CFD Modeling and Experimental Analysis of a Homogeneously Charged Turbulent Jet Ignition System in a Rapid Compression Machine

Gholamisheeri, Masumeh; Thelen, Bryce; Toulson, Elisa

doi:10.4271/2017-01-0557

Cited by 20 publications

(17 citation statements)

References 25 publications

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“…In this study, the use of the LES turbulence model resulted in an improvement in burn rate and peak pressure compared to using RANS turbulence models. A comparison between the numerical pressure traces resulting from RANS and LES turbulence models are provided in the study of Gholamisheeri et al 26 To estimate the approximate amount of unburned mass that is trapped in the crevice volumes of the TJI system and the associated pressure rise due to this unburned mass, a preliminary calculation was performed. The pressure, temperature, volume and total mass at TDC are known (temperature is calculated with the polytropic compression assumption).…”

Section: Resultsmentioning

confidence: 99%

“…It should be mentioned that the performance of the reduced mechanism compared to the comprehensive mechanism was studied, and the reliability of the reduced mechanism in ignition delay estimation along with burn rate calculations were validated against the experimental measurements. 26 The aforementioned mechanism reduction was performed using the zero-dimensional utility tools in Converge. The computational time taken to obtain numerical solution is linearly proportional to the number of reactions or the square of the number of species.…”

Section: Numerical Specificationsmentioning

confidence: 99%

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Large eddy simulation of a homogeneously charged turbulent jet ignition system

Gholamisheeri

Givler

Toulson

2017

International Journal of Engine Research

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Transient jet ignition of a homogeneous methane air mixture in a turbulent jet ignition system is studied computationally using a large eddy simulation turbulence model. The jet discharges from a prechamber into a main combustion chamber via one or more orifice(s) and provides a distributed ignition source in turbulent jet ignition. The effect of orifice size and stoichiometry is studied numerically using the Converge computational fluid dynamics code. A reduced kinetic mechanism is used for combustion along with a Smagorinsky sub-model for turbulence modeling. The computed pressure traces are compared with experimental measurements through rapid compression machine tests. Computational fluid dynamics results are in acceptable agreement with the experimental data during compression and the early stage of combustion; however, an over-prediction of peak pressure was reported. Peak pressure error is in the range of 0.1%-4% for Reynolds-averaged Navier-Stokes simulation estimation compared to the experimental measurements. This error is a function of mixture stoichiometry and unburned gas temperature. The error calculation showed that with the large eddy simulation model, 1% and 12% improvements in peak pressure and burn rate estimations, respectively, were achieved compared to Reynolds-averaged Navier-Stokes results. The reduced large eddy simulation error relative to the Reynolds-averaged Navier-Stokes simulations were considered to be in the acceptable range; however, further improvements could be achieved through validation and testing of additional turbulence models. In addition, computational fluid dynamics temperature contours for various nozzle orifices and air-fuel ratios are compared to achieve deeper insight into the turbulent jet ignition combustion process in the rapid compression machine combustion cylinder. The numerical iso-surface temperature contours were obtained which enabled three-dimensional views of the flame propagation, the jet discharge, ignition and extinction events. The heat release process and regeneration of mid-range temperature iso-surfaces (1200 K) were not visible through the experimental images.

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Section: Resultsmentioning

confidence: 99%

Section: Numerical Specificationsmentioning

confidence: 99%

Large eddy simulation of a homogeneously charged turbulent jet ignition system

Gholamisheeri

Givler

Toulson

2017

International Journal of Engine Research

Self Cite

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“…This is the main reason why the twozone combustion model is used. To simulate this relationship between a b and v b , the value of a b is calculated by equation (19)…”

Section: Two-zone Combustion Modelmentioning

confidence: 99%

“…Third, parameters, c pre in equation (19), k in equation (9), and Dt d in equation (20), are calibrated by matching the pre-chamber pressure during the early stage of combustion (-25°to 0°ACTDC (after combustion top dead center) in Figure 8). Then, parameters, c main in equation (19), d f in equation 14, A and E A =R u in equation 23, are adjusted according to the pre-chamber pressure in the later stage of the combustion. After the parameters in the pre-chamber model are calibrated, the main-chamber parameters can be calibrated by matching the main-chamber simulated pressure curve to be the same as the experimental one.…”

Section: Model Calibration and Validationmentioning

confidence: 99%

“…This confirms the necessity of the pre-chamber fuel vaporization model. Figure 10 presents the value of coefficient a b in equation (19), see the solid line. There are two switch points around 211°and 0°ACTDC on this line, corresponding to the two points when the mass flow between the two chambers changes its direction.…”

Section: Model Calibration and Validationmentioning

confidence: 99%

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A control-oriented combustion model for a turbulent jet ignition engine using liquid fuel

Song

Vedula

Zhu

et al. 2017

International Journal of Engine Research

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A control-oriented engine model is necessary for developing and validating the associated engine control strategies. For engines equipped with the turbulent jet ignition system, the interaction between the pre-and main-combustion chambers should be considered in the control-oriented model for model-based control strategies that optimize the overall thermal efficiency in real-time. Therefore, a two-zone combustion model based on the newly proposed parametervarying Wiebe function is proposed. Since the engine uses the liquid fuel, a pre-chamber air-fuel mixing and vaporization model are also developed. The model was validated using the experimental data from a single-cylinder turbulent jet ignition engine under different operational conditions, and the simulation results show a good agreement with the experimental data. The relative simulation error of the in-cylinder pressure is less than 8%. For most of the other pressure-related variables, such as indicated mean effective pressure and main-chamber burn duration, the relative errors are within 5%.

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Improvement of performance and emission in a lean‐burn gas fueled spark ignition engine by using a new pre‐chamber

Kheyrollahi

Jafarmadar

Khalilarya

et al. 2021

Env Prog and Sustain Energy

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Lean burn combustion of natural gas in spark-ignited engines is a promising approach to improving engine performance and efficiency by reducing pollutant emissions and better fuel consumption. However, inducing excessive lean mixture to the engine makes the combustion unstable, and misfire happens in a significant number of cycles. The pre-chamber ignition technology is a useful solution that can make sparkignition engines more efficient. In this study, the lean mixture's combustion was empirically investigated with a new pre-chamber spark plug in a one-cylinder engine fueled with natural gas. Tests were performed at 11.5, 13.5, and 16 compression ratios and a wide range of air-fuel ratios. With the pre-chamber spark plug usage, the lean operating limit is enlarged by 10%-45% and gives 4% and 3% the average lower in-cylinder pressure and exhaust gas temperature than the conventional spark ignition system. The brake-specific fuel consumption was improved by 4%-11% using the pre-chamber spark ignition. The HC, CO, and NOx formation is about 11%, 16.3%, and 10% lower than the conventional spark ignition usage. Outcomes confirmed that the new design pre-chamber plug gives 1% improved COV IMEP than the standard spark plug. The use of pre-chamber due to the lean-burn combustion causes larger ignition delay and increases brake thermal efficiency by up to 9%. It can be concluded that the pre-chamber increases the ignition ability, and the lean mixture limit is extended.

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CFD Modeling and Experimental Analysis of a Homogeneously Charged Turbulent Jet Ignition System in a Rapid Compression Machine

Cited by 20 publications

References 25 publications

Large eddy simulation of a homogeneously charged turbulent jet ignition system

Large eddy simulation of a homogeneously charged turbulent jet ignition system

A control-oriented combustion model for a turbulent jet ignition engine using liquid fuel

Improvement of performance and emission in a lean‐burn gas fueled spark ignition engine by using a new pre‐chamber

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