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Characteristics-Based Finite-Volume Solution for Natural Convection Around a Horizontal Cylinder  [PDF]
Seyed Esmail Razavi,Farzad Barar,Vahid Farhangmehr
Journal of Applied Sciences , 2008,
Abstract: In the current investigation, a Characteristics-Based (CB) finite-volume solution was developed to improve the convergence rate and the solution stability of the numerical simulation of incompressible viscous flows. The Artificial Compressibility Method (ACM) as a pre-conditioner was taken into account in our study. A fifth-order Runge-Kutta scheme has been used for marching in time. Local time stepping and implicit residual smoothing were applied as convergence acceleration techniques. The convective fluxes have been calculated by a Roe-like high-order flux splitting scheme. The viscous and thermal conduction terms were found by a second-order technique. This method admitted high Courant-Friedrichs-Levy (CFL) numbers and revealed a good convergence rate and accuracy within a wide range of Rayleigh numbers from 1 to 10000 for natural convection flow around a horizontal circular cylinder which is chosen as a case study. The obtained results were compared with available benchmark data in literature and showed a high consensus with them.
Combustion Model and Control Parameter Optimization Methods for Single Cylinder Diesel Engine  [PDF]
Bambang Wahono,Harutoshi Ogai
Journal of Optimization , 2014, DOI: 10.1155/2014/135163
Abstract: This research presents a method to construct a combustion model and a method to optimize some control parameters of diesel engine in order to develop a model-based control system. The construction purpose of the model is to appropriately manage some control parameters to obtain the values of fuel consumption and emission as the engine output objectives. Stepwise method considering multicollinearity was applied to construct combustion model with the polynomial model. Using the experimental data of a single cylinder diesel engine, the model of power, BSFC, , and soot on multiple injection diesel engines was built. The proposed method succesfully developed the model that describes control parameters in relation to the engine outputs. Although many control devices can be mounted to diesel engine, optimization technique is required to utilize this method in finding optimal engine operating conditions efficiently beside the existing development of individual emission control methods. Particle swarm optimization (PSO) was used to calculate control parameters to optimize fuel consumption and emission based on the model. The proposed method is able to calculate control parameters efficiently to optimize evaluation item based on the model. Finally, the model which added PSO then was compiled in a microcontroller. 1. Introduction Currently, energy and environmental pollution have become hot topics. Public and private transportations system plays an important role in people’s life. Vehicle has become one of the most important factors in this system. In Jakarta, it is reported that 70% exhaust gas pollution is from vehicles [1]. Internal combustion engine is the main power of the vehicle. The global challenge in internal combustion engine is the reduction of exhaust gas such as soot, [2, 3], CO, HC, and particulate matter (PM) emissions from vehicles by improving fuel consumption without sacrificing the vehicle performance. On the other side, most internal combustion engine methods that reduce either or soot emissions cause an increase in the other emissions [4]. Recently, with the environmental restrictions and sustainable development, pollution standards have been more and more stringent. For example, in Japan, the standard of diesel engine emission regulation is very high. In 2003 the MOE finalized very stringent 2005 emission standards for both light and heavy vehicles although it remained relaxed through the 1990s. In 2005 heavy-duty emission standards , ) were the most stringent diesel emission regulations in the world. In 2009, this standards were more
Nureddin Dinler,Nuri Yucel
Thermal Science , 2010, DOI: tsci10041001d
Abstract: Combustion is an important subject of internal combustion engine studies. To reduce the air pollution from internal combustion engines and to increase the engine performance, it is required to increase combustion efficiency. In this study, effects of air/fuel ratio were investigated numerically. An axisymmetrical internal combustion engine was modeled in order to simulate in-cylinder engine flow and combustion. Two dimensional transient continuity, momentum, turbulence, energy, and combustion equations were solved. The k-e turbulence model was employed. The fuel mass fraction transport equation was used for modeling of the combustion. For this purpose a computational fluid dynamics code was developed by using the finite volume method with FORTRAN programming code. The moving mesh was utilized to simulate the piston motion. The developed code simulates four strokes of engine continuously. In the case of laminar flow combustion, Arrhenius type combustion equations were employed. In the case of turbulent flow combustion, eddy break-up model was employed. Results were given for rich, stoichiometric, and lean mixtures in contour graphs. Contour graphs showed that lean mixture (l = 1.1) has longer combustion duration.
Dynamics of a working process approximated to combustion at constant pressure  [PDF]
Andrusenko Sergey Evgenevich,Matveev Yury Ivanovich,Andrusenko Oleg Evgenevich
Vestnik of Astrakhan State Technical University. Series: Marine Engineering and Technologies , 2011,
Abstract: The process of fuel combustion in the cylinder is considered in the paper. The interaction of the fuel combustion process with the gas distribution system and the fuel injection into the cylinder is investigated. The interconnection of the advance angle of fuel injection with the dynamics of loads on engine parts is studied. Experimental observations connected with fuel adjustment and parameter changes in working processes of the diesel engine are described. Practical advice is also given to the adjustment of fuel combustion and fuel expansion processes.
Simulation of in-cylinder processes in a DI diesel engine with various injection timings
S. M. Jameel Basha,P. Issac Prasad,K. Rajagopal
Journal of Engineering and Applied Sciences , 2009,
Abstract: The gas motion inside the engine cylinder plays a very important role in determining the thermal efficiency of an internal combustion engine. A better understanding of in cylinder gas motion will be helpful in optimizing engine deign parameters. An attempt has been made to study the combustion processes in a compression ignition engine and simulation was done using computational fluid dynamic (CFD) code FLUENT. An Ax symmetric turbulent combustion flow with heat transfer is to be modeled for a flat piston 4-stroke diesel engine. The unsteady compressible conservation equations for mass (Continuity), axial and radial momentum, energy, species concentration equations can express the flow field and combustion in ax symmetric engine cylinder. Turbulent flow modeling and combustion modeling was analyzed in formulating and developing a model for combustion process.
Qualitative Analysis of Coating Flows on a Rotating Horizontal Cylinder
Marina Chugunova,Roman M. Taranets
International Journal of Differential Equations , 2012, DOI: 10.1155/2012/570283
Abstract: We consider a nonlinear 4th-order degenerate parabolic partial differential equation that arises in modelling the dynamics of an incompressible thin liquid film on the outer surface of a rotating horizontal cylinder in the presence of gravity. The parameters involved determine a rich variety of qualitatively different flows. We obtain sufficient conditions for finite speed of support propagation and for waiting time phenomena by application of a new extension of Stampacchia's lemma for a system of functional equations.
Concept of Hydrodynamic Load Analysis of Fixed Jacket Structure – An Overview of Horizontal Cylinder
Aliyu Baba
International Journal of Engineering Research , 2014,
Abstract: This paper focuses on the analysis of hydrodynamic loads on fixed offshore structures (horizontal cylinder) that are operating in shallow water and are often subjected to huge wave loading. For the purpose of this study, linear (Airy) wave theory was adopted together with the application of (21) in the load computation. The loads for six different sea states were computed using spread sheet for the following values of time t = 0, T/4, T/2.
Analysis of a Single Cylinder Combustion Engine Using CFD  [PDF]
G.Suresh Babu,S.D.V.S.Jagadeesh,U.B.Saicharan,P.R.S.Praneeth
International Journal of Innovative Technology and Exploring Engineering , 2013,
Abstract: If we consider the reasons for the Environmental Pollution from the last few decades, it is clear that most of the pollution is because of the hike in the usage of “Fossil fuels” in the transportation. Our attempts to build much energy efficient vehicles and demand for these vehicles are increasing accordingly. From the practical observations we can clearly understand that the UN-burnt fuels in the combustion chamber of an automobile engine causes the pollution and this UN-burnt fuels (carbon particles) will come out through muffler present to the automobile, which causes the pollution in the environment by releasing them. Our project is to understand these effects in a much more meticulous way and suggest few developments that can be made in this particular field. For this we would like to take up the case study of the single cylinder spark ignition engine of 4 stroke and their current efficiency level and the major drawbacks of them. Today, the use of software tools in the field of research and Industry has become inevitable because of the complexities that we are facing at present and the ease with which such problems can be solved using these tools. For an Engineer of this generation, it is a need to be proficient in using these tools. Hence, we would like to model the combustion system in ICEM-CFD and make the analysis of this in CFD.
A New Method to Determine the Start and End of Combustion in an Internal Combustion Engine Using Entropy Changes  [cached]
Mohand Tazerout,Olivier Le Corre,A. Ramesh
International Journal of Thermodynamics , 2000, DOI: 10.5541/ijot.33
Abstract: Simulation studies indicated that the start and end of combustion in an internal combustion engine could be determined from the points of minimum and maximum entropy in the cycle. This method was further used to predict the beginning and end of the combustion process from experimentally obtained pressure crank angle data from a natural gas operated, single cylinder, spark ignition engine. The end of combustion always matched well with the point of maximum entropy. The start of combustion could be determined easily from the rate of change of entropy, which showed a sharp change at ignition. Results closely agreed with those obtained from a heat release analysis.
Experimental Investigation of Oxygen Enriched air intake on Combustion Parameters of a Single Cylinder Diesel Engine
International Journal of Engineering Science and Technology , 2010,
Abstract: In the present experimental work a computerized Single cylinder Diesel engine with data acquisition system was used to study the effects of oxygen enriched air intake on combustion parameters. Increasing the oxygen content with the air leads to faster burn rates and the ability to burn more fuel at the same stoichiometery. Addedoxygen in the combustion air leads to shorter ignition delays and offers more potential for burning diesel. Oxy-fuel combustion reduces the volume of flue gases and reduces the effects of green house effect also. Engine test has been carried out in the above said engine for different loads and the following combustion parameters like Ignition delay, Combustion duration, Heat release and Cylinder pressure was discussed.
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