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

2005 ◽  
Author(s):  
Song-Charng Kong ◽  
Hoojoong Kim ◽  
Rolf D. Reitz ◽  
Yongmo Kim
Keyword(s):  
Diesel Engine ◽  
Chemical Reactions ◽  
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 CFD 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.

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.

Applying the Representative Interactive Flamelet Model to Evaluate the Potential Effect of Wall Heat Transfer on Soot Emissions in a Small-Bore Direct-Injection Diesel Engine

2002 ◽  
Vol 124 (4) ◽  
pp. 1042-1052 ◽  
Author(s):  
C. Hergart ◽  
N. Peters
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Direct Injection ◽  
Particle Growth ◽  
Potential Effect ◽  
Two Phase ◽  
Flamelet Model ◽  
Detailed Chemistry ◽  
Direct Injection Diesel Engine ◽  
Soot Emissions

Capturing the physics related to the processes occurring in the two-phase flow of a direct-injection diesel engine requires a highly sophisticated modeling approach. The representative interactive flamelet (RIF) model has gained widespread attention owing to its ability of correctly describing ignition, combustion, and pollutant formation phenomena. This is achieved by incorporating very detailed chemistry for the gas phase as well as for the soot particle growth and oxidation, without imposing any significant computational penalty. This study addresses the part load soot underprediction of the model, which has been observed in previous investigations. By assigning flamelets, which are exposed to the walls of the combustion chamber, with heat losses calculated in a computational fluid dynamics (CFD) code, predictions of the soot emissions in a small-bore direct-injection diesel engine are substationally improved. It is concluded that the experimentally observed emissions of soot may have their origin in flame quenching at the relatively cold combustion chamber walls.

Optimization Method and Simulation Study of a Diesel Engine Using Full Variable Valve Motions

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Yong Lu ◽  
Daniel B. Olsen
Keyword(s):  
Diesel Engine ◽  
Internal Combustion Engines ◽  
Fuel Efficiency ◽  
Optimization Method ◽  
Simulation Software ◽  
Volumetric Efficiency ◽  
Engine Simulation ◽  
Valve Motion ◽  
Simulation Results ◽  
Variable Valve

Variable valve timing technologies for internal combustion engines are used to improve power, torque, and increase fuel efficiency. Details of a new solution are presented in this paper for optimizing valve motions of a full variable valve actuation (FVVA) system. The optimization is conducted at different speeds by varying full variable valve motion (variable exhaust open angle, intake close angle, velocity of opening and closing, overlap, dwell duration, and lift) parameters simultaneously; the final optimized valve motions of CY4102 diesel engine are given. The CY4102 diesel engine with standard cam drives is used in large quantities in Asia. An optimized electrohydraulic actuation motion used for the FVVA system is presented. The electrohydraulic actuation and optimized valve motions were applied to the CY4102 diesel engine and modeled using gt-power engine simulation software. Advantages in terms of volumetric efficiency, maximum power, brake efficiency, and fuel consumption are compared with baseline results. Simulation results show that brake power is improved between 12.8% and 19.5% and torque is improved by 10%. Brake thermal efficiency and volumetric efficiency also show improvement. Modeling and simulation results show significant advantages of the full variable valve motion over standard cam drives.

scholarly journals Dynamic modeling of a small open Joule cycle reciprocating Ericsson engine: simulation results

2013 ◽  
Vol 1 (3) ◽  
pp. 109-117 ◽  
Author(s):  
F. Lontsi ◽  
O. Hamandjoda ◽  
K. F. Djanna ◽  
P. Stouffs ◽  
J. Nganhou
Keyword(s):  
Dynamic Modeling ◽  
Engine Simulation ◽  
Simulation Results

COMPUTATIONAL STUDY ON COMBUSTION AND EMISSION CHARACTERISTIC OF PILOTED FLAMES BY VARYING COMPOSITION CO2 OF SIMULATED BIOGAS

2017 ◽  
Vol 79 (7-3) ◽  
Author(s):  
Khor Chin Keat ◽  
M. F. Mohd Yasin ◽  
M. A. Wahid ◽  
A. Saat ◽  
A. S. Md Yudin
Keyword(s):  
Computational Study ◽  
Flame Temperature ◽  
Dilution Effect ◽  
Co2 Concentration ◽  
Nox Emission ◽  
Combustion Model ◽  
Emission Characteristic ◽  
Measured Temperature ◽  
Flamelet Model ◽  
Detailed Chemistry

This study investigates the performance of flamelet model technique in predicting the behavior of piloted flame.A non-premixed methane flame of a piloted burner is simulated in OpenFOAM. A detailed chemistry of methane oxidation is integrated with the flamelet combustion model using probability density function (pdf) approach. The turbulence modelling adopts Reynolds Average Navier Stokes (RANS) framework with standard k-ε model. A comparison with experimental data demonstrates good agreement between the predicted and the measured temperature profiles in axial and radial directions. Recently, one of major concern with combustion system is the emission of pollution specially NOx emission. Reduction of the pollutions can be achieved by varying the composition of CO2 in biogas. In addition, the effect of the composition of biogas on NOx emission of piloted burner is still not understood. Therefore, understanding the behavior composition of CO2 in biogas is important that could affect the emission of pollution. In the present study, the use of biogas with composition of 10 to 30 percent of CO2 is simulated to study the effects of biogas composition on NOx emission. The comparison between biogas and pure methane are done based on the distribution of NOx, CO2, CH4, and temperature at different height above the burner. At varying composition of CO2 in biogas, the NOx emission for biogas with 30 percent CO2 is greatly reduced compared to that of 10 percent CO2. This is due to the reduction of the post flame temperature that is produced by the dilution effect at high CO2 concentration.  

Piston-Liner Thermal Resistance Model for Diesel Engine Simulation: Part 1: Formulation and Tuning

1991 ◽  
Vol 205 (5) ◽  
pp. 343-352 ◽  
Author(s):  
Y Rasihhan ◽  
F J Wallace
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Thermal Resistance ◽  
Direct Injection ◽  
Transfer Model ◽  
Conductive Heat ◽  
Axially Symmetric ◽  
Engine Simulation ◽  
Axial Movement ◽  
Resistance Model

A simple, effective and computationally economical piston-liner thermal resistance model for diesel engine simulation is described. In the model, the detailed shape of the piston and its axial movement and interaction with liner nodes are all taken into account. An imaginary node within the piston provides the necessary temperature difference between the piston and the liner nodes for conductive heat transfer, which is expected to reverse its direction with liner insulation. In the liner, an axially symmetric two-dimensional heat-transfer model is used. Later the piston-liner model is tuned for the experimental single cylinder, direct injection, Petter PH 1W engine used at Bath University, against the experimental piston temperature and liner temperature distribution.

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