scholarly journals A Mapping Approach for Efficient CFD Simulation of Low-Speed Large-Bore Marine Engine with Pre-Chamber and Dual-Fuel Operation

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6126
Author(s):  
Ying Ye ◽  
Zongyu Yue ◽  
Hu Wang ◽  
Haifeng Liu ◽  
Chaohui Wu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Cfd Simulation ◽  
Exothermic Reaction ◽  
Combustion Process ◽  
Equation Model ◽  
Dual Fuel ◽  
Marine Engine ◽  
Mapping Approach ◽  
Effective Manner ◽  
Depth Analysis

A natural-gas-diesel dual-fuel marine engine with a pre-chamber is a promising solution for ocean transportation to meet the International Maritime Organization (IMO) emission regulations. This engine system employs a pre-chamber with direct injection of diesel to ignite premixed natural gas due to its higher ignition energy, which can enable lower lean limit and higher thermal efficiency. The dual-fuel pre-chamber marine engine presents complex multi-regime combustion characteristics in- and outside the pre-chamber, thus posing challenges in its numerical simulation in a cost-effective manner. Therefore, this paper presents a three-dimensional modeling study for the multi-regime combustion in a large-bore two-stroke marine dual-fuel engine, proposing a novel mapping approach, which couples the well-stirred reactor (WSR) model with the G-equation model to achieve high computational accuracy and efficiency simultaneously. In-depth analysis is performed using representative exothermic reaction (RXR) analysis and premixed turbulent combustion fundamentals to better understand the combustion process and to provide guidance in the selection of mapping timing. The results show that the use of mapping to switch from the WSR to the G-equation model can effectively reduce the runtime significantly by 71.5%, meanwhile maintaining similar accuracies in predictions of in-cylinder pressure traces, HRR and NOx emissions, compared to using WSR all along. Additionally, the choice of mapping timing based on several parameters is preliminarily discussed.

scholarly journals A Numerical Study on the Combustion Process and Emission Characteristics of a Natural Gas-Diesel Dual-Fuel Marine Engine at Full Load

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1342
Author(s):  
Van Chien Pham ◽  
Jae-Hyuk Choi ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Kyunam Park ◽  
...  
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Simulation Software ◽  
Dual Fuel ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Cylinder Pressure ◽  
Marine Engine ◽  
Full Load ◽  
Simulation Results

This paper presents research on the combustion and emission characteristics of a four-stroke Natural gas–Diesel dual-fuel marine engine at full load. The AVL FIRE R2018a (AVL List GmbH, Graz, Austria) simulation software was used to conduct three-dimensional simulations of the combustion process and emission formations inside the engine cylinder in both diesel and dual-fuel mode to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were then compared and showed a good agreement with the measured values reported in the engine’s shop test technical data. The simulation results showed reductions in the in-cylinder pressure and temperature peaks by 1.7% and 6.75%, while NO, soot, CO, and CO2 emissions were reduced up to 96%, 96%, 86%, and 15.9%, respectively, in the dual-fuel mode in comparison with the diesel mode. The results also show better and more uniform combustion at the late stage of the combustions inside the cylinder when operating the engine in the dual-fuel mode. Analyzing the emission characteristics and the engine performance when the injection timing varies shows that, operating the engine in the dual-fuel mode with an injection timing of 12 crank angle degrees before the top dead center is the best solution to reduce emissions while keeping the optimal engine power.

Simulation Research on Combustion Process in a Natural Gas-Diesel Dual-Fuel Marine Engine

2014 ◽  
Vol 525 ◽  
pp. 227-231 ◽  
Author(s):  
Min Xiao ◽  
Chun Long Feng
Keyword(s):  
Natural Gas ◽  
Total Energy ◽  
Combustion Process ◽  
Power Reduction ◽  
Dual Fuel ◽  
Injection Timing ◽  
Simulation Research ◽  
Injection Duration ◽  
Medium Speed ◽  
The Right

In order to solve the problem of Diesel natural gas dual fuel engine, such as power reduction, low charging efficiency, the conception of diesel engine fueled with pilot-ignited directly-injected liquefied natural gas is put forward. On the basis of this theory, a medium speed diesel of the marine is refitted into dual fuel engine, in order to keep original power, decrease the temperature of combustion and reduce emission. The LNG injection timing, duration of LNG injection and the different ratios the pilot diesel to total energy are studied the method of AVL FIRE software. Conclusions are as follows: When the different ratios pilot diesel to total energy is 0.5%, the engine can not work; Delaying the LNG injection timing, shortening the LNG injection duration and choose the right ratios pilot diesel to total energy can reach the indicated power of original machine, and the NOx emissions level will be greatly reduced.

Numerical Simulation of a Large Bore Dual Fuel Marine Engine Using Tabulated Detailed Reaction Mechanisms

2019 ◽  
Author(s):  
Sascha Andree ◽  
Dmitry Goryntsev ◽  
Martin Theile ◽  
Björn Henke ◽  
Karsten Schleef ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Natural Gas ◽  
Chemical Reaction ◽  
Reaction Mechanisms ◽  
Combustion Process ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Start Of Injection ◽  
Flamelet Generated Manifold ◽  
Dual Fuel Combustion

Abstract The simulation of a diesel natural gas dual fuel combustion process is the topic of this paper. Based on a detailed chemical reaction mechanism, which was applied for such a dual fuel combustion, the complete internal combustion engine process was simulated. Two single fuel combustion reaction mechanisms from literature were merged, to consider the simultaneous reaction paths of diesel and natural gas. N-heptane was chosen as a surrogate for diesel. The chemical reaction mechanisms are solved by applying a tabulation method using the software tool AVL Tabkin™. In combination with a Flamelet Generated Manifold (FGM) combustion model, this leads to a reduction of computational effort compared to a direct solving of the reaction mechanism, because of a decoupling of chemistry and flow calculations. Turbulence was modelled using an unsteady Reynolds-Averaged Navier Stokes (URANS) model. In comparison to conventional combustion models, this approach allows for detailed investigations of the complex ignition process of the dual fuel combustion process. The unexpected inversely proportional relationship between start of injection (SOI) and start of combustion (SOC), a later start of injection makes for an earlier combustion of the main load, is only one of these interesting combustion phenomena, which can now be analyzed in detail. Further investigations are done for different engine load points and multiple pilot injection strategies. The simulation results are confirmed by experimental measurements at a medium speed dual fuel single cylinder research engine.

scholarly journals Use of Adaptive Injection Strategies to Increase the Full Load Limit of RCCI Operation

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Reed Hanson ◽  
Andrew Ickes ◽  
Thomas Wallner
Keyword(s):  
Natural Gas ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Experimental Testing ◽  
Peak Load ◽  
Combustion Process ◽  
Pressure Rise ◽  
Dual Fuel ◽  
The Impact ◽  
Injection Strategies

Dual-fuel combustion using port-injection of low reactivity fuel combined with direct injection (DI) of a higher reactivity fuel, otherwise known as reactivity controlled compression ignition (RCCI), has been shown as a method to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending to high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. One way to accomplish this is to use a very low reactivity fuel such as natural gas. In this work, experimental testing was conducted on a 13 l multicylinder heavy-duty diesel engine modified to operate using RCCI combustion with port injection of natural gas and DI of diesel fuel. Engine testing was conducted at an engine speed of 1200 rpm over a wide variety of loads and injection conditions. The impact on dual-fuel engine performance and emissions with respect to varying the fuel injection parameters is quantified within this study. The injection strategies used in the work were found to affect the combustion process in similar ways to both conventional diesel combustion (CDC) and RCCI combustion for phasing control and emissions performance. As the load is increased, the port fuel injection (PFI) quantity was reduced to keep peak cylinder pressure (PCP) and maximum pressure rise rate (MPRR) under the imposed limits. Overall, the peak load using the new injection strategy was shown to reach 22 bar brake mean effective pressure (BMEP) with a peak brake thermal efficiency (BTE) of 47.6%.

Investigation of the High-Pressure-Dual-Fuel (HPDF) combustion process of natural gas on a fully optically accessible research engine

2019 ◽  
Author(s):  
Stephan Gleis ◽  
Stephanie Frankl ◽  
Dominik Waligorski ◽  
Dr.-Ing. Maximilian Prager ◽  
Prof. Dr.-Ing. Georg Wachtmeister
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Combustion Process ◽  
Dual Fuel

scholarly journals EFFECT OF CNG IN A FUEL DOSE ON THE COMBUSTION PROCESS OF A COMPRESSION-IGNITION ENGINE

Transport ◽  
2015 ◽  
Vol 30 (2) ◽  
pp. 162-171 ◽  
Author(s):  
Maciej Mikulski ◽  
Sławomir Wierzbicki
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Alternative Fuels ◽  
Combustion Process ◽  
Diesel Oil ◽  
Dual Fuel ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Compression Ignition Engines ◽  
Main Component

Currently, one of the major trends in the research of contemporary combustion engines involves the potential use of alternative fuels. Considerable attention has been devoted to methane, which is the main component of Natural Gas (NG) and can also be obtained by purification of biogas. In compression-ignition engines fired with methane or Compressed Natural Gas (CNG), it is necessary to apply a dual-fuel feeding system. This paper presents the effect of the proportion of CNG in a fuel dose on the process of combustion. The recorded time series of pressure in a combustion chamber was used to determine the repeatability of the combustion process and the change of fuel compression-ignition delay in the combustion chamber. It has been showed that NG does not burn completely in a dual-fuel engine. The best conditions for combustion are ensured with higher concentrations of gaseous fuel. NG ignition does not take place simultaneously with diesel oil ignition. Moreover, if a divided dose of diesel is injected, NG ignition probably takes place at two points, as diesel oil.

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