Non-uniform ignition processes in rapid-compression machines

Elsworth, J.E.; Haskell, W. W.; Read, I.A.

doi:10.1016/0010-2180(69)90115-1

Cited by 23 publications

(9 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We estimate that by themselves, temperature variations on the order of 150 K would be required to bring homogenous kinetic predictions into line with experimental observations in [27]. It has also been hypothesized that catalytic effects due to the presence of small particles in the gas [27,37,38] could be important in some observations. We also add to this hypothesis that catalytic surface effects may occur in reflected shock experiments in the mild ignition regime, since end-wall/corner tube surfaces can be estimated to have fast transient heating times [39] in comparison to the experimentally measured chemical ignition delays, for example, under the conditions studied in [27].…”

Section: Discussionmentioning

confidence: 57%

“…Types of perturbations on ignition delay measurements for rapid compression experiments discussed in the literature include surface contamination, particles as catalytic centers, and impurities [37,38]. On the other hand, Walton et al [6,50] report the presence of pre-ignition reaction fronts as well as particles in the reaction chamber.…”

Section: Similar Results In Terms Of Perturbations Of Chemical Inductmentioning

confidence: 99%

“…15 K [36]. Very recently Ruscic et al [37] have updated this heat of formation to 2.94 ± 0.06 kcal/mole. This change makes no significant differences in the level of comparison of computations with the targets utilized in the present work and appears in the Chemkin data files available from the authors.…”

Section: Updated Kinetic Mechanisms For Co Ch 2 O and Ch 3 Oh Combumentioning

confidence: 99%

See 2 more Smart Citations

Chemical Kinetics in Support of Syngas Turbine Combustion

Dryer¹

2007

View full text Add to dashboard Cite

Executive SummaryThis document is the final report on an overall program formulated to extend our prior work in developing and validating kinetic models for the CO/hydrogen/oxygen reaction by carefully analyzing the individual and interactive behavior of specific elementary and subsets of elementary reactions at conditions of interest to syngas combustion in gas turbines. A summary of the tasks performed under this work are: 1. Determine experimentally the third body efficiencies in H+O 2 +M = HO 2 +M (R1) for CO 2 Results are summarized in this document and its appendices. Three archival papers which contain a majority of the research results have appeared. Those results not published elsewhere are highlighted here, and will appear as part of future publications. Portions of the work appearing in the above publications were also supported in part by the Department of Energy under Grant No. DE-FG02-86ER-13503.As a result of and during the research under the present contract, we became aware of other reported results that revealed substantial differences between experimental characterizations of ignition delays for syngas mixtures and ignition delay predictions based upon homogenous kinetic modeling. We adjusted emphasis of Task 2 to understand the source of these noted disparities because of their key importance to developing lean premixed combustion technologies of syngas turbine applications. In performing Task 3, we also suggest for the first time the very significant effect that metal carbonyls may have on syngas combustion properties. This work is fully detailed in Appendix C. The work on metal carbonyl effects is entirely computational in nature. Pursuit of experimental verification of these interactions was beyond the scope of the present work.3 Results over this Progress Period ApproachThe present research further extended our prior work in developing and validating kinetic models for the CO/hydrogen/oxygen principally studied under Department of Energy Grant No. DE-FG02-86ER-13503, by providing additional experimental data using a Variable Pressure Flow Reactor (VPFR) on the collisional efficiencies of water and carbon dioxide in the reaction H+O 2 +M = HO 2 + M (R1) by carefully analyzing the individual and interactive behavior of specific elementary and subsets of elementary reactions at the conditions of interest, and by extending computational model comparisons with data obtained in this program and those appearing in the literature since 2004 to further test and refine the model at conditions relevant to gas turbine applications. Additionally, syngas contaminant species such as small hydrocarbons (e.g., methane) and other combustion gas components (e.g. NO x ) have been identified and it is suspected that these contaminants may affect syngas chemistry in gas turbine applications, particularly in mixing regions of entering fuel and air. These contaminants can have significant influence on some of the kinetic behavior. The initial research plan was to investigate only the effects of small local amo...

show abstract

Section: Discussionmentioning

confidence: 57%

Section: Similar Results In Terms Of Perturbations Of Chemical Inductmentioning

confidence: 99%

Section: Updated Kinetic Mechanisms For Co Ch 2 O and Ch 3 Oh Combumentioning

confidence: 99%

See 1 more Smart Citation

Chemical Kinetics in Support of Syngas Turbine Combustion

Dryer¹

2007

View full text Add to dashboard Cite

show abstract

“…(18) through the time-scale τ 0 , which is dependent on k and T u (see Eq. (17)). The composition of the particles is initialized from a beta-distribution: 21 Compression Ratio, ξ in which the coefficients α, β, and γ are expressed in terms of Z and T 2 Z :…”

Section: Effect Of Initial Turbulence Level On the Ignition Dynamicsmentioning

confidence: 99%

“…Front-like combustion modes have been reported for hydrocarbon and hydrogen fuel mixtures. 5,13,17 Images suggest that these flame-propagation modes and combustion non-uniformities are initiated by mixture impurities. 17 In principle, such effects can be incorporated into the proposed model, if the underlying combustion-physical mechanisms, triggering this combustion mode, are understood.…”

Section: Introductionmentioning

confidence: 99%

Reconcile Discrepancies of Current Syngas Kinetics Models by Considering Turbulence Effects on Ignition Delay at Gas-Turbine Relevant Operating Conditions

Ihme

2011

49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

View full text Add to dashboard Cite

With the increasing interest in utilizing syngas in gas turbine applications, the characterization of H2/CO reaction chemistry under high-pressure and moderate-temperature operating conditions has been the focus of recent investigations. Different chemical-kinetics and hydrodynamic processes have been identified as being responsible for the discrepancies between experimental measurements and kinetic predictions of syngas ignition delay times. This paper complements previous studies, and provides insight on the role of turbulence fluctuations and small-scale mixture inhomogeneities on the syngas combustion process. To this end, an analytic model has been developed that describes the turbulence amplification and combustion in the so-called adiabatic core region of a rapid compression machine (RCM). In this formulation, enhancement of turbulence and small-scale mixture fluctuations during the RCM compression phase are modeled using rapid distortion theory. The subsequent ignition and combustion processes are described using a Lagrangian Fokker-Planck model which considers turbulence/chemistry interaction and detailed reaction chemistry. The model was applied to different syngas mixtures and operating conditions, including pressures up to 20 atm and temperatures between 600 and 1300 K. Parametric studies showed that the model captures experimentally observed trends of reduced ignition delay and prolonged reaction progress during the ignition phase. A Damköhler criterion was introduced in order to characterize the sensitivity of the induction chemistry to turbulence fluctuations. Results suggest that syngas mixtures with Damhöhler numbers below 100 exhibit increasing sensitivity to turbulence and mixture fluctuations. Initial turbulence levels of less than 0.01 percent of the mean flow are sufficient in reducing the ignition delay times by several orders of magnitude. This study shows that the turbulence/chemistry interaction plays an equally important role in affecting the syngas ignition chemistry, and requires consideration in addition to chemical-kinetics and hydrodynamic processes, previously identified as leading mechanisms for the observed discrepancy in syngas combustion at low-temperature operating conditions.

show abstract

Syngas Production, Storage, Compression and Use in Gas Turbines

Yang

Zhou

et al. 2020

Biofuels and Biorefineries

View full text Add to dashboard Cite

This chapters analyses syngas production through pyrolysis and gasification, its compression and its use in gas turbines. Syngas compression can be performed during or after thermal treatment processes. Important points are discussed related to syngas ignition, syngas explosion limit at high temperatures and high pressures and syngas combustion kinetics. Kinetic aspects influence ignition and final emissions which are obtained at the completion of the combustion process. The chapter is organised into four subsections, dealing with (1) innovative syngas production plants, (2) syngas compressors and compression process, (3) syngas ignition in both heterogeneous and homogeneous systems and (4) syngas combustion kinetics and experimental methods. Particular attention is given to ignition regions that affect the kinetics, namely systems that operate at temperatures higher than 1000 K can have strong ignition, whereas those operating at lower temperatures have weak ignition.

show abstract

Non-uniform ignition processes in rapid-compression machines

Cited by 23 publications

References 5 publications

Chemical Kinetics in Support of Syngas Turbine Combustion

Chemical Kinetics in Support of Syngas Turbine Combustion

Reconcile Discrepancies of Current Syngas Kinetics Models by Considering Turbulence Effects on Ignition Delay at Gas-Turbine Relevant Operating Conditions

Syngas Production, Storage, Compression and Use in Gas Turbines

Contact Info

Product

Resources

About