Aminuddin Saat

Effect of diluted and preheated oxidizer on the emission of methane flameless combustion

In combustion process, reduction of emissions often accompanies with output efficiency reduction. It means, by using current combustion technique it is difficult to obtainlow pollution and high level of efficiency in the same time. In new combustion system, low NOxengines and burners are studied particularly. Recently flameless or Moderate and Intensive Low oxygen Dilution (MILD) combustion has received special attention in terms of low harmful emissions and low energy consumption. Behavior of combustion with highly preheated air was analyzed to study the change of combustion regime and the reason for the compatibility of high performance and low NOx production. Sustainability of combustion under low oxygen concentration was examined when; the combustion air temperature was above the self-ignition temperature of the fuel. This paper purposes to analyze the NOx emission quantity in conventional combustion and flameless combustion by Chemical Equilibrium with Applications (CEA) software.

Effect of Vertical Baffle Installation on Forced Convective Heat Transfer in Channel Having a Backward Facing Step

In this study, forced convective heat transfer is considered in channel over a backward facing step having a baffle on the top wall. Four different geometries with different expansion ratios and different type of baffles are numerically investigated. The study clearly shows that the geometry with expansion ratio 2 and solid baffle has the highest Nusselt number compared to other geometries. Considering both Nusselt number and skin friction coefficient for all four geometries clearly illustrated an increase in average Nusselt number by increasing the expansion ratio. This study clearly shows that mounting a slotted baffle at the top wall instead of a solid baffle caused a decline in average Nusselt number. It is also found that for geometry with expansion ratio of 3 and a slotted baffle on the top of the channel, skin friction coefficient in both bottom wall and step wall has its minimal compared to other geometries.

Investigation of Vortex Reacting Flows in Asymmetric Meso Scale Combustor

In the current study computational and experimental investigations of a turbulent asymmetric vortex flame is presented. The three dimensional flow fields have been described using a computational methodology that impalements the kε turbulence model. The computational model is validated for isothermal flow. Moreover, the visible flame structure was captured by direct photography at a wide range of equivalence ratios in order to emphasize the exceptional stability of such flame. The mechanism of flame stability and interaction with the forced vortex field is preliminarily discussed. Finally, the basic characteristics of the asymmetric vortex flames are concluded.

Analysis of Variable Intake Runner Lengths and Intake Valve Open Timings on Engine Performances

In this paper, engine simulation tool is used to investigate the effect of variable intake manifold and variable valve timing technologies on the engine performance at full load engine conditions. Here, an engine model of 1.6 litre four cylinders, four stroke spark ignition (SI) engine is constructed using GT-Power software to represent the real engine conditions. This constructed model is then correlated to the experimental data to make sure the accuracy of this model. The comparison results of volumetric efficiency (VE), intake manifold air pressure (MAP), exhaust manifold back pressure (BckPress) and brake specific fuel consumption (BSFC) show very well agreement with the differences of less than 4%. Then this correlated model is used to predict the engine performance at various intake runner lengths (IRL) and various intake valve open (IVO) timings. Design of experiment and optimisation tool are applied to obtain optimum parameters. Here, several configurations of IRL and IVO timing are proposed to give several options during the engine development work. A significant improvement is found at configuration of variable IVO timing and variable IRL compared to fixed IVO timing and fixed IRL.

Review of Numerical Studies on NOx Emission in the Flameless Combustion

Today one source of pollution emission in the combustion of fossil fuels is the formation of nitrogen oxides. To solve this problem many technologies have been introduced such as flameless combustion. Flameless combustion is of a great interest since it simultaneously provides higher thermal efficiency together with controlling the pollutant emission such as NOX. In this technology, the preheat temperature of the combustion air must be higher than the auto-ignition temperature of the reactant mixture. In this study, papers showing the numerical studies on the flameless combustion to reduce NOX emission are presented.

Main Steam Temperature Modeling Based on Levenberg-Marquardt Learning Algorithm

Main steam temperature is one of the most important parameters in coal fired power plant. Main steam temperature is often describe as non-linear and large inertia with long dead time parameters. This paper present main steam temperature modeling method using neural network with Levenberg-Marquardt learning algorithm. The result of the simulation showed that the main steam temperature modeling based on neural network with Levenberg-Marqurdt learning algorithm is able to replicate closely the actual plant behavior. Generator output, main steam flow, main steam pressure and total spraywater flow are proven to be the main parameters affected the behavior of main steam temperature in coal fired power plant.

Effects of CO2 Dilution on the Premixed Combustion of CH4 in Microcombustor

A numerical study on premixed combustion of CH4 + CO2 + Air in two dimensional is done. Parameters of inlet velocity and temperature of fuel and combustor geometry and size are considers the same but the CO2 dilution rate changes. Results of this simulation shows that while the CO2 dilution rate increases, flame temperature and velocity decrease. There is a limitation for increasing of CO2 in the mixture. If amount of CO2 in the mixture goes beyond the 47.7%, the fuel will lose its ability to be ignited and thus there will be no flame in the combustor. In addition, knowing the maximum temperature of flame may help to analyze the combustion process and choose suitable material in manufacturing the micro combustor.

Effects of Firing Mode on the Performance of Flameless Combustion: A Review Paper

Flameless combustion is of a great interest since it simultaneously provides higher thermal efficiency together with controlling the pollutant emission such as NOX. This technology has been used to provide large energy savings in power system and industrial heating applications. In this technology, the preheat temperature of the combustion air must be higher than the auto-ignition temperature of the reactant mixture. In this review, papers concern the effect of firing mode to reduce pollutant emissions such as NOX emission and combustion efficiency for flameless combustion were reviewed. Summaries on the influences of the firing mode in the flameless combustion were presented, discussed and analyzed. The review concludes that all the previous studies have asserted that a parallel firing mode gives much lower pollutant emissions and high efficiency compared with staggered and counter modes.

Simulation of corrected mass flow and non-adiabatic efficiency on a turbocharger

The aim of this project is to evaluate turbine’s performance based on its actual condition. Holset H3B nozzles turbine geometry was used as simulation model. Turbine’s actual working condition was simulated using finite volume method (FVM). Three-dimensional Navier Stoke equations with heat convection loss via turbine volute are solved. The parameters studied are corrected mass flow and turbine’s efficiency at different heat transfer coefficients. Temperature difference within turbine’s volute is the major factor that deteriorates turbine’s efficiency. It is found that the higher the heat transfer coefficient, the lower turbine’s efficiency will be.

Pulse Detonation Engine Research Development at High Speed Reacting Flow Laboratory - HiREF, Universiti Teknologi Malaysia

The Pulse detonation Engine (PDE) research program has been started at High Speed Reacting Flow Laboratory (HiREF), Universiti Teknologi Malaysia (UTM) since 2005. The studies began with a single pulse detonation study for detailed investigation of detonation characteristics of various fuels and followed by development of repetitive PDE engine, performance study and augmentation of thrust using various types of ejectors. This paper summarizes the laboratory facilities, research activities conducted and the output from all of the related research programs.