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The analysis of the ECFM-3Z combustion model in the marine 4-stroke engine for the exhaust gas composition

Kowalski J.

Journal of Polish CIMAC

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2014

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Vol. 9, no 1

95--102

EN

The paper presents ECFM-3Z combustion model analysis in the marine, 4-stroke diesel engine. The purpose of the modeling was to determine the composition of the exhaust gas. This composition depends on the composition of the combustible mixture, combustion time and thermodynamic conditions prevailing in the engine cylinder during the working process. Mentioned parameters are variable in time and space, and therefore require the use of 3-dimensional model based on the finite volume method, taking into account the fuel injection, brake-up and evaporation, mixing with air, auto-ignition and combustion. All models presented in the literature are adapted to the parameters of relatively small engines. Different marine engine parameters require significant modifications taking into account the heat exchange with the structural elements of the engine, leakage through piston rings and energy losses by riction. It should also be noted that dimensions of the marine engine require careful optimization of spatial moving meshes according to computation time and quality of results. Paper presents influence of mixing time, start of injection and autoignition delay on modeling results of the exhaust gas composition.

2

Assessment of the 3-D combustion model in the marine 4-stroke engine

Kowalski J.

Journal of Polish CIMAC

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2014

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Vol. 9, no 1

79--86

EN

The aim of this research is to formation of the model of combustion process in the marine, 4 -stroke, diesel engine. The chosen object of research is a laboratory AL25/30 engine. For achievement of the aim, laboratory measurements are made and the results are used to determine the boundary and initial conditions. In addition, measurements of the fuel injection shape are made on the test bench and are made a faithful geometric model of structural components of the engine cylinder. The obtained data has been implemented in the three - dimensional model comprising the fuel injection phenomena, the brake - up and the evaporation of fuel, auto - ignition, flame propagation and heat exchange with the structural elements of the engine cylinder. As a result of activities succeeded in creating a model of the combustion process in the cylinder, which has been positively validated due to the maximum combustion pressure and the temperature of the exhaust gases. Obtained results of calculations also allowed verifying the assumption of negligible auto-ignition delay. The adopted ECFM - 3Z model of the ignition and combustion, used for modeling of combustion in diesel engines, showed the calculated size of the auto - ignition delay of 7 - 8 ° CA.

3

Validation of the Numerical Simulation of Iso-octane Auto-ignition Delay Time in Rapid Compression Machine with the Use of ECFM-3Z (Extended Coherent Flame Model - 3 Zones) Combustion Model Against Experimental Data

Jaworski P., Priesching P., Teodorczyk A., Bandel W.

Archivum Combustionis

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2010

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Vol. 30 nr 1-2

1-14

EN

Nowadays combustion models come up to the requirements of engineers. Numerical simulations show good agreement with experimental results of the compression ignition (CI) and spark ignition (SI) engines. Controlled auto-ignition (CAI) has emerged as one of the most promising engine technologies with the potential to combine fuel efficiency and improved emissions performance. Despite considerable advantages controlling the combustion is still an area of on-going research. The combustion models used for engine simulations are not well prepared and they have to be validated with experimental data. In this paper the first step of setting up of the combustion model is presented with the use of experimental results from three different rapid compression machine (RCM) experiments. That kind of work has to be performed before real engine calculations, to give the brief view on the differences in the experimental and simulation data. Also during this work an improved thermodynamic database for the ECFM-3Z combustion model in the FIRE software was introduced.