A quasi-dimensional combustion model for spark ignition engines fueled with gasoline–methanol blends

2017 ◽  
Vol 232 (1) ◽  
pp. 57-74 ◽  
Author(s):  
Duc-Khanh Nguyen ◽  
Louis Sileghem ◽  
Sebastian Verhelst
Keyword(s):  
Ignition Delay ◽  
Burning Velocity ◽  
Measurement Data ◽  
Lewis Number ◽  
Combustion Model ◽  
Laminar Burning Velocity ◽  
Velocity Correlation ◽  
Flame Kernel ◽  
Initial Flame ◽  
Better Than

The current work provides a quasi-dimensional model for the combustion of methanol–gasoline blends. New correlations for the laminar burning velocity of gasoline and methanol are developed and used together with a mixing rule to calculate the laminar burning velocity of the blends. Several factors (such as the laminar burning velocity, initial flame kernel, residual gas fraction, turbulence, etc.) have been investigated and the sensitivity of these factors and the used sub-models on the predictive performance was assessed. The simulation results were compared with measurement data from two engines on different gasoline–methanol blends. The results show the importance of the laminar burning velocity correlation, the method of initializing combustion and the turbulent burning velocity model. The newly developed laminar burning velocity correlation of gasoline performed equally or better than the existing correlations and the newly developed correlation of methanol outperformed the other correlations. The initial flame kernel size had a strong influence on the ignition delay. Changing the initial flame kernel to reproduce the same ignition delay was very effective to improve the simulations. Several turbulent combustion models were tested with the newly developed laminar burning velocity correlations and optimized ignition delay. In conclusion, the model of Bradley reproduced the trend going from gasoline to methanol much better than others due to the inclusion of the Lewis number.

Development of a Simulation Code for Hydrogen Fuelled SI Engines

2006 ◽  
Author(s):  
Sebastian Verhelst ◽  
Roger Sierens ◽  
Stefaan Verstraeten
Keyword(s):  
Alternative Energy ◽  
Equivalence Ratio ◽  
Internal Combustion Engines ◽  
Burning Velocity ◽  
Combustion Model ◽  
Laminar Burning Velocity ◽  
Velocity Correlation ◽  
Model Framework ◽  
Economic Point ◽  
Velocity Models

Hydrogen is an attractive alternative energy carrier, which could make harmful emissions, global warming and the insecurity concerning oil supply a thing of the past. Hydrogen internal combustion engines can be introduced relatively easily, from a technological as well as from an economic point of view. This paper discusses the development of a model for the combustion of hydrogen in spark ignition engines, which has lead to a simulation program that can assist the optimization of these engines. The importance of a laminar burning velocity correlation taking stretch and instability effects into account is shown. The effects are particularly strong for the highly diffusive hydrogen molecule. In this paper, a laminar burning velocity correlation published previously by two of the authors is combined with a number of turbulent burning velocity models in a quasi-dimensional two-zone combustion model framework. After calibration of the combustion model for a reference condition, simulation results are compared with experimental cylinder pressure data recorded on a single cylinder hydrogen engine. Correspondence between simulation and measurement is shown for varying equivalence ratio, ignition timing and compression ratio. All models performed well for varying ignition timings and compression ratios; the real test proved to be the ability of the models to predict the effects of a varying equivalence ratio, this lead to a clear distinction in the models.

A Laminar Burning Velocity Correlation for Hydrogen/Air Mixtures Valid at Spark-Ignition Engine Conditions

2003 ◽  
Author(s):  
Sebastian Verhelst ◽  
Roger Sierens
Keyword(s):  
Chemical Kinetics ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Spark Ignition ◽  
Flame Speed ◽  
Spark Ignition Engine ◽  
Laminar Flame Speed ◽  
Spark Ignition Engines ◽  
Laminar Burning Velocity ◽  
Velocity Correlation

During the development of a quasi-dimensional simulation programme for the combustion of hydrogen in spark-ignition engines, the lack of a suitable laminar flame speed formula for hydrogen/air mixtures became apparent. A literature survey shows that none of the existing correlations covers the entire temperature, pressure and mixture composition range as encountered in spark-ignition engines. Moreover, there is ambiguity concerning the pressure dependence of the laminar burning velocity of hydrogen/air mixtures. Finally, no data exists on the influence of residual gases. This paper looks at several reaction mechanisms found in the literature for the kinetics of hydrogen/oxygen mixtures, after which one is selected that corresponds best with available experimental data. An extensive set of simulations with a one-dimensional chemical kinetics code is performed to calculate the laminar flame speed of hydrogen/air mixtures, in a wide range of mixture compositions and initial pressures and temperatures. The use of a chemical kinetics code permits the calculation of any desired set of conditions and enables the estimation of interactions, e.g. between pressure and temperature effects. Finally, a laminar burning velocity correlation is presented, valid for air-to-fuel equivalence ratios λ between 1 and 3 (fuel-to-air equivalence ratio 0.33 < φ < 1), initial pressures between 1 bar and 16 bar, initial temperatures between 300 K and 800 K and residual gas fractions up to 30 vol%. These conditions are sufficient to cover the entire operating range of hydrogen fuelled spark-ignition engines.

Numerical study on laminar burning velocity and ignition delay time of ammonia flame with hydrogen addition

Energy ◽  
2017 ◽  
Vol 126 ◽  
pp. 796-809 ◽  
Author(s):  
Jun Li ◽  
Hongyu Huang ◽  
Noriyuki Kobayashi ◽  
Chenguang Wang ◽  
Haoran Yuan
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Numerical Study ◽  
Burning Velocity ◽  
Laminar Burning Velocity ◽  
Hydrogen Addition

Laminar burning velocity and structure of coal dust flames using a unity Lewis number CFD model

2018 ◽  
Vol 190 ◽  
pp. 87-102 ◽  
Author(s):  
Chris T. Cloney ◽  
Robert C. Ripley ◽  
Michael J. Pegg ◽  
Paul R. Amyotte
Keyword(s):  
Coal Dust ◽  
Burning Velocity ◽  
Lewis Number ◽  
Laminar Burning Velocity ◽  
Cfd Model

scholarly journals Laminar Burning Velocity and Ignition Delay Time of Oxygenated Biofuel

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3562
Author(s):  
Fekadu Mosisa Wako ◽  
Gianmaria Pio ◽  
Ernesto Salzano
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Burning Velocity ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Complete Characterization ◽  
Experimental Investigations ◽  
Laminar Burning Velocity ◽  
Alternative Sources

The need for lowering the environmental impacts has incentivized the investigation of biomass and biofuels as possible alternative sources for energy supply. Among the others, oxygenated bio-derived molecules such as alcohols, esters, acids, aldehydes, and furans are attractive substances as chemical feedstock and for sustainable energy production. Indeed, the presence of oxygen atoms limits the production of aromatic compounds, improves combustion efficiency (thus heat production) and alleviates the formation of carbon soot. On the other hand, the variability of their composition has represented one of the major challenges for the complete characterization of combustion behaviour. This work gives an overview of the current understanding of the detailed chemical mechanisms, as well as experimental investigations characterizing the combustion process of these species, with an emphasis on the laminar burning velocity and the ignition delay time. From the review, the common intermediates for the most relevant functional groups and combustion of biofuels were identified. The gathered information can be intended for the sake of core mechanism generation.

scholarly journals Numerical Study of Hydrogen Auto-Ignition Process in an Isotropic and Anisotropic Turbulent Field

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1869
Author(s):  
Agnieszka Wawrzak ◽  
Artur Tyliszczak
Keyword(s):  
Ignition Delay ◽  
Numerical Study ◽  
Maximum Temperature ◽  
Combustion Model ◽  
Ignition Process ◽  
Length Scales ◽  
Flame Kernel ◽  
Turbulent Field ◽  
Auto Ignition ◽  
Turbulence Length

The physical mechanisms underlying the dynamics of the flame kernel in stationary isotropic and anisotropic turbulent field are studied using large eddy simulations (LES) combined with a pdf approach method for the combustion model closure. Special attention is given to the ignition scenario, ignition delay, size and shape of the flame kernel among different turbulent regimes. Different stages of ignition are analysed for various levels of the initial velocity fluctuations and turbulence length scales. Impact of these parameters is found small for the ignition delay time but turns out to be significant during the flame kernel propagation phase and persists up to the stabilisation stage. In general, it is found that in the isotropic conditions, the flame growth and the rise of the maximum temperature in the domain are more dependent on the initial fluctuations level and the length scales. In the anisotropic regimes, these parameters have a substantial influence on the flame only during the initial phase of its development.

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