Advanced Materials Research Vol. 1016

Abstract: In this work, the application of Generalized Differential Quadrature Method (GDQM) to solve a variable viscosity channel flow under constant magnetic field is investigated. The governing equations for channel flow in between two infinite horizontal parallel porous plates subject to convective surface boundary conditions are given in dimensional and non-dimensional forms, pointing out the dimensionless parameters used. These equations are discretized using the GDQM, and solved via Newton Raphson Method. Effects of magnetic field on incompressible electrically conducting fluid velocity and temperature profiles are presented in plots.

Abstract: In this work, two-dimensional inviscid supersonic flow in nozzle has been investigated using CFD schemes and characteristics method. The employed scheme is MacCormack’s finite volume method. Our own code CHARMAC, was written using MATLAB environment. Standard boundary conditions and the grid parameters were considered to solve the problem. Before analyzing the flow by CFD method, we obtained the ideal nozzle geometry using the method of characteristics for a 2D divergent Nozzle. Using 2D nozzle flow relations, an optimal throat area is found. At the end we compare the results with the advection upstream splitting Method (Ausm) and Fluent.

Abstract: The paper deals with the load of the head of the engine. Head of SI engine, which has molded seat of intake and exhaust valve, is one of the most complex parts of the engine. It contains intake and exhaust ports, spark plugs, timing of the mechanism and channels for cooling and lubrication. Much of the final form of this component also contributes its load, which is both heat and mechanical. The biggest influence on the deformation of embedded saddles exhaust valve has a temperature distribution in the cylinder head. These temperatures are influenced by many factors, especially temperature and coolant flow, load and engine speed, which affect the combustion process and exhaust gas temperature (the engine mode is constantly changing, therefore the thermal load on the valve seats is different). In our paper we will only deal with the heat load of the cylinder head of the engine. Currently, the most common use of appropriate software tools for determining the distribution as voltage or temperature. The simulation results may not always be identical to the actual situation, so it is necessary to perform by verification. The paper described measurements of temperature on the inserted valve seats cylinder head of the engine.

Abstract: In this study the performance, exhaust emission characteristics and combustion process of the engine fueled with hydrogen-diesel blends were compared to diesel fuel. Hydrogen was blended with diesel fuel at the volumetric ratios of 5%, 10% and 20%. AVL BOOST software was dedicated to simulate the performance and emission values for various blends of hydrogen with diesel fuel. The simulation results showed that hydrogen addition to diesel fuel improve both engine performance and exhaust emmisions.

Abstract: Flame spreading over liquid fuels is a common phenomenon involving in accidental fuel leakage in aircraft crash or oil tanker which may result in many casualties and economic losses. Comparative experiments are conducted concerning flame spread over aviation kerosene (RP5) and 0# diesel at a variety of initial fuel temperatures. The threshold value of initial fuel temperature for liquid-phase and gas-phase controlled flame spread is approximately 17 °C larger than liquid’s flashpoint for both oils. For a given initial fuel temperature, due to low volatility and ignitability of 0# diesel, its flame spread rate is smaller than that of RP5, while the length of the horizontal subsurface convection flow is larger. Given the difference in flame speed, fire accidents for RP5 are potentially more hazardous than those of 0# diesel. Moreover, the variation trend of subsurface convection flow length falls nearly linearly with the initial fuel temperature for both fuels.

Abstract: This paper describes the analysis of the fundamental effect of synthetic gas combustion in a can-type combustor using Computational Fluid Dynamic(CFD). Emphasis is given towards the effect of variation of methane to the flame profile, temperature distribution and heat flux in the combustor. In this study, the composition of hydrogen in the syngas was fixed at 30% while methane and carbon monoxide were varied. Results show that the flame temperature and NO_x emissions are highly dependent on the composition of methane in the syngas fuel. Nevertheless, the overall NO_x emission for all cases is relatively lower than the conventional pure natural gas combustion.

Abstract: In this study the influences of ethanol addition to gasoline on an spark ignition engine performance and emissions were explored. AVL BOOST software was used to simulate the performance and emission characteristics of different ethanol-gasoline blends. The blended fuels contain 5%, 10% and 15% of ethanol by volume, and indicated as B95E5, B90E10, and B85E15, respectively. The results showed that ethanol addition to gasoline fuel improve combustion process, decrease CO emissions and reduce BSFC of the SI engine.

Abstract: Diesel engines become popular from this point of view because of their high thermal efficiency. However, new and developing technologies are expected to lower their emission levels. Atomization of the fuel has a vital importance in order to control heat release rate and exhaust emission during combustion. With the known injection devices, atomization of the fuel is realized with high pressure systems such as common rail direct injectors (CRD) which operate at pressures exceeding 1300 bar. However, atomization of the fuel by simply increasing injection pressure can create cavitation erosion which may lead to mechanical failure of the nozzle. Utilization of air in diesel engine injectors will increase fuel atomization, provides more complete combustion of any diesel fuel consumed, enhance fuel economy and results in lower engine emissions. Therefore the aim of this study is to design a special injection device for use in a diesel engine which improves combustion by mixing air and fuel inside itself at optimum ratio. Proper air inlet pressure was determined for favorable diesel air mixing by investigation of the flow behavior in a newly designed injection device with the help of computational fluid dynamics based software. Three different air inlet pressures (20, 30 and 40 bar) are simulated and the contours of turbulence intensity, velocity and volume fraction of diesel fuel are discussed, and compared with each other.

Abstract: In this paper I am dealing with a general analysis of problems burning of lean hydrogen mixtures in combustion engines. During burning of very lean mixtures burning procedure is over lasted with characteristic features. They need to be removed or reduced. One of these features is low power of engines operating by lean mixtures, which can be partially removed with the help of supercharging such engines. In the second part of the paper I am dealing with a design of supercharging system for a three-cylinder engine with volume 1,2 dm³.

Abstract: Various problems of the task-level robot learning from demonstration has received substantial attention recently. Among other, we can mention investigation of motor primitives. In particular, different rhythmic motor tasks are very important. Recently, the approximate period problem was considered as a model for the investigation of sequences of motor primitives. In this paper, we consider the approximate period problem and some modifications of the problem for the investigation of sequences of rhythmic motor primitives.