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Published: August 02, 2008
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Article type: Appendix
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Article type: Appendix
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Article type: Index
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A1-A5
Published: August 02, 2008
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Shuichi SAWADA, Seiichi HARUUCHI, Shingo YOSHIDA, Masaaki IZUMI
Article type: Article
Session ID: 2109
Published: August 02, 2008
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A Solid Oxide Fuel Cell (SOFC) with flat-tubular structure has been developed. The SOFCs were composed of 8molY_2O_3-ZrO_2 (YSZ) electrolyte, Ni-YSZ anode and La_<0.8>Sr_<0.2>MnO_3 cathode. The SOFCs had a feature that fuel gas was homogeneously supplied to fuel-electrodes with fuel gas pipes made of heat-resistant alloy. The cell of 50cm^2 active area was operated to achieve maximum power density of 0.23W/cm^2 at 1000℃. The effect of the fuel gas pipes on the cell performance was recognized, because the performance was two times as high as that of SOFC without the fuel gas pipes. About 24% of this performance difference was occurred by ohmic losses.
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Yusuke SAKAMOTO, Naoki SHIKAZONO
Article type: Article
Session ID: 2110
Published: August 02, 2008
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Anode microstructure parameters were quantified by SEM-EDX measurements and the dependence of polarization characteristics on the anode microstructure parameters is investigated experimentally. Anode microstructure was successfully imaged and quantified by ultra low voltage SEM and by means of stereology. Cell voltage measurements and impedance spectroscopy were performed at 650 and 750℃ with hydrogen diluted by nitrogen as a fuel. A quantitative relationship between measured polarization and microstructure parameters, e.g., three phase boundary length, contiguity, etc., was discussed. Finally, a cell with an anode functional layer (AFL) was fabricated to investigate the possibility of improving both activation and concentration polarization characteristics.
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Katsunori HANAMURA, Shinichi YANO, Shiko Nakamura, Manabu IHARA
Article type: Article
Session ID: 2111
Published: August 02, 2008
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A proton-conducting anode Ni/GDC-BCY was proposed for a high power density Solid-Oxide-Fuel-Cell. The electric characteristics were investigated through alternative current impedance measurement. The most striking feature is that, using the anode Ni/GDC-BCY (90%:10%), the polarized resistance which indicates an overpotential in anode is reduced to the half of that of the conventional anode Ni/GDC. It is clarified that since much amount of hydrogen might be adsorbed on the surface of each BCY particulate distributed in the anode, adsorbed oxygen which is transferred as oxide ions through GDC particulates has large chance to react with the adsorbed hydrogen.
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Tetsuya Ichikawa, Shinji Kimijima
Article type: Article
Session ID: 2112
Published: August 02, 2008
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This paper refers to the experimental performance evaluation of a tubular type steam reformer for indirect internal reforming in solid oxide fuel cell power generation systems. In the experiment, the spherical ruthenium catalysts were filled inside the reactor. Methane, steam and carbon dioxide mixture was supplied into the reactor, which was set inside the electric furnace. The composition of dry gas after reforming was measured with a gas chromatograph equipment. Throughout the experiments, we obtained the relationship between the methane conversion ratio to concentration of carbon dioxide. It was clarified that the reforming temperature, the methane, steam and carbon dioxide mixture to methane ratio and the fuel flow rate affected the methane conversion ratio. However, concentration of carbon dioxide didn't affect methane conversion ratio at high temperature. In any conditions of carbon dioxide concentration, the composition of dry gas after reforming proceeds to equilibrium state.
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Yosuke Komatsu, Shinji Kimijima
Article type: Article
Session ID: 2113
Published: August 02, 2008
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In this paper, the performance evaluation of a solid oxide fuel cell-micro gas turbine hybrid power generation system under the part load operation by using the system analysis method was studied. The present analysis code includes a distributed parameter model of the cell stack module. The standard power output of the whole system is set at 220kW. The variable turbine rotational speed operation scheme is adopted for the part load operation. Throughout the analyses, it is clarified that the power generation efficiency of the hybrid system decreases together with the power output. The major reason for the performance degradation is the operating temperature reduction in the SOFC module, which is caused by decreasing the fuel supply and the heat generation in the cells.
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Ryuji ANDO, Gyoko NAGAYAMA, Takaharu TSURUTA
Article type: Article
Session ID: 2114
Published: August 02, 2008
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We applied the anodic etching to fabricate porous silicon for the application to the micro fuel cell. The effects of anodic etching conditions (i.e. the resistivity, voltage, current density, electrolyte concentration and illumination etc.) on the pore size and porosity were investigated. The porous silicon filled with electrolyte was used as a porous silicon membrane (PSM) in a micro fuel cell system. It was found that the Nafion filled PSM (in containing 3mol/l H_2SO_4 and 20% Nation solution) worked well and a maximum power density of 89.2 mW/cm^2 were achieved under the flow rate of 100ml/min for H_2 and 200ml/min for air.
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Atsushi NAKAMURA, Zhili CHEN
Article type: Article
Session ID: 2115
Published: August 02, 2008
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In order to improve gas diffusion properties and avoid flooding, a technique for forming a catalyst layer of globe-shaped particles on polymer membrane was developed by using an ultrasonic atomizer for atomizing catalyst ink to globe-shaped particles. It was confirmed that MEA (Membrane Electrode Assembly) of catalyst layer of globe-shaped particles had a higher power generation performance compared with that of catalyst ink applied by traditional spraying method.
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Yoshihiro KUROTA, Yuta CHIBA, Eiji EJIRI
Article type: Article
Session ID: 2116
Published: August 02, 2008
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The cause of a sudden power breakdown was experimentally investigated for a banded structure membrane fuel cell module (rated power of 120 W), which consisted of 20 polymer electrolyte fuel cells laid in a plane. The results show that the module operated for much longer than 1 hour in the case of 80% of fuel utilization, however, it experienced a sudden power breakdown in the case of 90% or 100% of fuel utilization. The results also show that a large temperature variation was found within a specific cell that caused a sudden power breakdown. It is noteworthy that the module operated in no more than 4 minutes when humidified hydrogen was supplied to the single cell.
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Jae Young SHIM, Shohji TSUSHIMA, Shuichiro HIRAI
Article type: Article
Session ID: 2117
Published: August 02, 2008
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In this study, the accelerated membrane degradation experiments for polymer electrolyte membrane fuel cells (PEMFCs) under OCV condition were conducted to investigate the membrane degradation behaviors under different supplying gas condition such as hydrogen/oxygen and hydrogen/air. Through the cross-sectional SEM images of the postmortem MEA, it is elucidated that the anode side of the membrane is more deteriorated under H_2 and O_2 condition. In contrast, it is affirmed that the cathode side of the membrane is more deteriorated under hydrogen and air condition. This phenomenon is caused by the discrepancy of oxygen crossover between oxygen and air due to the partial pressure difference. To investigate the crossover effect on the membrane degradation, it is performed to detect the O_2 crossover in the MEA using Direct Gas Mass Spectroscopy. Numerical approach of the membrane degradation rate is performed with the experimental results. The calculated results were well matched to the experimental results.
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Yutaka TASAKI, Shixue WANG, Pierre Boillat, Gabriel Frei, Gunther G. S ...
Article type: Article
Session ID: 2118
Published: August 02, 2008
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The mass transfer characteristics of gas diffusion layer (GDL) are closely related to cell performance in PEFC. In this study, following simultaneous measuring method was tried out, namely, the oxygen diffusivity of porous media with moisture was measured by using an experimental apparatus consist of oxygen sensor based on galvanic battery, and liquid water distribution in porous medium was visualized by using Neutron Radiography. It was confirmed that the method was effective in analyzing relationship between liquid water distribution and oxygen diffusivity. The relationship has been studied for hybrid type porous media.
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Yuki UEMURA, So MANABE, Takuto ARAKI, Mitsuyuki NAGAHAMA, Kazuo ONDA
Article type: Article
Session ID: 2119
Published: August 02, 2008
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Proton conductivity of polymer electrolyte membrane (PEM), which is used as electrolyte of the PEFC, depends on water content of PEM. It is very difficult to measure local water transport phenomena, so we use numerical analysis to grasp this effect. In this study, the effect of water in a PEFC was discussed by comparing experimental results with analytical results, which were conducted by unsteady two-dimensional model. Analytical results showed good agreement with experimental results of voltage response after sudden supplied gas humidity change for the conditions without flooding. In addition to these study, by calculating humidity distributions in a PEFC, we illustrated the relationship between water content of PEM and cell voltage.
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Yoshinobu FUJII, Shohji TSUSHIMA, Shuichiro HIRAI
Article type: Article
Session ID: 2120
Published: August 02, 2008
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For implementation of higher performance of Polymer Electrolyte Membrane Fuel Cells (PEMFCs) under low humidity condition, water management is essential to keep membrane hydration. To establish water management, it is strongly necessary to understand the water transport in PEMFCs. In this study, the effect of the micro porous layer (MPL) and counter-flow mode under low humidity condition on water transport was examined. Tunable Diode Laser Absorption Spectroscopy (TDLAS) measurement system, which can measure water vapor concentration in the PEMFCs channels, was used in order to investigate water transport between the cathode and the anode side. The experimental results showed that the MPL enhances transport of generated water from the cathode side catalyst layer to the anode side channel through the membrane, and it results in improvement of membrane hydration. The results also showed that improvement of performance at the gas inlet region is caused by counter-flow mode.
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Hiroyuki TAKAMATSU, Yutaka TABE, Kazusige KIKUTA, Takemi CHIKAHISA
Article type: Article
Session ID: 2121
Published: August 02, 2008
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To decrease the usage of the Pt catalyst in polymer electrolyte membrane fuel cell (PEMFC), optimization of catalyst layer structure and three-phase zone is one of key issues. In this study, numerical simulation was conducted to investigate the relation between the structure of cathode catalyst layer and cell performance (over voltage and current density). From the calculation results, suitable structures, porosity and polymer electrolyte thickness, for gas diffusion and proton conduction were clarified.
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Masato HIRAMATSU, Shigeru HAYASHI, Shigehiko KANEKO, Yudai YAMASAKI
Article type: Article
Session ID: 2122
Published: August 02, 2008
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In this study, combustion field in a combustor designed for small size gas turbine fueled by low calorific gas was visualized by OF-PLIF method. To investigate the effect of mixing, air fuel ratio and combustion length, rectangular combustor is used. In addition, to verify the fact that flameless combustion is realized in our homemade small size combustor, cylindrical transparent combustor with the same size is used. Visualized pictures explain previously obtained data well.
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Yuji IWASAKI, Masaharu KOMIYAMA, Kenichiro TAKEISHI, Chisako TANAKA, K ...
Article type: Article
Session ID: 2123
Published: August 02, 2008
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In heavy-duty gas turbine engines, the turbine inlet temperature increases year by year to improve thermal efficiency. But, at the same time, this leads to the increase of NOx emissions. One of the most promising approaches for gaseous fuel(natural gas) to reduce NOx emissions is the adoption of lean premixed combustion. With lean premixed combustion, locally high temperature regions which are attributed to mixture inhomogeneity are suppressed, and so it has large effect in reducing NOx. However, in the case that it is applied to combustor, since fuel and air are separately supplied because of preventing flashback, it is needed to burn the mixture after sufficient mixing. In this study, we examined the air-fuel mixing characteristics in the unburned region where is adjacent to flame zone in Lean Premix Combustor with Swirling Flow. The mixing characteristics were evaluated by measuring the instantaneous concentration of mixed gaseous fuel which contains acetone as a tracer, using planar laser-induced fluorescence(P-LIF). Simultaneously, we measured the instantaneous flame temperature by Rayleigh scattering method, and investigated correlation between mixing characteristics in the unburned side and temperature distribution in the burned side.
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Satoshi Tanimura, Masakazu Nose, Koichi Ishizaka, Satoshi Takiguchi
Article type: Article
Session ID: 2124
Published: August 02, 2008
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The latest heavy duty gas turbine is designed to operate with a Turbine Inlet Temperature (TIT) of 1500℃. This elevated temperature results in high thermal efficiency but also can induce relatively high emissions. A new Dry Low NOx (DLN) combustor is developed to improve this class turbine compliance with stringent environmental regulations imposed around world. In addition to targeting an environmentally friendly combustor with lower emissions, the re-designed DLN combustor also improves the stability margin. Verification tests of the new DLN combustor were conducted in a M501G1 gas turbine at MHI's T-Point. In addition to verifying lower emission levels, these tests confirmed a wide stable operation margin as well as the reliability and durability of the components.
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Tetsuo Abiko, Junichi Tsujii, Naoki Kashi
Article type: Article
Session ID: 2125
Published: August 02, 2008
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It is necessary to calculate a transient temperature profile of gas turbine recuperator for estimation of mechanical life. In case of distributed power generation, such estimation is very important because the equipment is usually operated as daily start up/shut down system. In order to calculate the temperature profile of plate-fm heat exchanger, simplified model is considered. Transient temperature profile can be calculated form the influence of both heat transfer form fluid and heat conduction of heat exchanger itself. Such numerical analysis gives to estimate the expected mechanical life of the equipment at initial evaluation and/or improvement effect of operational modification.
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Shin'ichi HIGUCHI, Hidefumi ARAKI, Tomomi KOGANEZAWA, Takanori SH ...
Article type: Article
Session ID: 2126
Published: August 02, 2008
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This paper describes advanced utilization of moisture in gas turbine systems for the purpose of improving thermal efficiency and output. We have proposed and been developing AHAT (Advanced Humid Air Turbine) system. The AHAT system is a system which uses existing mutual technologies and aims high performance equal to that of the HAT system. After many studies and elemental tests, a 4MW-class pilot plant was planned and built in order to verify feasibility of the AHAT system from the viewpoints of heat cycle characteristic and engineering. The gas turbine consists of a two-stage centrifugal compressor (pressure ratio of 8), a reverse-flow type single-can combustor, and a two-stage axial-flow turbine. The plant thermal efficiency exceeded 40%LHV.
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Yoji Okita, Chiyuki Nakamata
Article type: Article
Session ID: 2127
Published: August 02, 2008
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This paper presents results of a computational study for the endwall film cooling of an annular nozzle cascade employing a circumferentially asymmetric contoured passage. The investigated geometrical parameters and the flow conditions are consistent with a generic modem HP-turbine nozzle. Rows of cylindrical film cooling holes on the contoured endwall are arranged with a design practice for the ordinary axisymmetric endwall. The solution domain, which includes the mainflow, cooling holes paths, and the coolant plenum, is discretized in the RANS equations with the realizable k-epsilon model. With the asymmetric endwall more uniform film coverage is achieved especially in the rear part of the passage and the laterally averaged effectiveness is also significantly improved in this region. The closer inspection of the calculated thermal field reveals that, with the asymmetric passage, the coolant ejected from the holes are less deflected, and it attaches better to the endwall in this rear part.
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Shohei MORI, Kenichiro TAKEISHI, Masaharu KOMIYAMA, Yutaka ODA, Takesh ...
Article type: Article
Session ID: 2128
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The performance of film cooling used for gas turbine vanes or blades depends on various factors. This paper discusses the mixing mechanism of film cooling by measuring the film cooling effectiveness distributions and spatial velocity distributions. In experiment, Laser-induced Fluorescence (LIF) has been utilized to measure film cooling effectiveness on the basis of heat/mass transfer analogy. Particle Image Velocimetry (PIV) has been used to measure velocity fields. Furthermore, the correlation between the flow fields and the film cooling effectiveness has been investigated by conducting LIF and PIV at the same time. The result shows that the mixing of film cooling air with mainstream is affected by large-scale vortex structure formed in a shear layer between the two flows.
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Satoshi Hada, Masaaki Matsuura, Tsuyoshi Kitamura, Eisaku Ito, Keizo T ...
Article type: Article
Session ID: 2129
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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In the development of 1700 degree gas turbines, the innovation of turbine cooling technology is important. Film cooling is widely used in order to reduce metal temperature and thermal stress. In this study, pressure sensitive paint technique was used to see the film effectiveness of the rotating blade endwall. The film effectiveness is low in the region of the endwall of the rotating blade compared to the region of the stationary vane endwall.
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Ken-ichi Funazaki, Haruki Fujiwara, Yousuke Kunii, Chiyuki Nakamata, Y ...
Article type: Article
Session ID: 2130
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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For modern aeroengines, it has become one of the important design issues to reduce weight as well as any kind of cost, while maintaining their high thermal efficiency. In this paper, we aim to trim weight of HP turbine blade while keeping enough space for cooling structure. We have searched for the optimum blade shapes that are much lighter than the original blade with similar aerodynamic performance by using Lattice Boltzmann Method for flow analysis and Multi Objective Genetic Algorithm for optimization. We tried to evaluate obtained blade with experiment.
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Katsuhiko ISHIDA
Article type: Article
Session ID: 2131
Published: August 02, 2008
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Hot gas ingestion from main flow into a rim cavity of turbine disks in a gas turbine engine was investigated by model test and CFD. In a model test rig, a model disk rotates in an annular flow path simulating gas path of a gas turbine engine. Main flow gas ingestion into the rim cavity was measured by tracer gas method. Eccentricity was set between rotating and static part as a driving force of ingestion. Measurement showed that eccentricity increases ingestion. CFD were carried out to reproduce results of measurements. The. results of CFD showed good agreement with tests. Then various eccentricity was set in CFD and its effects on seal performance was investigated.
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Jun HASHIMOTO
Article type: Article
Session ID: 2209
Published: August 02, 2008
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In this study, effect of diluent gas on combustion characteristics of stretched flames of two-component fuel mixtures are investigated by chemical kinetics computations. Lean and rich mixtures having nearly the same laminar burning velocity are prepared by adding diluent gas to fuel and O_2, where the hydrogen additional rate δ are varied from 0 to 1. One of N_2, Ar and CO_2 is selected as a diluent gas. As a result, it is elucidated that Markstein numbers of mixtures diluted with CO_2 are smaller than that of mixtures dilueted with N_2 or Ar. Characteristics of response to flame stretch are discussed in light of the lewis number and chemical reaction mechanisms.
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Shin-ichi INAGE, Muhammet Ebret, Kazuki Abe
Article type: Article
Session ID: 2210
Published: August 02, 2008
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The united model, which is applicable to the premixed and diffusion flame using of author's premixed combustion model. To verify the accuracy of the model, the turbulent opposed diffusion flame presented by Mastorakos was numerically simulated, as an example of a turbulent diffusion flame. The overall thickness of temperature and mass fraction profiles were in good agreement with experimental data. These comparisons with the experimental data and this agreement confirmed the proposed unified model was able to accurately simulate diffusion flame under the certain flame stretch.
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Hiromi KOIZUMI, Tomihiro ASAI, Shohei YOSHIDA
Article type: Article
Session ID: 2211
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The authors have been developing the dry low-NOx combustion technology for hydrogen-containing gas fuels. This paper experimentally investigates the NOx emission characteristics of the combustion of the hydrogen-containing gases using a cluster burner. Combustion tests were carried out under atmospheric pressure. The combustion gas temperature at the exit of the burner ranged from 1200 to 1750℃. The conclusion is that: (1) The NOx emissions increased with the content of hydrogen in fuel due to the increases in flame temperature both in the central region of the combustion chamber and in the outer region just downstream of the burner. (2) The stable combustion of high-hydrogen-containing gas (the content was up to 83%) was obtained without flashback.
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Toshiaki KITAGAWA, Kosuke MARUYAMA, Kunihiro KADO, Akihiro HAYAKAWA
Article type: Article
Session ID: 2213
Published: August 02, 2008
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The effects of dilution of iso-octane/air mixtures with CO_2 on outwardly propagating laminar and turbulent flames were studied at the equivalence ratio of 1.0, the initial pressures from 0.10 to 0.50MPa and the dilution rate from 0 to 0.10. Turbulence intensity was set to 0.80 and 1.59m/s. The unstretched laminar burning velocity and the Markstein number decreased as the dilution rate increased. The ratios of turbulent to unstretched laminar burning velocities at a constant Peclet number increased with increasing turbulence Karlovitz number and decreasing Markstein number.
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Takayuki TAJIRI, Kimitoshi TANOUE, Fumio SHIMADA
Article type: Article
Session ID: 2214
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Experimental studies are conducted on extinction of non-premixed dimethyl ether (DME) flames stabilized in the counterflow configuration. Studies are carried out by injecting a fuel stream made up of fuel and inert gas (N_2 or CO_2 or Ar or He) from one duct an oxidizer stream made up ofO_2 and inert gas (N_2 or CO_2 Ar or He) from the other duct. Critical conditions of extinction are measured by increasing the flow rate of the counterdowing streams until the flame extinguishes. Numerical studies are also performed using detailed chemistry at conditions corresponding to those used in the experiments and compared with measurements. The present study highlights the examination of the influence of equilibrium flame temperature, flame structure and kind of mert gas on extinction properties of DME. Results are compared and discussed in terms of Lewis number effect.
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Kazuto SUGIYAMA, Katsuhiko TAKEDA, Toshihiro MITAKE
Article type: Article
Session ID: 2215
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Setiapraja HARI, Toshihiro NAKAMURA, Hideyuki OGAWA
Article type: Article
Session ID: 2216
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Diesel combustion characteristics of high ignitability ether and ethanol blend fuels were examined to establish utilization of ethanol in diesel engines with high efficient and clean combustion. Diethylene glycol dimethyl ether (GGM) with very high ignitability and high oxygen content was blended with ethanol to maintain stable ignition with smokefree combustion. The results shows smokefree, mild, and clean combustion is realized with the DGM-ethanol blend fuel even with large quantity of EGR and with low injection pressures. However, the ethanol content in blend fuel was limited below 50 % to suppress rapid combustion and misfiring due to deterioration of ignitability.
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Masazumi TAKAYASU, Syunsuke KUBO, Wira JAZAIR, Tomoaki YATSUFUSA, Yosh ...
Article type: Article
Session ID: 2217
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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In order to improve emissions from a diesel engine fuelled by rapeseed oil (SVO), this study investigated the effects of using water-emulsified (W-SVO) and ethanol-blended (E-SVO) rapeseed oil on emissions. Results show that SVO produces lower smoke compared with gas oil at high load despite of the increase of NO_x. Both W-SVO and E-SVO are effective to reduce both NO_x and particulate emissions at high load. In particular, W-SVO has a great effect on NO_x reduction with keeping low particulate emissions. However, W-SVO produces high HC and CO emissions at low load. SOF emission with SVO at low load cannot be sufficiently improved by using W-SVO and E-SVO due to high viscosity and high distillation temperature.
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Kiyoshi KAWASAKI, Shingo NAGATA, Koji YAMANE
Article type: Article
Session ID: 2218
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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For detecting the heat release profile of the natural gas HCCI combustion by using ion current measurement, the relationship between ion current signal and heat release rate were investigated fbr various operating conditions. Obtained results show that ion current signal arises just after the start of heat release, and they reaches their peak value simultaneously. Also, there is the almost linear relationship between their peak value, whlle the relationship is affected by EGR ratio.
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Masashi ONO, En NIN, Yusuke SOMA, Masato NAKAJIMA, Akira IIJIMA, Hideo ...
Article type: Article
Session ID: 2219
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The cellulosic liquefaction fuel (CLF) is made from woods by direct liquefaction process and CLF can be mixed with diesel fuel when fuel temperatures are higher than 30 [℃]. The purpose of study is to analyze the ignition characteristics of CLF on cold start condition. In cold start test, the engine is started without warm-up and the transient performance is measured. CLF is mixed with diesel fuel and the blended ratio of CLF is changed, and tests are made at full load injection setting. The blended fuel can be ignited and burned immediately after the engine is started, when the blended ratio of CLF is up to 20 [wt%]. The crank angle at ignition delays and the maximum combustion pressure decreases as the blended ratio of CLF increases because CLF includes a lot of aromatic hydrocarbons. However, the ignition delay and combustion pressure reduction are gradually improved as the engine is warmed-up.
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Mikiya ARAKI, Yasuhiro FUJIWARA, Seiichi SHIGA, Hisao NAKAMURA, Tomio ...
Article type: Article
Session ID: 2220
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Accuracy of an injection rate measurement of a gaseous fuel injector was improved by modification of flow modeling and static pressure correction. A port fuel injection gaseous fuel injector was used. The injection pressure was set at 255 kPa(g), and the injection duration was varied from 5 to 20 ms. Nitrogen gas was used as the test gas. The test gas was injected into a pipe from the injector, and the static pressure history was acquired with a piezoelectronic pressure transducer. One-dimensional, compressible, inviscid, adiabatic flow was assumed, and the instantaneous mass flow rate inside the pipe was estimated using newly modified equations. By integrating the injection rate during the injection duration, the total amount of mass flow per one stroke was calculated. The data obtained by the injection rate meter are compared to that of the calibration test, and it is shown that the injection rate measurement was carried out within the error of 2 to 3 %.
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Naotake FUJITA, Hiroshi KON, Michio KITANO, Yisilahaiti ABULIZI
Article type: Article
Session ID: 2221
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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We made a study on the combustion chamber deposit (CCD) formation on a piston crown surface in a small two-stroke spark ignition engine. Lubrication oil flows were observed by generating CCD streaks (CCDS) from many small drilled holes on the piston crown. To understand the temperature influence on the heat degradation of the lubricant oil, (1) the oil on the conical cavity was heated statically in an electric furnace, and (2) oil was also dropped on the heated incline plate. The deposit streaks were formed on the heated plate along the oil flow line.
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Ryota KATO, Takeshi OKAMOTO, Mitsuru KONNO
Article type: Article
Session ID: 2222
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Rice bran oil, which is distilled from a residual product of rice milling process, is substantially the only domestically-produced vegetable oil. In this study, fuel properties of rice bran methyl ester (RBME) were investigated. Engine test was also conducted using a small DI CI engine. In addition, the effect of 5wt%RBME blending to diesel fuel was examined. The results showed that RBME met standard specifications of neat FAME in JASO, and that the low temperature fluidity was better than PME and oxidation stability was better than RME. Smoke emission of RBME was much lower than that of diesel fuel. It was also found that RBME blending into diesel fuel had potential for low temperature fluidity deterioration.
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Eiji KINOSHITA, Yusuke KUMANDA, Seiji TAKATA
Article type: Article
Session ID: 2223
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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In order to use palm oil as an alternative diesel fuel, the combustion characteristics and exhaust emissions of the blend fuel of palm oil butyl ester (PBE) and palm kernel oil butyl ester (PKBE) are investigated using a DI diesel engine, and are compared with that of PBE, PKBE and JIS No.2 gas oil. As a result, the pour point of the blend fuel decreases with increase in the blend ratio of PKBE to PBE. The thermal efficiency of the blend fuel is almost the same as that of the other test fuels. Also, the exhaust emissions of the blend fuel reduce with increase in the blend ratio, and are lower than those of PBE and the gas oil. From the experimental results, it is concluded that PBE/PKBE is a good alternative diesel fuel.
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Ryosuke SATO, Akira MEZAKI, Toshinori TAKAGI, Mitsuru KONNO
Article type: Article
Session ID: 2224
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The effect of NO and NH_3 doping on high temperature reaction (HTR) was examined. Numerical analysis based on detailed chemical kinetic reaction model was conducted for methane/air homogeneous charge compression ignition (HCCI) process as the representative of the HTR. The calculation results were verified experimentally using a single cylinder HCCI test engine. From engine experiment, it was shown that a small amount of NO and NH3 strongly promoted methane oxidation, meanwhile a larger amount suppressed the promotion effect. The detailed reaction mechanism on the effect of NO and NH_3 doping was discussed based on elementary reaction analysis.
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Kazuki KANEKO, Yasufumi YOSHIMOTO
Article type: Article
Session ID: 2225
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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This paper investigates the fuel injection characteristics, engine performance, and emissions of a small single cylinder DI diesel engine using fuels of fatty acid methyl ester (FAME) such as methyl oleate (OME) and methyl laurate (LME). The delay in injection was examined by measuring the time difference between the start of pressure rise in the injection pipe and the start of injection. With OME there was a shorter injection delay than with ordinary gas oil. The results of the measurements of fuel injection rates also showed that FAME fuels prolong the injection and that the mean energy supply rates decrease due to the lower calorific value. Compared with gas oil, the FAME fuels showed similar brake thermal efficiencies at high loads, and the smoke densities were significantly lower under whole load conditions. The ignition delay with LME was similar to gas oil, while the OME showed better ignitability than LME.
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Masato NAKAJIMA, Yusuke SOMA, Masashi ONO, En NIN, Akira IIJIMA, Hideo ...
Article type: Article
Session ID: 2226
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The purpose of this study is to compare the diesel engine performance of several fatty acid methyl esters (FAMEs). Tests are conducted by using three kinds of FAME made from coconuts oil, tallow (beef suet) and soybean. The test engine is driven by the electrical motor without engine warm-up, and the fuel is started to inject at the full load setting when the engine revolution reaches 3000 rpm. Indicator diagrams are taken until the engine reaches stable condition, and the ignitability and combustion characteristics of three neat FAMEs are compared from indicator diagrams. The smoke, hydrocarbon and carbon monoxide concentrations are improved by FAMEs compared with diesel fuel. The coconut-oil methyl ester and tallow methyl ester has a good ignition characteristics because both coconut-oil and tallow include a lot of saturated fatty acid. The break mean effective pressure and thermal efficiency of soybean methyl ester are lowest among three FAMEs.
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Ryosuke SHIINA, Mikiya ARAKI, Lai CHEN, Hisao NAKAMURA, Seiichi SHIGA, ...
Article type: Article
Session ID: 2227
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The objective of the present study is to reveal the combustion and emission characteristics of a spark-ignition engine fuelled with three kinds of gaseous fuels; H_2, CO and CH_4 which are produced from gasification process of a biomass fuel. Under WOT and 1500 rpm condition, CO gas shows lower thermal efficiency than H_2 and CH_4, although it gives higher combustion temperature which is supported by the higher exhaust gas temperature and much higher NOx emissions than those for CH_4. At around the phi of 0.4 H_2 shows almost comparable thermal efficiency with that for CH_4 at its stoichiometric condition, which must be derived by the faster burn of main flame propagation.
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Yutaka Masuda, Zhili Chen
Article type: Article
Session ID: 2228
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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This study was focused on investigating solubility of ethanol blended diesel fuel by temperature and combustion mechanism. Solubility between ethanol-diesel blend in E20 (ethanol accounts for 20% of ethanol-diesel blend) was achieved by heating fuel to 323K. By adding ethanol, ignition delay was observed due to low cetane number, and a decrease in the peak of rate of heat release was observed due to low reaction speed and mixture leanness by ignition delay. Although mixing ethanol changed the combustion characteristics in a PCI, favorable combustion characteristics was only observed in low loads, in mixing ratio up to E20.
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Nobuyasu SUZUKI, Sohichi SASAKI, Hidechito HAYASHI
Article type: Article
Session ID: 2701
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Kenichi SAKODA, Shoji YAMADA
Article type: Article
Session ID: 2702
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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To investigate the source of aerodynamic noise caused by turbulent flow in the sirocco fan, the measurement of the downstream of sirocco fan by hot-wire probe and numerical simulation was carried out. Through the consideration of measurement result and numerical simulation of flow pattern in the casing, the flow which can become the sound source was divided into two pattern. The velocity fluctuation of the flow which passed at the nub side was larger than the velocity fluctuation of the flow which passed at the inlet side in low frequency region.
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Takuya FUCHI, Jiro FUNAKI, Akira TAKUSHIMA, Seiji SATO, Katsuya HIRATA
Article type: Article
Session ID: 2703
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The present study is a fundamental approach to develop the measuring technology for minute fluctuating pressures on the 3D blade surface of a fan rotating with arbitrary rotation-axis direction, where we are required to correct the gravitational-force effect and the centrifugal-force effect for accurate measurements. The working fluid is air. A rotating pressure transducer with an arbitrary attitude is closely sealed by a shroud. The rotational motions with arbitrary attitudes are realised by fixing the pressure transducer to a cantilever which is rotates with a motor-driven disc with a diameter of 500[mm] and a thickness of 5[mm]. As a result, we have successfully estimated both the effects on the pressure-transducer signal.
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Takahito Kamatsuka, Hidechito Hayashi, Hironobu Teraoka, Zhiming Zheng ...
Article type: Article
Session ID: 2705
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The squirrel cage fan is used in many facilities for high pressure and large of flow rates, and is desired to improve the fan efficiency. In this paper, this type of fan with the large span was researched. The fluid and sound characteristics are experimentally analyzed at out of the impeller and in the scroll casing. It is cleared that the flow is fairly biased to the center and it is emerged the large circulation region over the half of span. The kinematic energy, at each scroll section, is not accumulated at the beginning of the scroll, but near the end of its. The sound energy from the fan is extremely turned out at the end of the scroll.
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