An approach to the assessment of dimethyl carbonate and ethanol effect as gasoline oxygenating agents under engine conditions via a Computational Fluid Dynamics model

2021 ◽  
pp. 1-29
Author(s):  
Sara Domínguez-Cardozo ◽  
Ana María Valencia-López ◽  
Felipe Bustamante
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Chemical Kinetics ◽  
Dimethyl Carbonate ◽  
Co2 Reduction ◽  
Detailed Chemistry ◽  
Starting Point ◽  
Soot Emissions ◽  
A Minor ◽  
Oxygenated Fuels

Abstract An ASTM-CFR engine was modeled through Computational Fluid Dynamics (CFD) coupled with chemical kinetics to evaluate the effect on combustion characteristics and engine emissions of dimethyl carbonate (DMC) and ethanol as gasoline components, the latter as reference oxygenating agent. Validation against experimental in-cylinder pressure data indicated adequate reproduction of these fuels combustion, all blends showing higher and earlier pressure peaks than neat gasoline (ca. 0.2 MPa and 2 CAD). Simulated temperatures were close for all fuels, though slightly advanced for the oxygenated blends (ca. 2 CAD). Similar behavior of the oxygenates was predicted regarding HC, CO and soot emissions: ca. 90% reduction in HC, CO, and soot emissions were observed, but ethanol displayed up to 3.5% CO2 reduction and 17% NOx increase, while DMC showed up to 7% decrease in CO2 and 6% increase in NOx. Considering the advantage of using chemical kinetics for combustion calculations in the CFD model, i.e., quantification of any species present in the reaction mechanism, including those difficult to observe/measure experimentally, concentrations of non-regulated emissions (e.g., formaldehyde) were studied. In particular, a minor increase in formaldehyde emissions was found with both oxygenated fuels. Albeit a first approach to assessing oxygenating compounds effects on gasoline combustion and emissions under engine conditions through a CFD + detailed chemistry model, the results underline the potential of DMC as gasoline oxygenating agent, and are a starting point for studying non-measured/non-regulated species and parametric engine analysis in future models.

Comparisons of Diesel PCCI Combustion Simulations Using a Representative Interactive Flamelet Model and Direct Integration of CFD With Detailed Chemistry

2006 ◽  
Vol 129 (1) ◽  
pp. 252-260 ◽  
Author(s):  
Song-Charng Kong ◽  
Hoojoong Kim ◽  
Rolf D. Reitz ◽  
Yongmo Kim
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Direct Integration ◽  
Computational Cell ◽  
Flamelet Model ◽  
Detailed Chemistry ◽  
Engine Simulation ◽  
Integration Approach ◽  
Simulation Results ◽  
Release Data

Diesel engine simulation results using two different combustion models are presented in this study, namely the representative interactive flamelet (RIF) model and the direct integration of computational fluid dynamics and CHEMKIN. Both models have been implemented into an improved version of the KIVA code. The KIVA/RIF model uses a single flamelet approach and also considers the effects of vaporization on turbulence-chemistry interactions. The KIVA/CHEMKIN model uses a direct integration approach that solves for the chemical reactions in each computational cell. The above two models are applied to simulate combustion and emissions in diesel engines with comparable results. Detailed comparisons of predicted heat release data and in-cylinder flows also indicate that both models predict very similar combustion characteristics. This is likely due to the fact that after ignition, combustion rates are mixing controlled rather than chemistry controlled under the diesel conditions studied.

Coupling Complex Reformer Chemical Kinetics with Three-Dimensional Computational Fluid Dynamics

2019 ◽  
Vol 25 (2) ◽  
pp. 1253-1262 ◽  
Author(s):  
Graham Goldin ◽  
Huayang Zhu ◽  
Kyle Kattke ◽  
Anthony Dean ◽  
Robert Braun ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Chemical Kinetics ◽  
Three Dimensional

A fully coupled computational fluid dynamics and multi-zone model with detailed chemical kinetics for the simulation of premixed charge compression ignition engines

2005 ◽  
Vol 6 (5) ◽  
pp. 497-512 ◽  
Author(s):  
A Babajimopoulos ◽  
D N Assanis ◽  
D L Flowers ◽  
S M Aceves ◽  
R P Hessel
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Chemical Kinetics ◽  
Zone Model ◽  
Compression Ignition ◽  
Detailed Chemical Kinetics ◽  
Fully Integrated ◽  
Fully Coupled ◽  
Detailed Chemical ◽  
The Ideal

Modelling the premixed charge compression ignition (PCCI) engine requires a balanced approach that captures both fluid motion as well as low- and high-temperature fuel oxidation. A fully integrated computational fluid dynamics (CFD) and chemistry scheme (i.e. detailed chemical kinetics solved in every cell of the CFD grid) would be the ideal PCCI modelling approach, but is computationally very expensive. As a result, modelling assumptions are required in order to develop tools that are computationally efficient, yet maintain an acceptable degree of accuracy. Multi-zone models have been previously shown accurately to capture geometry-dependent processes in homogeneous charge compression ignition (HCCI) engines. In the presented work, KIVA-3V is fully coupled with a multi-zone model with detailed chemical kinetics. Computational efficiency is achieved by utilizing a low-resolution discretization to solve detailed chemical kinetics in the multi-zone model compared with a relatively high-resolution CFD solution. The multi-zone model communicates with KIVA-3V at each computational timestep, as in the ideal fully integrated case. The composition of the cells, however, is mapped back and forth between KTVA-3V and the multi-zone model, introducing significant computational time savings. The methodology uses a novel re-mapping technique that can account for both temperature and composition non-uniformities in the cylinder. Validation cases were developed by solving the detailed chemistry in every cell of a KIVA-3V grid. The new methodology shows very good agreement with the detailed solutions in terms of ignition timing, burn duration, and emissions.

Additive Manufacturing in the Design of an Engine Air Particle Separator

2015 ◽  
Author(s):  
Alexander D. Cozier ◽  
Kyle E. Harned ◽  
Margaret A. Riley ◽  
Benjamin H. Raabe ◽  
Andrew D. Sommers ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Additive Manufacturing ◽  
Radial Distance ◽  
Injection System ◽  
Test Bed ◽  
Design Iteration ◽  
Starting Point ◽  
Particle Separator

Engine air particle separators are an important technology for aircraft operating in dusty environments. Using either vorticity or inertia to separate particles from the airstream entering the engine staves off premature filter failure that can compromise mission performance. While a body of literature exists on engine air particle separators, it is widely recognized that their design is significantly constrained by traditional manufacturing methods, and that this limits the generation of experimental data available to develop further insight into their design. Computational fluid dynamics can provide a starting point, but such simulations of complex, turbulent, particle-laden flow require considerable time and extensive computing resources while carrying no guarantee of accuracy. Additive manufacturing offers an attractive solution. It is capable of producing complex geometries quickly and economically, facilitating rapid design iteration and generation of experimental data. This work, sponsored by the Air Force Research Laboratory, focuses on the design of an engine air particle separator for use on an unmanned aerial vehicle. The sponsor’s dual intent was to advance engine air particle separator design and, more importantly, showcase the capabilities of additive manufacturing in the design development process for aerospace components. Free from manufacturing constraints, novel particle separator designs were considered. Using computational fluid dynamics to evaluate non-laden flow characteristics such as pressure drop, these designs were evaluated and compared to more conventional inertial and vortex designs. From this analysis a hybrid design that combines features of both the inertial and vortex separators was chosen for testing. Using the fan from a wind tunnel as a source of flow, a custom test section was created and instrumented that included an upstream particle injection system and separate flow paths for clean and dirty air (which in and of itself is geometrically complex and was fabricated using additive manufacturing). Although experiments are ongoing, one interesting result has already emerged. One particular design parameter from the literature for inertial particle separators is the ratio of the axial to radial distance between the splitter and the hump (or, the peak of the inner body) as measured from the central axis. This ratio is essentially a measure of the severity of the flow deflection for which other authors have suggested a “rule of thumb” for its proportions. Our results show that this rule may also be extended to some hybrid particle separators (such as the one examined in this work), where vorticity is introduced upstream of the hump. This project has demonstrated the power of additive manufacturing in product design and development. Its near limitless geometric possibilities allowed the team to examine areas of the design space that were previously unexplored. Further, after developing the test bed, the team demonstrated the ability to complete a full design iteration in one day — testing in the morning, analyzing results and designing the next prototype in the afternoon, and printing the next prototype overnight.

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