Quasi-dimensional, multi-zone combustion modelling of turbulent entrainment and flame stretch for a spark ignition engine fuelled with hydrogen-enriched biogas

Rakopoulos, C.D.; Michos, Constantine N.

doi:10.1504/ijvd.2009.024239

Cited by 8 publications

(16 citation statements)

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“…A full description of the multi-zone closed-cycle simulation in its zero-dimensional form has been previously reported in detail in references [22] and [23], while its upgrading to the present quasi-dimensional formulation has been analytically presented in reference [21]. Therefore, only a brief outline of its basic features, which are needed for first-law analysis, will be provided here.…”

Section: General Description Of the Multi-zone Closed-cycle Simulationmentioning

confidence: 99%

“…This is a quasidimensional multi-zone combustion model, which is based on the combination of turbulent entrainment theory and flame stretch concepts for the prediction of burning rates. The equations of the multi-zone formulation [21][22][23] are not provided here; they concern the burned gases behind the flame. The present description will, rather, focus on the modelling of the burning process, which occurs in the region of the turbulent flame.…”

Section: Combustion Modelmentioning

confidence: 99%

“…where the various derivatives with respect to CA are computed during the first-law analysis of engine operation [21][22][23]45].…”

Section: Availability Balance Equationmentioning

confidence: 99%

“…In this work, an experimentally validated, closedcycle simulation code [21], incorporating a quasidimensional multi-zone combustion model that is based on turbulent entrainment theory and flame stretch concepts for the prediction of burning rates, is further extended to include second-law analysis. Application is made for a single-cylinder, homogeneous charge, SI engine fuelled with biogas, with hydrogen added up to the extent of 15 vol %.…”

Section: Introductionmentioning

confidence: 99%

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Studying the effects of hydrogen addition on the second-law balance of a biogas-fuelled spark ignition engine by use of a quasi-dimensional multi-zone combustion model

Rakopoulos

Michos

Giakoumis

2008

Proceedings of the Institution of Mechanical Engineers, Part D:

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Although a first-law analysis can show the improvement that hydrogen addition impacts on the performance of a biogas-fuelled spark-ignition (SI) engine, additional benefits can be revealed when the second law of thermodynamics is brought into perspective. It is theoretically expected that hydrogen enrichment in biogas can increase the second-law efficiency of engine operation by reducing the combustion-generated irreversibilities, because of the fundamental differences in the mechanism of entropy generation between hydrogen and traditional hydrocarbon combustion. In this study, an experimentally validated closed-cycle simulation code, incorporating a quasi-dimensional multi-zone combustion model that is based on the combination of turbulent entrainment theory and flame stretch concepts for the prediction of burning rates, is further extended to include second-law analysis for the purpose of quantifying the respective improvements. The analysis is applied for a single-cylinder homogeneous charge SI engine, fuelled with biogas-hydrogen blends, with up to 15 vol % hydrogen in the fuel mixture, when operated at 1500 r/min, wide-open throttle, fuel-to-air equivalence ratio of 0.9, and ignition timing of 20u crank angle before top dead centre. Among the major findings derived from the second-law balance during the closed part of the engine cycle is the increase in the second-law efficiency from 40.85 per cent to 42.41 per cent with hydrogen addition, accompanied by a simultaneous decrease in the combustion irreversibilities from 18.25 per cent to 17.18 per cent of the total availability of the charge at inlet valve closing. It is also illustrated how both the increase in the combustion temperatures and the decrease in the combustion duration with increasing hydrogen content result in a reduction in the combustion irreversibilities. The degree of thermodynamic perfection of the combustion process from the second-law point of view is quantified by using two (differently defined) combustion exergetic efficiencies, whose maximum values during the combustion process increase with hydrogen enrichment from 49.70 per cent to 53.45 per cent and from 86.01 per cent to 87.33 per cent, respectively.

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Section: General Description Of the Multi-zone Closed-cycle Simulationmentioning

confidence: 99%

Section: Combustion Modelmentioning

confidence: 99%

“…where the various derivatives with respect to CA are computed during the first-law analysis of engine operation [21][22][23]45].…”

Section: Availability Balance Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Studying the effects of hydrogen addition on the second-law balance of a biogas-fuelled spark ignition engine by use of a quasi-dimensional multi-zone combustion model

Rakopoulos

Michos

Giakoumis

2008

Proceedings of the Institution of Mechanical Engineers, Part D:

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show abstract

“…While for port-fuel-injected, spark-ignited engines, some successful models have been already reported in literature [11][12][13][14][15][16][17][18], even considering gaseous fuels, a few open issues still remain on diesel combustion [3][4][5][6][7][8][9][10]. In high-speed, direct-injected (HSDI) diesel engines, combustion is strictly subsequent to droplet atomization and mixing with the surrounding air.…”

Section: Introductionmentioning

confidence: 99%

Development and calibration of an enhanced quasi-dimensional combustion model for HSDI diesel engines

Perini

Mattarelli

2011

International Journal of Engine Research

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The paper describes the development and validation of a quasi-dimensional combustion model, applicable to any type of high-speed direct-injection (HSDI) diesel engines. In this model, the fundamental in-cylinder processes are taken into account, including turbulence, fuel injection, spray dynamics, ignition, and combustion. In comparison with similar models presented in the literature, a more physical description of average in-cylinder turbulence properties and their interaction with spray dynamics is introduced, as well as a detailed modelling of fuel jet wall impingement. Some experimental measures available in the literature and three-dimensional computational fluid dynamics simulations were considered to calibrate the modelling parameters. These improved sub-models make results accuracy less dependent on the calibration carried out on each engine, so that the same parameter setting can be successfully applied to different combustion chamber configurations. The model was first applied to a small HSDI turbocharged diesel engine. The specific calibration was supported by both experimental and simulation results, the latest being obtained from the threedimensional computational fluid dynamics analyses. Then, a different diesel engine was simulated, adopting the same set-up of the model parameters. For both engines, the comparison between experiments and simulation showed a very good agreement in terms of in-cylinder pressures and heat release rates, as well as of average in-cylinder turbulence properties. It is worth mentioning that the two engines had a quite different unit displacement, i.e. 312 and 697 cm 3 , respectively. As a conclusion, this model was demonstrated to be a reliable tool for addressing the optimization of the main engine design parameters, such as injection rates and timings, combustion chamber base geometry, and so forth.

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Generation of combustion irreversibilities in a spark ignition engine under biogas–hydrogen mixtures fueling

Rakopoulos

Michos

2009

International Journal of Hydrogen Energy

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Quasi-dimensional, multi-zone combustion modelling of turbulent entrainment and flame stretch for a spark ignition engine fuelled with hydrogen-enriched biogas

Cited by 8 publications

References 0 publications

Studying the effects of hydrogen addition on the second-law balance of a biogas-fuelled spark ignition engine by use of a quasi-dimensional multi-zone combustion model

Studying the effects of hydrogen addition on the second-law balance of a biogas-fuelled spark ignition engine by use of a quasi-dimensional multi-zone combustion model

Development and calibration of an enhanced quasi-dimensional combustion model for HSDI diesel engines

Generation of combustion irreversibilities in a spark ignition engine under biogas–hydrogen mixtures fueling

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