The proceedings of the JSME annual meeting
Online ISSN : 2433-1325
2002.4
Displaying 1-50 of 150 articles from this issue
  • Article type: Cover
    Pages Cover1-
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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  • Article type: Appendix
    Pages App1-
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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  • Article type: Index
    Pages Toc1-
    Published: September 20, 2002
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  • Tadashi TOKUDA, Shigeru MORI, Junichi SATO, Mitsuhiro TSUE, Michikata ...
    Article type: Article
    Pages 1-2
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Considering exhaustion of natural resources, the vast quantities of coal are very attractive for human beings and expected to play an important role in the future. On the other hand, the amount of environmental pollutant is more discharged than any other fossil fuels in combustion. Therefore, high temperature air combustion technology of pulverized coal is under development as an innovative combustion technology in order to decrease amounts of environmental pollutant. In this study, effects of oxygen concentration on ignition process of a single coal particle in high temperature were investigated.
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  • Harunori NAGATA, Atsushi FUJII, Kenichi ITO, Tsuyoshi TOTANI, Isao KUD ...
    Article type: Article
    Pages 3-4
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Ignition delays of fuel particle clusters that are inserted in a high-temperature environment are measured by changing the ambient temperature and the interval between fuel particles. To eliminate the effect of natural convection on the phenomena, ignition experiments are conducted under microgravity conditions. A qualitative discussion using numerical results about the ignition of a spherical cluster of fuel particles is made also to interpret the experimental results. Main conclusions obtained are in the followings. Ignition delay of a fuel particle cluster quickly immersed into a hot environment has a minimum at a certain interval between particles, and the minimum ignition delay is shorter than that of a single particle. This ignition delay behavior is common to previous results reported for droplet array ignition. The cause of this behavior is the long characteristic reaction time compared to the characteristic fuel mass transfer rate. Depending on the ambient temperature, the following two phenomena occur : (1) The ignition delay becomes minimum for a larger particle interval with increasing the ambient temperature because the volatilization time, which decreases with increasing the particle interval, is more dominant with increasing the ambient temperature. For higher ambient temperatures, the ignition delay is expected to decrease monotonically with increasing the particle interval because the reaction time should be negligible small comparing with the volatilization time. (2) An envelope flame appears for a larger particle interval with decreasing the ambient temperature because more amount of fuel gas is accumulated around the cluster at ignition for lower ambient temperatures.
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  • Ichiro Naruse, Daisuke KAMIHASHIRA, Khairil
    Article type: Article
    Pages 5-6
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Particle size and composition distributions of ash particles in both reacting coal and depositing layer are analyzed, using CCSEM (Computer Controlled Scanning Microscope), to study behaviors of ash particles included in the reacting coal and deposition phenomena. For the behaviors of ash particles in the reacting coal, fraction of the coarse particles gradually increases due to coagulation, so that the composition of the coarse particles also changes during evolution and combustion processes of volatile matter. For structure of the deposit layer, on the other hand, fine particles of size less than 3μm mainly consist of the initial layer for three types of coal, and the thickness was about 30μm. Growth behavior of the deposit at the stagnation depended on the coal type. The deposition phenomena take place due to preference of both particle size and composition.
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  • Takayuki HIROSE, Rong He, Toshiyuki SUDA, Masafumi KAWAI, Tetsuya HIRA ...
    Article type: Article
    Pages 7-8
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    High-Temperature Air Combustion Technology (HiCOT) of pulverized coal combustion is expected to improve the combustion efficiency of coal and to reduce NO_x emission. The objective of this research is to predict the combustion behavior of the pulverized coal in such a furnace with optimum design, which fully utilizes the advantage of HiCOT technique. Especially, char combustion behavior under high-temperature air condition is numerically calculated using the Fractal Reaction Model and compared with the experimental data. From the results of the calculation, this new reaction model in high temperature air combustion condition predicts the conversion of the pulverized coal more highly than the conventional model. Comparing with the experimental data, the new model can predict the char conversion better than the conventional model in the early stage of char combustion.
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  • Toshiyuki SUDA, Makoto TAKAFUJI, Tetsuya HIRATA, Junichi SATO
    Article type: Article
    Pages 9-10
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    The combustion behavior of pulverized coal in high temperature air combustion condition has been studied using a regenerative type furnace. High temperature air over 800℃ is produced by heat exchange from the exhaust gas using heat storage honeycombs. In order to control the ash deposition on the honeycombs, cyclone is used to collect fly ash in the exhaust gas. Pulverized coal is fed into the furnace at the rate of 7kg/h continuously along the center of the furnace. Excess air ratio is fixed to 1.2. Combustion behavior is recorded by CCD camera, and temperature distribution in the furnace is measured by thermocouple. Composition of the exhaust gas is measured by a gas analyzer. From the results, pulverized coal flame is stabilized by high temperature air although the inlet of pulverized coal and high temperature air is separated. NO_x concentration in the exhaust gas is reduced to 32% of that in the condition which pulverized coal and air is supplied axis symmetrically. Ash deposition on the honeycombs can be controlled using cyclone and soot blowing technique.
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  • Kuniaki IMAMIYA, Akiko OKAJIMA, Kunihide KAZAOKA, Kohei SEYAMA, Satosh ...
    Article type: Article
    Pages 11-12
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    From the view point of effective use of solid waste fuels in the combustion furnaces, it is very important to examine the combustion characteristics of solid waste fuels in high temperature environment. Experiments have been carried out to elucidate the influence of initial diameter of solid waste fuels on their combustion properties such as ignition delay, total burning time and mass burning rate. The experimental conditions are 550℃ to 1100℃ of ambient temperature and 21% of oxygen concentration and the range of initial diameter of fuel sphere is 2.0mm to 5.0mm.
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  • Takeshi HATANAKA, Akio KITAJIMA, Masao TAKEUCHI, Tatsuo MIYADERA, Masa ...
    Article type: Article
    Pages 13-14
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Combustion experiments in a laboratory-scale fluidized bed reactor were performed to elucidate the effects of combustion temperature on PCDD/Fs formation during incineration of model wastes with polyvinyl chloride or sodium chloride as a chlorine source and copper chloride as a catalyst. Each temperature of primary and secondary combustion zones in the reactor was set independently to 700,800,and 900C using external electric heaters. The PCDD/Fs concentration is reduced as the temperature of the secondary combustion zone increase. It is effective to keep the temperature of the secondary combustion zone high enough to reduce their release during the waste incineration. On the other hand, as the temperature of the primary combustion zone rises, the PCDD/Fs concentration also increases. This result is probably related to the devolatilization rate of the solid waste in the primary combustion zone. The temperature decrease slows the devolatilization rate and promotes mixing of oxygen and volatile matters from the solid waste. This contributes to completing combustion reactions, resulting in reducing the PCDD/Fs concentration.
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  • Takafumi TSUIKI, Osamu FUJITA, Kenichi ITO
    Article type: Article
    Pages 15-16
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    The interaction between diffusion flame and solid surface placed near the flame are studied experimentally. The main parameters are air temperature and wall temperature. The effects of these parameters on soot distribution in diffusion flame and soot deposition to the solid wall have been studied. Microgravity experiments at Japan Microgravity Center (JAMIC) has been carried out to attain very stable diffusion flame along solid surface.
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  • Tomotsugu OGAWA, Shinsaku YAHATA, Daisuke SEGAWA, Toshikazu KADOTA, Ta ...
    Article type: Article
    Pages 17-18
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    The effects of fluctuation of the fuel flow velocity on the behavior of cylindrical-burner diffusion flame of methane were examined experimentally, with frequency of fuel-flow velocity fluctuation, mean fuel-flow velocity and temperature of ambient air and fuel as experimental parameters. The range of the flame length variation normalized by the flame length without flow fluctuation was found to decrease to zero with increasing the frequency, regardless of the mean fuel-flow velocity. At higher temperatures, flickering of the flame was suppressed even under normal gravity. The effect of the frequency on the flame length at higher temperatures under normal gravity became almost the same as that at room temperature under microgravity.
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  • Kaname SATO, Yoichi CHIBA, Yasunori OBARA
    Article type: Article
    Pages 19-20
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Heating System including this newly developed combustor serves to supply warm air and moisture to control atmosphere in greenhouse to grow trees, vegetables, flowers etc. We developed the high performance combustor adapted fuel-air counter flow. It is confirmed experimentally that the combustor attained to save 18% of fuel running cost, compared with current fuel-air conical supply combustor. The combusting flow go through along the periphery of inner wall of combustor and exhausts from the annular exit port provided at the apposite side of fuel inlet. The counter airflow nozzle is designed for higher heat transfer efficiency and stable flame. The flow structure for holding the flame is investigated.
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  • Tomohiro DENDA, Hironao HANAI, Kaoru MARUTA, Takashi NIIOKA, Minoru SU ...
    Article type: Article
    Pages 21-22
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Numerical calculation was performed to obtain extinction limits of counterflow diffusion flames for blended fuels of CO/H_2 and CO/CH_4,which are produced by thermal decomposition in incinerators. The computer code PRIMIX was converted into a calculation program for counterflow flames, and GRI-Mech ver.2.11 was used as a chemical scheme, eliminating reactions of N and including the radiation heat loss. The stretch rate at extinction of the blended fuel CO/CH_4 has a maximum at a certain mixture ratio as has been shown in the burning velocity. The effects of diluents such as CO_2 and H_2O were also calculated because blended fuels are always diluted by those inert diluents, showing that the stretch rate at extinction has a maximum at a certain dilution rate as well as the mixture ratio of fuels.
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  • Takaaki MOHRI, Toshiaki YOSHIOKA, Yoshikazu HOZUMI, Tetsu SHIOZAKI, To ...
    Article type: Article
    Pages 23-24
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    In 1999,a national project on the development of an advanced Steam Reformer was indicated. The project's objective is to break through design constraints experienced on conventional Steam Reformer for Hydrogen, Methanol, GTL, DME, Ammonia and other synthesis Gas Plants. This paper describes major results of the project up to March 2002.
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  • Shigeo MARUYAMA, Shohei CHIASHI, Yuhei MIYAUCHI
    Article type: Article
    Pages 25-26
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    We have demonstrated the high-quality and low-temperature generation of single-walled carbon nanotubes (SWNTs) by utilizing gas phase alcohols (methanol and ethanol) over iron and cobalt catalytic metal particles supported with zeolite. SWNTs were observed by SEM and TEM, and analyzed by Raman spectroscopy. Raman spectra revealed that the diameter of SWNTs had the dependency on the generation temperature and gas flow rate. In order to create nanotube devices, we tried to generate SWNTs on a silicon wafer. Very small amount of Fe/Co supported with zeolite particles was located on a silicon wafer, and SWNTs were generated by catalyst chemical vapor deposition (CCVD) technique from ethanol at 900℃. SWNTs on a silicon wafer were generated from the surface of zeolite particles and the bundles of SWNTs were running on the silicon surface.
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  • Masahiko SHIBAHARA, Yasuhiro AZUMA, Masashi KATSUKI
    Article type: Article
    Pages 27-28
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Oxidation and heating processes of Ag surface are simulated using the molecular dynamics method in order to analyze adsorptive probability and energy transfer of O_2 molecule to Ag surface. We have investigated effects of surface temperature and adherent molecules, such as Ar, Kr and Xe molecules on reaction probability and energy transfer to Ag surface in molecular scale Reaction probability of O_2 molecules is much different depending on kinds of adherent molecules on Ag surface. Dynamic behaviors of adherent molecules on Ag surface affect reaction probability substantially when translation energy of O_2 molecules is relatively small. Energy transfer from O_2 molecule to Ag surface is also dependent on physical properties and dynamic behaviors of adherent molecules.
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  • Hiroo YUGAMI, Hitoshi SAI, Yshiaki KANAMORI, Kazuhiro HANE
    Article type: Article
    Pages 29-30
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Control of optical properties of materials has been investigated for efficient thermal energy utilization. Applying the resonant effect between periodic microstructured surface structure and photons, the spectrally selective thermal radiation surface, this is so-called selective emitter, is made on Si and high temperature metals by means of micro-machining techniques. These selective emitters can be applied to Solar thermophotovoltaic systems selective solar absorber, and sky radiator etc. Thermal radiation spectra of the emitters are measured at high temperatures and selective emission due to the surface microstructures is clearly observed. Numerical calculations based on rigorous coupled-wave analysis (RCWA) are also performed to predict spectral properties of the emitters.
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  • Shigeo MARUYAMA, Kazunori TESHIMA
    Article type: Article
    Pages 31-32
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Crystal growth process of silicon was studied by molecular dynamics method using the Tersoff-C potential. The newly developed crystallization system that consisted of an amorphous Si cluster on an amorphous surface with a small number of seed atoms was used. With this configuration, the artifacts due to the periodic boundary condition could to completely neglected. From the time profiled of the Si crystal nuclei size, the classical critical nuclei size was estimated to be 50 to 100 atoms and the incubation period became shorter when the seed atoms became larger. The growth velocity of crystallization interface was estimated to be around 23cm/s.
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  • Takashi Tokumasu, Kenjiro Kamijyo, Taku Ohara, Yoichiro Matsumoto
    Article type: Article
    Pages 33-34
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    In this paper the effect of rotational degree of freedom on the properties of liquid is analyzed by the Molecular Dynamics (MD) Method. Oxygen is assumed as the liquid and molecules are assumed as both monatomic and diatomic one. 2 center Lennard-Jones (2CLJ) potential is assumed as the intermolecular potential for diatomic molecules and Lennard-Jones (LJ) potential is used for monatomic molecule. Simulations are performed at various combinations of density and temperature and an Equation of State (EOS) of each liquid is obtained by using these results. The parameters of each potential are determined so that the critical temperature and density are consistent with each other. The properties of liquid such as, latent heat, specific heat, thermal conductivity and surface tension are compared with each other and the effect of rotational degree of freedom on the properties of liquid is investigated.
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  • Shinichi TSUDA, Takashi TOKUMASU, Kenjiro KAMIJO, Yoichiro MATSUMOTO
    Article type: Article
    Pages 35-36
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Heterogeneous bubble nucleation in liquid oxygen including helium or nitrogen is simulated by usint the molecular dynamics method. Molecular interaction is given as Lennard-Jones potential, and each potential parameter is determined so that it well expresses the thermodynamic properties of factual fluids. In the case that helium is the impurity, clustering of helium molecules is observed through the simulation and these clusters are considered to become bubble nuclei. On the other hand, nitrogen molecules do not make a cluster in liquid oxygen under the same condition, and bubble is formed based on the density fluctuation as same as unary liquid oxygen. Therefore, helium in the liquid oxygen has a fairly stronger action to make clusters as bubble nuclei.
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  • Gota KIKUGAWA, Shu TAKAGI, Yoichiro MATSUMOTO
    Article type: Article
    Pages 37-38
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    A molecular dynamics simulation of an aqueous surfactant system : water liquid and alcohols below the liquid saturation density is carried out to investigate the stability of "nanobubbles" and the structure of the gas-liquid interface. To analyze the effect of the surfactant structure, volume, and polarization on the stability of bubble nuclei, we use TIP3P water as the solvent molecules and 1-propanol, 1-pentanol, 1-heptanol as the surfactant molecules. The intramolecular energy and motion of all molecules is taken into account, by applying the AMBER force field. Adding polarized surfactants to the metastable state of liquid in which bubble nuclei cannot exist stably, it is found that a stable bubble is formed and hydroxyl groups of surfactants tend to point to the liquid phase at the gas-liquid interface. It is also shown that the longer hydrophobic chains the surfactants have, the more stably the bubble nuclei can exist.
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  • Hiroyuki MATSUURA, Iwao FUJIMASA, Tetsuya NEMOTO, MASAHIRO Nakano
    Article type: Article
    Pages 39-40
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    We constructed a new Flagellar model based on Quantum Physics, and this model for the transduction of energy in bacterial flagellar motor was presented. We proposed that Lagrageian were made of the four main parts, i.e. MotA-FliG complex, water molecules, dissipative terms and rotor of Flagellar. In this model, the flux of ions across the channel interacts with the charges, which existed in the wall of ionic channel. In this results, stochastic resonance generated between the Mot-A Flig-G complex and the ions. The MotA-FliG complex produced travelling waves in one of the subcomponents of the motor, the C ring. This wave stabilized the cyclical movement of the channel which generated the rotating force.
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  • Ken OGISO
    Article type: Article
    Pages 41-42
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    In heat transfer from a higher temperature reservoir to a lower temperature one, by applying a reversible Carnot engine between those heat reservoirs, it is clarified that the entropy generation due to heat transfer is identical to the entropy generation due to the work lost by throwing away total Carnot work, which could be obtainable by the imaginary reversible process, into a lower temperature heat reservoir. By these procedures, thermodynamic grounds for heat transfer engineering, which seems to have been somewhat obscure to date, has clearly been established.
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  • Hisashi TANAKA, Shigefumi NISHIO
    Article type: Article
    Pages 43-44
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Utilization of low-temperature waste heat is one of key technologies for energy utilization because its direct use as heat is not always available due to mismatch between demand and supply of heat. We believe that a low-cost and maintenance-free prime mover is suitable to overcome such situations and thermoacoustic engines are the type of such prime movers. However, in most cases, the waste heat is carried by gas flow and then the heat exchanger between the gas flow and the prime mover must be large. In the present paper, a new type of thermoacoustic engine is proposed and the possibility removing the heat exchanger is examined analytically.
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  • Toshio TOMIMURA, Asako ONIZUKA, Kouji HAMANO, Ryozo ECHIGO
    Article type: Article
    Pages 45-46
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    To investigate the heat transfer characteristics of a multi-layered type of gas-to-gas heat exchanger, a series of experiments have been performed. The present heat exchanger is composed of two, three, four or five porous medium sections separated by opaque solid walls; that is, the low and high temperature sections in a two-layered type system and the low, first and second high temperature sections with the first and second heat recovery sections in a five-layer type system for instance. The effects of the inlet temperature of the high temperature gas, the optical thickness of the porous metal plates, and the heat exchanger structure (i.e. the number of layers) on the temperature distributions in the system and the heat recovery rate are clarified.
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  • Akira TAKIMOTO, Keigo HATTA, Ryouta DOBASHI
    Article type: Article
    Pages 47-48
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    High efficiency of gas absorption may be one of the important techniques for protection of global environment. We have proposed the new method for Carbon Dioxide gas absorption, that is the condensate film method by utilizing condensation process and the solution condensate method. In present investigation, a new concept of the enhancement of gas absorption by utilizing Zeolite particles with mist formation was proposed, and its proof experiment was conducted with regard to the gas absorption rate in vertical cooling tube. Comparing the present proposed method with falling liquid film method and our past-proposed methods, the effectiveness of the gas absorption through the Zeolite particle and mist droplets was clarified.
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  • Tadashige KAWAKAMI
    Article type: Article
    Pages 49-50
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Experiments have been carried out to examine the lean limits of propane-air mixtures in a combustion tube under microgravity. The microgravity technique achieved in a freely falling chamber is employed because the realization of symmetrical flame propagation in a combustion tube is possible. Experimental condition for the initial mixtures corresponds to room temperature and 0.1 MPa and the fuel used is propane of 99.9% purity. The experimental results show that (1) the flame propagation behavior of propane-air mixtures in a combustion tube close to lower propagation limit is irregular during the burning process, (2) under microgravity its propagation limit shifts to lower value more than that obtained under normal gravity, (3) the minimum flame speed of lean propane-air mixtures under microgravity is about 10cm/s.
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  • Takayoshi SOGAWA, Tetsuro OBARA, Shigeharu OHYAGI
    Article type: Article
    Pages 51-52
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    This research investigated the characteristic of the flame front in a constant volume chamber experimentally, in order to clarify the fundamental character of a hydrogen-air flame under the background of the safety and environmental problems. In this report, effects of the initial pressure on the instability of flame front, the maximum pressure, the burning time and the NOx formation were studied.
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  • Touki UDA, Yuji WATANABE, Shu TAKAGI, Yoichiro Matsumoto
    Article type: Article
    Pages 53-54
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    The behavior of a single bubble rising in water with some surfactant dissolved is analyzed numerically and experimentally. Marangoni effect due to adsorption of the surfactant is taken into consideration. As a surfactant, 1-Pentanol, 3-Pentanol, 2-Octanol, Triton X-100 is chosen. And then, it is found that the bubble motion strongly depends on the physical properties of each surfactant such as kinetic constant, desorption constant, saturation adsorption etc. It showed good agreement of drag coefficient between experimental result and numerical one, even for narrow transient area from clean bubble to rigid sphere. In addition, a new method is proposed to estimate unknown surface properties of surfactant in water.
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  • Kohji IWANAMI, Shigeo FUJIKAWA, Takeru YANO, Makoto ICHIJO
    Article type: Article
    Pages 55-56
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    The paper is concerned with the nonequilibrium condensation from a vapor to a liquid phase on the plane endwall of a shock tube behind a reflected shock wave. The growth of a liquid film on the endwall is measured by an optical interferometer using a laser beam. The experiment is carefully conducted on the precisely designed apparatus, and thereby the condensation coefficient of methanol vapor is determined in a wide range of vapor-liquid conditions from near to far from equilibrium states. The result shows that the condensation coefficient increases with the increase of the ratio of vapor and liquid temperatures, and it decreases with the increase of the ration of number densities of vapor and saturated vapor at the interface. Near vapor-liquid equilibrium conditions, the measured condensation coefficient agrees well with the one by molecular dynamics simulation.
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  • Takaharu TSURUTA, Gyoko NAGAYAMA
    Article type: Article
    Pages 57-58
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    We are proposing a formulation on the condensation coefficient of vapor molecule at liquid-vapor interface based on molecular dynamics studies. The equation is a function of translation energy of incident molecule and surface temperature : σ_c=α[1-βexp{-mv^2_z/(2kT)}], Where v_z is the velocity component perendicular to the surface, k the Boltzmann constant, m the mass of molecule, T the temperature of liquid surface. The parameters α and β are constants describing characteristics of surface structure. It is found that the transition state theory gives us values α and β theoretically. We are therefore able to have a general expression of condensation coefficient. In order to describe the temperature profile in the vicinity of the liquid surface we should use the formulation instead of the conventional condensation coefficient with uniform value.
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  • Katsuhiro SHIRONO, Hirofumi DAIGUJI
    Article type: Article
    Pages 59-60
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Zeolite is one of the functional materials controling air qualities, such as humidity or environmental particles. To predict and control adsorption or diffusion process precisely, it is important to clarify the structural and dynamical properties of adsorbed substances inside zeolite on a molecular level. In the present study, x-ray diffraction measurement and molecular dynamics simulation of zeolites NaX and NaY with various amount of water were carried out to clarify the distribution of water inside zeolites. The both results show that water molecules are distributed orderly inside zeolites and Na atoms strongly affect the distribution of water.
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  • Mitsuharu OGUMA, Shinichi GOTO
    Article type: Article
    Pages 61-62
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    For better understanding the combustion characteristics of DME, emission intensities of DME combustion radicals from pre-mixed burner flame were measured by using spectroscope and photomultiplier. Large peaks of emission intensity from pre-mixed and diffusion DME flames were shown near 310 nm, 430 nm and 515 nm. They are OH, CH and C_2 radicals respectively. However, the emission intensity of diffusion DME flame was lower than that of pre-mixed DME flames. Comparing DME with butane pre-mixed flame, the peaks of emission intensities fueled with butane were much stronger than that with DME. In case of diffusion butane flame, there is continuous spectrum over 350 nm.
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  • Yuichi OHWADA, Youhei SHIGEMI, Shigeharu KOBORI, Shuichi KAJITANI
    Article type: Article
    Pages 63-64
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    The auto ignition and combustion behaviors of dimethyl ether (DME) fuel as homogeneous mixture with air was investigated at gas density of constant by using a rapid compression machine technique. The ignition delay of DME-air premixture increases with increasing equivalence ratio at the constant stroke where as the ignition delay both of C_2H_6-air mixture and of C_3H_8-air mixture decreases with increasing equivalence ratio. The ignition delay of C_3H_8 was a function of mixture temperature and equivalence ratio at the constant gas density, but the ignition delay of DME in the Arrhenius Plot was roughly independent on equivalence ratio.
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  • Kenichi TANIOKA, Toshihiro NAKASATO, Mitsuru KONNO, Shuichi KAJITANI, ...
    Article type: Article
    Pages 65-66
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Bio-diesel-fuel (BDF) and dimethyl ether (DME) can control an increase of carbon dioxide in the atmosphere from the viewpoint of carbon neutral, since they are biomass derived fuel. For diesel engine application, DME has problems of poor lubricity and low heating value, and BDF has problems of smoke emission and high viscosity. It can be make up for those faults of each other, by compounding the fuels. In this study, first a compatibility of both fuels was examined, then engine performance, exhaust emissions, and combustion characteristics of BDF/DME composite fuel were investigated using a small DI diesel engine. As the results, smoke emission was remarkably reduced with the composite fuel, and good thermal efficiency comparable to diesel fuel operation was achieved.
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  • Koji YAMANE, Yuzuru SHIMAMOTO
    Article type: Article
    Pages 67-68
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    This paper describes the feasibility of exhaust oxidation catalyst to reduce exhaust emissions from Biodiesel Fueled DI diesel engines. Biodiesel fuel is essentially free of sulphur, so that an increase in PM emission by sulphate formation on oxidation catalyst will be prevented. In this study, effects of sulphur contents in fuel and exhaust temperature on reducing of Smoke, PM, HC, Co, NOx, HCHO and CH3CHO emissions was investigated via experiments using neat or blended fuel of Biodiesel and gas-oil. From experimental results, it was found that PM emission for Biodiesel fuel presents higher reduction rate than that for gas-oil at partial loads. And the reduction rate of emissions by oxidation catalyst drastically decreases for exhaust temperature under 450K.
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  • Takayuki MINEMATSU, Taku IBUKI, Hideyuki OGAWA, Noboru MIYAMOTO
    Article type: Article
    Pages 69-70
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Decaline, which is promising as a future gas-to-liquid (GTL) fuel through efficient direct conversion from methane, has properties appropriate for a diesel fuel. With neat decaline, when NOx is maintained at near present regulation levels by EGR and retarded fuel injection timings, smoke is remarkably reduced without sacrifice in SBEC in comparison with ordinary diesel fuel. With 20% addition of either cyclohexane or n-hexane to decaline, BSEC and smoke improve while NOx slightly increases. In particular, cyclohexane addition significantly reduces smoke emissions. Compared with ordinary diesel fuel, the trade-offs between smoke and NOx and between BSEC and NOx are remarkably improved with decaline-cyclohexane blends and application of EGR.
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  • Toshio SHUDO, Tomoharu KUNINAGA, Takayuki HASEGAWA
    Article type: Article
    Pages 71-72
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    The research proposes reduction of cooling loss in hydrogen combustion by direct injection stratified charge, and analyzes its characteristics. The stratified charge combustion in the research adopts direct fuel injection into lean mixture and spark ignition. The stratification is controlled by a fraction of directly injected fuel to the totally supplied fuel. A lowered temperature of the burning gas around the combustion chamber wall due to the lean mixture by the stratification is expected to reduce effectively the cooling loss from burning gas to the wall. The characteristics are analyzed in a constant volume combustion vessel by using measured pressure data and burned gas compositions. Flame propagation is also observed by shlieren photography.
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  • Takenori TOKIOKA, Kenichi YUASA, Yoshihiko MATSUURA, Yoshiyuki KIDOGUC ...
    Article type: Article
    Pages 73-74
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    A new hydrogen direct-injection SI engine employing a rhombic link Z-crankshaft mechanism has been developed. The engine was operated for a single combustion cycle. Experimental results show that Z-crankshaft engine keeps relatively high pressure under condition of late spark timing due to piston motion caused by the mechanism. Ignition during injection period results in lower initial pressure rise, which means that rapid combustion of hydrogen can be controled by diffusion burning of hydrogen jet. Neumerical simulation shows that Z-crankshaft engine is useful, in particular, under high speed operating condition for hydrogen combustion because this engine reduces pressure rise with keeping high power when engine speed is increased.
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  • Hiroshi SEKITA, Kozo UCHIYAMA, Seiichi SHIGA, Hisao NAKAMURA, Tomio Ob ...
    Article type: Article
    Pages 75-76
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    The objective of the present study is to examine the possibility to realize stratified combustion in a 2-stroke spark-ignition engine fueled with CNG. A two-cylinder racing engine with the stroke volume of 397cc was used. Through a preliminary experiment, utilizing several techniques of flow rate measurement, a reliable measurement of CNG flow rate could be established and some gas dynamic effect in engine was suggested. By applying Scavenging port injection, remarkable improvement of BSFC can clearly be shown in comparison with the homogeneously charge operation with a gas mixer.
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  • Takashi SAKURAI, Akinori OOKO, Tetsuro OBARA, Shigeharu OHYAGI
    Article type: Article
    Pages 77-78
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    A Pulse detonation endgine (PDE) holds promise to increase performance of air breathing propulsion systems by taking advantage of high cycle efficiency due to the constant volume heat addition characteristics of detonative combustion. In this study, a multiple cycle test up to 10Hz was conducted to demonstrate the feasibility of multiple cycle operation of PDE.
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  • Seiichi SHIGA, Youichi MIYASHITA, Kenji NISHIDA, Shizuo YAGI, Yoshihar ...
    Article type: Article
    Pages 79-80
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    This paper presents an investigation into the effect of voer-expansion cycle with late-closing of intake valves on the engine performance in a gasoline engine. A larger single-cylinder test engine with the stroke volume of 650cc was used with four kinds of expansion ratio (geometrical compression ratio) from 10 to 25 and four sets of intake valve closure timings from 0 to 110 deg C. A. ABDC. Late-closing has an effect of decreasing the pumping work, but higher expansion ratio increases the friction work. Combining the higher expansion ratio with the late-closing determines the mechanical efficiency on the basis of these two contrastive effects. The indicated thermal efficiency is mostly determined by the expansion ratio and is little affected by the nominal compression ratio. The value of the indicated thermal efficiency reaches 48% at most which is almost comparable with the value of diesel engines. The brake thermal efficiency is determined by both the mechanical efficiency and the indicated efficiency.
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  • Daisuke KURASHIMA, Kazuyuki NARUSAWA, Morimasa HAYASHIDA, Daiki KAWANA ...
    Article type: Article
    Pages 81-82
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    This paper covers our investigation into a decline in productivity resulting from hydrogen fuel containing impurities in methanol reforming type fuel cells. Here, Various experiments and analyses were conducted to determine the adverse effect of CO, CH_4,HCHO and HCOOH poisoning on the performance of FC, and investigations into poisoning on dependence of the type of catalyst electrodes between Pt and Pt-Ru alloy were carried out. As the results, CO poisoning can be decreased by adding Ru onto catalyst electrodes. However, we confirmed that the performance became worse about two times by adding Ru as for HCHO and HCOOH poisoning.
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  • Kenji MUROOKA, Kazuyuki NARUSAWA, Morimasa HAYASHIDA, Daisuke KURASHIM ...
    Article type: Article
    Pages 83-84
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    This paper covers our investigation into a decline in productivity resulting from hydrogen fuel containing impurities in methanol reforming type fuel cells. Here, we had several investigations into poisoning using reforming gas adopting STR and ATR method. The results are summarized as follows : 1) The influence of CO_2 and N_2 mixed into fuel was examined. It could confirm that the poisoning didn't occur with these gases, therefore, the quantities of partial pressure decline phenomenon of hydrogen gas caused by mixing these gases are thought to be the same. 2) Experiments were carried out by using the gas formed from reformer. The progress of poisoning of this case is complex, however explanation of this phenomenon became possible by taking CO poisoning and the influence of partial pressure decline phenomenon of hydrogen gas into consideration.
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  • Seitaro MISAWA, Hidenori KOSAKA, Yukio MATSUI
    Article type: Article
    Pages 85-86
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    To investigate the effect of carbon numbers of fuel on ignition delay, Ignition delays of mixtures of n-heptane/air, n-decane/air, n-dodecane/air, and n-tridecane/air were measured using a shock tube. Results showed that the increase in carbon number of fuel shortens the ignition delay of fuel mixture at the temperatures in a range of negative temperature coefficient (NTC) region.
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  • Kazunori YOSHITOMI, Seigaku TANIZAWA, Akitomo ITO, Takayoshi TAKANO, H ...
    Article type: Article
    Pages 87-88
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    The ignition phenomena of diesel fuel spray injected with medium injection pressure were investigated and it is clarified that ignition occurs at a certain point near the surface of spray liquid column before breakup. Based on this result, the blowing-off limited ignition model was considered under the concept that the fuel vaporized from liquid surface begins to be activated immediately after the velocity gradient at liquid column surface decreases down to a certain level and this leads to ignition. A functional relation between various factors and ignition delay, derived based on this model, well analyzed the ignition delay data. Ignition investigation using a single cylinder engine revealed that the effects of EGR rate, related to O_2 concentration, can be analyzed comprehensively based on the above model.
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  • Tadayoshi IHARA, Akihiro KATSUURA, Tsunenari FUTAGI, Takuji ISHIYAMA, ...
    Article type: Article
    Pages 89-90
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    Experimental study was carried out by using a constant volume vessel in order to study the effects of ambient pressure and injection conditions on temperature dependency of ignition delay in n-heptane spray. The results show that at a low ambient pressure the NTC behavior with accompanying two stage ignition is observed. At a high ambient pressure, higher injection pressure causes shorter pressure recovery delay. This tendency is also observed at a low ambient pressure. However, at a temperature in the NTC region, hot flame is delayed by the enhancement of mixing.
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  • Naofumi SENDOH, Norimasa IIDA
    Article type: Article
    Pages 91-92
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    In order to make clear the effects of fuel properties on the ignition of the homogeneous and dilute diesel fuel spray made by hi-pressure injection and micro-hole nozzle, mixed fuel with n-Decane (Cetane Number : 78.8) and α-Metylnaphthalene (Cetane Number : 0) were used in this study. These mixed fuel had different Cetane Numbers but made to have same n-Decane partial equivalence ratio in fuel spray (φnD) by using different hole-diameter nozzle. The ignition delay under the condition that ignition occurred during fuel injection period (diffusion condition) depended on nozzle diameter. On the other hands in the case that ignition (premix condition) occurred after injection ignition delay depended on φnD. The combustion efficiency is also affected by φnD in the premix condition.
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  • Yasushi OHGA, Hajime ISHII, Jin KUSAKA, Yuichi GOTO, Yasuhiro DAISHO
    Article type: Article
    Pages 93-94
    Published: September 20, 2002
    Released on J-STAGE: August 01, 2017
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    A numerical study was carried out to predict ignition delay times by using KIVA-3 combined with the ignition model, which is based on Livengood-Wu theory. N-heptane was selected on the basis of similarity of cetane number to diesel oil. The experimental data for n-heptane^<(1)> was referred to certify the adjustment of this model. The computational results show relatively good agreement between computational predictions and experiments.
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