Computer Simulation of Combustion Process in a Piston Engine With a Porous Medium Regenerator

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Lei Zhou ◽  
Maozhao Xie ◽  
Ming Jia ◽  
Junrui Shi
Keyword(s):  
Porous Medium ◽  
Combustion Process ◽  
Kinetic Mechanism ◽  
Combustion Efficiency ◽  
Pollutant Emissions ◽  
Mixture Formation ◽  
Computational Fluid Dynamics Cfd ◽  
Reduce Emissions ◽  
Detailed Kinetic Mechanism ◽  
Reciprocating Movement

In the regenerative engine, effective heat exchange and recurrence between gas and solid can be achieved by the reciprocating movement of a porous medium regenerator in the cylinder, which considerably promotes the fuel-air mixture formation and a homogeneous and stable combustion. A two-dimensional numerical model for the regenerative engine is presented in this study based on a modified version of the engine computational fluid dynamics (CFD) software KIVA-3V. The engine was fueled with methane and a detailed kinetic mechanism was used to describe its oxidation process. The characteristics of combustion and emission of the engine were computed and analyzed under different equivalence ratios and porosities of the regenerator. Comparisons with the prototype engine without the regenerator were conducted. Results show that the regenerative engine has advantages in both combustion efficiency and pollutant emissions over the prototype engine and that using lower equivalence ratios can reduce emissions significantly, while the effect of the porosity is dependent on the equivalence ratio used.

scholarly journals Combustion Optimization for Coal Fired Power Plant Boilers Based on Improved Distributed ELM and Distributed PSO

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1036 ◽  
Author(s):  
Xinying Xu ◽  
Qi Chen ◽  
Mifeng Ren ◽  
Lan Cheng ◽  
Jun Xie
Keyword(s):  
Power Plant ◽  
Combustion Process ◽  
Optimization Method ◽  
Combustion Efficiency ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Nox Emissions ◽  
Coupling Characteristics ◽  
Learning Machine ◽  
Combustion Optimization

Increasing the combustion efficiency of power plant boilers and reducing pollutant emissions are important for energy conservation and environmental protection. The power plant boiler combustion process is a complex multi-input/multi-output system, with a high degree of nonlinearity and strong coupling characteristics. It is necessary to optimize the boiler combustion model by means of artificial intelligence methods. However, the traditional intelligent algorithms cannot deal effectively with the massive and high dimensional power station data. In this paper, a distributed combustion optimization method for boilers is proposed. The MapReduce programming framework is used to parallelize the proposed algorithm model and improve its ability to deal with big data. An improved distributed extreme learning machine is used to establish the combustion system model aiming at boiler combustion efficiency and NOx emission. The distributed particle swarm optimization algorithm based on MapReduce is used to optimize the input parameters of boiler combustion model, and weighted coefficient method is used to solve the multi-objective optimization problem (boiler combustion efficiency and NOx emissions). According to the experimental analysis, the results show that the method can optimize the boiler combustion efficiency and NOx emissions by combining different weight coefficients as needed.

Numerical Simulation of Direct Injection Engine With Using Porous Medium

2012 ◽  
Author(s):  
Arash Mohammadi ◽  
Ali Jazayeri ◽  
Masoud Ziabasharhagh
Keyword(s):  
Porous Medium ◽  
Direct Injection ◽  
Combustion Process ◽  
Packed Bed ◽  
Published Data ◽  
Mixture Formation ◽  
Flammability Limits ◽  
Ic Engine ◽  
Engine Simulation ◽  
Wide Range

Porous media (PM) has interesting advantages in compared with free flame combustion due to the higher burning rates, the increased power range, the extension of the lean flammability limits, and the low emissions of pollutants. Future clean internal combustion (IC) engines should have had minimum emissions level (for both gaseous and particulate matter) under possible lowest fuel consumption permitted in a wide range of speed, loads and having good transient response. These parameters strongly depend on mixture formation and combustion processes which are difficult to be controlled in a conventional engine. This may be achieved by realization of homogeneous combustion process in engine. This paper deals with the simulation of direct injection IC engine equipped with a chemically inert PM, with cylindrical geometry to homogenize and stabilize the combustion of engine. A 3D numerical model for PM engine is presented in this study based on a modified version of the KIVA-3V code. Due to lack of any published data for PM engines, numerical results of thermal and combustion wave propagation in a porous medium are compared with experimental data of lean methane-air mixture under filtration in packed bed and very good agreement is seen. For PM engine simulation methane as a fuel is injected directly inside hot PM that is assumed, mounted in cylinder head. Lean mixture is formed and volumetric combustion occurs in PM and in-cylinder. Mixture formation, pressure and temperature distribution in both phases of PM and in-cylinder fluid with the production of pollutants CO and NO and also effects of injection time in the closed part of the cycle are studied.

scholarly journals POSSIBILITIES TO REDUCE POLLUTANT EMISSIONS IN NAVAL DIESEL ENGINES

2020 ◽  
Vol 10 (3) ◽  
pp. 5-9
Author(s):  
Mihail Lucian DUMITRACHE ◽  
Catalin FAITAR
Keyword(s):  
Mathematical Models ◽  
Computer Technology ◽  
Combustion Process ◽  
Difficult Problem ◽  
Production Costs ◽  
Pollutant Emissions ◽  
Mixture Formation ◽  
Complex Process ◽  
Emission Estimation ◽  
Over Time

The combustion process is, by far, the most important and complex process that takes place in engines. Its importance is given by the fact that it provides the flow of energy used in the engine and is the source of all pollutant emissions, the efficiency of the engine being directly influenced by it. The mechanisms of combustion are particularly complex and are not fully known even today, the most difficult problem being the mechanisms of mixture formation and the chemistry of the combustion process. Over time, depending on the evolution of knowledge in the field and computer technology, various mathematical models have been developed, which have. Emission estimation and theoretical verification, in the first phase, of the solutions applicable to in-service enginescould greatly reduce research and production costs, given that there are a variety of engines onboard ships and measurements in operation are very difficult.

Non-Premixed CH4 Combustion in a Porous Medium

2009 ◽  
Author(s):  
A. Tarokh ◽  
A. A. Mohamad ◽  
L. Jiang
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Combustion Zone ◽  
Combustion Process ◽  
Fiber Material ◽  
Combustion Efficiency ◽  
Premixed Combustion ◽  
Maximum Temperature ◽  
Wall Functions ◽  
Ch4 Combustion

Combustion process is the major contributor to the air pollution, such as CO, unburned hydrocarbon, soot and NOx, etc. Porous media can be a good candidate for improving the combustion efficiency and reducing pollution formation. Premixed combustion has been extensively investigated in the literature, experimentally and computationally. However, investigation of non-premixed combustion in porous media is limited in the open literature, which is the topic of this paper. The present work deals with the numerical modeling of methane/air non-premixed combustion in porous media. Physical problem that is considered here is fuel jet which is injected to the air in free flame case and injected into a porous medium, in the porous medium combustion case. The flow is assumed turbulent and standard k-ε model with standard wall functions is used in the simulation. The solid porous structure is assumed to be composed of alumina fiber material with temperature dependent heat conductivity. Discrete Ordinate method is used to solve radiative transport equations. The governing equations are solved using finite volume method. The results show that the combustion in porous media has superior combustion efficiency and significantly lower NOx and CO emissions compare to the free flame. This is due to the lower maximum temperature in porous media combustion. In comparison with the free flame case where the combustion zone is narrow and long, the results shows the combustion zone in porous media is shorter in axial and wider in radial direction.

Numerical study on the combustion characteristics in a porous-free flame burner for lean mixtures

2019 ◽  
Vol 234 (4) ◽  
pp. 935-945 ◽  
Author(s):  
Seyed Amin Ghorashi ◽  
Seyed Mohammad Hashemi ◽  
Seyed Abdolmehdi Hashemi ◽  
Mahdi Mollamahdi
Keyword(s):  
Porous Medium ◽  
Numerical Study ◽  
Combustion Process ◽  
Experimental Tests ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Numerical Results ◽  
Flame Stability ◽  
Porous Burner ◽  
Flame Burner

The present work implements a numerical simulation to investigate the combustion process in a porous-free flame burner. The non-equilibrium thermal condition is performed, and discretization and solving of the governing equations are conducted in a two-dimensional axisymmetric model. In order to simulate the combustion process, a reduced chemical kinetic mechanism of GRI 3.0, which includes 16 species and 41 reactions, is used. In order to prove the precision of the numerical method, some experimental tests are carried out and the numerical results are in a good agreement with the experimental measurements. The numerical results demonstrate that the porous-free flame burner has a higher flame stability compared to the conventional porous burner and the radiative efficiency of the porous-free flame burner is less than the porous burner. In addition, an increase in thermal conduction of the porous medium leads to an extension in the flame stability. In addition, the results show that with decreasing the pore density of porous medium, the flame stability is extended.

KESAN SUDUT PUSARAN TERHADAP PEMBAKARAN MENGGUNAKAN PEMUSAR JEJARIAN DWI ALIRAN

2015 ◽  
Vol 77 (8) ◽  
Author(s):  
Muhammad Roslan Rahim ◽  
Mohammad Nazri Mohd Ja’afar
Keyword(s):  
Swirling Flow ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Flame Length ◽  
Pollutant Emissions ◽  
Pollutant Emission ◽  
Flame Stability ◽  
Wide Spread ◽  
Blue Colour ◽  
The One

Development of combustion systems which involves retrofitting or design of new burners, is made to reduce the formation of pollutant emissions. The reduction of this pollutant emission results from the complete mixing of fuel and air during the combustion process. Meanwhile, non-complete mixing of fuel and air during combustion process can cause ignition problem and create problems in terms of flame stability and combustion efficiency. This article describes a study on the effects of swirling flow generated by a double radial swirler on flame characteristics that is related to the emission of NO. The double radial swirlers used in this study have the angles of 30°/40°, 30°/50° and 30°/60°. Diesel is used as a fuel in this study. The results show that all double radial swirlers used have different effects on the flame characteristics and temperature profile. From all these double radial swirlers, the one with an angle of 30°/60° produces flame with high temperature, short flame length with blue colour and wide spread.

scholarly journals Pollutant Emissions and Combustion Efficiency Assessment of Engines Using Biodiesel

2020 ◽  
Vol 10 (23) ◽  
pp. 8646
Author(s):  
Juan Carlos Paredes Rojas ◽  
Christopher Rene Torres San Miguel ◽  
Rubén Vázquez Medina ◽  
José Alfredo Leal Naranjo ◽  
Fernando Elí Ortiz Hernàndez ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Diesel Engine ◽  
Analytical Study ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Pollutant Emissions ◽  
Technical Problems ◽  
Biodiesel Blends ◽  
Electric Generator ◽  
Efficiency Assessment

This paper evaluates the biodiesel produced by a biodiesel plant located in the Mexican Centre for Cleaner Production (CMP + L by its acronym in Spanish) of the National Polytechnic Institute of Mexico. Pollutant emissions from two types of engines were studied: a low power monocylinder engine and a 30-kW electric generator diesel engine. The tests were performed with the following blends: B5, B10, B15, B20, B30, B40, and B50. Parameters such as carbon monoxide, nitrogen oxide, hydrocarbons, and combustion efficiency were analyzed, as well as sulfur dioxide, oxygen, and combustion temperatures. It was demonstrated that NOx increases as the percentage of biodiesel increases, while CO decreases slightly using the monocylinder engine. In the case of the electric generator diesel engine, the B5 mixture had the highest trend for NOx and the lowest trend for CO. Likewise, combustion efficiency was found to be severely affected by the biodiesel blends, i.e., from B5 to B20. An analytical study and experimental thermography tests of the combustion process with biodiesel blends were carried out, and the technical problems of operation when incorporating biodiesel blends are presented.

Experimental Validation for Control-Oriented Modeling of Multi-Cylinder HCCI Diesel Engines

2006 ◽  
Author(s):  
Marcello Canova ◽  
Shawn Midlam-Mohler ◽  
Yann Guezennec ◽  
Giorgio Rizzoni ◽  
Luca Garzarella ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Soot Formation ◽  
Direct Injection ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Injection System ◽  
Compression Ignition ◽  
Mixture Formation ◽  
Hcci Combustion

Homogeneous Charge Compression Ignition (HCCI) is a combustion process based on a lean, homogeneous, premixed charge reacting and burning uniformly throughout the mixture volume. This principle leads to a consistent decrease in NOx and PM emissions, while the combustion efficiency remains comparable to traditional Compression Ignition Direct Injection (CIDI) engines at low and mid-load operations. However, understanding and controlling the combustion process is still extremely difficult, as well as finding a proper method for the fuel introduction. A viable method consists of premixing the charge by applying a proper fuel atomization device in the intake port, thus decoupling the HCCI mixture formation from the traditional in-cylinder injection. This avoids the traditional drawbacks associated to external Diesel mixture preparation, such as high intake heating, low compression ratio, wall wetting, and soot formation. The system, previously developed and tested on a single-cylinder engine, has been successfully applied to multi-cylinder Diesel engine for automotive applications. Building on previous modeling and experimental work, the paper reports a detailed experimental analysis of HCCI combustion with external mixture formation. In the considered testing setup, the fuel atomizer has been applied to a four-cylinder turbo-charged Common Rail Diesel engine equipped with a cooled EGR system. In order to extend the knowledge on the process and to provide a large base of data for the identification of Control-Oriented Models, Diesel-fueled HCCI combustion has been characterized over different values of loads, EGR dilution and boost pressures. The data collected were then used for the validation of a HCCI Diesel engine model that was previously built for steady state and transient simulation and for control purposes. The experimental results obtained, especially considering the emission levels and efficiency, suggest that the technology developed for external mixture formation is a feasible upgrade for automotive Diesel engines without introducing additional design efforts or constraints on the DI combustion and injection system.

Improvements in Efficiency and Mixture Formation for an Innovative Diesel HCCI Concept

2009 ◽  
Author(s):  
E. Musu ◽  
R. Rossi ◽  
R. Gentili
Keyword(s):  
Combustion Process ◽  
Pressure Rise ◽  
Pollutant Emissions ◽  
Spontaneous Ignition ◽  
Exhaust Gas ◽  
Mixture Formation ◽  
Hcci Combustion ◽  
Gas Recirculation ◽  
Transfer Flow ◽  
Homogeneous Charge

Homogeneous-charge, compression-ignition (HCCI) combustion is triggered by spontaneous ignition in dilute homogeneous mixtures. The combustion rate must be reduced by suitable solutions such as high rates of Exhaust Gas Recirculation (EGR) and/or lean mixtures. HCCI is considered to be a very effective way to reduce engine pollutant emissions, however only a few production engines have been built. HCCI combustion currently cannot be extended to the whole engine operating range, especially to high loads, since the use of EGR displaces air from the cylinder, limiting engine mean effective pressure, thus the engine must be able to operate also in conventional mode. This paper concerns a study of an innovative concept to control HCCI combustion in diesel-fueled engines. The concept consists in forming a pre-compressed homogeneous charge outside the cylinder and in gradually admitting it into the cylinder during the combustion process. In this way, combustion can be controlled by the transfer flow rate, and high pressure rise rates, typical of standard HCCI combustion, can be avoided. This new combustion concept has been called Homogenous Charge Progressive Combustion (HCPC). This paper concerns CFD analysis focused on improving efficiency and reducing pollutant emissions considering a new HCPC engine configuration. Results show an indicated efficiency around 45% and a consistent reduction of soot emission compared to conventional diesel engine.

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