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2017-10-08
Technical Paper
2017-01-2197
Vignesh Pandian Muthuramalingam, Anders Karlsson
Owing to increased interest in blended fuels for automotive applications, a great deal of understanding is sought for the behavior of multicomponent fuel sprays. This sets a new requirement on spray model since the volatility of the fuel components in a blend can vary substantially. It calls for careful solution to implement the differential evaporation process concerning thermodynamic equilibrium while maintaining a robust solution. This work presents the Volvo Stochastic Blob and Bubble (VSB2) spray model for multicomponent fuels. A direct numerical method is used to calculate the evaporation of multicomponent fuel droplets. The multicomponent fuel model is implemented into OpenFoam CFD code and the case simulated is a constant volume combustion vessel. The CFD code is used to calculate liquid penetration length for surrogate diesel (n-dodecane)-gasoline (iso-octane) blend and the result is compared with experimental data.
2017-10-08
Technical Paper
2017-01-2422
Na Li, Fenlian Huang, Yuhua Bi, Yueqiang Xu, Lizhong Shen, Dewen Jia
The assembly of connecting rod bearing and crankpin is a key friction pair which offers an important guarantee for stable operation of diesel engine. Specific to the non-road 2-cylinder diesel engine developed independently and based on the theory of elasto-hydrodynamic lubrication as well as multi-body dynamics, this paper establishes a multi-body dynamics model for connecting rod bearing of the 2D25 horizontal diesel engine and makes a research on the influence of bearing width, bearing clearance, and oil inlet position and diameter upon lubrication of connecting rod bearing, taking into consideration that of the surface appearance of bearing bush and the elastic deformation of bearing bush and axle journal upon the same. Research results show that bearing width and bearing clearance are the major factors that influence lubrication characteristics of connecting rod bearing while oil inlet position and diameter only have a small influence on such characteristics.
2017-10-08
Technical Paper
2017-01-2384
Ijhar H. Rusli, Svetlana Aleksandrova, Humberto Medina, Stephen F. Benjamin
The effect of the residual swirl from the turbocharger turbine on the catalyst flow distribution has been investigated experimentally and numerically. A swirling flow rig with a moving-block swirl generator was used to generate swirling flow in a sudden expansion diffuser with a wash-coated diesel oxidation catalyst (DOC) downstream. Hot-wire anemometry (HWA) was used to measure the axial and tangential velocities of the swirling flow upstream of the diffuser expansion and the axial velocity downstream the monolith. Pressure along the diffuser wall was measured using Scanivalve pressure scanners. With no swirl, the results show that the flow is highly non-uniform in the catalyst monolith with maximum velocities near the diffuser axis. High non-uniformity is also exhibited at high swirl levels with highest velocities near the diffuser wall. An intermediate swirl level exists where the flow is uniform.
2017-10-08
Technical Paper
2017-01-2382
Tul Suthiprasert, Sirichai Jirawongnuson, Ekathai Wirojsakunchai, Tanet Aroonsrisopon, Krisada Wannatong, Atsawin Salee
One of the most important challenges on implementing Diesel Dual Fuel (DDF) engine into the vast market is CH4 emission in its exhaust. This is due to the fact that CH4 is hard to oxidize at lower temperature environment of DDF exhaust comparing to that of conventional or bi-fuel engines. In addition, another parameter such as exhaust flow rate, specie concentration, especially CO, C3H8, and water have tremendous impact on Diesel Oxidation Catalyst performance on reducing CH4. Combining of all these factors together, a study of CH4 reduction is a major research problems that researchers around the world are keen to gain more fundamental understandings. In this work, a new CH4 kinetic model, which is based on Langmuir Hinshelwood mechanism, including CO, C3H8, and water is implemented into 1-D and 3-D Catalytic Converter models. The CH4 kinetic model is calibrated with the experiment by using synthetic exhaust gas generator.
2017-10-08
Technical Paper
2017-01-2201
Zhongye Cao, Tianyou Wang, Kai Sun, Lei Cui, Yong Gui
For uniflow scavenged two-stroke marine diesel engines, the main function of scavenging process is to replace the burned gas with fresh charge. The end state of scavenging process is integral to the subsequent compression and combustion, thereby affecting the engine’s fuel economy, power output and emissions. In this paper, a complete working cycle of a large marine diesel engine was simulated by using the 3D-CFD software CONVERGE. The model was validated by mesh sensitivity test and experiment data. Based on this calibrated model, the influences of swirl ratio and exhaust valve closing (EVC) timing on the scavenging process were investigated. The parameters evaluating the performance of scavenging process were introduced. The results show that, by adjusting the swirl orientation angle(SOA) from SOA=10° to SOA=30°, different swirl ratios are generated and have obvious differences in flow characteristics and scavenging performance.
2017-10-08
Technical Paper
2017-01-2190
Alessandro D'Adamo, Marco Del Pecchia, Sebastiano Breda, Fabio Berni, Stefano Fontanesi, Jens Prager
CFD simulations of reacting flows are fundamental investigation tools used to predict combustion behaviour and pollutants formation in modern spark-ignition internal combustion engines. Most of the flamelet-based combustion models adopted in current simulations use the fuel/air/residual laminar flame speed as a background to predict the turbulent flame speed. This in turn is a fundamental requirement to model the effective burn rate. The consolidated approach in engine combustion simulations relies on the adoption of empirical correlations for laminar flame speed, which are derived from fitting activity of combustion experiments. However, these last are conducted at largely different pressure and temperature ranges from those encountered in engines: for this reason, correlation extrapolation at engine conditions is inevitably accepted and relevant differences between proposed correlations emerge even for the same fuel and conditions.
2017-10-08
Technical Paper
2017-01-2186
Lukas Urban, Michael Grill, Sebastian Hann, Michael Bargende
The development of IC engines is a complex process where 0D/1D-simulation tools became more important in the past few years. Different designs can be investigated in very early stages of the development process without the expensive buildup of prototypes and it is possible to get reliable results with passable effort. The quality of the overall simulation results depends on the quality of the sub-models. Simulation of the combustion process in natural-gas SI engines relies on predictive models for burn rates and knock. Existing knock models for gasoline fuels are based on a time-integrated ignition delay, using a fitted Arrhenius equation. Within a research project an enhanced knock-model approach for methane based fuels was developed. Chemical kinetics models were used to calculate the auto-ignition times for various temperatures, pressures and air-fuel-ratios (AFR).
2017-10-08
Technical Paper
2017-01-2252
Weihua Sun, Wei Du, Xuefei Dai, Xiangdong Bai, Zhiping Wu
Getting real cylinder pressure is the basis of engine combustion analysis. Because of the advantages of good thermal performance, fast response, small size, high accuracy, large range and so on, piezoelectric quartz sensor is widely used in the measurement of the cylinder pressure. But this kind of sensor can only get the dynamic cylinder pressure which may not represent the real one. In this situation, the cylinder pressure needs to be corrected by some method. It also could cause great result divergences of the combustion analysis by using different cylinder pressure correction methods. This paper aims to acquire a proper cylinder pressure correction method by carrying out the theory analysis based on ideal gas equation and experiment research of cylinder pressure on a turbocharged eight-cylinder diesel engine.
2017-10-08
Technical Paper
2017-01-2460
Wenbin Liu, Qiang Song, Yiting Li, Wanbang Zhao
In this paper, a novel driver model is proposed to track vehicle speed in MIL (Model-in-the-Loop) test system, which has structural consistency with HIL (Hardware-in-the-Loop) test system. First, the MIL test system which contains models of driver, vehicle and test bench is established. Second, according to the connections of the established models in Matlab/Simulink environment, the vehicle speed is calculated in vehicle model. Emphatically, through the deviation between driving cycle speed and calculated vehicle speed, PI controller in driver model adjusts the vehicle speed to ideal point through sending the torque command to drive motor, the ILC (Iterative Learning Control) controller modifies and stores P value of PI controller. Then, in order to obtain the better modification of PI controller, iterative learning control algorithm is deeply researched in term of types and parameters.
2017-10-08
Technical Paper
2017-01-2333
Marcos Gutierrez, Andres Castillo, Juan Iniguez, Gorky Reyes
The aim for cleaner and more efficient energy from the internal combustion engines makes necessary to ensure the conditions for the exploitation of alternative fuels. The vibrations on engines are primarily understood as effects of mechanical failures, but the engine vibration is subject of the fuel combustion effects too. This effects will depend on the fuel type and its capacity to be burned. The vibrations of a diesel engine were measured and analyzed with a frequency spectrum calculated with Fast Fourier Transforms. The engine was operated with a fuel blend from 10 % recycled lubricating oil with 90% diesel as well as only diesel. It was found the engine operation with this fuel blend has a lower vibration level in comparison with the use of pure diesel. The goal of this research is to determine the properties of the fuel blend, which provides more stability to the engine by means of vibrations reduction.
2017-10-08
Technical Paper
2017-01-2193
Andreas Nygren, Anders Karlsson
When developing new combustion concepts, CFD simulations is a powerful tool. The modeling of spray formation is a challenging but important part when it comes to CFD modelling of non-premixed combustion. There is a large difference in the accuracy and robustness among different spray models and their implementation in different CFD codes. In the work presented in this paper a spray model, designated as VSB2 has been implemented in OpenFOAM. VSB2 differ from traditional spray models by replacing the Lagrangian parcels with stochastic blobs. The stochastic blobs consists of a droplet size distribution rather than equal sized droplets, as is the case with the traditional parcel. The VSB2 model has previously been thoroughly validated for spray formation and combustion of n-heptane. The aim of this study was to validate the VSB2 spray model for ethanol spray formation and combustion as a step in modelling dual-fuel combustion with alcohol and diesel.
2017-10-08
Technical Paper
2017-01-2199
Maria Cristina Cameretti, Vincenzo De Bellis, Luca Romagnuolo, Agostino Iorio, Luigi Maresca
Engine manufacturers are continually committed to find proper technical solutions to meet the more and more stringent CO2 emission targets fixed worldwide. Many strategies have been already developed, or are currently under study, to attain the above objectives. A tendency is however emerging towards more innovative combustion concepts, able to efficiently burn lean or highly diluted mixtures. To this aim, the enhancement of turbulence intensity inside the combustion chamber has a great importance, contributing to improve the burning rate, increase the thermal efficiency, and also reduce the cyclic variability. It is well-known that turbulence production inside the combustion chamber is mainly achieved during the intake stroke. Moreover, it is strongly affected by the intake duct geometry and orientation with respect to a plane perpendicular to the cylinder axis.
2017-10-08
Technical Paper
2017-01-2194
Mateusz Pucilowski, Mehdi Jangi, Sam Shamun, Martin Tuner, Xue-Song Bai
Experimental heavy-duty DICI methanol engine is studied under high compression ratio conditions (CR=27). The fuel is injected with common-rail injector close to the top-dead-center (TDC) position with three different injector pressures, leading to a spray formation causing a so called wall-wetting. Numerical simulations using RANS/LPT/WSR and PDF models are employed to investigate the local conditions of the injection and combustion process. The CFD results are compared with the pressure trace and emissions from the metal engine experiment. It is shown that the simulations captured the same trend of increased amount of unburned hydrocarbons at higher injection pressures. Moreover, the intake temperature adjustments were required to correctly capture the ignition delay time when WSR model was used, whereas with the PDF method such adjustments were not needed.
2017-10-08
Technical Paper
2017-01-2455
Vikram Chopra
This paper reports on the design of a synchronizer brake based on permanent magnets, capable of braking with an active zero-slip load. Eddy-current brakes are widely used in automation and transportation applications; however, their use is limited by the rotor speed. For low-speed and high-torque applications, designs based on permanent magnets are better suited. Zero-slip braking torque is increased by the use of permanent magnets but, consequently, so is the cogging torque. At first, the synchronizer brake was designed with 16 surface magnets on the rotor. However, in order to reduce the permanent magnet mass, the rotor was re-designed with half the number of surface magnets. This novel design helped lower cogging torque and fabrication costs. Simulation of the design, using the 3D transient with motion solver in commercial finite element software, showed promising results.
2017-10-08
Technical Paper
2017-01-2202
Shiyou Yang
This work presents an application of two sub-models relative to chemical-kinetics-based turbulent pre-mixed combustion modeling approach on the simulation of burn rate and emissions of spark ignition engines. In present paper, the justification of turbulent pre-mixed combustion modeling directly based on chemical kinetics plus a turbulence model is given briefly. Two sub-models relative to this kind of pre-mixed combustion modeling approach are described generally, including a practical PRF (primary reference fuel) chemical kinetics mechanism which can correctly capture the laminar flame speed under a wide range of Ford SI (spark ignition) engines/operating conditions, and an advanced spark plug ignition model which has been developed by Ford recently.
2017-10-08
Technical Paper
2017-01-2256
Muhammad Umer Waqas, Kai Morganti, Jean-Baptiste Masurier, Bengt Johansson
Future internal combustion engines demand higher efficiency, progression towards is limited by antiknock quality of present fuels and energy economics in octane enhancement. A possible solution is Octane-on-Demand, that uses a combination of high and low octane fuels in separated tanks to generate fuels of the required octane rating according to demand. Methanol, a RON 109 fuel was selected as the high octane fuel and five low octane fuels were used as base fuel. These were FACE (Fuels for Advanced Combustion Engines) gasolines, more specifically FACE I, J and A and their primary reference fuels (iso-octane/n-heptane). Experiments were conducted with a modified Cooperative Fuel Research (CFR) engine. For SI combustion mode the CFR operated at RON and MON conditions. The engine i.e. also operated in HCCI mode to get the auto ignition properties at lean conditions (λ=3).
2017-10-08
Technical Paper
2017-01-2280
Yuzuru Nada, So Morimoto, Yoshiyuki Kidoguchi, Ryu Kaya, Hideaki Nakano, Shinichi Kobayashi
In our previous studies, we have developed natural gas engines operating under lean conditions to improve thermal efficiency and emission characteristics. We applied a sub-chamber injection system to our engines, in which natural gas is directly injected into a combustion sub-chamber in order to completely separate stoichiometric mixture in the sub-chamber from ultra-lean mixture in the main chamber. The results obtained from engine tests demonstrated excellent performance of our engines in view point of efficiency and NOx emissions. However, we have poor knowledge of mixture distributions in the combustion chambers to understand the mechanism of the improvements. The aim of this paper is to clarify the mixture formation in combustion chambers by means of numerical simulations in the combustion chamber with and without the sub-chamber at a variety of operating conditions.
2017-10-08
Technical Paper
2017-01-2371
Hiroki Kambe, Naoto Mizobuchi, Eriko Matsumura
Diesel Particulate filter (DPF) is installed as after treatment device of exhaust gas in diesel engine, and it collects Particulate Matter (PM). However, as the operation time of engine increases, the PM is accumulated in the DPF, resulting in deterioration of PM collection efficiency and increase in pressure loss. Therefore, Post injection has been attracted attention as the DPF regeneration method for burning and removing PM in the DPF. But, Post injection causes oil dilution when fuel is injected at the middle to late stage of expansion stroke. Oil dilution are concern to decrease the stroke lubricity of piston movement and the thermal efficiency. In order to estimate deposition amount of fuel spray that influences oil film, we should elucidate spray impingement behavior on wall surface of oil film, to research more from the behavior of in-cylinder spray during post injection.
2017-10-08
Technical Paper
2017-01-2378
Takayuki Ogata, Mikio Makino, Takashi Aoki, Takehide Shimoda, Kyohei Kato, Takahiko Nakatani, Koji Nagata, Claus Dieter Vogt, Yoshitaka Ito, Dominic Thier
In order to meet the challenging CO2 targets beyond 2020 despite keeping high performance engines, Gasoline Direct Injection (GDI) technology usually combined with charged aspiration is expanding in the automotive industry. While providing more efficient powertrains to reduce fuel consumption one side effect of GDI is the increased particle formation during the combustion process. For the first time for GDI from September 2014 there is a Particle Number (PN) limit of 6E12 #/km, which will be further reduced by one order of magnitude to 6E11 #/km effective from September 2017 to be the same level as applied to Diesel engines. In addition to the PN limit of the certification cycle NEDC further certification of Real Driving Emissions (RDE) including portable PN measurements are under discussion by the European Commission. RDE test procedure requires stable and low emissions in a wide range of engine operations and durable over a distance of 160 000 km.
2017-10-08
Technical Paper
2017-01-2407
Michael Bardon, Greg Pucher, David Gardiner, Javier Ariztegui, Roger Cracknell, Heather Hamje, Leonardo Pellegrini, David Rickeard
Low Temperature Combustion using compression ignition may provide high efficiency combined with low emissions of oxides of nitrogen and soot. This process is facilitated by fuels with lower cetane number than standard diesel fuel. Mixtures of gasoline and diesel (“dieseline”) may be one way of achieving this, but a practical concern is the flammability of the headspace vapours in the vehicle fuel tank. A mathematical model is presented that predicts the flammability of the headspace vapours in a tank containing mixtures of gasoline and diesel fuel. Fourteen hydrocarbons and ethanol represent the volatile components. Heavier components are treated as non-volatile diluents in the liquid phase. The non-ideality of the blends of hydrocarbons and ethanol is accounted for using activity coefficients.
2017-10-08
Technical Paper
2017-01-2411
Henry Guo, Wenchuan Jia, DeDong Xie
A smart waste gate (WG) turbocharger controls boost by bypassing turbine flow through the WG port which allows optimizing both low and high speed engine performance. However, the WG port in the turbine housing involves much complex geometry which leads to potentially higher thermal stress and plastic strain if design is improper. This paper first presents the common thermal cracking problems at port zone and then shows finite element analysis (FEA) results for one design. The predicted location correlates well with the observed failure port location. A design study with key parameters for the port is conducted under same boundary conditions. Key parameters include height H, inner diameter D and inner diameter fillet r of the port. Totally 13 designs are analyzed under packaging and performance limitation. Accumulated plastic strain (APS) from FEA is used to evaluate different designs. Curves are plotted to show the relationship between APS and design parameters.
2017-10-08
Technical Paper
2017-01-2424
Shemin Zhang, Huaping Li, Tao Chen, Nan Jiang, Xinzhen Tan, Limei Deng, Qingsong Xia, Paul Kapus, Mingtang Ma, Wei Li, Junqiang Zhang, Qingjun Ma, Yong Xia
In recent years, more attentions have been paid to stringent legislation on fuel and emissions. Turbocharged downsizing DI engine is playing an increasing vital role in OEM’s powertrain strategies. Dongfeng Motor (DFM) has developed a new type of 1.0-liter 3 cylinder TGDI gasoline engine to meet the requirements of China 4th stage fuel consumption regulations and the China 6 emission standards. In this paper, the concepts of DFM 3-cylinder 1.0TGDI gasoline engine are explored to meet the powerful performance (torque 190Nm/1500-4500rpm and power 95kW/5500rpm), excellent part-load BSFC and NVH targets to ensure the drivers could enjoy the powerful output in quiet and comfortable environment without concerning about the fuel cost and pollution. The combustion system with side-mounted 6-hole direct injector and 200bar injection pressure has been optimized by CFD simulation and transparent engine investigation.
2017-10-08
Technical Paper
2017-01-2450
Chao Xu, Fuyuan Yang, Jinyu Zhang
Power-split is highlighted as the most popular concept for full hybrid electric vehicles (HEV). However, the energy management and design of power-split heavy duty truck under Chinese driving conditions still need to be investigated. In this paper, the parametric design and an equivalent consumption minimization strategy (ECMS) for the power-split heavy duty truck are presented. Besides, the influence of a penalty factor also discussed. Meanwhile, two different methods to search the engine operation point has been proposed. And the simulation shows both fuel consumption can satisfy the second phase fuel consumption standard and the third phase fuel consumption standard which will be implemented in 2020, in the C-WTVC (Chinese-World Transient Vehicle Cycle). Based on ECMS a design for generator motor and traction motor in power-split heavy duty truck has been processed. The fuel consumption has been indicted to decrease, with the motor power increasing.
2017-10-08
Technical Paper
2017-01-2444
Yanzhong Wang, Guanhua Song
High-speed rotating gears are generally lubricated by fuel injection. Lubricating oil is driven by high-speed rotating gear, and some lubricants will be excited into oil mist, so that the gears are in the gas-liquid mixed environment. In this paper, the computational fluid dynamics model of the fuel injection cooling process is established based on the gear heat transfer behavior under the fuel injection condition. The influence of different fuel injection parameters on the liquid-solid two-phase convective heat transfer coefficient is obtained. On this basis, the accurate boundary conditions of gear temperature field calculation are analyzed by studying the heat transfer behavior of high speed gear injection lubrication. The calculation model of gear temperature based on fuel injection lubrication is established, and the temperature field distribution of gear is obtained.
2017-10-08
Technical Paper
2017-01-2457
Rickard Arvidsson, Tomas McKelvey
A two-state forward dynamic programming algorithm is evaluated in a series hybrid drive-train application with the objective to minimize fuel consumption when look-ahead information is available. The states in the new method are battery state-of-charge and engine speed. The new method is compared to one-state dynamic programming optimization methods where the requested generator power is found such that the fuel consumption is minimized and engine speed is given by the optimum power-speed efficiency line. The other method compared is to run the engine at a given operating point where the system efficiency is highest, finding the combination of engine run requests over the drive-cycle that minimizes the fuel consumption. The work has included the engine torque and generator power as control signals and is evaluated in a full vehicle-simulation model based on the Volvo Car Corporation VSIM tool.
2017-10-08
Technical Paper
2017-01-2208
Tao Liu, Ziwang Lu, Guangyu Tian
To further explore the potential of fuel economy for hybrid electric vehicle (HEV) , an adaptive energy management strategy (EMS) considering driver’s power demand reasonability is proposed, which is necessary to reduce fuel consumption, emission and traffic congestion. To get accurate and reliable control strategy two aspects are the most important: 1) a rigorous and organized modeling approach to describe complicated powertrain system of HEV, 2) a trade off between optimization and real time. The Energetic Macroscopic Representation (EMR) is a graphical synthetic description of electromechanical conversion system based on energy flow. Based on Energetic Macroscopic Representation (EMR) a powertrain architecture of HEV is constructed. Generally EMS includes rule based that can be used online with suboptimal solution and optimization based that ensures the minimum fuel consumption with heavy computation duty and requirement of prior knowledge.
2017-10-08
Technical Paper
2017-01-2185
Chao He, Jiaqiang Li, Longqing Zhao, Yanyan Wang, Wei Gu
More and more stringent emission regulations and the desire to reduce fuel consumption lead to an increasing demand for precise and close-loop combustion control of diesel engines. Cylinder pressure-based combustion control is gradually used for diesel engines in order to enhance emission robustness and reduce fuel consumption. However, it increases the cost. In this paper, a new prediction method of combustion parameters including cylinder pressure is presented for diesel engines. The experiment was carried out on a engine test bench to obtain the ECU (Electronic Control Unit) signals of a heavy-duty diesel engine by calibration software. The combustion parameters is measured by a combustion analyzer, such cylinder pressure, combustion center of gravity (CA50) and the maximum combustion temperature (MCT). A combustion model using genetic programming (GP) is built.
2017-10-08
Technical Paper
2017-01-2188
Bruno S. Soriano, Edward S. Richardson, Stephanie Schlatter, Yuri M. Wright
Dual-fuel combustion is an attractive approach for utilising alternative fuels such as natural gas in compression-ignition internal combustion engines. In this concept, a more reactive fuel is injected in order to provide a source of ignition for the premixed natural gas/air, combining the high efficiency of a compression-ignition engine with the relatively low emissions associated with natural gas. The flame modes present in dual-fuel engines impose a challenge for existing turbulent combustion models. Following ignition, flame propagates through a partially-reacted and inhomogeneous mixture of the two fuels. The objective of this study is to test a new modelling approach that combines the ability of the Conditional Moment Closure (CMC) approach to describe autoignition of fuel sprays with the ability of the G-equation approach to describe the subsequent flame propagation.
2017-10-08
Technical Paper
2017-01-2196
Giuseppe Cicalese, Fabio Berni, Stefano Fontanesi, Alessandro D'Adamo, Enrico Andreoli
High performance Diesel engines are characterized by remarkable thermo-mechanical loads. Therefore, compared to spark ignition engines, designers are forced to increase component strength in order to avoid failures. By the way, 3D-CFD simulations represent a powerful tool for the evaluation of the engine thermal field and may be used by designers, along with FEM analysis, to prevent thermo-mechanical failures. The current work aims at providing an integrated in-cylinder/CHT methodology for the estimation of a Diesel engine thermal field. On one hand, in-cylinder simulations are fundamental to evaluate not only the global heat transfer at the combustion chamber walls, but also its point-wise distribution. In particular, thanks to an improved heat transfer model based on a modified thermal wall function, wall heat fluxes due to combustion are correctly estimated.
2017-10-08
Technical Paper
2017-01-2192
Shenghui Zhong, Zhijun Peng, Yu Li, Hailin Li, Fan Zhang
A 3D DNS (Three-dimensional direct numerical simulation) study with detailed chemical kinetic mechanism of methane has been performed to investigate the characteristic of turbulent premixed oxy-fuel combustion relevant to traditional spark ignition (SI) engine conditions. H2O and CO2 are adopted as the dilution agents in oxy-fuel combustion. In order to keep a consistent temperature profile compared with those of air-fired cases, 73% and 66% of H2O and CO2 in oxidizer by volume ratio are used. At first, laminar premixed flames are conducted to study the effect of the dilution molar fraction on the process of flame propagation. It is found that decreasing the dilution molar fraction will increase the flame propagation speed in both H2O and CO2 dilution cases, and there exists a temperature limitation because of chemical equilibrium.
Viewing 1 to 30 of 36102

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