Effect of Sauter Mean Diameter on Combustion Related Parameters in a Large-Bore Marine Diesel Engine

1999 ◽  
Author(s):  
Stanislav N. Danov ◽  
Ashwani K. Gupta
Keyword(s):  
Diesel Engine ◽  
Droplet Size ◽  
Fuel Injection ◽  
Combustion Process ◽  
Injection Rate ◽  
Gas Mixture ◽  
Fuel Droplet ◽  
Compression Pressure ◽  
Chain Reactions ◽  
Fuel Vaporization

Abstract A mathematical model of combustion process in a diesel engine has been developed according to the theory of chain reactions for the higher hydrocarbon compounds. The instantaneous rates of fuel vaporization and combustion are defined in terms of the current values of temperature, pressure, concentration of fuel vapors, overall diffusion rate, fuel injection rate, and mean fuel droplet size in terms of the SMD. Numerical experiments have been carried out for investigating the interdependency between various combustion-related parameters. Specifically, the effect of fuel droplet size (in terms of SMD) on the subsequent combustion parameters, such as, pressure, temperature, thermodynamic properties of air/gas mixture, heat transfer, fuel vaporization, combustion rate, current A/F ratio and gas mixture composition. In addition the integral indicator parameters of the engine, such as, mean indicated pressure, peak pressure, compression pressure have been analyzed.

Understanding of Diesel Engine Combustion Process via Mathematical Modeling: Part 2 — Results

1997 ◽  
Author(s):  
Stanislav N. Danov ◽  
Ashwani K. Gupta
Keyword(s):  
Diesel Engine ◽  
Diffusion Flame ◽  
Numerical Experiments ◽  
Fuel Injection ◽  
Combustion Process ◽  
Gas Mixture ◽  
Vaporization Rate ◽  
Atomization Process ◽  
And Diffusion ◽  
Integral Indicator

Abstract In the companion Part 1 of this two part series paper a mathematical model of combustion process in a diesel engine was presented having both premixed and diffusion flame. The combustion of fuel vaporized during the self-ignition delay period is modeled according to the conditions of premixed flame. A kinetic differential equation has been created for modeling this kind of combustion. The combustion of fuel during the injection process is modeled according to the theory of diffusion flames. This process is strongly influenced by processes of fuel injection, vaporization and diffusion. The atomization process is taken into account by means of the Sauter mean diameter (SMD) of fuel droplets. The instantaneous vaporization rate is defined by the current value of temperature, pressure, concentration of fuel vapors and the mean fuel droplet size in terms of the SMD. The mathematical model includes differential equations describing the processes of fuel injection, vaporization, heat transfer and combustion in both premixed and diffusion flame that occurs in the engine cylinder. The above equations are solved together with the differential equation of the first law of thermodynamics expressing the energy conversion process in the cylinder of diesel engine. The fourth-order Runge-Kutta method is applied for obtaining numerical solution of the system of differential equations. The model is calibrated and validated for two different turbocharged diesel engines — 8DKRN 74/160 and Sulzer-6RLB-66. The analysis is performed on a PC using FORTRAN 90. The comparison between the experimental data and numerical results shows very good agreement. Numerical experiments have been carried out for examining the combustion behavior in the cylinder of a marine DI diesel engine Sulzer 6RLB-66 having a cylinder diameter of 0.66 m bore and stroke of 1.4 m. The influence of the quality of fuel atomization process, estimated via the SMD, on the fuel vaporization rate and overall combustion rate has been evaluated. This influence is quantified and the results show very strong influence of SMD on the vaporization and combustion process, both with respect to the maximum rates and the duration of the processes. In addition numerical experiments have been carried out for determining the effect of duration of fuel injection and the beginning of fuel injection (degrees of crank angle rotation before TDC) on subsequent combustion parameters and integral indicator parameters of the engine. These results show that ratio: “amount of fuel burnt under the premixed flame conditions / amount of fuel burnt under diffusion flame conditions” for one cycle varies significantly with the change in fuel injection duration. The model provides both the instantaneous values of engine parameters in the cylinder (i.e., temperature, pressure, current air-gas mixture composition, heat transfer rate, thermo-physical properties of the air-gas mixture, etc.) and integral indicator engine parameters (mean indicated pressure, specific fuel consumption, efficiency, etc.). A comparison between experimental and modeling data show gratifying results.

1D Engine Simulation of a Small HSDI Diesel Engine Applying a Predictive Combustion Model

2006 ◽  
Author(s):  
T. Cerri ◽  
A. Onorati ◽  
E. Mattarelli
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Numerical Approach ◽  
Injection Rate ◽  
Operating Conditions ◽  
Combustion Model ◽  
Full Load ◽  
Partial Load

The paper analyses, by means of a parallel experimental and computational investigation, the performances of a small HSDI turbocharged Diesel engine. As far as the numerical approach is concerned, an in-house ID research code for the simulation of the whole engine system has been enhanced by the introduction of a multi-zone quasi-dimensional combustion model, tailored for multi-jet direct injection Diesel engines. This model takes into account the most relevant issues of the combustion process: the spray development, the in-cylinder air-fuel mixing process, the ignition and formation of the main pollutant species, such as nitrogen oxides and particulate. The prediction of the spray basic patterns requires the previous knowledge of the fuel injection rate. Since the direct measure of this quantity at each operating condition is not a very practical proceeding, an empirical model has been developed in order to provide reasonably accurate injection laws from a few experimental characteristic curves. The results of the simulation at full load are compared to experiments, showing a good agreement on brake performance and emissions. Furthermore, the combustion model tuned at full load has been applied without any change to the analysis of some operating conditions at partial load. Still, the numerical simulation provided results which qualitatively agree with experiments.

Diesel engine performance mapping using a parametrized mixing time model

2017 ◽  
Vol 19 (2) ◽  
pp. 202-213 ◽  
Author(s):  
Michal Pasternak ◽  
Fabian Mauss ◽  
Christian Klauer ◽  
Andrea Matrisciano
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Mixing Time ◽  
Combustion Process ◽  
Engine Performance ◽  
Injection Timing ◽  
Engine Control ◽  
Reactor Model ◽  
Time Model ◽  
Tabulated Chemistry

A numerical platform is presented for diesel engine performance mapping. The platform employs a zero-dimensional stochastic reactor model for the simulation of engine in-cylinder processes. n-Heptane is used as diesel surrogate for the modeling of fuel oxidation and emission formation. The overall simulation process is carried out in an automated manner using a genetic algorithm. The probability density function formulation of the stochastic reactor model enables an insight into the locality of turbulence–chemistry interactions that characterize the combustion process in diesel engines. The interactions are accounted for by the modeling of representative mixing time. The mixing time is parametrized with known engine operating parameters such as load, speed and fuel injection strategy. The detailed chemistry consideration and mixing time parametrization enable the extrapolation of engine performance parameters beyond the operating points used for model training. The results show that the model responds correctly to the changes of engine control parameters such as fuel injection timing and exhaust gas recirculation rate. It is demonstrated that the method developed can be applied to the prediction of engine load–speed maps for exhaust NOx, indicated mean effective pressure and fuel consumption. The maps can be derived from the limited experimental data available for model calibration. Significant speedup of the simulations process can be achieved using tabulated chemistry. Overall, the method presented can be considered as a bridge between the experimental works and the development of mean value engine models for engine control applications.

Study on the Transient Injection Rate of Each Nozzle Hole in the Combustion Process of Diesel Engine

2020 ◽  
Vol 143 (7) ◽  
Author(s):  
Liying Zhou ◽  
Yu Liang
Keyword(s):  
Diesel Engine ◽  
Exothermic Reaction ◽  
Combustion Process ◽  
Injection Rate ◽  
Dynamics Simulation ◽  
Ratio Distribution ◽  
Fuel Distribution ◽  
Injection Quantity ◽  
Nozzle Hole ◽  
Injection Rates

Abstract Based on the measured injection rates obtained from the spray momentum experiment, the three-dimensional computational fluid dynamics simulation study on the effect of injection rate from each nozzle hole on spray characteristics and combustion process was conducted for a one-cylinder diesel engine. The simulation model was successfully verified by the data of the experiment. The results show that at the beginning and mid-stages of injection, the nozzles with a higher transient injection rate exhibit higher jet velocity, bigger spray penetration distance, and wider equivalence ratio distribution. Besides, the disturbance induced by fuel injection on their surrounding gas is higher. Due to the difference in injection rates from each nozzle hole in the cylinder, gas–fuel mixtures are non-uniform. In the case of measured injection rates from each nozzle hole, Hole 4 records the highest instantaneous injection rate. This results in the injection of more fuel during ignition delay. More heat generated from thermal chain reactions raises fuel spray temperatures and quicker ignition of mixtures. In the case of uniform simulated injection rate (injection quantity values are the same as in the previous case), more uniform flow fields and stronger small swirl motions were generated that enhance fuel atomization and mixture formations. At the later stages of injection and combustion, quicker diesel fuel burning rate with a centralized exothermic reaction process occurs due to in-cylinder uniform fuel distribution and air motion. In the case of simulating uniform injection rate from three holes and non-injection from one (same injection quantity values as previous cases), uneven fuel distribution that occurs in the cylinder will result in poor mixture formations and subsequently poor combustion, and more afterburning will occur.

Diesel Engine Intake Condition Control-Oriented Models for Active Fuel Injection Profile Control

2011 ◽  
Author(s):  
Fengjun Yan ◽  
Junmin Wang
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
High Fidelity ◽  
Exhaust Gas ◽  
Engine Model ◽  
Profile Control ◽  
Gas Recirculation

Fueling control in Diesel engines is not only of significance to the combustion process in one particular cycle, but also influences the subsequent dynamics of air-path loop and combustion events, particularly when exhaust gas recirculation (EGR) is employed. To better reveal such inherently interactive relations, this paper presents a physics-based, control-oriented model describing the dynamics of the intake conditions with fuel injection profile being its input for Diesel engines equipped with EGR and turbocharging systems. The effectiveness of this model is validated by comparing the predictive results with those produced by a high-fidelity 1-D computational GT-Power engine model.

Simulation and Optimization of the Combustion Process of Diesel Engine

2014 ◽  
Vol 488-489 ◽  
pp. 918-922
Author(s):  
Guan Qiang Ruan ◽  
Zhen Dong Zhang ◽  
Jin Run Cheng
Keyword(s):  
Numerical Calculation ◽  
Diesel Engine ◽  
Mass Fraction ◽  
Fuel Injection ◽  
Dynamic Performance ◽  
Combustion Process ◽  
Engine Fuel ◽  
Cylinder Pressure ◽  
Simulation And Optimization ◽  
Simulation Results

In order to improve the performance of the diesel engine, the original engine fuel injection advance angle is optimized, and a new advance angle of fuel injection is proposed in this paper. By numerical calculation with simulation of software FIRE, the effect of different combustion chamber structures on the cylinder pressure, temperature, accumulated heat release and the parameters such as NOx mass fraction was analyzed. From the simulation results, the optimized fuel injection advance angle had greatly improved the diesel combustion and emission performance. Finally, via experimental verification, the engine with optimized fuel injection advance angle has better dynamic performance, as well as less emission than original machine.

scholarly journals Influence of Fuel Injection, Turbocharging and EGR Systems Control on Combustion Parameters in an Automotive Diesel Engine

2019 ◽  
Vol 9 (3) ◽  
pp. 484 ◽  
Author(s):  
Giorgio Zamboni
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Alternative Fuels ◽  
Fuel Injection ◽  
Combustion Process ◽  
Environmental Parameters ◽  
Operating Conditions ◽  
Combustion Noise ◽  
First Derivative ◽  
Test Sets

Indicated pressure diagrams were measured during experimental campaigns on the control of fuel injection, turbocharging and hybrid exhaust gas recirculation systems in an automotive downsized diesel engine. Three-part load operating conditions were selected for four test sets, where strategies aimed at the reduction of NOX emissions and fuel consumption, limiting penalties in soot emissions and combustion noise were applied to the selected systems. Processing of in-cylinder pressure signal, its first derivative and curves of the rate of heat release allowed us to evaluate seven parameters related to the combustion centre and duration, maximum values of pressure, heat release and its first derivative, heat released in the premixed phase and a combustion noise indicator. Relationships between these quantities and engine operating, energy and environmental parameters were then obtained by referring to the four test sets. In the paper, the most significant links are presented and discussed, aiming at a better understanding of the influence of control variables on the combustion process and the effects on engine behaviour. The proposed methodology proved to be a consistent tool for this analysis, useful for supporting the application of alternative fuels or advanced combustion modes.

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