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2017-03-28
Technical Paper
2017-01-1014
David Moyer, Roger Khami, Andrew Bellis, Thomas Luley
Engine Air Induction Systems Hydrocarbon Trap (HC Trap) Designs, to limit evaporative fuel emissions, have evolved over time. This paper discusses a range of HC Traps that have evolved in Engine Air Induction Systems. (AIS) The early Zeolite Flow through Hydrocarbon Trap utilized an exhaust catalyst technology internal stainless steel furnace brazed substrate coated with Zeolite media. This HC Trap was installed in the AIS Clean Air Tube. This design was heavy, complicated, and expensive but met the urgency of the implementation of the new evaporative emissions regulation. The latest Ford Motor Company HC Trap is a simple plastic tray containing activated carbon with breathable non-woven polyester cover. This design has been made common across multiple vehicle lines with planned production annual volume in the millions. The cost of the latest HC Trap Bypass design is approximately 5% of the original Stainless Steel Zeolite Flow Through HC Trap.
2017-03-28
Technical Paper
2017-01-0898
Jongwon Lee, Sedoo Oh, Kyung Sub Joo, Seyoung Yi, Kyoung-Pyo Ha, Seongbaek Joo
Abstract The engine indicated torque is not delivered entirely to the wheels, because it is lowered by losses, such as the pumping, mechanical friction and front auxiliary power consumption. The front auxiliary belt drive system is a big power consumer-fueling and operating the various accessory devices, such as air conditioning compressor, electric alternator, and power steering pump. The standard fuel economy test does not consider the auxiliary driving torque when it is activated during the actual driving condition and it is considered a five-cycle correction factor only. Therefore, research on improving the front end auxiliary drive (FEAD) system is still relevant in the immediate future, particularly regarding the air conditioning compressor and the electric alternator. An exertion to minimize the auxiliary loss is much smaller than the sustained effort required to reduce engine friction loss.
2017-03-28
Technical Paper
2017-01-0654
Haiqiao Wei, Dengquan Feng, Mingzhang pan, JiaYing PAN
Abstract Combustion characteristics of neat 2-methylfuran (MF), 10% and 20% volumetric fraction 2-methylfuran gasoline blends were experimentally investigated in a single cylinder spark ignition engine, and the results were benchmarked against that of the research on octane number 97 neat gasoline. The investigation focused on the performance of cyclic variation of MF and its blends, and the effects of spark ignition timing, compression ratio, and exhaust gas recirculation (EGR) were studied. Experiments were conducted at the engine speed of 1500 rpm, and loads between 7 and 11 bar indicated mean effective pressure (IMEP) with using stoichiometric air-fuel ratio mixture. Index of the coefficient of variation of IMEP (COVIMEP) was used to evaluate the combustion stability of the tested fuels. The results show that neat MF and MF gasoline blended fuels have superior combustion stability compared with gasoline.
2017-03-28
Technical Paper
2017-01-0699
Sampad Mukhopadhyay, Sunil Srinivas Badavath, Naeim Henein
Abstract The superior fuel economy of direct injection internal combustion engines (diesel and gasoline) is related to use of a high compression ratio to auto-ignite the fuel and the overall lean combustible mixture. Two of the major problems in diesel engine emissions are the NOx and soot emissions, which are caused by the heterogeneity of the charge and the properties of the diesel fuel. Conventional Direct Injection Spark Ignition Gasoline engines don't have these problems because of the fuel properties particularly its volatility. However, its efficiency and specific power output are limited by the knock, knock produced preignition and the sporadic preignition phenomenon. The Gasoline Direct Injection Compression Ignition (GDICI) engine combines the superior features of the two engines by increasing the compression ratio and use of gasoline as a fuel.
2017-03-28
Technical Paper
2017-01-0694
Tae Joong Wang, Jong Yoon Lee, Seung Kwon Hwang, Ja Yun Cho, Jeong Keun Park, Woong Gun Lee, Tae Sub Kim, Sang Won Jeong, Tae Kuk Kim
Abstract Doosan Infracore Corporation has developed the combustion system of a brand-new DX12 heavy-duty diesel engine equipped for 38 ~ 50 tonnage excavators and 4.2 ~ 4.5 m3 bucket-size wheel loaders which are mainly targeted to emerging countries. A variety of advanced combustion technologies were incorporated in the design of the DX12 engine to meet Tier3 emission legislation even with a mechanically controlled fuel injection equipment while ensuring around 2 % improvement in fuel consumption as well as over 8 % increase in rated power than its Tier2 predecessor. Mechanical-type diesel engine has a couple of significant advantages especially in terms of cost and maintenance compared to electronic-type counterpart. In addition, mechanical fuel system is better able to tolerate a low fuel quality which is potentially possible in emerging countries.
2017-03-28
Technical Paper
2017-01-0701
Aaron M. Bertram, Song-Charng Kong
Abstract The objective of this work was to identify methods of reliably predicting optimum operating conditions in an experimental compression ignition engine using multiple injections. Abstract modeling offered an efficient way to predict large volumes data, when compared with simulation, although the initial cost of constructing such models can be large. This work aims to reduce that initial cost by adding knowledge about the favorable network structures and training rules which are discovered. The data were gathered from a high pressure common rail direct injection turbocharged compression ignition engine utilizing a high EGR configuration. The range of design parameters were relatively large; 100 MPa - 240 MPa for fuel pressure, up to 62% EGR using a modified, long-route, low pressure EGR system, while the pilot timing, main timing, and pilot ratio were free within the safe operating window for the engine.
2017-03-28
Technical Paper
2017-01-0720
Omar Ramadan, Luc Menard, David Gardiner, Aaron Wilcox, Gary Webster
Abstract This paper is a continuation of work previously discussed in SAE 2014-01-0179 [1] and SAE 2015-01-0805 [2], which was intended to improve the capability and precision of the Ignition Quality Tester (IQT™) and associated ASTM D6890 [3]/CEN EN 15195 [4]/EI IP 498 [5] Test Methods. The results presented in those two papers indicated how the new generation of IQT™ with the TALM Precision Package upgrade can markedly improve the precision of the ASTM D6890, CEN EN 15195 and EI IP 498 Derived Cetane Number (DCN) test methods. This paper will evaluate the performance of the upgraded instruments over the past 21 months of their participation in ASTM’s National Fuel Exchange Group (NEG) diesel fuel exchange program.
2017-03-28
Technical Paper
2017-01-0874
Thorsten Langhorst, Felix Rosenthal, Thomas Koch
Abstract Throughout the world cost-efficient Naphtha streams are available in refineries. Owing to less processing, CO2 emissions emitted in the course of production of these fuels are significantly lower than with conventional fuels. In common CI/SI engines, however, the deployment of Naphtha is considerably restricted due to unfavourable fuel properties, e.g. low cetane/octane numbers. Former investigations illustrated high knocking tendency for SI applications and severe pressure rise for CI combustion. Moreover, the focus of past publications was on passenger vehicle applications. Hence, this paper centers on heavy-duty stationary engine applications. Consequently, measures to increase the technically feasible IMEP with regard to limitations in knocking behaviour and pressure rise were explored whilst maintaining efficient combustion and low emissions.
2017-03-28
Journal Article
2017-01-0578
Pinaki Pal, Daniel Probst, Yuanjiang Pei, Yu Zhang, Michael Traver, David Cleary, Sibendu Som
Abstract Fuels in the gasoline auto-ignition range (Research Octane Number (RON) > 60) have been demonstrated to be effective alternatives to diesel fuel in compression ignition engines. Such fuels allow more time for mixing with oxygen before combustion starts, owing to longer ignition delay. Moreover, by controlling fuel injection timing, it can be ensured that the in-cylinder mixture is “premixed enough” before combustion occurs to prevent soot formation while remaining “sufficiently inhomogeneous” in order to avoid excessive heat release rates. Gasoline compression ignition (GCI) has the potential to offer diesel-like efficiency at a lower cost and can be achieved with fuels such as low-octane straight run gasoline which require significantly less processing in the refinery compared to today’s fuels.
2017-03-28
Technical Paper
2017-01-0937
David Culbertson, James Pradun, Magdi Khair, Jeff Diestelmeier
Abstract Tightening regulations throughout the world demand a reduction in fuel consumption and NOX emission levels, creating an increasing need for additional heat for SCR aftertreatment. A durable and low cost heating system is needed for vehicles with hybrid or 24Vdc electricity. Recent development efforts have resulted in much smaller and lower cost heating systems for electrical systems ranging from 400 to 24Vdc. Test results demonstrate the feasibility of reducing the size of the heater and the relationship of heater power to the amount of time required to heat the exhaust. Intelligent solid state switching enables the heater to be smaller without compromising durability.
2017-03-28
Technical Paper
2017-01-0726
Muhammad Waqas, Nimal Naser, Mani Sarathy, Jeroen Feijs, Kai Morganti, Gustav Nyrenstedt, Bengt Johansson
Abstract Gasoline-ethanol-methanol (GEM) blends, with constant stoichiometric air-to-fuel ratio (iso-stoichiometric blending rule) and equivalent to binary gasoline-ethanol blends (E2, E5, E10 and E15 in % vol.), were defined to investigate the effect of methanol and combined mixtures of ethanol and methanol when blended with three FACE (Fuels for Advanced Combustion Engines) Gasolines, I, J and A corresponding to RON 70.2, 73.8 and 83.9, respectively, and their corresponding Primary Reference Fuels (PRFs). A Cooperative Fuel Research (CFR) engine was used under Spark Ignition and Homogeneous Charge Compression Ignited modes. An ignition quality tester was utilized in the Compression Ignition mode. One of the promising properties of GEM blends, which are derived using the iso-stoichiometric blending rule, is that they maintain a constant octane number, which has led to the introduction of methanol as a drop-in fuel to supplement bio-derived ethanol.
2017-03-28
Technical Paper
2017-01-0707
Srinivas Padala, Minh Khoi Le, Yoshihiro Wachi, Yuji Ikeda
Abstract The effect of microwave enhanced plasma (MW Plasma) on diesel spray combustion was investigated inside a constant volume high pressure chamber. A microwave-enhanced plasma system, in which plasma discharge generated by a spark plug was amplified using microwave pulses, was used as plasma source. This plasma was introduced to the soot cloud after the occurrence of autoignition, downstream of the flame lift-off position to allow additional plasma-generated oxidizers to be entrained into the hot combustion products. Planar laser induced incandescence (PLII) diagnostics were performed with laser sheet formed from 532 nm Nd:YAG laser to estimate possible soot reduction effect of MW plasma. A semi-quantitative comparison was made between without-plasma conventional diesel combustion and with-plasma combustion; with LII performed at different jet cross-sections in the combustion chamber.
2017-03-28
Technical Paper
2017-01-0717
Metin Korkmaz, Rene Zweigel, Kai Niemietz, Bernhard Jochim, Dirk Abel, Heinz Pitsch
Abstract For compliance with legislative regulations as well as restricted resources of fossil fuel, it is essential to further reduce engine-out emissions and increase engine efficiency. As a result of lower peak temperatures and increased homogeneity, premixed Low-Temperature Combustion (LTC) has the potential to simultaneously reduce nitrogen oxides (BSNOx) and soot. However, LTC can lead to higher emissions of unburnt total hydrocarbons (BSTHC) and carbon monoxide (BSCO). Furthermore, losses in efficiency are often observed, due to early combustion phasing (CA50) before top dead center (bTDC). Various studies have shown possibilities to counteract these drawbacks, such as split-injection strategies or different nozzle geometries. In this work, the combination of both is investigated. Three different nozzle geometries with included spray angles of 100°, 120°, and 148° and four injection strategies are applied to investigate the engine performance.
2017-03-28
Technical Paper
2017-01-0840
Carlo Beatrice, Marianna Migliaccio, Alessandro Montanaro, Valentina Fraioli, Pierpaolo Napolitano, Luigi Allocca
Abstract In the aim of reducing CO2 emissions and fuel consumption, the improvement of the diesel engine performance is based on the optimization of the whole combustion system efficiency. The focus of new technological solutions is devoted to the optimization of thermodynamic efficiency especially in terms of reduction of losses of heat exchange. In this context, it is required a continuous development of the engine combustion system, first of all the injection system and in particular the nozzle design. To this reason in the present paper a new concept of an open nozzle spray was investigated as a possible solution for application on diesel engines. The study concerns some experimental and numerical activities on a prototype of an open nozzle. An external supplier provided the prototypal version of the injector, with a dedicated piezoelectric actuation system, and with an appropriate choice of geometrical design parameters.
2017-03-28
Technical Paper
2017-01-0810
Jan-Hendrik Redmann, Maik Beutler, Jennifer Kensler, Martin Luebbers, Roger Cracknell
Abstract In light of increasingly stringent CO2 emission targets, Original Equipment Manufacturers (OEM) have been driven to develop engines which deliver improved combustion efficiency and reduce energy losses. In spark ignition engines one strategy which can be used to reach this goal is the full utilization of fuel octane number. Octane number is the fuel´s knock resistance and is characterized as research octane number (RON) and motor octane number (MON). Engine knock is caused by the undesired self-ignition of the fuel air mixture ahead of the flame front initiated by the spark. It leads to pressure fluctuations that can severely damage the engine. Modern vehicles utilize different strategies to avoid knock. One extreme strategy assumes a weak fuel quality and, to protect the engine, retards the spark timing at the expense of combustion efficiency. The other extreme carefully detects knock in every engine cycle and retards the spark timing only when knock is detected.
2017-03-28
Technical Paper
2017-01-0805
Jue Li, Tushar K. Bera, Michael Parkes, Timothy J. Jacobs
Abstract This paper investigates the effect of the cetane number (CN) of a diesel fuel on the energy balance between a light duty (1.9L) and medium duty (4.5L) diesel engine. The two engines have a similar stroke to bore (S/B) ratio, and all other control parameters including: geometric compression ratio, cylinder number, stroke, and combustion chamber, have been kept the same, meaning that only the displacement changes between the engine platforms. Two Coordinating Research Council (CRC) diesel fuels for advanced combustion engines (FACE) were studied. The two fuels were selected to have a similar distillation profile and aromatic content, but varying CN. The effects on the energy balance of the engines were considered at two operating conditions; a “low load” condition of 1500 rev/min (RPM) and nominally 1.88 bar brake mean effective pressure (BMEP), and a “medium load” condition of 1500 RPM and 5.65 BMEP.
2017-03-28
Technical Paper
2017-01-1640
Peng Liu, Liyun Fan, Wenbo Peng, Xiuzhen Ma, Enzhe Song
Abstract A novel high-speed electromagnetic actuator for electronic fuel injection system (EFIS) of diesel engine is proposed in this paper. By using a permanent magnet and an annular flange, the design of the novel actuator aims to overcome the inherent drawbacks of the conventional solenoid electromagnetic actuator, such as high power consumption and so on. A method of multi-objective optimization combined with response surface methodology and Genetic Algorithm (GA) is employed to obtain the optimal design of the novel actuator. First, combined with design of experiments and finite element analysis, the second order polynomial response surface models (SOPRSM) of electromagnetic forces are produced by the least square principle. Second, the complete multi-objective optimization mathematical model (MOMM) of the novel actuator based on SOPRSM is built, aiming to maximize the net electromagnetic force on the armature and minimize the drive current.
2017-03-28
Technical Paper
2017-01-0534
Bojan S. Jander, Roland Baar
Abstract The knowledge of thermal behavior of combustion engines is extremely important e.g. to predict engine warm up or to calculate engine friction and finally to optimize fuel consumption. Typically, thermal engine behavior is modeled using look-up tables or semi-physical models to calculate the temperatures of structure, coolant and oil. Using look-up tables can result in inaccurate results due to interpolation and extrapolation; semi-physical modeling leads to high computation time. This work introduces a new kind of model to calculate thermal behavior of combustion engines using an artificial neural network (ANN) which is highly accurate and extremely fast. The neural network is a multi-layered feed-forward network; it is trained by data generated with a validated semi-physical model. Output data of the ANN-based model are calculated with nonlinear transformation of input data and weighting of these transformations.
2017-03-28
Technical Paper
2017-01-0543
Oliver Hofmann, Shijin Han, Daniel Rixen
Abstract This study discusses model-based injection rate estimation in common rail diesel injectors exhibiting aging phenomena. Since they result in unexpected injection behavior, aging effects like coking or cavitation may impair combustion performance, which justifies the need for new modeling and estimation approaches. To predict injection characteristics, a simulation model for the bottom section of the injector is introduced, with a main focus on modeling the hydraulic components. Using rail pressure and control piston lift as inputs, a reduced model is then derived in state-space representation, which may be used for the application of an observer in hardware-in-the-loop (HIL) environments. Both models are compared and validated with experimental data, with which they show good agreement. Aging effects and nozzle wear, which result in model uncertainties, are considered using a fault model in combination with an extended Kalman filter (EKF) observer scheme.
2017-03-28
Technical Paper
2017-01-0537
Murat Ates, Ronald D. Matthews, Matthew J. Hall
Abstract A quasi-dimensional model for a direct injection diesel engine was developed based on experiments at Sandia National Laboratory. The Sandia researchers obtained images describing diesel spray evolution, spray mixing, premixed combustion, mixing controlled combustion, soot formation, and NOx formation. Dec [1] combined all of the available images to develop a conceptual diesel combustion model to describe diesel combustion from the start of injection up to the quasi-steady form of the jet. The end of injection behavior was left undescribed in this conceptual model because no clear image was available due to the chaotic behavior of diesel combustion. A conceptual end-of-injection diesel combustion behavior model was developed to capture diesel combustion throughout its life span. The compression, expansion, and gas exchange stages are modeled via zero-dimensional single zone calculations.
2017-03-28
Technical Paper
2017-01-0553
Lorenzo Sforza, Tommaso Lucchini, Angelo Onorati, Xiucheng Zhu, Seong-Young Lee
Abstract Objective of this work is the incorporation of the flame stretch effects in an Eulerian-Lagrangian model for premixed SI combustion in order to describe ignition and flame propagation under highly inhomogeneous flow conditions. To this end, effects of energy transfer from electrical circuit and turbulent flame propagation were fully decoupled. The first ones are taken into account by Lagrangian particles whose main purpose is to generate an initial burned field in the computational domain. Turbulent flame development is instead considered only in the Eulerian gas phase for a better description of the local flow effects. To improve the model predictive capabilities, flame stretch effects were introduced in the turbulent combustion model by using formulations coming from the asymptotic theory and recently verified by means of DNS studies. Experiments carried out at Michigan Tech University in a pressurized, constant-volume vessel were used to validate the proposed approach.
2017-03-28
Technical Paper
2017-01-0547
Zvonimir Petranovic, Wilfried Edelbauer, Milan Vujanović, Peter Priesching, Reinhard Tatschl, Neven Duić
Abstract Commonly, the spray process in Direct Injection (DI) diesel engines is modeled with the Euler Lagrangian discrete droplet approach which has limited validity in the dense spray region, close to the injector nozzle hole exit. In the presented research, a new reactive spray modelling method has been developed and used within the 3D RANS CFD framework. The spray process was modelled with the Euler Eulerian multiphase approach, extended to the size-of-classes approach which ensures reliable interphase momentum transfer description. In this approach, both the gas and the discrete phase are considered as continuum, and divided into classes according to the ascending droplet diameter. The combustion process was modelled by taking into account chemical kinetics and by solving general gas phase reaction equations.
2017-03-28
Technical Paper
2017-01-0571
Tim Lackmann, Tommaso Lucchini, Gianluca D'Errico, Alan Kerstein, Michael Oevermann
Abstract Many new combustion concepts are currently being investigated to further improve engines in terms of both efficiency and emissions. Examples include homogeneous charge compression ignition (HCCI), lean stratified premixed combustion, stratified charge compression ignition (SCCI), and high levels of exhaust gas recirculation (EGR) in diesel engines, known as low temperature combustion (LTC). All of these combustion concepts have in common that the temperatures are lower than in traditional spark ignition or diesel engines. To further improve and develop combustion concepts for clean and highly efficient engines, it is necessary to develop new computational tools that can be used to describe and optimize processes in nonstandard conditions, such as low temperature combustion.
2017-03-28
Technical Paper
2017-01-0574
Ishan Verma, Ellen Meeks, Eric Bish, Martin Kuntz, Karthik Puduppakkam, Long Liang, Chitralkumar Naik
Abstract Emissions from Diesel engines have been a major concern for many years, particularly with regards to the impact of NOx and particulate matter on human health. Exhaust gas re-circulation (EGR) is a widely used method in diesel engines for controlling NOx production. While EGR rates can be varied to ensure engine performance and reduce NOx emissions, EGR also influences the ignition delay, reduces the peak combustion temperature and increases particulate emissions. Moreover, the injection timing directly affects NOx and particulate emissions under the broad and highly variable operating conditions. An effective CFD-based design tool for diesel engines must therefore include robust and accurate predictive capabilities for combustion and pollutant formation, to address the complex design tradeoffs. The objective of the present study is to evaluate CFD modeling of diesel engine combustion and emissions for various combinations of EGR rates and injection timings.
2017-03-28
Technical Paper
2017-01-0579
Stephane Chevillard, Olivier Colin, Julien Bohbot, Mingjie Wang, Eric Pomraning, P. K. Senecal
Abstract Nowadays Spark Ignition (SI) engine developments focus on downsizing, in order to increase the engine load level and consequently its efficiency. As a side effect, knock occurrence is strongly increased. The current strategy to avoid knock is to reduce the spark advance which limits the potential of downsizing in terms of consumption reduction. Reducing the engine propensity to knock is therefore a first order subject for car manufacturers. Engineers need competitive tools to tackle such a complex phenomenon. In this paper the 3D RANS simulations ability to satisfactorily represent knock tendencies is demonstrated. ECFM (Extended Coherent Flame Model) has been recently implemented by IFPEN in CONVERGE and coupled with TKI (Tabulated Kinetics Ignition) to represent Auto-Ignition in SI engine. These models have been applied on a single cylinder engine configuration dedicated to abnormal combustion study.
2017-03-28
Technical Paper
2017-01-0577
Bersan Akkurt, Hayri Yigit Akargun, L. M. T. Somers, N. G. Deen, Ricardo Novella, Eduardo Javier Pérez-Sánchez
Abstract Advanced Computational Fluid Dynamics (CFD) modeling of reacting sprays provides access to information not available even applying the most advanced experimental techniques. This is particularly evident if the combustion model handles detailed chemical kinetic models efficiently to describe the fuel auto-ignition and oxidation processes. Complex chemistry also provides the temporal evolution of key species closely related to emissions formation, such as polycyclic aromatic hydrocarbons (PAHs) that are well-known as soot precursors. In this framework, present investigation focuses on the analysis of the so-called Spray-A combustion characteristics using two different flamelet-based combustion models. Both Reynolds-Averaged Navier-Stokes (RANS) and Large-Eddy Simulation (LES) predictions are combined to study not only the averaged spray characteristics, but also the relevance of different realizations in this particular problem.
2017-03-28
Technical Paper
2017-01-0560
Mateusz Pucilowski, Mehdi Jangi, Sam Shamun, Changle Li, Martin Tuner, Xue-Song Bai
Abstract Methanol as an alternative fuel in internal combustion engines has an advantage in decreasing emissions of greenhouse gases and soot. Hence, developing of a high performance internal combustion engine operating with methanol has attracted the attention in industry and academic research community. This paper presents a numerical study of methanol combustion at different start-of-injection (SOI) in a direct injection compression ignition (DICI) engine supported by experimental studies. The aim is to investigate the combustion behavior of methanol with single and double injection at close to top-dead-center (TDC) conditions. The experimental engine is a modified version of a heavy duty D13 Scania engine. URANS simulations are performed for various injection timings with delayed SOI towards TDC, aiming at analyzing the characteristics of partially premixed combustion (PPC).
2017-03-28
Technical Paper
2017-01-0559
Lucas Eder, Constantin Kiesling, Peter Priesching, Gerhard Pirker, Andreas Wimmer
Abstract Using natural gas as a fuel in internal combustion engines is a promising way to obtain efficient power generation with relatively low environmental impact. Dual fuel operation is especially interesting because it can combine the safety and reliability of the basic diesel concept with fuel flexibility. To deal with the greater number of degrees of freedom caused by the interaction of two fuels and combining different combustion regimes, it is imperative to use simulation methods in the development process to gain a better understanding of the combustion behavior. This paper presents current research into ignition and combustion of a premixed natural gas/air charge with a diesel pilot spray in a large bore diesel ignited gas engine with a focus on 3D-CFD simulation. Special attention was paid to injection and combustion. The highly transient behavior of the diesel injector especially at small injection quantities poses challenges to the numerical simulation of the spray.
2017-03-28
Technical Paper
2017-01-0561
Federico Perini, Kan Zha, Stephen Busch, Rolf Reitz
Abstract In this work, linear, non-linear and a generalized renormalization group (RNG) two-equation RANS turbulence models of the k-epsilon form were compared for the prediction of turbulent compressible flows in diesel engines. The object-oriented, multidimensional parallel code FRESCO, developed at the University of Wisconsin, was used to test the alternative models versus the standard k-epsilon model. Test cases featured the academic backward facing step and the impinging gas jet in a quiescent chamber. Diesel engine flows featured high-pressure spray injection in a constant volume vessel from the Engine Combustion Network (ECN), as well as intake flows in a high-swirl diesel engine. For the engine intake flows, a model of the Sandia National Laboratories 1.9L light-duty single cylinder optical engine was used.
2017-03-28
Technical Paper
2017-01-0564
Prithwish Kundu, Muhsin Ameen, Umesh Unnikrishnan, Sibendu Som
Abstract Modeling unsteady turbulent flame development in lifted spray flames is important as a strong correlation exists between pollutant formation and the transient flame features such as auto-ignition, flame propagation and flame stabilization. Detailed chemistry mechanisms with large number of species are required to resolve the chemical kinetics accurately. These factors make high-fidelity simulation of engine combustion computationally expensive. In this work, a turbulent combustion model is proposed based on tabulation of flamelets. The aim is to develop a comprehensive combustion modeling approach incorporating detailed chemistry mechanisms, turbulence models and highly resolved grids leveraging the computational cost advantage of tabulation. A novel technique of implementing unsteady flamelet libraries without the use of progress variables is implemented for igniting sprays called Tabulated Flamelet Model (TFM).
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