The amount of woody biomass resources in Aichi Prefecture and Toyone Village was estimated on the basis of theoretical and actual production efficiencies. Five factors should be considered at the steady production of reduced carbon from carbon dioxide by sunlight in woods. The ratio of leaf to forest area, the reflection of sunlight on leaf surface, the conversion efficiency from the light energy, efficiency of optical system, and of dark reaction are 0.70, 0.82, 0.24, 0.31, and 0.92 respectively. On the other hand, four factors are in the timber production stage. The energy consumption loss for the daily life of woods, the waste at the forest, the thinner woods to main cutting production, and the thinning are 0.50, 0.47, 0.435, 0.44, respectively. The total efficiency was calculated and the result was 0.0023. Furthermore, near fiscal year 2000, primary energy consumption in Aichi Prefecture is1.48×10⁹ GJ/year, so it is 2200 times than the present production amount and 300 times the best theoretical production amount.

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In order to use wet biomass such as sewage sludge as fuels thermochemical energy conversion systems, we studied on a steam heating treatment using saturated steam at 473 K for wet biomass fuelization. In order to clarify the mechanisms of various effects of this treatment such as drying period shortening effect, heating value increase and stinky order reduction, components of raw materials, solid products and gas products were analyzed. As a result, we found that the drying period of solid products was much shorter than that of the raw sewage sludge in air-dry condition and the moisture content of the solid products became less than 30 wt% within 2 day after treatment. In addition, we found that the heating value of the solid products increased by applying this treatment. This is because of solubilization of a part of volatiles matter. As for stinky odor, the concentrations of the gas components include sulfur from solid product reduced by this treatment. There are two reasons of stinky odor reduction. One is the desulferization effect of this treatment, and another be masking effect of organic acids as by-product of this treatment.

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The industrial carbon dioxide discharge is a serious problem of the global environment. The biomass is carbon neutral energy and can be used as an alternative fuel. The object of this paper is to cut down the fossil consumption in a small-scale oil-burning furnace by wood powder and A-heavy oil. The wood powder, which has a size of 150 pm and is made of thinned lumber, is blended into A-heavy oil flame. A wood powder nozzle is used to directly supply the wood powder to the flame in the same axial direction. The combustion characteristics are experimentally investigated. As the wood powder increases, the temperature and the calorific value in furnace is increased, CO concentration is decreased. The particulate matter produced by A-heavy oil is significantly decreased. It is found that the wood powder is available to energy saving and emission control.

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Vitrification process environmentally contribute to volume reduction and detoxification of residues such as bottom ash and fly ash from municipal solid waste (MSW) incineration, and recycle them as resources which can help to mitigate shortage of landfill capacity. The vitrification system however, makes heavy use of thermal energy to gain high temterature for ash melting. While recently the gasification and melting system plant that the energy consumption is reduced by using the waste heat value on it's own has come into action, a great number of conventional plants consist of stoker type incinerator and ash melting furnace are expected to reduce the energy consumption. A pratical study of integrated ash-melting process into solid waste incinerator to gain the energy efficiency was conducted at 105t/d MSW stoker-type incineration plant, which had achieved stable low air-ratio combustion previously. The test demonstrated that the integrated ash melting system was available for practical use with no adverse affect on the combustibility of incinerator and that the energy efficiency was improved overall.

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We have been developing small-scale gasification and power generation systems utilizing solid wastes. Based on the R & D achievements, a local town in Japan has built a 1 t/h scale slagging MSW (Municipal Solid Waste) gasifier combined with 900 kW dual-fueled diesel engines. This town will receives meat-and-bone meals to mix with MSW and feeds them into the plant as biomass fuels. It is expected that this plant will utilize 0.5 t/h MSW and 0.5 t/h meat-and-bone meals as fuels to generate 900 kW electric power. This paper describes the outline of this plant and discusses about effects of fuel composition and gasification air ratio on gasification performance as well as power generation results.

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The performance of radial flow turbines having low rotational speed and low noise level, which can be used for wave energy conversion using the oscillating water column (OWC) principle, has been studied by a number of researchers. According to previous studies, the efficiency of radial turbine with fixed guide vanes was not so high because there are large differences between the absolute outlet flow angle and setting angle of the downstream guide vane, and the downstream guide vane doesn't work as a diffuser. In order to develop a high performance radial turbine for wave energy conversion, a radial turbine with pitch-controlled guide vanes has been proposed and manufactured in the study. The presented radial turbine has been investigated experimentally by model testing using an oscillating airflow rig. Then, the experimental results have been compared with those of the conventional radial turbine, i.e., the radial turbine with fixed guide vanes. As a result, the running characteristics of the presented radial turbine under steady and sinusoidal airflow conditions have been clarified. Furthermore, it seems that the presented radial turbine is superior to the conventional radial turbine.

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The Wells turbine is a self-rectifying air turbine which is expected to be widely used in wave energy devices with the oscillating water column (OWC). According to previous studies, however, the Wells turbine has inherent disadvantages in comparison with conventional turbines : lower efficiency and poorer stating characteristic. In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plate on the turbine characteristics has been invistigated experimentally by model testing using an oscillating airflow rig. And then, the characteristics of the Wells turbine with end plates have been compared with those of the original Wells turbine, i. e., the turbine without end plate. As a result, it is found that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine and the characteristics are dependent on the size and position of end plate.

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This paper aims to investigate velocity fields in a cerebral aneurysm and also distributions of wall shear stresses (WSS) using stereoscopic particle image velocimetry (stereoscopic PIV) measurement of flow in an in vitro model. The present in vitro model has the realistic vessel geometry of middle cerebral artery (MCA), which is reconstructed from computed tomography (CT) images. Since stereoscopic PIV is applied to the measurement, a new calibration technique has been developed in order to measure the flow in complex geometry. In this method, two laser beams are used to create to create calibration points. And the accuracy of this method is comparable with that of the conventional calibration technique using a calibration plate. The experimental results at the steady state show that the flow from the parent artery mostly goes into the aneurysm rather than into the branching arteries. Two vortices along the aneurysm are observed in the measurement model. The WSS are calculated from the velocities, which are obtained by the PIV measurement. The result shows that the magnitude of WSS averaged over the aneurysm is lower than that of WSS averaged over the rest of the blood vessels.

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With respect to vibration problems of a guide vane, this vibration phenomenon seems to be generated by the fluid exciting force, which works on the guide vane in unsteady flow field. Thus, in order to understand the vibration mechanism of the guide vane, it is important to reveal unsteady flow field in the curved pipe with the guide vane. In this study, the difference of flow condition between a curved circular pipe and an elbow pipe fitting was inventigated by Computational Fluid Dynamics (CFD) using Reynolds Averaged Navier-Stokes Simulation (RANS). As a result of this study, there is no big difference between both flow conditions. Moreover, unsteady flow field in the curved circular pipe was investigated by Particle Image Velocimetry (PIV) measurements. This experiment was mainly carried out with focusing on unsteady flow field around the trailing edge of the guide vane. The results show that the vortex street is sometimes generated from the trailing edge of the guide vane.

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A method for performing aeroacoustic simulation, where the acoustic field is split from the flow field, is applied to the flow around an automobile rear-view mirror placed on a large solid plane. The flow can be obtained by performing large eddy simulation for the incompressible flow equations on colocated grids, while the acoustic equations are defined by the difference between the compressible and the incompressible flow equations, and solved by the finite volume method with the fourth order WENO scheme. The non-reflecting boundary conditions with a perfectly matched layer are applied to the outer boundary. Calculated results show clear sound emissions, where acoustic streamlines as propagation path are depicted based on acoustic intensity vectors. In this paper, two kinds of mirror shape, i.e., the eases with and without a strong vortex at the tip of a rear-view mirror are compared. Calculated results show some differences between them in the acoustic field. The sound pressure related with the pressure frequency of the generated vortex is increased in all directions, though the propagation path dose not show a large difference except near part of the body surface.

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The number of computational cells assigned to a small bubble is liable to be small in a volume tracking simulation of a poly-dispersed bubbly flow. The volume tracking method is, therefore, expected to at least give qualitatively reasonable predictions of bubble motion without assigning many cells. In this study, bubble motions in stagnant water and shear flows were simulated with low spatial resolutions using a volume tracking method proposed in our previous study. As a result, we confirmed that (1) the method could yield correct characteristics of rising velocity and lateral motion of bubbles, and (2) the bubble volume and interface sharpness were kept well even after a bubble had experienced a large deformation in a strong shear flow.

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The present paper reports the experimental and numerical study of shock wave propagation under saltwater sealed in aluminum containers. This study is the fundamental research on shock sterilization for development of ship's ballast water treatment technique. In the experiment we carried out the impact experiment with a gas gun to generate strong shock waves in saltwater. We confirmed that no leakage of saltwater from the aluminum container was obtained after shock events. The shock pressure fluctuations were measured with piezofilm gauges. Several hundred MPa pressure behind the first shock wave under the saltwater was obtained by the experiments. The FEM simulation, using the Johnson-Cook model for aluminum material and the Tait equation for salt-water, was carried out in order to predict the shock phenomena in both aluminum and saltwater. The computational results showed the states of stress and pressure in the container and indicated good agreements with the experimental results on the first shock pressure profiles at the impact velocities less than 200 m/s qualitatively and quantitatively.

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Experimental and numerical studies are reported on the vortex breakdown phenomenon in an enclosed cylindrical container in which a top endwall rotates at an angular velocity Ω, and a bottom endwall rotates at an angular velocity Ω_b, and a colinder sidewall is stationary. Regime boundaries for the vertex breakdown, the location of the stagnation point of breakdown bubble and the attendant global flow features are in good agreement between the experimental and numerical results. The flow behavior is examined an |Ω_b/Ω| was varied for several combinations of the cylinder aspect ratios and the rotational Reynolds numbers based on Ω. For a co-rotation (Ω_b/Ω>0), the breakdown bubble is located closer to the bottom endwall. For sufficiently large values of Ω_b/Ω, the bubble adheres to the bottom endwall. When Ω_b/Ω becames close to 1, the meridional-plane flow tends to become antisymmetric with respect to the midplane of the cylinder. For a counter-rotation (Ω_b/Ω<0), the bubble moves toward the top endwall. Finally, as|Ω_b/Ω| is further increased, the bubble ceases to exist. The Brown and Lopez criterion based on the production of the negative azimuthal vorticity is considered using the present numerical results.

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One of the objectives of this study is to present devices of generating ideal oscillating grid turbulence in a rotating tank. Secondary flow which prevents the generation of ideal grid turbulence was suppressed by narrowing the space between the turbulence generation grid and the tank wall, modifying the support of the grid, and installing an inner cylinder. By means of the devices, the secondary flow disappears in the inner cylinder, and the turbulent flow becomes homogeneous in the stationary tank. Then, flow visualization experiments were conducted on the oscillating grid turbulence in the rotating tank. The flow structure is almost homogeneous in the vicinity of the grid, and the longitudinal vortex like structures appear on the rotating flow. The number of the longitudinal vortex structures increases and their shape become thin and straight with increasing the system rotation. The dye injection experiment also shows that the dye diffusion is suppressed by the rotation.

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The collision frequency of inertia particles in turbulent flows is governed by a wide range of scales of flow motion. Recent studies have shown that large-scale energetic eddies dominate the relative velocity between two colliding particles (the turbulent transport effect), whereas small-scale dissipative eddies can enhance the collision frequency significantly by inducing local non-uniform particle distribution (the accumulation effect). In this study, we have developed an integrated collision kernel model, which takes into account both the turbulence effects and can predict collision frequencies at arbitrary Reynolds numbers and particle inertia. In addition, we have implemented the developed collision kernel model into a large-eddy simulation (LES). We have performed our developed LES for particle collision growth in an isotropic evolving turbulence. A direct numerical simulation (DNS) for the same system has also been done. Comparison between our LES and DNS predictions has confirmed that our LES can predict the particle collision growth in the turbulent flow.

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A swirling flow through a curved diffuser of circular cross-section was examined experimentally. First, the experiment was performed for airflow at a bulk mean velocity where the inlet of the diffuser of W_a1≈8.7m/s, corresponding to the Reynolds number of 60 000. The distribution of the wall pressure was measured and three components of mean velocity were obtained over the pipe crosssection by means of the technique of rotating a probe with an inclined hot wire. Secondly, the waveform of pipe vibration and axial velocity was measured in the range of Reynolds number from 20 000 to 80 000 and of dimensionless angular momentum of swirling flow from 0.13 to 1.01 and the measured results were analyzed by FFT. Based on the results obtained, physical explanations were given to the phenomena obtained in the diffuser.

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A nanoscale laser induced fluorescence technique was proposed by using fluorescent dye and evanescent wave with total internal reflection of laser beam. The present study focused on the two-dimensional measurement of zeta-potential at the microchannel wall, which is an electrostatic charge of the wall surface and a characteristic property of an electroosmotic flow field. The evanescent wave, which decays exponentially from the wall, was used as an excitation light of the fluorescent dye. The fluorescent intensity in the vicinity of wall detected by a CCD camera is closely related to the zeta-potestial. Two kinds of fluorescent dye solution with different ionic concentration were injected into a T-shaped microchannel, and formed a mixing flow field in the junction area. The two-dimensional distribution of zeta-potential was measured at the microchannel wall in a pressure driven flow field. A transverse gradient of zeta-potential was observed in the mixing field, and the two-dimensional distribution of zeta-potential was changed by the difference in the averaged velocity. To understand the ion motion in the mixing flow field, the three-dimensional structure of flow field was analyzed by velocity measurement using micron-resolution particle image velocimetry and numerical simulation. It is concluded that the two-dimensional distribution of zeta-potential at the microchannel wall was dependent on the ion motion in the flow field, which was governed by convection and molecular diffusion.

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In this paper, two types of ultrasonic measurement techniques are attempted to obtain liquid and gas velocity distributions in bubbly flow. The first attempt is that the both of liquid and gas velocity distributions are obtained using an ultrasonic basic frequency and its echo signals. In order to separate the signals reflected on liquid-gas interfaces and particles, thresholding based on the ultrasonic echo intensity is applied. However, it is difficult to extract completely the echo signals reflected on the tracer particles. In order to overcome the difficulty, a multi-wave ultranonic transducer (TDX) is applied. The TDX consisted of two piezoelectric elements that have different basic frequency. The liquid velocity distribution is obtained using an ultrasonic velocity profiles (UVP) monitor at 8 MHz ultrasonic frequency, and the rising velocity of bubbles is measured using cross-correlation method at 2 MHz ultrasonic frequency. Using the technique, both of the liquid and gas velocity distributions are obtained accurately using the TDX.

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A particle separation technique in a sub-milli channel has been developed by utilizing acoustic radiation and electrostatic forces, which will be applicable to microfluidic devices. In the present study these forces act simultaneously on particles perpendicular to the flow direction. When the acoustic radiation force was applied by an ultrasound transducer, large and small particles in a buffer solution were trapped at nodal positions in the standing field, which was equal to half of the wavelength in the transverse direction. On simultaneous application of electric field to the channel, both forces acted on particles. Thus the magnitude of each force was estimated by using particle image and particle tracking velocimetry, by which the relationship between the acoustic radiation and electrostatic force acting on particles was investigated in order to separate particles in the flow field. Large particles were trapped at nodes by the acoustic radiation force without being affected by the electrostatic force, while small particles were moved toward anodes by the electrostatic force. This means that the particle separation based on diameter was accomplished by the present technique.

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This paper treats the flow instabilities in a mixed flow pump with a vaned diffuser. Tested pump has a positive slope of the head-flow performance curve at about 65% flow rate of BEP (Best Efficiency Point). In order to investigate this phenomenon, pressure fluctuation measurements and dynamic PIV (Particle Image Velocimetry) measurements have been performed. As a result, it is found that unstable performance is caused by a rotating stall in the vaned diffuser. The flow from impeller exit is influenced on the large scaled backflow generated periodically from the vaned diffuser. Moreover, the backflow is induced by the strong vortex developed at the leading edge of diffuser vane. Based on PIV pictures, the relationship between the static pressure at the inlet of diffuser vane and the internal flow conditions is clarified.

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The characteristics of a floating type wave energy conversion device with an Oscillating Water Column (OWC) are investigated with an experiment and the two-dimensional eigenfunction expansion method proposed in a previous report. The floating device captures the wave energy using the heaving, pitching and surging motion of the device and the heaving motion of OWC. The experiment and the numerical analysis are carried out on the condition in which the floating body is moored and fixed on the water surface. It is confirmed that the numerical results give good agreement with experimental data.

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Shallow grooves “J-groove” formed on a casing wall can suppress the several anomalous phenomena in turbomachineries. In the present study, J-groove was applied to an inducer to suppress the rotating cavitation. Through the experiments under various conditions with and without J-groove, it was clarified that rotating cavitation can be almost suppressed by using J-groove. However, it was found that cavitation surge occurs at relatively high cavitation number. Flow field and cavity at tip were examined to clarify the effect of J-groove on the flow in an inducer.

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Nucleation process of single-walled carbon nanotubes (SWNTs) in the catalytic chemical vapor deposition method is studied using molecular dynamics simulations. A nanotube cap structure is generated when pieces of the hexagonal network structure extending from inside the cluster merged above the metal surface. Furthermore, interaction between catalytic metals and carbon atoms on formation process of SWNTs are studied using the home-made many-body potentials based on density functional theory calculations of small metal-carbon binary clusters. The Co cluster has a partially crystal structure where metal atoms are regularly allocated and embedded in the hexagonal carbon network. On the other hand, carbon atoms cover the entire surface of the Fe cluster. This implies stronger interaction between the graphitic lattice and Co atoms than Fe atoms. The difference of graphitization ability may reflect the ability as a catalyst on the formation process of an SWNT.

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Interaction between catalytic metals and carbon atoms in formation process of single-walled carbon nanotubes (SWNTs) is studied by classical molecular dynamics simulation with the newly-developed many-body potential functions between carbon atoms and several transition metal atoms. A Co cluster has a crystal structure where metal atoms are regularly allocated and embedded in the hexagonal carbon network. On the other hand, carbon atoms cover the entire surface in case of the Fe cluster. The number of hexagonal rings in the Co cluster increases about twice as fast as the one in the Fe cluster. This implies that the graphitic lattice interacts more strongly with Co atoms than with Fe atoms. The difference of graphitization ability may reflect the ability as a catalyst in the formation process of SWNTs.

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Nucleation process of single-walled carbon nanotubes (SWNTs) from a transition metal cluster on a substrate is studied by using a classical molecular dynamics (MD) simulation. For describing the effect of the substrate, averaged one-dimensional Lennard-Jones potential is employed between the metal cluster and the bottom boundary of the simulation cell. The parameters of the averaged one-dimensional Lennard-Jones potential describe the different degree of wettability. Nucleation process of nanotube caps from Ni₁₀₈Ni₂₅₆and Ni₅₀₀clusters on a substrate are compared. Moreover, wettability of the Ni cluster and the Ni-Carbide cluster is compared by MD simulation of annealing process on a substrate. Finally, results are compared with the nucleation process of SWNT from a non-supported cluster for discussing of the role of the substrate at a nucleation stage of SWNT.

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Comprehensive study on the quantitative local thermal conductivity measurement with a thermal conductance and contact temperature combination method by the scanning thermal microscope (SThM) was conducted. The micro cantilever probe including heater, thermocouple, thermopile and electrode for contact thermocouple, and the sample preparation method of coating gold thin film as another electrode of the contact thermocouple were developed. The experiment in the force curve mode to gold and glass regions showed that heat flow and contact temperature are simultaneously measured as varying a contact load, and that the method detects difference in thermal conductivity between the two regions. Numerical simulation of the contact region by thermal conduction model shows that conductance of the flat body with the thin film is described as the combination of conductance near the contact region, one in the film and one in the body. Reasonableness and a perspective of the method were also discussed through analyzing a derivation method of conductivity and a spatial resolution of the method

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Local temperature variation beneath boiling bubble was measured with a MEMS (Micro Electro-Mechanical Systems) integrated sensor to investigate a boiling heat transfer mechanism. The sensor consisting two trigger heaters and six thin film thermocouples across the heaters within 880 region on a silicon or glass substrate can measure temperature distribution of heating surface with less than 0.1 ms temporal resolution. As a result, measured temperature variations can be brought into correspondence with the bubble behavior taken by a synchronized high-speed video. The temperature variations also show a formation of micro layer, extension of a local dryout region and rewetting with bubble departure. Based on the measurement, a state transition chart of the heating wall beneath the bubble in temporal and spatial domain can be drawn. This study presents a new approach method to the heat transfer mechanism of mucleate boiling.

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The possibility and applicability of thermal recycling of wasted PET-resin has been investigated in the open atmospheric operation by supplying PET-resin powder as an auxiliary fuel to a proposed twin-fuelled burner. In the preceding experiments, reactive flows and burning processes of PET-particles were investigated using PIV/PTV measurements. Appearances of flying PET-particles were also observed by using the pulse laser and the particle diameter was evaluated as an equivalent diameter. According to the results, some key factors for reducing the unburnt rate of PET-particles were clarified. In this paper, by taking these factors into consideration, an experimental attempt at reducing unburnt particle emission in the recycled PET-resin powder combustion is carried out by varying the PET-powder supply pipe diameter. The result specifies experimentally that the increase in the dispersion degree of PET-particles reduces the unburnt rate of PET-powder.

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Ignition is a transient combustion phenomenon and one of the most difficult and complex problems, which include a lot of physical and chemical processes, so that it has not yet been explained suficiently. In the present study, the ignition characteristics of methane-air mixture were investigated by numerical analysis using detailed chemical kinetics. In order to clarify the effect of geometric condition of ignition source and flow field on ignition characteristics, ignition processes for 1-D plane model, 2-D plane model and axisymmetric model were examined comparatively. The following conclusions were reached : (1) Ignition characteristics are better for the case where the heat is hard to radiate to surrounding fluid, but the reaction mechanism of ignition is almost the same. (2) The elementary reactions, which are important at the moment of ignition, are as follows : CH₃ + O →CH₂O + H, CH₃ + O → CO + H + H₂, and H + O₂ → O + OH. (3) The success and failure of ignition andthe ignition delay depend on the supplying manners of ignition energy, especially heating time and ignition source shape.

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Effects of swirl motion and buoyancy force on the mixing performance of a confined multiple jet mounted flush with a baffle plate in a small chamber were numerically investigated under laminar flow conditions. The swirl motion was induced by circumferentially-inclined jets surrounding the central jet. The buoyancy force was applied to the multiple jet by changing the operating direction of the gravity against the axis of the chamber. In the swirl flow cases, the reverse flow formed downstream of the baffle plate was restrained gradually with an increase in swirl number, which incurs the deterioration of the mixing performance in comparison to the non-swirl case. In the buoyancy-accompanied flow cases, asymmetric angle between the directions of the gravity force and the central jet led to poor mixing performance. This trend was more noticeable in the compound flow case of the swirl motion and the buoyancy force.

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A hybrid bearing effectively stabilized by water evaporation from ultra-fine porous medium is proposed and its basic characteristics are clarified by numerical simulation and experiment. The proposed bearing aims to be applied to MGT (Micro Gas Turbine) and has mainly three advantages suitable for application to MGT. The first is the stability improved by water evaporation from ultra-fine porous medium. The second is the effective lubrication by liquid water at the start and stop of the journal rotation. The third is the cooling effect on the high-temperature journal due to water evaporation. A fundamental experiment from water lubrication to vapor lubrication via transition state has been carried out. The experiment indicated the potential of vapor lubrication and confirmed the stable start-up at water lubrication.

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High efficiency pulverized coal power plant technology, especially the system design for high temperature turbines, is discussed. It is believed that a 700-deg C class steam turbine system will be realized with Ni-based super alloys. The super alloys are more expensive than current materials like 12%Cr steels though its high temperature strength is excellent. In addition, the size of the alloys is limited for the current design because the quality of large Ni alloys is not high enough. Therefore, it is necessary to study new design concepts to utilize the alloys. The key concept is the optimized combination of steam turbine cooling and the super alloys. By adopting cooling to all turbines, it becomes possible not to use the super alloys for the turbines except valves, and relative thermal efficiency reduction from the system without cooling is 0.4%. If reheat turbines are cooled, the relative thermal efficiency reduction from the system without cooling is only 0.2% though it is necessary to use the super alloys for VHPT (Very High Pressure Turbine).

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Oxygenated fuels with different oxygen content and molecular structure were used, and effects of oxygenated fuel on soot volume fraction and soot particle sizes were investigated by Time-Resolved LII (Laser induced incandescence) in a diesel spray flame. Soot particle formation was measured in a constant volume combustion vessel that was able to simulate the diesel engine conditions. Fuels used in this study were n-heptane, four ethers that contain (-O-) bond in molecular structure ; Dibuthyl ether (DBE), Diethylene glycol dibuthyl ether (DGB), Diethylene glycol diethyl ether (DGE), Diethylene glycol dimethyl ether (DGM), two esters that contain (-COO-) bond ; Buthyl acetate (BA), Ethyl acetate (EA). Oxygen content in oxygenated fuel changes from 12.3 wt-% to 36.4 wt-%. Soot volume fraction decreases in proportion to oxygen content in same molecular structured oxgenated fuel. Ether is more effective than ester in reducing soot volume fraction and suppressing the growth of soot particle diameter. And, by the application of oxygenated fuel, though soot volume fraction decreases, small soot particles are formed with high number density.

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