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Article type: Index
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Akiko OKAJIMA, Toshio KUROSAKA, Mamoru SUYARI, Satoshi OKAJIMA
Article type: Article
Session ID: 1901
Published: September 04, 2004
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Experiment has been carried out to examine the combustion behavior of solid waste fuels containing moisture in high temperature and low oxygen atmosphere. The ranges of ambient temperature in the electric furnace are 600 ℃ to 1400℃ and 0% to 40% of moisture content. The test sample used is food of Nishiki-Koi because it is very similar to RDF and town wastes on physical property and chemical composition. The size of test sample is sphere of 3 mm in diameter. The results obtained in the study are as follows: (1) There are no influence of moisture on flaming duration, char combustion period and mass burning rate, though the ignition delay is markedly affected by moisture content.(2) Even at 1400℃ of ambient temperature the chemical effect to combustion behavior of solid waste fuels does not appear.
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Tadashige Kawakami
Article type: Article
Session ID: 1902
Published: September 04, 2004
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Experiments have been carried out with extremely lean, quiescent hydrocarbon-air mixtures to examine the influence of flame propagation direction under normal gravity and microgravity conditions on propagation limit and distance of flame propagation in a tube and the appearance mechanism of cellular flame. Experimental condition for the initial mixtures corresponds to room temperature and 0.1 MPa and the fuels used are propane and methane of 99.9% purity, respectively. The main conclusions are follows:(l) Flame shape and distance of flame propagation are affected by the direction under normal gravity.(2) Cellular flames are appeared not only lean methane-air mixtures but propane-air mixture near the lean limit under microgravity.(S) The range of distance of flame propagation under normal and microgravity conditions can possible to distinguish.
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Norio OHIWA, Yojiro ISHINO
Article type: Article
Session ID: 1903
Published: September 04, 2004
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In this paper the behavior of the propagating flame in the plane premixed shear flow after the spark ignition at the midpoint between two adjacent organized eddies is simulated using the discrete vortex method and is compared with the results of the two-directional and high-speed schlieren observations. In the numerical simulation, the higher uniform mixture velocity is varied from 4.0 m/s to 6.0 m/s at 1.0 m/s intervals with the lower uniform mixture velocity kept constant at 2.5 m/s and the equivalence ratio is varied from φ = 0.7 to 0.9 at 0.1 intervals. Detailed comparison of the results numerically simulated with those experimentally obtained clarifies that not only temporal variation of the flame appearances with the equivalence ratio and the velocity difference but also the selective growth rate agrees extremely well with each other.
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Ryuji YAMAKITA, Tsuyoshi SATO, Yojiro ISHINO, Norio OHIWA
Article type: Article
Session ID: 1904
Published: September 04, 2004
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The possibility of thermal recycling of recycled PET-resin for industrial burner systems has been investigated both in the in-furnace and the open atmospheric operations by supplying PET-resin powder as an auxiliary fuel to the improved commercial LPG-fueled ceramic burner. These results showed that a large part of PET-powder is exhausted without burn-out in the open atmospheric operation, whereas it is perfectly consumed in the in-furnace operation. In this paper, in order to reduce an amount of unburnt PET-particles in the open atmospheric operation, reactive flow and burning processes of PET-particles are investigated using PIV/PTV measurements. Appearances of flying PET-particles are also observed using the pulse laser and the particle diameter are evaluated by calculating the equivalent diameter. According to the results, key factors for effective bum-up of PET-particles are finally discussed.
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Tamio IDA, Manabu FUCHIHATA, Shuko Takeda
Article type: Article
Session ID: 1905
Published: September 04, 2004
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Harvesting, transportation, energy conversion and the high-efficient utilization, cascade method and marke formation besides become with the indispensable element in order to utilize the biomass resource. This stud was obtained combustion stability of methane fermentation biogas (0.6CH_4+0.4CO_2) from the livestock excrement resources. The microflame of biogas fuels were formed by the diffusion flame on the coppered straight pipes of inner diameter 0.02mm〜1.5mm. It was suggested that minimum mixing spatial scale changed by the each mixing ratio of the bio-fuel gas.
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Manabu FUCHIHATA, Shuko TAKEDA, Tamio IDA
Article type: Article
Session ID: 1906
Published: September 04, 2004
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Light oil based oil-in-water emulsion fuels are applied to a direct-injection diesel engine. Fuel consumption and the emission of NOX, HC, CO are measured along with the variation of dispersed waterdrop diameter. As a result, fuel consumption rate decreases as the waterdrop diameter increases. NO_x emissions of the emulsion fuels are lower than of light oil, and are lowered as the waterdrop diameter decreases. HC emission for the emulsion fuel of the largest waterdrop diameter is lower than those for smaller waterdrop diameter emulsions. From the result of the observation of open spray flames, it is considered that those tendencies are the effect of the acceleration of the flame speed caused by microexplosions.
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Keisuke UCHIDA, Takashi SUZUKI, Yasufumi OGURI, Masatake YOSHIDA
Article type: Article
Session ID: 1907
Published: September 04, 2004
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Measurement and analysis of burner flame spectrum with the biomass blended liquid fuel was done to investigate the combustion characteristics of biomass fuels. The experimental apparatus was mainly constructed of fuel vaporizing and mixing device, laminar flow burner, reflection spectroscope, and a digital camera. Four kinds of pure fuel and four kinds of blended fuel were used and the equivalence ratio was changed as the experimental parameter. As the results, it was obtained that the main radical luminescence existing in the flame, its changing tendency against the equivalence ratio, and the possibility of estimating the equivalence ratio with the ratio of luminous intensity of two different radical.
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Yu AKASHI, Osamu FUJITA, Kiyotaka YAMANE, Norio ANZAWA
Article type: Article
Session ID: 1908
Published: September 04, 2004
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A premixed type foam dispersed combustion is a new combustion system. This system can attain low excess air ratio premixed combustion even with liquid fuel, so it has high thermal efficiency. This paper aims at the prediction of flame stability by numerical simulation based on heat recirculation model. As a result, a blow-off in high combustion load and a quenching in low combustion load can be predicted and importance of taking into account the changing in stand-off distance is emphasized. The prediction shows that high emissivity of porous plate and large burner size leads to better flame stability.
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Koji FUMOTO, Hideaki YAMAGISHI
Article type: Article
Session ID: 1909
Published: September 04, 2004
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Numerical studies for transportation of cold thermal energy have been performed. This research investigated the use of the natural cold thermal energy of ice as the cold heat source for other areas. The storage ice is made in a 20 ft type insulated container using the natural heat during winter. The container is then subsequently stored in a cool climate until summer. Ice produced in this way can be transported to areas and cities where the demand for cold energy is high. As a result, it is shown that CO2 emission can be controlled by using the cold thermal energy of the conveyed ice.
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Hideaki KAWABATA, Yoshihiko SASAKI, Masashi KATO, Atsushi TSUJIMORI
Article type: Article
Session ID: 1910
Published: September 04, 2004
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In previous report, the absorption cycle which is able to drive without an electric solution pump is propose. To realize this cycle the porous material which is inserted in the generator is used to keep the pressure difference between the high pressure vapor and the low pressure liquid. Then some experiments were done to examine the pressure and temperature difference using capillary pumping. In this research, the generator was improved and the heat rate of the generator and the evaporator were measured.
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Kazuo KARA, Masahiro INOUE, Masato FURUKAWA
Article type: Article
Session ID: 1911
Published: September 04, 2004
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Heat transfer is investigated for high pressure ratio air flow in square minichannel, which are machined on the oxygen free copper block. The size of the channels are 0.3, 0.6, 1.0 and 2.0mm, and the length are 10, 20, 50 and 100mm. The pressure ratio is changed widely up to the flow chokes at the exit. It is found that the heat transfer coefficient is about 7.3 times greater than fully developed turbulent pipe flow. Experimental result show that 75 percent of the total heat transfer is achieved in 10 percent inlet portion of the whole channel.
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Eiji NISHIWAKI, Naoki ONDA, Keisuke TAKESHITA, Yoshiharu AMANO, Takumi ...
Article type: Article
Session ID: 1912
Published: September 04, 2004
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This paper reports about the mechanism of pump error at starting-up of ammonia-absorption refrigerator, and the countermeasure for it. First, the authors analyzed relations between the pump error and the transitional change of state at the absorber. Then, the starting-up experiments to evaluate the countermeasure for the pump error are carried out. Consequently, there is the optimum ammonia-water solution flow rate through the spray nozzle of the absorber. And no pump error occurs at the solution flow rate.
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Tetsushi BIWA, Yusuke TASHIRO, Yuki UEDA, Motoki KOZUKA, Taichi YAZAKI
Article type: Article
Session ID: 1913
Published: September 04, 2004
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We demonstrate amplification and strong damping of the acoustic intensity in a resonator using thermoacoustic energy conversions. A regenerator is installed in the middle of the resonator, and a steep temperature gradient is made along it. A resonant acoustic waveis produced in the resonator by an acoustic driver at the end. We experimentally determined the acoustic intensity entering and leaving the regenerator. As a result, we obtained the thermoacoustic amplification in case of a positive temperature gradient, and damping in a negative one.The present experimental result would contribute to the development of new acoustic devices usingthermoacousticenergy conversions.
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Koji MATSUBARA, Kazuki OGASAWARA, Tomoyuki SUZUKI, Tsuyoshi SUTO, Muts ...
Article type: Article
Session ID: 1914
Published: September 04, 2004
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We developed numerical method predicting environmental thermal load for a cubic box. This method is based on control volume method where cubic box is decomposed into six walls and inner air. In evaluation of heat transfer coefficient on wall surfaces, wind speed, wall surface temperature and box size are taken into account. Experimental data using a small box of 100x100x100mm^3 and a large box of 2210x1790x2050 mm^3 were acquired, and numerical scheme was validated through comparison between simulation and experiment..
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Mitsuo WAKAMATSU, Masaru TEZUKA, Tatsuo SHIGETA, Yoshihiko OGITA, Hiro ...
Article type: Article
Session ID: 1915
Published: September 04, 2004
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In the design of the several power plant systems, deep sea water (DSW) is used as the cooling water to increase the heat exchanger efficiency of the large scale power plant. DSW has useful characteristics such as purity effect, all season low temperature cooling water and rich nutrient. The objective of this study is to evaluate of heat exchanger effect utilizing DSW. Heat exchanger models were straight annulus tube type with cold sea water inner tube and hot water annular tube. In these experiments, DSW and surface sea water(SSW) was used for cooling water. Inner tube pressure loss and several positions temperature of heat exchanger were measured at long continuous operation, about one year. From these experimental results, pressure loss coefficient of SSW increased about 1.26 times compared with initial condition value. But pressure loss coefficient of DSW was almost equal to initial value. Therefore overall coefficient of heat transmission of SSW decreased about 0.70 times as initial condition value. But overall coefficient of heat transmission of DSW was hold near the initial level. The cause of pressure loss coefficient increase phenomenon and overall coefficient of heat transmission decrease phenomenon under SSW cooling condition are regarded as inner tube attachment dirt. It was confirmed that using purity DSW for heat exchanger was more effective.
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Yuki UEDA, Tetsushi BIWA, Takao SUMI, Katsuyoshi KUMAZAWA, Kazushi TAC ...
Article type: Article
Session ID: 1916
Published: September 04, 2004
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We built and tested a thermoacoustic Stirling cooler. This cooler is composed of a looped tube and resonator. The energy conversions through the Stirling cycle are achieved by acoustically oscillating fluid in two regenerators located in the looped tube. In one of the regenerators, axial heat flow is converted into acoustic power flow, and in the other, heat pump effects are induced by the generated acoustic power flow. The lowest temperature of-26℃ was obtained when input power was 850 W. This type of cooler works without any moving parts like pistons. Therefore the cooler is potentially a powerful tool for application to generate refrigeration.
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Koichi ARAGA, Minoru KANNO, Keiji MURATA
Article type: Article
Session ID: 1917
Published: September 04, 2004
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In surfactant solution (TTAB+NaSal), the pipe friction factor and heat transfer coefficients were investigated. The straight circular tube of D=5.05 mm in diameter and L=2900 mm in total length was used. In the drag reduction flow, in order to break micelle structures and to promote heat transfer, the "micelle breaker" was installed in the upper stream of the testsection. As a result of the experiments, in surfactant solution (lOOOppm), compared with the case of water, the friction factor decreased 74% in Re=21000, and NuPr^<-1/3> decreased 78%. However, installation of the micelle breaker increased NuPr^<-1/3> by 2.6 times compared with the case where it does not install. Although the effect of drag reduction disappeared by micelle breaker, it was mostly recovered in the measurement section.
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Koichi ARAGA, Minoru KANNO, Keiji MURATA
Article type: Article
Session ID: 1918
Published: September 04, 2004
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This paper presents an experimental investigation on flow and heat transfer characteristics of surfactant solution - air two-phase flow. Friction factors and heat transfer coefficients were measured in two-phase flow produced by injecting air into the in-tube flow of surfactant solution (TTAB+NaSa, lOOOppm). This test tube is 5.0mm in inner diameter, and 2800mm in total length. Fiction factors and heat transfer coefficients for surfactant solution - air two-phase flow were larger than those for single flow, but smaller than those for water - air two-phase flow. This seems to be due to drag reduction effects of micelle structure formed.
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Yoshiro MIYAZAKI
Article type: Article
Session ID: 1919
Published: September 04, 2004
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This paper describes an analytical study on operating characteristics of oscillating heat pipes. The study is based on the theory of self-excited oscillation that the pressure and the void fraction excite the other. It gives the wave velocity. In order to determine the frequency and the amplitude, two assumptions are introduced that the heat transport rate is proportional to the gradient of pressure oscillation and that the moved distance of oscillatory flow is around the half of a turn length. The amplitude and the frequency of pressure oscillation obtained by the analysis are compared with experimental results and good agreements are obtained.
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Shigeki HIRASAWA, Mitsuaki HANEDA, Satoshi HIRANO, Toshio TOMIMURA
Article type: Article
Session ID: 1920
Published: September 04, 2004
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Friction Stir Welding (FSW) is a new metal-joining process and the mixing of materials was investigated numerically by assuming materials to be many particles connected with springs. The particles near the pin or the shoulder at the advancing side are mixed well. When the temperature is low and plastic effect of the spring is week, void defects are found behind the advancing side. These results agree with experimental results. Using the calculation results of the material flow, the temperature distribution was numerically investigated. Results indicate that the temperature on the advancing side is higher than that on retreating side.
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Izuru SENAHA, Minoru YAGA, Kenyu OYAKAWA
Article type: Article
Session ID: 1921
Published: September 04, 2004
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In this report, the objective is to examine the structure of the longitudinal vortices and their influence on heat transfer in a pipe. The experiment was performed with four blade type vortex generator of various ratios as a high thermal performance type obtained by the previous study. The streamwise and circumferential heat transfer coefficients in a pipe were measured for air flow over a range of Reynolds number Re=1.8〜4.8×10^4. The interference phenomenon of the longitudinal vortices were visualized by means of smoke flow. From these experimental results, we make clear about the most suitable ratio of the vortex generators size to the pipe diameter.
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Hitoshi SUTO, Yasuo HATTORI
Article type: Article
Session ID: 1922
Published: September 04, 2004
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Large eddy simulation (LES) was performed for flow and heat transfer in a wavy wall channel. Low-Mach-number approximation was used to treat the effects of density variation. Smagorinsky model and mixed-time-scale (MTS) model were used as subgrid scale (SGS) model. Compared were mean value and fluctuating intensity of velocity in three kinds of grid systems Gl (64×65×64), G2 (64×51×64) and G3 (32×31×32), the grid dependency of simulation was sufficiently small in the finer resolution, Gl and G2. Discussion was also given to the effect of stable stratification, and the reduction in Froude number was found to greatly decrease the heat transfer rate on the ascending part of the wavy wall.
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Akihiro NAKANO, Satoru MOMOKI, Toru SHIGECHI
Article type: Article
Session ID: 2001
Published: September 04, 2004
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A numerical analysis was made on film boiling from a heated plate facing downwards immersed in saturated water at the atmospheric pressure, using the SOLA-VOF method modified for evaporation. The horizontal vapor film thickness at the edge of the heated plate was determined with reference to the analysis of Shigechi-Yamada and Nishio et al., and treated as constant. Also, the Nusselt number was examined in comparison with the semi-empirical equation based on the Nishio et al.'s correlation.
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Tadanobu UEDA, Masuo KAJI, Toru SAWAI, Takashi NOJIMA
Article type: Article
Session ID: 2002
Published: September 04, 2004
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Void fraction, frictional pressure loss and heat transfer coefficient were measured for vertical upward heated air-water two-phase flow in a 1.03mm I.D. stainless steel tube to investigate heat transfer and flow characteristics of two-phase flow in minichannel. Flow regimes were observed using high speed video camera. Void fraction was correlated with drift flux model better than Smith's correlation when α>0.7, but did not agree with both correlations when α<0.7. Frictional pressure losses agreed with Chisolm-Laird's equation at relatively large liquid Reynolds number. At low liquid Reynolds number, experimental results were close to Mishima-Hibiki's modified Chisolm-Laird's equation. Pressure loss was affected by flow regime at low liquid Reynolds number. Heat transfer coefficient fairly agreed with the results of ordinary inner diameter tube except for low liquid velocities.
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Jongdock PARK, Katsuya FUKUDA, Qiusheng LIU
Article type: Article
Session ID: 2003
Published: September 04, 2004
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The knowledge for saturated and subcooled pool boiling CHF mechanisms is becoming increasingly important as the fundamental database for the design such as the high heat flux cooling systems using subcooled liquid pool boiling, the thermal control system of microelectronic assemblies and so on. Steady-state and transient boiling heat transfer characteristics for highly wetting liquid due to an exponentially increasing heat input with time have been investigated. Steady-state and transient critical heat fluxes (CHFs) were measured by using a 1.0 mm-diameter horizontal cylinder in a pool of highly wetting liquid such as ethanol with periods ranging from about 10 ms to 20s for wide ranges of subcooling and pressure. The transient CHFs depending on the periods were divided into two principal groups: the first one was in long period and the CHF occurred with fully developed nucleate boiling heat transfer processes, and the second one was in short period with explosive boiling heat transfer processes from non-boiling and the direct transition to film boiling occurred. The CHFs increase with an increase in subcooling at test pressures and they are independent of pressures at high subcoolings.
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Shinya KATO, Ryuji YAMAKITA, Yojiro ISHINO, Norio OHIWA
Article type: Article
Session ID: 2004
Published: September 04, 2004
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In order to burn plastic-resin powder as an alternative fuel and to realize effective thermal recycling of recycled plastic-resin, it is necessary to elucidate fundamental characteristics of a plastic-resin particle subjected to abrupt heating. The abrupt heating method using the burnt gas as a heat source is employed in this study. High-speed microscopic observations of the physical and chemical processes of a plastic-resin particle after abrupt heating are made by combining a microscope with a high-speed CCD video camera. Heating and burning properties of a micro plastic-resin particle are discussed and compared with those estimated by a simplified spherically one-dimensional analysis.
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Yohei NOHARA, Shigeo KIMURA, Atsushi OKAJIMA, Takahiro KIWATA
Article type: Article
Session ID: 2005
Published: September 04, 2004
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Fundamental study on solidifying of aqueous binary solution in a rectangular box was carried out.The system is cooled from the upper boundary and heated from below. In this study, experiments were conducted for different initial concentrations and cooling temperatures using aqueous sodium nitrate solution. In the experiments, we measured convecting flows, solid layer thicknesses, temperature and concentration distributions. If the temperature difference between cooling temperature and freezing point is large, solid phase grew as a mushy layer. In the liquid region, the concentration is nearly uniform, resulting from vigorous convection. We also developed a one-dimensional model on solidification of aqueous binary solution when cooled from the top, accounting for vigorous convection in the liquid region.
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Masahiro KIHARA, Koji MIYAZAKI, Hiroshi TSUKAMOTO
Article type: Article
Session ID: 2006
Published: September 04, 2004
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In this paper we explore the radiative properties of photonic crystals structured by silica perticles. It could be fabricated by colloid process for large area. Silica particles formed ccp structure self-assembly. We measured the reflectivity of the sample by using an FT-IR microscope, and explored the properties of angular dependence, and discussed its radiative properties for using the control of heat radiation.
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Shin-ichi BABA, Shizuo SOUZAWA, Masatoshi YAMAJI, Masahiro ISHIHARA
Article type: Article
Session ID: 2007
Published: September 04, 2004
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This paper describes the neutron irradiation effects on dimensional change and thermal expansion rates for heat resistant ceramics, a carbon/carbon composite and SiC/SiC composite materials promising for nuclear engineering application. A series of irradiation tests was performed using the Japan Materials Testing Reactor (JMTR) with irradiation temperatures from 573 to 1173 K at fast neutron fluences from 1.8×10^<24> to 1.1×10^<25> m^<-2> (E>1MeV). In the post-irradiation examinations, measurements were made on (1)dimensional changes and (2)thermal expansions. Obtained results for the C/C and SiC/SiC composites were compared with other data in existing literatures in this paper.
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Masayuki Takeda, Shuichi Kajitani, Satoshi Hashimoto, Junko Kaneko, Ta ...
Article type: Article
Session ID: 2101
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The DME spray characteristic is a factor to control the engine performance. Then it is very important to know the temperature change of the fuel in the nozzle sac during fuel injection, because of the physical properties of DME are affected by the temperature and pressure extremely. And so, temperature survey in the nozzle sac carried out in order to know the condition of fuel during engine operation. As a result, DME injection was similar to the gas jet clarified. Then, split injection carried out in order to improve engine performance. As a result, In the case of two stage injection, the engine performance of DME operation exceeded compared with the engine performance of diesel fuel operation.
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Keisuke TORII, Shuichi KAJITANI, Masaki SHIWA, Masayuki TAKEDA
Article type: Article
Session ID: 2102
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In order to know the basic data of DME spray characteristics, the effect of injection pressure and injection nozzle diameter on the injection rate, spray angle and spray tip penetration distance and spray volume are examined. The former is measured by the use of Bosch injection rate measuring system, and later are analyzed by the use of constant volume vessel and schlieren method. Constant volume vessel was controlled by nitrogen gas. Result from spray visualization experiment, DME spray volume decreases, when the ambient pressure is heightened. It is cause decrease the specific volume by the ambient pressure increased. And, the effect of nozzle diameter and injection pressure to the spray angle decreases, when the ambient pressure is heightened.
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Kotaro Suzaki, Mituaki Ohtomo, Nozomu Kannno, Atsumu Tezaki
Article type: Article
Session ID: 2103
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Recent chemical kinetics study of CH_3OCH_2 + O_2 reaction with the direct detection of HO_2 suggested that the established dimethyl-ether (DME) oxidation model may be revised in terms of the rate constant and branching fractions in CH_2OCH_2O_2H decomposition reactions (reaction 4), where originally only OH + 2HCHO product channel has been considered. In this study, we simulated the combustion in an HCCI engine of DME fuel using the detailed oxidation model with and without revising the reaction 4. It was found that the reduction of k_4 promotes both of cool and hot ignitions, whereas including a pathway producing HO_2 decelerates the cool ignition but reduces the period between cool and hot ignitions, corresponding to the increase of cool ignition heat releases.
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Tomoya TSUJI, Kensuke SASAKI, Toshihiko HIAKI, Atsushi MOTOTANI, Hiros ...
Article type: Article
Session ID: 2104
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Using two apparatus developed in this study, P-V-T relation, at 350.00, 360.00, 370.00, 390.00, and 402.00 K, and vapor pressure, in the range from 238.31 to 397.67 K, were measured for dimethyl ether (DME). Based on corresponding state theory, the constants in Benedict-Webb-Rubin (BWR) equation of state were determined for DME. The calculation results showed good reproducibility for the experimental data of P-V-T relation and vapor pressure. Applying some thermodynamic relations, we predicted not only latent heat of vaporization, isobaric heat capacity, and speed of sound for pure DME but vapor-liquid equilibrium of the binary and ternary mixtures containing DME and light hydrocarbons.
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Masahito ASANO, Mitsuru KONNO, Shin-ichi GOTO
Article type: Article
Session ID: 2105
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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To calculate dimethyl ether (DME) spray characteristics, fuel properties in wide temperature range are needed. To evaluate the properties, the estimation methods for liquid density, vapor pressure, latent heat of vaporization, surface tension, enthalpy, liquid viscosity, thermal conductivity and specific heat, were examined for DME. COSTALD eq. (liquid density), Goldhammer-Gambil eq. (surface tension), Wagner eq. (vapor pressure), Pitzer eq. (latent heat of vaporization), integration of Rihani-Doraiswamy eq. (enthalpy) gave appropriate evaluation results, while sufficient evaluation methods were not found for thermal conductivity and specific heat. For liquid viscosity, an empirical equation was obtained.
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Ryuzaburo Nagata
Article type: Article
Session ID: 2106
Published: September 04, 2004
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Bio energy has gotten a lot of attention recently in addressing the problem of global warming and estabishing a recycling-based society. "Bio energy" means renewable biomass resources to produce an array of energy related products. The term "biomass" means any plant-derived and non-fossil-derived organic matter such as wood wastes and raw garbage. It is called "carbon neutral" and does not contribute to increase of carbon dioxide like fossil fuel resources. This report shows an example of simultaneous production of heat and power using a gas engine cogeneration unit with biogas obtained by methane fermertation of excretory substance in a livestock farm.
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Kiyoshi KAWASAKI, Kazutaka SONE, Koji YAMANE
Article type: Article
Session ID: 2107
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this study, the reaction condition to obtain the biodiesel with the best properties from a soybean oil and an ethanol was revealed. In addition, engine tests were carried out using the Dl-diesel engine equipped with the common-rail injection system fuelled by a soybean-oil ethyl ester;SEE, a soybean- oil methyl ester;SME and a JIS-2D fuel. Experimental results have shown that the engine performance and exhaust emissions of SEE are very similar to other tested fuels and SEE has the high potential for a diesel-fuel substitute.
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Yoshimitsu WADA, Yoshiaki KITTA, Akihiro YAMAGUCHI, Jiro SENDA, Hajime ...
Article type: Article
Session ID: 2108
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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We have proposed a conceptual research with fuel approach to develop understanding for potential use of fuels in terms of further improvement of thermal efficiency and exhaust emissions because they provide the significant effect on diesel engine performance. As a result, we could conclude that mixing of high volatile fuel into low volatile fuel has a possibility to control the spray and combustion processes. However, for instance, high volatility component has low ignitability, which leads to longer ignition delay, with regard to straight-chain alkane. Thus, understanding the ignition behavior of mixed fuel consisting of high and low ignitability fuels is of particular importance as ignition delay dominates the combustion process related to exhaust emissions and thermal efficiency. In this paper, an ignition experiment was conducted to investigate the ignition characteristics of mixed fuel. The experiment includes the measurement of pressure waveform and CH chemiluminescence, which indicates the onset of heat release, in order to discuss about ignition processes of mixed fuel. The results provided conclusions that the ignition of mixed fuel was initiated by high ignitability fuel and affected by volatility of high ignitability fuel.
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Jun HASHIMOTO, Hideki KIDO, Masanori FUKUDA
Article type: Article
Session ID: 2109
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this study, combustion characteristics and flame structures of low temperature flames of lean hydrogen mixtures were investigated by chemical kinetics computations. Mixtures having nearly the same laminar burning velocity were prepared by adding nitrogen to hydrogen-oxygen mixtures where the equivalence ratio was varied. The initial pressure was varied from 1 to 4 atm. As a result, it was clarified that low temperature reactions (R05-R06-R04) were dominative in these flames regardless of the initial pressure, however, there were differences in flame structures and combustion characteristics depending on the equivalence ratio.
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Katsuya SAIJYO, Takafumi KOJIMA, Kazuie NISHIWAKI
Article type: Article
Session ID: 2110
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A combustion process in an HCCI engine has been simulated using CFD code in conjunction with a 5-step global reaction model for hydrocarbon fuels. The Large Eddy Simulation (LES) was employed to describe turbulent transport. The calculations were performed for homogeneous and heterogeneous mixtures of EGR gas and fuel-air mixture. From the calculation results of combustion process, it is found that the heat release rate for the heterogeneous case is more moderate than that for the homogeneous case.
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Kentaro GOTO, Akira IIJIMA, Koji YOSHIDA, Hideo SHOJI
Article type: Article
Session ID: 2111
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Homogeneous Charge Compression Ignition (HCCI) combustion has attracted considerable interest in recent years as a new combustion concept for internal combustion engines. On the other hand, two combustion concepts proposed for two-cycle spark-ignition (SI) engines are Active Thermo-Atmosphere Combustion (ATAC) and Activated Radical (AR) combustion. The authors undertook this study to examine the similarities and differences between HCCI combustion and ATAC (AR) combustion. Differences in the low-temperature oxidation reaction behavior between these two combustion processes were made clear using one test engine.
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Tomiyuki Sasaki, Youichi Kawaguchi, Masaru Ogura
Article type: Article
Session ID: 2112
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Premixed compression ignition is considered to be effective for the simultaneous reduction of soot and NOx emissions. However, it is a problem for control of ignition timing to be difficult. In this study, the variable valve timing mechanism (VVT) for the compression ignition timing control was applied to DI diesel engine. The compression ignition was carried out by temperature control in cylinder by using VVT. And, engine performance and exhaust emission were investigated about the influence of the valve timing and the fuel injection timing. As a result, it was proved that the control of ignition timing is possible by controlling early exhaust valve closing timing. Premixed compression ignition combustion at low load is possible by early exhaust valve closing timing. Also, NOx and soot were remarkably decreased by early fuel injection without increase of fuel consumption.
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Youich Kawaguchi, Tomiyuki Sasaki, Masaru Ogura
Article type: Article
Session ID: 2113
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper is described about the influence of the early exhaust valve closing timing to the performance of premixed compression ignition gasoline engine and its combustion by using VVT. In case of early injection timing, the combustion becomes slow as much as lean air fuel ratio, and the expansion work increases, and thermal efficiency improves. Moreover, rapid combustion was shown in rich air fuel ratio, and thermal efficiency decreased as a result of the decrease of indicated mean effective pressure. In case of delay fuel injection timing, thermal efficiency decreases in lean air fuel ratio, and improves in rich.
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Masatoshi SUZUKI, Satoshi IIJIMA, Yasuo MORIYOSHI, Masaki SANO
Article type: Article
Session ID: 2114
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In reciprocating internal combustion engines, the piston stops in a moment at top dead center, so there exists a necessary time to proceed combustion. However more slowing piston motion around top dead center, does it have a possibility to increase cylinder pressure and may lead to an increase of degree of constant volume? In order to verify this idea, the engine with slower piston motion by active piston control was tested. It was revealed that the increased heat loss cancelled out all other favorable features such as lower pumping loss and increase in degree of constant volume.
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Yasuo MORIYOSHI, Masaki SANO, Masatoshi SUZUKI, Satoshi IIJIMA
Article type: Article
Session ID: 2115
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A test engine which has longer expansion stroke than compression stroke and enables a slow piston-movement during combustion period was built. The experimental data indicated an increase in degree of constant volume, but did not show an increase in thermal efficiency. In order to clarify this reason, numerical simulations are conducted in this paper. As a result, the gain due to the increase in degree of constant volume caused by piston-motion during combustion was found not exceeding the loss by increased heat loss. Numerical analysis deduced that increasing the piston-movement near TDC rather achieves an improvement of thermal efficiency in case that a rapid combustion was realized.
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Daisuke YAMASHITA, Soonpyo KWEON, Norimasa IIDA
Article type: Article
Session ID: 2116
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Homogeneous Charge Compression Ignition (HCCI) engine is regarded as next generation engine in terms of high thermal efficiency and low emissions. However, it has some problems such as difficulty of controlling auto-ignition timing, knocking,and unburned gas. In this study, Methane which is high ignition temperature and DME which is low ignition temperature are applied to fuels, and the method of using Methane/DME mixing fuel is suggested to control auto-ignition timing. In addition, the effect of mixing proportion of Methane/DME on auto-ignition timing, auto-ignition temperature, and IMEP is searched.
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