Reactive computational fluid dynamics modelling of methane–hydrogen admixtures in internal combustion engines: Part I – RANS

2020 ◽  
pp. 146808742091638
Author(s):  
Jann Koch ◽  
Christian Schürch ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Internal Combustion Engines ◽  
Turbulent Flame ◽  
Internal Combustion ◽  
Flame Speed ◽  
Combustion Engines ◽  
Hydrogen Addition ◽  
Dynamics Modelling ◽  
Modelling Approach

The effects of hydrogen addition to internal combustion engines operated by natural gas/methane has been widely demonstrated experimentally in the literature. Already small hydrogen contents in the fuel show promising benefits with respect to increased engine efficiency, lower CO2 emissions, extended lean operating limits and a higher exhaust gas recirculation tolerance while maintaining the knock resistance of methane. In this article, the influence of hydrogen addition to methane on a spark ignited single cylinder engine is investigated. This article proposes a modelling approach to consider hydrogen addition within three-dimensional reactive computational fluid dynamics in order to establish a framework to gain further insights into the involved processes. Experiments have been performed on a single-cylinder spark-ignition engine situated at a test bed and cater as reference data for validating the proposed reactive computational fluid dynamics modelling approach based around the G-Equation combustion model. Within the course of the first part, crucial aspects relevant to the modelling of the mean engine cycle are highlighted. In this article, a simplified early combustion phase model which considers the transition towards a fully developed turbulent flame following ignition is introduced, along with a second submodel considering combined effects of the walls. The sensitivity of the combustion process towards the modelling approach is presented. The submodels were calibrated for a reference operating point, and a sweep in hydrogen content in the fuel as well as stoichiometric and lean operation has been considered. It is shown that the flame speed coefficient A appearing in the used turbulent flame speed closure, weighting the influence of the turbulent fluctuating speed [Formula: see text], has to be adjusted for different hydrogen contents. The introduced submodels allowed for significant improvement of the in-cylinder pressure and heat release rate evolution throughout all considered operating conditions.

Reactive computational fluid dynamics modelling methane–hydrogen admixtures in internal combustion engines part II: Large eddy simulation

2020 ◽  
pp. 146808742091034
Author(s):  
Jann Koch ◽  
Christian Schürch ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Large Eddy Simulation ◽  
Combustion Process ◽  
Flame Speed ◽  
Hydrogen Addition ◽  
Eddy Simulation ◽  
Modelling Framework ◽  
Large Eddy ◽  
Dynamics Modelling

Fuels based on admixtures of methane/natural gas and hydrogen are a promising way to reduce CO2 emissions of spark ignition engines and increase their efficiency. A lot of work was conducted experimentally, whereas only limited numerical work is available in the context of three-dimensional modelling of the full engine cycle. This work addresses this fact by proposing a reactive computational fluid dynamics modelling framework to consider the effects of hydrogen addition on the combustion process. Part I of this two-part study focuses on the modelling and crucial considerations in order to predict the mean cycle based on the G-equation combustion model using the Reynolds-averaged Navier–Stokes equations. There, the effect of increased burning speed was globally captured by increasing the flame speed coefficient A, appearing in the considered flame speed closure. The proposed simplified modelling of the early flame stage proved to be robust for the conducted hydrogen variation from 0 to 50 vol% H2 for stoichiometric and lean operation. Scope of this work, Part II, are cyclic fluctuations and the hydrogen influence thereon using large eddy simulation and the proposed modelling framework. The model is probed towards its capabilities to predict the fluctuation of the combustion process for 0 and 50 vol% H2 and correlations influencing the observed peak pressure of the individual cycle are presented. It is shown that the considered approach is capable to reproduce the cyclic fluctuations of the combustion process under the influence of hydrogen addition as well as lean operation. The importance of the early flame phase with respect to arising fluctuations is highlighted as well as the contribution of the resolved scales in terms of the flame front wrinkling.

scholarly journals A zonal approach for estimating pressure ratio at compressor extreme off-design conditions

2018 ◽  
Vol 20 (4) ◽  
pp. 393-404 ◽  
Author(s):  
José Galindo ◽  
Roberto Navarro ◽  
Luis Miguel García-Cuevas ◽  
Daniel Tarí ◽  
Hadi Tartoussi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Pressure Ratio ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Combustion Engines ◽  
One Dimensional ◽  
Performance Map

Zero-dimensional/one-dimensional computational fluid dynamics codes are used to simulate the performance of complete internal combustion engines. In such codes, the operation of a turbocharger compressor is usually addressed employing its performance map. However, simulation of engine transients may drive the compressor to work at operating conditions outside the region provided by the manufacturer map. Therefore, a method is required to extrapolate the performance map to extended off-design conditions. This work examines several extrapolating methods at the different off-design regions, namely, low-pressure ratio zone, low-speed zone and high-speed zone. The accuracy of the methods is assessed with the aid of compressor extreme off-design measurements. In this way, the best method is selected for each region and the manufacturer map is used in design conditions, resulting in a zonal extrapolating approach aiming to preserve accuracy. The transitions between extrapolated zones are corrected, avoiding discontinuities and instabilities.

scholarly journals THE COMBUSTION ENGINE INTAKE MANIFOLD CFD MODELING DEPENDING ON THE AIRBOX CONFIGURATION

2021 ◽  
Vol 2021 (6) ◽  
pp. 5421-5425
Author(s):  
MICHAL RICHTAR ◽  
◽  
PETRA MUCKOVA ◽  
JAN FAMFULIK ◽  
JAKUB SMIRAUS ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Stationary Flow ◽  
Cfd Modeling ◽  
Intake Manifold ◽  
Combustion Engines ◽  
Computational Fluid Dynamics Cfd

The aim of the article is to present the possibilities of application of computational fluid dynamics (CFD) to modelling of air flow in combustion engine intake manifold depending on airbox configuration. The non-stationary flow occurs in internal combustion engines. This is a specific type of flow characterized by the fact that the variables depend not only on the position but also on the time. The intake manifold dimension and geometry strongly effects intake air amount. The basic target goal is to investigate how the intake trumpet position in the airbox impacts the filling of the combustion chamber. Furthermore, the effect of different distances between the trumpet neck and the airbox wall in this paper will be compared.

scholarly journals Overset grids for fluid dynamics analysis of internal combustion engines

2017 ◽  
Vol 126 ◽  
pp. 979-986 ◽  
Author(s):  
Andrea Berton ◽  
Fabrizio D’Orrico ◽  
Matteo Sideri
Keyword(s):  
Fluid Dynamics ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Dynamics Analysis ◽  
Combustion Engines ◽  
Overset Grids

Large eddy simulation analysis of the turbulent flow in an optically accessible internal combustion engine using the overset mesh technique

2020 ◽  
pp. 146808741989646
Author(s):  
Federico Rulli ◽  
Alessio Barbato ◽  
Stefano Fontanesi ◽  
Alessandro d’Adamo
Keyword(s):  
Fluid Dynamics ◽  
Large Eddy Simulation ◽  
Internal Combustion Engine ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Mesh Technique

Computational fluid dynamics has become a fundamental tool for the design and development of internal combustion engines. The meshing strategy plays a central role in the computational efficiency, in the management of the moving components of the engine and in the accuracy of results. The overset mesh approach, usually referred to also as chimera grid or composite grid, was rarely applied to the simulation of internal combustion engines, mainly because of the difficulty in adapting the technique to the specific complexities of internal combustion engine flows. The article demonstrates the feasibility and the effectiveness of the overset mesh technique application to internal combustion engines, thanks to a purposely designed meshing approach. In particular, the technique is used to analyze the cycle-to-cycle variability of internal combustion engine flows using large eddy simulation. Fifty large eddy simulation cycles are performed on the well-known TCC-III engine in motored condition. Results are analyzed in terms of tumble center trajectory and using proper orthogonal decomposition to objectively characterize the spatial and temporal evolution of turbulent flow field in internal combustion engines. In particular, an original decomposition method previously applied by the authors to the TCC-III measured flow fields is here extended to computational fluid dynamics results.

Urea Using in Piston Engines’ Exhaust Gases Treatment Systems

2017 ◽  
Vol 6 (4) ◽  
pp. 40-49
Author(s):  
В. Марков ◽  
V. Markov ◽  
Л. Мягков ◽  
L. Myagkov ◽  
Н. Маластовский ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Thermal Decomposition ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Calculation Procedure ◽  
Combustion Engines ◽  
Ansys Fluent ◽  
Exhaust Gases ◽  
Efficiency Estimation

Development and updating of systems for internal-combustion engines’ exhaust gases treatment under tightened limits for toxics emissions continues to be an urgent issue. The usage of computational fluid dynamics methods in the design of such systems presents a significant practical value. In this work has been considered and realized a calculation procedure for evaporation and thermal decomposition of urea in SCR-systems based on ANSYS Fluent. The calculated results have been compared with existing experimental data. It has been concluded that the developed calculation procedure can be used for efficiency estimation of SCRsystems for internal-combustion engines’ exhaust gases.

Three-dimensional computational fluid dynamics simulation of hydrogen engines using a turbulent flame speed closure combustion model

2012 ◽  
Vol 13 (5) ◽  
pp. 464-481 ◽  
Author(s):  
Udo Gerke ◽  
Konstantinos Boulouchos
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Laminar Flame ◽  
Turbulent Flame ◽  
Three Dimensional ◽  
Flame Speed ◽  
Combustion Model ◽  
Laminar Flame Speed ◽  
Release Rates ◽  
Turbulent Flame Speed

The mixture formation and combustion process of a hydrogen direct-injection internal combustion engine is computed using a modified version of a commercial three-dimensional computational fluid dynamics code. The aim of the work is the evaluation of hydrogen laminar flame speed correlations and turbulent flame speed closures with respect to combustion of premixed and stratified mixtures at various levels of air-to-fuel equivalence ratio. Heat-release rates derived from in-cylinder pressure traces are used for the validation of the combustion simulations. A turbulent combustion model with closures for a turbulent flame speed is investigated. The value of the computed heat-release rates mainly depends on the quality of laminar burning velocities and standard of turbulence quantities provided to the combustion model. Combustion simulations performed with experimentally derived laminar flame speed data give better results than those using laminar flame speeds obtained from a kinetic scheme. However, experimental data of hydrogen laminar flame speeds found in the literature are limited regarding the range of pressures, temperatures and air-to-fuel equivalence ratios, and do not comply with the demand of high-pressure engine-relevant conditions.

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