A Two-Step Combustion Model of Iso-Octane for 3D CFD Combustion Simulation in SI Engines

2019 ◽  
Author(s):  
Xingyuan Su ◽  
Brian Chang ◽  
Haiwen Ge ◽  
Lurun Zhong
Keyword(s):  
Combustion Model ◽  
Combustion Simulation ◽  
Si Engines

Numerical Analysis of Hydrogen Risk Related Severe Accident Scenario in Chinese PWR

2016 ◽  
Author(s):  
Yang Fan ◽  
Sergey Kudriakov ◽  
Studer Etienne ◽  
Zou Zhiqiang ◽  
Hongxing Yu
Keyword(s):  
Large Scale ◽  
Complex Geometry ◽  
Combustion Process ◽  
Structure Design ◽  
Hydrogen Combustion ◽  
Severe Accident ◽  
Combustion Model ◽  
Combustion Simulation ◽  
Integrity Analysis ◽  
Safety Applications

Based on the fact that the pressure loads generated in hydrogen combustion process may jeopardize the integrity of the containment during severe accident, and the changing rate as well as the maximum value of the pressure loads are governed by the flame propagation process, it is important to simulate the hydrogen combustion process with proper methodology. Due to the insufficiency understanding of the turbulent combustion and the difficulties of hydrogen combustion simulation in large scale and complex geometry, explosion safety applications are always based on simplified combustion model, for which the validation work and specified conservative parameter is required. In this study, an methodology combining CFD analysis and model validation based on large scale combustion experiments (HDR E12 and HYCOM01/02) is built up. And domestic hydrogen combustion process in the containment during severe accident is simulated. This study provides solid basis for structure design and integrity analysis of the containment.

Development and Validation of an Ignition Model for SI Engines

2006 ◽  
Author(s):  
Stefania Falfari ◽  
Gian Marco Bianchi
Keyword(s):  
Cfd Simulation ◽  
Combustion Process ◽  
Three Dimensional ◽  
Electrical Energy ◽  
Combustion Model ◽  
Test Case ◽  
Ignition Process ◽  
Mean Flow ◽  
Flame Kernel ◽  
Si Engines

In SI engines the ignition process strongly affects the combustion process. Its accurate modelling becomes a key issue for a design-oriented CFD simulation of the combustion process. Different approaches to simulate ignition have been proposed. The common base is decoupling the physics related to the very first ignition phase when a plasma is formed from that of the development of the flame kernel. The critical point of ignition models is related to the capability of representing the effect of ignition system characteristics, the criterion used for flame deposit and the initialisation of the combustion model. This paper aims to present and validates extensively an ignition model suited for CFD calculation of premixed combustion. The ignition model implemented in a customized version of the Kiva 3 code is coupled with ECFM Flamelet combustion model. The ignition model simulates the plasma/kernel expansion based on a lump evaluation of main ignition processes (i.e., breakdown, arc-phase and glow phase). A double switch criterion based on physical and numerical consideration is used to switch to the main combustion model. The Herweg and Maly experimental test case has been used to check the model capability. In particular, two different ignition systems having different amount of electrical energy released during spark discharge are considered. Comparisons with experimental results allowed testing the model with respect to its capability to reproduce the effects of mixture equivalence ratio, mean flow, turbulence and spark energy on flame kernel development as never done before in three-dimensional RANS CFD combustion modelling of premixed flames.

Simulation of Methanol-Air Two-Phase Flames Using Various Turbulent Combustion Models

2009 ◽  
Author(s):  
F. Wang ◽  
Y. Huang ◽  
Y. Z. Wu
Keyword(s):  
Experimental Data ◽  
Turbulent Combustion ◽  
Turbulent Jet ◽  
Combustion Model ◽  
Air Flow Rate ◽  
Two Phase ◽  
Jet Flame ◽  
Combustion Simulation ◽  
Turbulent Combustion Model ◽  
Turbulent Models

Though fossil fuel is running out, liquid fuels nowadays still provide the most energy used by industrial furnaces, automotive and aero engines. How to predict a two-phase turbulent combustion flame is still a big problem to designers. Generally, the liquid fuel is sprayed and mixed with oxygen, and the flame characteristics depends on the fuel atomization, the fuel droplet spatial distribution, and its interaction with the turbulent oxidizer flow field: turbulent heat, mass and momentum transfer, complicated chemical kinetics, and turbulent-chemistry interaction. Turbulent combustion model is a key point for the two phase combustion simulation. For its short time consuming, Reynolds Averaged Navier Stokes (RANS) method nowadays still is the major tool for gas turbine chamber (GTC) designers, but there is not a universal method in RANS GTC spray combustion simulation at present especially for the two-phase turbulent combustion. The Eddy-Break-Up turbulent combustion model (EBU), Eddy Dissipation Concept turbulent combustion model (EDC), steady Laminar Flame-let turbulent combustion Model (LFM) and the Composition PDF transport turbulent combustion model (CPDF) are all widely used models. In this paper, these four turbulent models are used to simulate a methane-air turbulent jet flame measured by Sandia Lab first, then three methanol-air two-phase turbulent flames, in order to know the ability of these turbulent models. In the gas turbulent jet flame simulation, the result of LFM model and CPDF model are in better agreement with the experimental data than those of the EBU and the EDC models’ results. The reason is that the EBU model and EDC model are overestimated the effect of turbulent. In the three different cases of the two phase combustion simulation, CPDF is the best. The prediction ability of the other three models is different in different cases. The EDC predictions are closer to the experimental data when the air flow rate value is lower, whereas the LFM predictions are better when the air flow rate value is higher.

Model-Based Combustion Duration and Ignition Timing Prediction for Combustion Phasing Control of a Spark-Ignition Engine Using In-Cylinder Pressure Sensors

2019 ◽  
Author(s):  
Xin Wang ◽  
Amir Khameneian ◽  
Paul Dice ◽  
Bo Chen ◽  
Mahdi Shahbakhti ◽  
...  
Keyword(s):  
Pressure Sensors ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Ignition Timing ◽  
Model Based ◽  
Crank Angle ◽  
Si Engines ◽  
Phasing Control

Abstract Combustion phasing, which can be defined as the crank angle of fifty percent mass fraction burned (CA50), is one of the most important parameters affecting engine efficiency, torque output, and emissions. In homogeneous spark-ignition (SI) engines, ignition timing control algorithms are typically map-based with several multipliers, which requires significant calibration efforts. This work presents a framework of model-based ignition timing prediction using a computationally efficient control-oriented combustion model for the purpose of real-time combustion phasing control. Burn duration from ignition timing to CA50 (ΔθIGN-CA50) on an individual cylinder cycle-by-cycle basis is predicted by the combustion model developed in this work. The model is based on the physics of turbulent flame propagation in SI engines and contains the most important control parameters, including ignition timing, variable valve timing, air-fuel ratio, and engine load mostly affected by combination of the throttle opening position and the previous three parameters. With 64 test points used for model calibration, the developed combustion model is shown to cover wide engine operating conditions, thereby significantly reducing the calibration effort. A Root Mean Square Error (RMSE) of 1.7 Crank Angle Degrees (CAD) and correlation coefficient (R2) of 0.95 illustrates the accuracy of the calibrated model. On-road vehicle testing data is used to evaluate the performance of the developed model-based burn duration and ignition timing algorithm. When comparing the model predicted burn duration and ignition timing with experimental data, 83% of the prediction error falls within ±3 CAD.

Performance Analysis and Valve Event Optimization for SI Engines Using Fractal Combustion Model

2006 ◽  
Author(s):  
Gerhard Regner ◽  
Ho Teng ◽  
Peter Van Wieren ◽  
Jae In Park ◽  
Soo Youl Park ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Combustion Model ◽  
Si Engines ◽  
Valve Event

Combustion in a high-speed rotary valve spark-ignition engine

2007 ◽  
Vol 221 (8) ◽  
pp. 971-990 ◽  
Author(s):  
P H P Chow ◽  
H C Watson ◽  
T Wallis
Keyword(s):  
High Speed ◽  
Combustion Process ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Rotary Valve ◽  
Combustion Simulation ◽  
Parametric Effects ◽  
Sensitivity Studies ◽  
Valve Engine ◽  
Data Sensitivity

The current paper describes a study of combustion in the Bishop rotary valve engine by means of computation simulations. The combustion model was developed for this research at speeds up to 18 000 r/min and the results from the simulation were compared with experimental data. Sensitivity studies were performed in order to investigate the parametric effects on the combustion simulation of the engine. The major finding of this study was that convection of the flame kernels occurs and has a strong influence on the performance of the engine. The results indicated some insights as to how the combustion process of the engine can be improved.

scholarly journals Development and Experimental Validation of an Adaptive, Piston-Damage-Based Combustion Control System for SI Engines: Part 2—Implementation of Adaptive Strategies

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5342
Author(s):  
Alessandro Brusa ◽  
Nicolò Cavina ◽  
Nahuel Rojo ◽  
Jacopo Mecagni ◽  
Enrico Corti ◽  
...  
Keyword(s):  
Closed Loop ◽  
Adaptive Strategies ◽  
Open Loop ◽  
Combustion Model ◽  
Phase Index ◽  
Spark Timing ◽  
Combustion Phase ◽  
Rapid Control Prototyping ◽  
Si Engines ◽  
Loop Chain

This work focuses on the implementation of innovative adaptive strategies and a closed-loop chain in a piston-damage-based combustion controller. In the previous paper (Part 1), implemented models and the open loop algorithm are described and validated by reproducing some vehicle maneuvers at the engine test cell. Such controller is further improved by implementing self-learning algorithms based on the analytical formulations of knock and the combustion model, to update the fuel Research Octane Number (RON) and the relationship between the combustion phase and the spark timing in real-time. These strategies are based on the availability of an on-board indicating system for the estimation of both the knock intensity and the combustion phase index. The equations used to develop the adaptive strategies are described in detail. A closed-loop chain is then added, and the complete controller is finally implemented in a Rapid Control Prototyping (RCP) device. The controller is validated with specific tests defined to verify the robustness and the accuracy of the adaptive strategies. Results of the online validation process are presented in the last part of the paper and the accuracy of the complete controller is finally demonstrated. Indeed, error between the cyclic and the target combustion phase index is within the range ±0.5 Crank Angle degrees (°CA), while the error between the measured and the calculated maximum in-cylinder pressure is included in the range ±5 bar, even when fuel RON or spark advance map is changing.

scholarly journals Investigation on heat transfer evaluation for a more efficient two-zone combustion model in the case of natural gas SI engines

2011 ◽  
Vol 31 (2-3) ◽  
pp. 319-328 ◽  
Author(s):  
Mohand Said Lounici ◽  
Khaled Loubar ◽  
Mourad Balistrou ◽  
Mohand Tazerout
Keyword(s):  
Heat Transfer ◽  
Natural Gas ◽  
Combustion Model ◽  
Si Engines
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