soot Temperature and Concentration in a Spark-ignited Direct-injection Engine PDF Download
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Author: Boris Dragomir Stojkovic
Publisher:
ISBN:
Category :
Languages : en
Pages : 302
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Author: Boris Dragomir Stojkovic
Publisher:
ISBN:
Category :
Languages : en
Pages : 302
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Book Description
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 778
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Book Description
Author:
Publisher:
ISBN:
Category : Optical instruments
Languages : en
Pages : 876
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Book Description
Publishes papers reporting on research and development in optical science and engineering and the practical applications of known optical science, engineering, and technology.
Author: P. M. Hughes
Publisher:
ISBN:
Category :
Languages : en
Pages : 33
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Book Description
"A technique termed "coherent, anti-Stokes Raman spectroscopy" (CARS) has been developed at the Combustion and Carbonization Research Laboratory of CANMET's Energy Research Laboratories for the measurement of temperature and species concentration. The advantages of this technique over conventional probing methods are improved temporal and spatial resolution; it is nonintrusive and turbulence parameters can be determined. This report discusses the theoretical basis for such a technique and some of the practical considerations involved in the optical arrangement. To apply this technique successfully, it was necessary to develop sophisticated software and hardware. The incorporation of these and the optics into a CARS system is discussed, together with the theory of its application"--Abstract, p. iii.
Author: Dale R. Tree
Publisher:
ISBN:
Category : Diesel motor
Languages : en
Pages : 16
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Book Description
In-cylinder measurements of soot particle size, number density and temperature have been made using optical measurements in a direct injection diesel engine. The measurements were made at one location approximately 5 mm long and 1.5 mm wide above the bowl near the head. Two optical techniques were used simultaneously involving light scattering extinction and radiation. An optical probe was designed and mounted in a modified exhaust valve which introduced a beam of light into the cylinder and collected the scattered and radiating light from the soot. The resulting measurements were semi-quantitative, giving an absolute uncertainty on the order of + or - 50% which was attributed mainly to the uncertainty of the optical properties of the soot and the heterogeneous nature of the soot cloud. Measurements at three speeds and three overall equivalence ratios were made. For all of the operating conditions the soot in the measurement volume increased in size to a maximum followed by a rapid decrease. The peak soot diameters were in a range of 30 - 50 nm. Peak soot diameter, soot volume fraction, and soot temperature appeared to increase with equivalence ratio at the measurement location. The results also suggested the soot cloud to be very dense with peak soot volume fraction near 4-6 x 10-6 and thick with a soot cloud thickness approximately 0.4 - 0.6 times the length from the piston to the head.
Author: Norman Chigier
Publisher: CRC Press
ISBN: 9781560320289
Category : Technology & Engineering
Languages : en
Pages : 556
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Book Description
The book begins with an introduction to the general problems of making measurements in high temperature and a presentation of chemically reacting flow systems. It describes each instrument with the various diagnostic techniques and discusses measurements that have been made in furnaces, flames, and rocket engines. The detailed measurement techniques described in this book cover a wide spectrum of applications in combustion systems, including gas turbine, rocket measurement techniques that were developed in laboratories. Information obtained on detailed temperature, velocity, particle size, and gas concentration distribution is leading to improve understanding of the chemical combustion process and to design imporvements in combustors.
Author: F. Zhao
Publisher: Elsevier
ISBN: 008055279X
Category : Technology & Engineering
Languages : en
Pages : 129
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Book Description
The process of fuel injection, spray atomization and vaporization, charge cooling, mixture preparation and the control of in-cylinder air motion are all being actively researched and this work is reviewed in detail and analyzed. The new technologies such as high-pressure, common-rail, gasoline injection systems and swirl-atomizing gasoline fuel injections are discussed in detail, as these technologies, along with computer control capabilities, have enabled the current new examination of an old objective; the direct-injection, stratified-charge (DISC), gasoline engine. The prior work on DISC engines that is relevant to current GDI engine development is also reviewed and discussed. The fuel economy and emission data for actual engine configurations have been obtained and assembled for all of the available GDI literature, and are reviewed and discussed in detail. The types of GDI engines are arranged in four classifications of decreasing complexity, and the advantages and disadvantages of each class are noted and explained. Emphasis is placed upon consensus trends and conclusions that are evident when taken as a whole; thus the GDI researcher is informed regarding the degree to which engine volumetric efficiency and compression ratio can be increased under optimized conditions, and as to the extent to which unburned hydrocarbon (UBHC), NOx and particulate emissions can be minimized for specific combustion strategies. The critical area of GDI fuel injector deposits and the associated effect on spray geometry and engine performance degradation are reviewed, and important system guidelines for minimizing deposition rates and deposit effects are presented. The capabilities and limitations of emission control techniques and after treatment hardware are reviewed in depth, and a compilation and discussion of areas of consensus on attaining European, Japanese and North American emission standards presented. All known research, prototype and production GDI engines worldwide are reviewed as to performance, emissions and fuel economy advantages, and for areas requiring further development. The engine schematics, control diagrams and specifications are compiled, and the emission control strategies are illustrated and discussed. The influence of lean-NOx catalysts on the development of late-injection, stratified-charge GDI engines is reviewed, and the relative merits of lean-burn, homogeneous, direct-injection engines as an option requiring less control complexity are analyzed.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
A semi-detailed soot model was successfully implemented in the KIVA3v2-ERC code, which features a discrete multi-component (DMC) fuel vaporization model. A spark ignition model and the G-equation turbulent flame propagation model were also implemented for modeling direct-injection spark-ignition (DISI) engines. Chemistry parallelization for the soot model was also successfully realized in this work. Chemistry parallelization and a newly developed chemistry solver (SpeedCHEM) further reduced the computational time and enabled the successful application of the final code (KIVA-DMC-detsoot-G-SC) to DISI engines with the consideration of multi-component surrogates for real gasoline fuels and 3-D full cylinder engine grids. The semi-detailed soot model considered: soot inception from a four-ring aromatic (A4), soot surface growth through acetylene (C2H2) and aromatics from single-ring to four-ring species (A1, A2, A3, A4), soot coagulation, and soot oxidation through O2 and OH. A reduced polycyclic aromatic hydrocarbon (PAH) chemistry mechanism was coupled with n-heptane, iso-octane and toluene chemistry mechanisms. The combination of the chemistry mechanisms and the soot model was then validated based on experiments in terms of ignition delay, fundamental premixed flames, SANDIA constant volume chamber spray combustion. The pyrolysis process is also a significant process for soot formation at the conditions of DISI engines. Important species for soot formation from toluene pyrolysis processes were also validated based on experiments, and then coupled with the current n-heptane/iso-octane/toluene/PAH chemistry mechanisms for application to DISI engines. The vaporization of wall films plays a significant role in soot formation and a grid-independent wall film vaporization model was formulated for predicting soot emissions near wall films Predicted in-cylinder pressure and particle size distributions (PSDs) were compared to available premixed engine experimental studies. Quantitative agreements of in-cylinder particle distributions are also obtained. The improved models were then applied to studies of soot emissions from early- and late-injection strategies in a four-valve single-cylinder gasoline DISI engine, and the trends were consistent with literature or experimental data.
Author: Alan C. Eckbreth
Publisher: CRC Press
ISBN: 1000124622
Category : Technology & Engineering
Languages : en
Pages : 630
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Book Description
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: Shawn Andres Reggeti
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 0
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Book Description
The compression ignition (diesel) engine continues to be an attractive option for vehicle powertrains, particularly in heavy- and medium-duty transportation. While offering many operational advantages including a high power output per unit weight, quick refueling capabilities, and reliability; the diesel engine is prone to produce significant emissions. Chief among these emissions are soot and nitrogen oxides (NOx). Combustion techniques that reduce soot tend to increase NOx and vice versa requiring an acceptable soot-NOx tradeoff. The optimization of this tradeoff has been a challenge in recent decades with the advent of advanced combustion strategies and alternative fuels. Soot measurements at engine relevant conditions are the focus of this work and critical to building understanding of these complex phenomena and to evaluate potential solutions. Two-color pyrometry (2CP) has been used over several decades to study engine-relevant combustion processes, but results are generally regarded as qualitative or semi-quantitative. The objective of this work is to advance the 2CP diagnostic to achieve reliable, spatially-resolved measurements of the soot in diesel-like fuel sprays. This outcome is accomplished by 1) developing a new optical design for 2CP to overcome common measurement errors in other designs, 2) performing a detailed uncertainty analysis to quantify errors, and 3) applying the new 2CP system to statistically analyze the soot behavior in a diesel-like fuel spray. First, a novel optical configuration was developed and constructed from off-the-shelf components to eliminate systematic errors of previous designs. In many current 2CP systems, large measurement errors can be introduced by parallax because lines of sight (LsOS) of the two wavelengths are not the same. The modified optical hardware, was shown to accurately resolve corresponding pixels at both wavelengths of a high-resolution optical target, indicating that the LsOS for both wavelengths are the same. Next, an experimental investigation of reacting diesel-like fuel sprays revealed steady experiment conditions with repeatable global parameters of combustion. Despite the similarity of global behavior across injections, significant spatial variation of soot was observed between repeated injection experiments. Computed average turbulent flame speed for each injection suggests that initial reaction rates, which are a function of local equivalence ratio, determine the variation. Motivated by the spatial variations of soot observed across injections, the 2CP technique was further refined for quantitative, spatially resolved measurements. A pixel-by-pixel calibration was applied to account for any non-uniformities in sensor response, increasing accuracy of the computed soot quantities at each pixel. Uncertainty analysis determined the reliability of each individual measurement. This study found that the largest relative uncertainties are associated with low soot concentrations. Highly uncertain soot measurements typically occur on the edges of the diffusion flame where is soot is most likely to be oxidized. However, these highly uncertain data had marginal impact on the total soot mass produced in the flame. Finally, a large 500-injection data set employed all the previously developed 2CP diagnostic capabilities to evaluate spatiotemporal sooting behavior in a diesel-like spray flame. Focusing on the gaps in the literature for temporal development of soot and detailed study of the statistical variability between injections, this work provides insights on soot formation in key regions: lift-off, core, and jet head. Total soot contribution from binned individual soot mass values indicate that large soot masses take longer to form, but are the first to oxidize. Overall, the majority of injections produced low soot, but a few produced exceptionally high soot by comparison.
