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Digital Twin test-bench Performance for marine diesel engine applications

Minchev Dmytro, Varbanets Roman, Shumylo Oleksandr, Zalozh Vitalii, Aleksandrovska Nadiia, Bratchenko Pavlo, Truong Thanh Hai

Polish Maritime Research

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2023

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nr 4

81--91

EN

The application of Digital Twins is a promising solution for enhancing the efficiency of marine power plant operation, particularly their important components – marine internal combustion engines (ICE). This work presents the concept of applying a Performance Digital Twin for monitoring the technical condition and diagnosing malfunctions of marine ICE, along with its implementation on an experimental test-bench, based on a marine diesel-generator. The main principles of implementing this concept involve data transmission technologies, from the sensors installed on the engine to a server. The Digital Twin, also operating on the server, is used to automatically process the acquired experimental data, accumulate statistics, determine the current technical state of the engine, identify possible malfunctions, and make decisions regarding changes in operating programs. The core element of the Digital Twin is a mathematical model of the marine diesel engine’s operating cycle. In its development, significant attention was devoted to refining the fuel combustion model, as the combustion processes significantly impact both the engine’s fuel efficiency and the level of toxic emissions of exhaust gases. The enhanced model differs from the base model, by considering the variable value of the average droplets’ diameter during fuel injection. This influence on fuel vapourisation, combustion, and the formation of toxic components is substantial, as shown. Using the example of calibrating the model to the test results of a diesel engine under 27 operating modes, it is demonstrated that the application of the improved combustion model allows better adjustment of the Digital Twin to experimental data, thus achieving a more accurate correspondence to a real engine.

2

Research on combustion mode of methanol micro-reciprocating piston internal combustion engine

Tang Gang Zhi, Wang Shuai Bin, Zhang Li, Shang Hui Chao

Diagnostyka

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2020

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Vol. 21, No. 1

97--103

EN

Constrained by the micro-space structure, it is proposed to use platinum wire incandescent ignition combustion mode to achieve the operation of internal combustion engine. However, the combustion test of the platinum wire incandescent ignition in miniature piston internal combustion engine shows: the combustion mode of micro-space platinum wire incandescent ignition has a poor combustion characteristic, low heat release rate, long combustion duration, and low combustion pressure. Therefore, a homogenous charge compression ignition mode is proposed to realize the operation of miniature internal combustion engine. However, it is found that the compression combustion cannot be come true in the cold start-up state of the micro engine. And the compression combustion in the first cycle was realized by the way of increasing the temperature of the cylinder block and platinum wire appropriately. The results show that: The maximum heat release rate is obviously improved and the combustion duration shortened by 28.6ºCA, and pmi increased by 76%. So, a novel hybrid combustion mode of in-cylinder compression combustion supported by the platinum wire incandescent ignition is put forward, through the way of adjusting the temperature of platinum wire, and this combustion mode is regarded as the ideal combustion mode of micro reciprocating piston internal combustion engine.

3

Predicting chemical flame lengths and lift-off heights in enclosed, oxy-methane diffusion flames at varying O2/CO2 oxidizer dilution ratios

Krishnamoorthy G., Ditaranto M.

Journal of Power Technologies

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2017

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Vol. 97, nr 4

370--377

EN

Experiments have shown reactor confinement, wall temperatures and radiative transfer to influence the flame length and lift-off characteristics of oxy-methane flames. In this study, the performances of the Shear Stress Transport (SST) k-ω turbulence model, a skeletal methane combustion mechanism (16 species and 41 reactions) and two weighted sum of gray gas models (WSGGM) towards capturing these flame characteristics are evaluated against measurements obtained from oxy-methane flames across a wide range of oxidizer O2/CO2 ratios and fuel Reynolds numbers. Gas composition, gas and wall temperatures, flame length measurements and inferences of lift-off heights from OH* chemiluminescence imaging are employed in the assessment. The corresponding numerical estimate of flame length and lift-off heights were made by determining the flame shape by the locus of points at which the CO concentrations reduce to 1% of their peak values within the flame. The predicted gas temperatures and compositions compared reasonably well against measurements. The criterion for defining the flame shape based on CO concentrations appears promising since the trends in chemical flame length and lift-off height predictions agreed reasonably well with the measurements across the range of oxidizer concentrations and fuel Reynolds numbers. Flame length prediction sensitivities to the wall temperatures and the WSGGM model were also assessed.

4

The theoretical investigation on influence the fuel spray geometry on the combustion and emission characteristic of the marine diesel engine

Kowalski J.

Combustion Engines

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2017

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R. 56, nr 2

101--107

EN

The paper presents an analysis of the influence of the fuel spray geometry on the combustion and emission characteristic of the marine 4-stroke Diesel engine. Presented analysis was prepared based on computational fluid dynamic model (CFD). Initial and boundary conditions of the model as well as data used to model validation were collected during the laboratory study. Calculations were conducted for two different fuel injectors with changed nozzle holes diameters, the number of nozzle holes and the angle between holes axis. The increase of the fuel nozzle holes diameter causes the decrease of the fuel spray tip penetration, but simultaneously the decrease of holes number causes that auto-ignition delay is not changed. The increase of the angle between holes axis from 150° to 158° causes fuel ingintion near cylinder head wall. Result of this is the increase of CO fraction. The deterioration of fuel combustion causes the decrease of NOx mass fraction in the cylinder also.

5

Optical identification of the combustion of air-fuel mixture surrounded by non-combustible gas in a rapid compression machine

Cieślik W., Pielecha I., Wisłocki K.

Archivum Combustionis

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2017

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Vol. 37 nr 2

93--106

EN

The influence of non-combustible gas injection on combustion rates in an engine cylinder with centrally positioned ignition point has been discussed. The flame temperature distribution and its changes were taken into account in this research. The analysis of the influence of exhaust gas content in the cylinder on the combustion process has been based on the interpretation of high speed camera images for the period from the ignition start to full flame coverage of the combustion chamber. Authors performed a comparative analysis of the combustion process thermodynamic parameters based on the obtained characteristics. In order to demonstrate the charge stratification influence and the proportion of flue gas in the cylinder, a flame propagation analysis was performed through high frequency image sampling and using the flame temperature distribution in the combustion volume. The two-color method was used for determining this temperature. A flame temperature distribution example at selected combustion process stages was presented as well as for the entire combustion process. A significant reduction in the area covered by the flame was shown to be the result of an increase in the flue gas proportion in the cylinder. The flame area reduction was found to be 46% when using a 25% EGR share, while with an EGR contribution of 40%, the flame area was decreased by 78%. The flame covered area reduction was the result of "fencing" of the flame from the cylinder walls by an exhaust gas layer. According to changes in the flame area, the largest share of high temperatures, in the range 1800-2000 K, has also decreased from around 19% to 23%.

6

Influence of fuel injector holes diameter on parameters of combustion process in the cylinder of the marine 4-stroke Diesel engine

Kowalski J.

Journal of Polish CIMEEAC

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2016

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Vol. 11, no 1

95--102

EN

The paper presents an analysis of the influence of the fuel injector nozzle holes diameter on parameters of the brake-up, evaporation and combustion process in the cylinder of the marine 4-stroke Diesel engine. Presented analysis was prepared in the basis on computational fluid dynamic model. Initial and boundary conditions of the model as well as data used to model validation were collected during the laboratory study. Calculations were conducted for nominal fuel holes diameter equals 0.375mm and diameters increased and decreased by 50μm and 100μm respectively. According to presented results the increase of the diameter of fuel nozzle holes causes the increase of fuel Sauter’s mean diameter in the initial stage of the injection process and the decrease of fuel process evaporation. The result of this phenomenon is the slowdown of the initial stage of the combustion process and the decrease of both pressure and temperature of combustion.

7

The theoretical study on influence of fuel injection pressure on combustion parameters of the marine 4-stroke engine

Kowalski J.

Journal of KONES

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2016

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Vol. 23, No. 1

161--168

EN

The manuscript presents the analysis of influence of fuel injection pressure on the combustion parameters of marine 4-stroke diesel engine. Analysis is based on computational fluid dynamic (CFD) model designed on the basis of the motion mesh of combustion chamber of the marine engine cylinder and air inlet and exhaust gas ducts. Presented model consists of models of fuel injection into combustion chamber, breaking-up and evaporation of the fuel, mixing with air and turbulent combustion with heat transfer to construction elements of the engine cylinder. Mentioned CFD model is validated according to boundary and initial conditions taken from direct measurements. The chosen research object is laboratory 4-stroke turbocharged Diesel engine with direct injection of the fuel and mechanically controlled of both cylinder valves and the injector. During the calculation the fuel dose, delivered into the engine cylinder was changed without any other changes in the initial and boundary conditions. This approach to the problem allows to the cause-effect analysis. The results of presented study are as follows: The increase of the fuel injection pressure causes the increase of fuel dose, delivered into the engine cylinder and the increase of intensity of both kinetic and diffusion stage of the combustion process. The result of this is the increase of pressure and temperature of the combustion and significant increase of the NOx fraction despite the decrease of the O2 content in the combustion chamber of the engine.

8

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.