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 A Novel Dual Fuel Reaction Mechanism for Ignition in Natural Gas–Diesel Combustion

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4396 ◽  
Author(s):  
Sebastian Schuh ◽  
Jens Frühhaber ◽  
Thomas Lauer ◽  
Franz Winter
Keyword(s):  
Reaction Mechanism ◽  
Natural Gas ◽  
Combustion Process ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Cfd Simulations ◽  
Surrogate Fuels ◽  
Ignition Delay Times ◽  
Computational Fluid Dynamics Cfd ◽  
Dual Fuel Combustion

In this study, a reaction mechanism is presented that is optimized for the simulation of the dual fuel combustion process using n-heptane and a mixture of methane/propane as surrogate fuels for diesel and natural gas, respectively. By comparing the measured and calculated ignition delay times (IDTs) of different homogeneous methane–propane–n-heptane mixtures, six different n-heptane mechanisms were investigated and evaluated. The selected mechanism was used for computational fluid dynamics (CFD) simulations to calculate the ignition of a diesel spray injected into air and a natural gas–air mixture. The observed deviations between the simulation results and the measurements performed with a rapid compression expansion machine (RCEM) and a combustion vessel motivated the adaptation of the mechanism by adjusting the Arrhenius parameters of individual reactions. For the identification of the reactions suitable for the mechanism adaption, sensitivity and flow analyzes were performed. The adjusted mechanism is able to describe ignition phenomena in the context of natural gas–diesel, i.e., dual fuel combustion.

scholarly journals Experimental Investigation and Benchmark Study of Oxidation of Methane–Propane–n-Heptane Mixtures at Pressures up to 100 bar

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3410 ◽  
Author(s):  
Sebastian Schuh ◽  
Ajoy Kumar Ramalingam ◽  
Heiko Minwegen ◽  
Karl Alexander Heufer ◽  
Franz Winter
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Suitable Model ◽  
Simulation Tools ◽  
Oxidation Of Methane ◽  
Ignition Delay Times ◽  
Development Costs ◽  
Dual Fuel Combustion

Dual fuel combustion exhibits a high degree of complexity due to the presence of different fuels like diesel and natural gas in initially different physical states and a spatially strongly varying mixing ratio. Optimizing this combustion process on an engine test bench is costly and time consuming. Cost reduction can be achieved by utilizing simulation tools. Although these tools cannot replace the application of test benches completely, the total development costs can be reduced by an educated combination of simulations and experiments. A suitable model for describing the reactions taking place in the combustion chamber is required to correctly reproduce the dual fuel combustion process. This is why in the presented study, four different reaction mechanisms are benchmarked to shock tube (ST) and rapid compression machine (RCM) measurements of ignition delay times (IDTs) at pressures between 60 and 100 bar and temperatures between 671 and 1284 K. To accommodate dual fuel relevant diesel-natural gas mixtures, methane–propane–n-heptane mixtures are considered as the surrogate. Additionally, the mechanisms AramcoMech 1.3, 2.0 and 3.0 are tested for methane–propane mixtures. The influence of pressure and propane/n-heptane content on the IDT based on the measurements is presented and the extent to which the mechanisms can reflect the IDT-changes discussed.

Experimental Investigation of the Natural Gas / Diesel Dual-Fuel Combustion Using a Rapid Compression Machine

2011 ◽  
Author(s):  
Julio C. C. Eg\ausquiza ◽  
Sergio L. Braga ◽  
Carlos V. M. Braga ◽  
Antonio C. S. Villela ◽  
Newton R. Moura
Keyword(s):  
Experimental Investigation ◽  
Natural Gas ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Rapid Compression Machine ◽  
Dual Fuel Combustion ◽  
Rapid Compression

New Dual-fuel Combustion Process for Passenger Car Engines

MTZ worldwide ◽  
2018 ◽  
Vol 79 (6) ◽  
pp. 60-67
Author(s):  
Florian Sprenger ◽  
Paul Fasching ◽  
Christina Granitz ◽  
Helmut Eichlseder
Keyword(s):  
Combustion Process ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Passenger Car ◽  
Dual Fuel Combustion

Ability of the Methane Number Index of a Fuel to Predict Rapid Combustion in Heavy Duty Dual Fuel Engines for North American Locomotives

2015 ◽  
Author(s):  
Daniel G. Van Alstine ◽  
David T. Montgomery ◽  
Timothy J. Callahan ◽  
Radu C. Florea
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Rapid Combustion ◽  
Dual Fuel Engines ◽  
Dual Fuel Combustion ◽  
Methane Number

Low natural gas prices have made the fuel an attractive alternative to diesel and other common fuels, particularly in applications that consume large quantities of fuel. The North American rail industry is examining the use of locomotives powered by dual fuel engines to realize savings in fuel costs. These dual fuel engines can substitute a large portion of the diesel fuel with natural gas that is premixed with the intake air. Engine knock in traditional premixed spark-ignited combustion is undesirable but well characterized by the Methane Number index, which quantifies the propensity of a gaseous fuel to autoignite after a period of time at high temperature. Originally developed for spark-ignited engines, the ability of the methane number index to predict a fuel’s “knock” behavior in dual fuel combustion is not as fully understood. The objective of this effort is to evaluate the ability of an existing methane number algorithm to predict rapid combustion in a dual fuel engine. Sets of specialized natural gas fuel blends that, according to the MWM methane number algorithm, should have similar knock characteristics are tested in a dual fuel engine and induced to experience rapid combustion. Test results and CFD analysis reveal that rapid or aggressive combustion rates happen late in the dual fuel combustion event with this engine hardware configuration. The transition from normal combustion to late rapid combustion is characterized by changes in the heat release rate profiles. In this study, the transition is also represented by a shift in the crank angle location of the combustion’s peak heat release rate. For fuels of similar methane number that should exhibit similar knock behavior, these transitions occur at significantly different relative air-fuel ratios, demonstrating that the existing MWM methane number algorithm, while excellent for spark-ignited engines, does not fully predict the propensity for rapid combustion to occur in a dual fuel engine within the scope of this study. This indicates that physical and chemical phenomena present in rapid or aggressive dual fuel combustion processes may differ from those in knocking spark-ignited combustion. In its current form a methane number algorithm can be used to conservatively rate dual fuel engines. It is possible that derivation of a new reactivity index that better predicts rapid combustion behavior of the gaseous fuel in dual fuel combustion would allow ratings to be less conservative.

Effects of N-Butanol Content on the Dual-Fuel Combustion Mode With CNG at Two Engine Speeds

2018 ◽  
Author(s):  
Xiangyu Meng ◽  
Wuqiang Long ◽  
Yihui Zhou ◽  
Mingshu Bi ◽  
Chia-Fon F. Lee
Keyword(s):  
Thermal Efficiency ◽  
Engine Speed ◽  
Direct Injection ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Combustion Mode ◽  
Start Of Injection ◽  
Wide Range ◽  
Pilot Fuel ◽  
Dual Fuel Combustion

Because of the potential to reduce NOx and PM emissions simultaneously and the utilization of biofuel, diesel/compressed natural gas (CNG) dual-fuel combustion mode with port injection of CNG and direct injection of diesel has been widely studied. While in comparison with conventional diesel combustion mode, the dual-fuel combustion mode generally leads lower thermal efficiency, especially at low and medium load, and higher carbon monoxide (CO) and total hydrocarbons (THC) emissions. In this work, n-butanol was blended with diesel as the pilot fuel to explore the possibility to improve the performance and emissions of dual-fuel combustion mode with CNG. Various pilot fuels of B0 (pure diesel), B10 (90% diesel/10% n-butanol by volume basis), B20 (80% diesel/20% n-butanol) and B30 (70% diesel/30% n-butanol) were compared at the CNG substitution rate of 70% by energy basis under the engine speeds of 1400 and 1800 rpm. The experiments were carried out by sweeping a wide range of pilot fuel start of injection timings based on the same total input energy including pilot fuel and CNG. As n-butanol was added into the pilot fuel, the pilot fuel/CNG/air mixture tends to be more homogeneous. The results showed that for the engine speed of 1400 rpm, pilot fuel with n-butanol addition leads to a slightly lower indicated thermal efficiency (ITE). B30 reveals much lower NOx emission and slightly higher THC emissions. For the engine speed of 1800 rpm, B20 can improve ITE and decrease the NOx and THC emissions simultaneously relative to B0.

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