A preliminary numerical study on the use of methanol as a Mono-Fuel for a large bore marine engine

A numerical study was carried out to investigate the effects of methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), and dimethyl ether (DME) on the combustion and emission characteristics of a four-stroke gas-diesel dual-fuel (DF) marine engine at full load. Three-dimensional simulations of the combustion process and emission formation inside the engine cylinder in the diesel and DF modes were performed using the AVL FIRE R2018a simulation software to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results agreed well with the measured values reported in the engine shop test technical data. The simulation results showed reductions in the in-cylinder peak pressure and temperatures, as well as the emission formations, in the DF modes in comparison to the diesel mode. The DF mode could significantly reduce nitric oxide (NO) emissions (up to 96.225%) of DME compared to the diesel mode. Meanwhile, C3H8 and CH4 fuels effectively reduced the soot (up to 82.78%) and carbon dioxide (CO2) emissions (by 21.33%), respectively, compared to the diesel mode. However, the results also showed longer ignition delay times of the combustion processes when the engine operated in the DF mode, particularly in the DME-diesel mode. The combustion and emission characteristics of the engine were also analyzed when varying the injection timing; the results showed that applying the injection timing adjustment method could further address NO emission problems but led to a decrease in the engine power. Therefore, it is necessary to consider the benefits and disadvantages of adopting the injection timing adjustment strategy to address certain engine emission problems. This study successfully analyzed the benefits of using various gas fuels as alternative fuels and the injection timing adjustment method in DF marine engines to meet the International Maritime Organization (IMO) emission regulations without the use of any emission after-treatment devices.

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A Numerical Study on the Design and Flow Patterns of Compressor Impeller in a Marine Engine Turbocharger

ASME 2004 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2004-0857 ◽

2004 ◽

Author(s):

Hong-Won Kim ◽

Seung-Hyup Ryu ◽

Sang-Hak Ghal ◽

Ji-Soo Ha

Keyword(s):

Centrifugal Compressor ◽

High Speed ◽

Numerical Study ◽

Three Dimensional ◽

Compressed Air ◽

Optimized Design ◽

Vaneless Diffuser ◽

Marine Engine ◽

Compressor Impeller ◽

Impeller Geometry

The centrifugal compressor design of the high-speed marine engine (500–900 kW) turbocharger has been done. Increased Higher compressed air and power density help improvement of the engine performance and power. The centrifugal compressor of the marine engine turbocharger is composed of impeller, 1st vaneless diffuser, vaned diffuser, 2nd vaneless diffuser and volute casing. The design process is achieved by three following stages. First, quasi-two dimensional code is used to determine the main geometry of the compressor. Second, three-dimensional compressible Navier-Stokes equation is applied to analyze the flow pattern and structures of the compressor blade loading. Here, among compressor impeller geometry, blade height variables are mainly changed. Smooth flow guidance has to precede and flow separation symptoms must not appear within compressor impeller. When the loading distribution is inadequate from blade hub to shroud, new curved profile should be designed to minimize the pressure loss. By analyzing the internal flow fields for the compressor impeller geometry variations, three dimensional impeller design profile has been confirmed. Compressed air pressure and mass flow rates from new optimized design were 2.7%, 27.3% higher than that of old one each other. Third, analyzed results are compared with experimental data for the verification of the present design method.

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The Numerical Study on the Performance Evaluations and Flow Structures for the Diffuser of Centrifugal Compressor in a Marine Engine Turbocharger

ASME 2006 Internal Combustion Engine Division Fall Technical Conference (ICEF2006) ◽

10.1115/icef2006-1546 ◽

2006 ◽

Author(s):

Hong-Won Kim ◽

Seung-Hyup Ryu ◽

Jong-Il Park ◽

Sang-Hak Ghal ◽

Ji-Soo Ha

Keyword(s):

Centrifugal Compressor ◽

High Efficiency ◽

Numerical Study ◽

Pressure Ratio ◽

Prediction Method ◽

Pressure Recovery ◽

Vaneless Diffuser ◽

Vaned Diffuser ◽

Marine Engine ◽

High Pressure Ratio

The centrifugal compressor of marine engine turbocharger is composed of impeller, 1st vaneless diffuser, vaned diffuser, 2nd vaneless diffuser and volute casing. An examination of the condition of the flow leaving the impeller exit kinetic energy often accounts for 30–50% of the shaft work input to the compressor stage, and for energy efficiency it is important to recover as much of this as possible. This is the function of the diffuser which follows the impeller. Effective pressure recovery downstream of an impeller is very important to realize a centrifugal compressor with high efficiency and high pressure ratio, and an appropriate selection of a diffuser for a specific impeller is a critical step to develop the compressor accordingly. The purpose of this study is to investigate the sensitivity of how compressor performances changes as vaned diffuser geometry is varied. Three kinds of vaned diffusers were studied and its results were compared. First vaned diffuser type is based on NACA airfoil and second is channel diffuser and third is conformal transformation of NACA 65 airfoil. Mean-line prediction method was applied to investigate the performance and stability for three kinds of diffusers. And CFD analyses have been done for comparison and detailed interior flow pattern study. In this study, the off design behavior of three different type of diffuser, given by mean-line prediction, was investigated using CFD results and selected best diffuser geometry which satisfy wider operating range and higher pressure recovery than the others. The numerical results were compared with experimental data for validation.

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Preliminary Numerical Study on Exhaust Emission Characteristics of Particulate Matters and Nitrogen Oxide in a Marine Engine for Marine Diesel Oil and Dimethyl Ether Fuel

Journal of Marine Science and Engineering ◽

10.3390/jmse8050316 ◽

2020 ◽

Vol 8 (5) ◽

pp. 316

Author(s):

Jinkyu Park ◽

Iksoo Choi ◽

Jungmo Oh ◽

Changhee Lee

Keyword(s):

Nitrogen Oxide ◽

Dimethyl Ether ◽

Alternative Fuels ◽

Numerical Study ◽

Alternative Fuel ◽

Diesel Oil ◽

Injection System ◽

Injection Timing ◽

Marine Engine ◽

Marine Diesel

As concerns regarding environmental pollution, energy security and future oil supply continue to grow, communities around the world are looking for non-petroleum-based alternative fuels along with advanced energy technologies (e.g., fuel cells) to increase energy use efficiency. Compared with the main alternative fuel candidates (e.g., methane, methanol, ethanol and Fischer–Tropsch fuels), dimethyl ether (DME) seems to have a significant potential to solve the aforementioned problems and can be used as a clean, high-efficiency compressed ignition fuel with reduced nitrogen oxide, sulphur oxide and particulate matter (PM) emissions. In this study, the results of experiments using a ship engine and numerical analysis were verified using AVL BOOST software. Based on these verifications, nitrogen oxide and PM reduction characteristics were numerically analysed by controlling the diameter and spraying time of the fuel nozzle, which is the fuel injection system of a marine engine. When DME fuel was used, nitrogen oxide and PM emissions were reduced by 40% and 90%, respectively, compared with marine diesel oil fuel. To prove the viability of DME as an alternative fuel, combustion and exhaust characteristics were analysed in accordance with injection timing and the variation of nozzle hole.

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