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Published: September 12, 2009
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Article type: Appendix
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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-A4
Published: September 12, 2009
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Yasuki KANSHA, Akira KISHIMOTO, Atsushi TSUTSUMI, Tsuguhiko NAKAGAWA
Article type: Article
Session ID: G0601-1-1
Published: September 12, 2009
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An innovative cryogenic air separation based on self-heat recuperation to reduce the energy consumption is proposed. In the proposed process, the heat of process streams is recuperated and exchanged with the process streams themselves by using the self-heat recuperation technology. As a result, not only latent heat but also sensible heat of the process stream are circulated in the process and the pressure of the column can be decreased compared with the high pressure part of the conventional cryogenic air separation in which high and low pressure columns are combined to exchange nitrogen latent heat with oxygen latent heat. Thus, the energy input of the main compressor which is located in front of the column can be drastically reduced. The simulation result demonstrates that the energy consumption for the proposed cryogenic air separation based on self-heat recuperation is more than 36% decreased as compared with the conventional cryogenic air separation.
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Norihide ISHIZAWA, Makoto TAGO, Masahiro SUGAWARA
Article type: Article
Session ID: G0601-1-3
Published: September 12, 2009
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In the past, a lot of studies in terms of phase change phenomenon of water in a rectangular cavity, a circular tube, and around a circular tube have been carried out by experiments and numerical calculations. The present study proposes a numerical calculation method based on both finite volume and temperature recovery methods for the solution of freezing and melting behavior of water. In this paper, the numerical result computed by the numerical calculation method has been compared with experimental results by other researchers in order to verify the validity of the numerical calculation method. As a result, numerical calculation results for both the shape of ice formation and streamlines in unfrozen water were in good agreement with the experimental ones previously obtained by other researchers.
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Naoki ONO, Yuta OTSUBO
Article type: Article
Session ID: G0601-1-4
Published: September 12, 2009
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In late years heat generation per a unit area of electronic devices such as CPU's increases, and efficient cooling technology has been required. In this study the authors investigated combination of impinging flow cooling and boiling heat transfer cooling inside mini channels. The impinging flow was realized by making T-junction structure with polyetheretherketone (PEEK). The authors performed observation of boiling bubbles inside mini channel and compared heat transfer characteristic for simple parallel flow channel and impinging flow channel. The flow channel has a square cross section, and one side of the channel was 3.0 mm in width. Transparent glasses were installed for flow and bubble observation. It was found from the experimental results that the impinging flow of T-junction showed different behavior about separation of boiling bubbles and gave higher cooling ability and lower thermal resistance.
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Katsuhiro KODANI, Hiroyasu OHTAKE, Yasuo KOIZUMI
Article type: Article
Session ID: G0601-1-5
Published: September 12, 2009
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Boiling heat transfer and enhancement of critical heat flux (CHF) of high-liquid-subcooling and high velocity water flow in a shorter and circular tube were investigated experimentally. The experiments were conducted in a range of velocity of water flow of 0.95m/s to 9.7 m/s and liquid subcooling of 20K to 50K. A test heater was made of thick copper block with 5mm internal diameter and 120 mm external diameter. The length of heater was 20mm : L/D was 4. The present experimental results showed that heat transfer coefficient and CHF increased as mass flux increased. The enhancement was caused by effect on shorter L/D, i.e., thermal entrance region effect. The enhancement of critical heat flux up to 10MW/m^2 was achieved in the present experiments. The boiling heat transfer characteristic was compared with Chen's correlation for conventional channel.
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Hirofumi YAMAUCHI, Yoshikazu TERAOKA, Koji MATSUMOTO
Article type: Article
Session ID: G0601-1-6
Published: September 12, 2009
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This study is focused on a W/O type emulsion with 70 % water contents for ice slurry formation of ice storage system. The emulsion was made from an oil-water mixture with a little amino group modified silicone oil additive. Ice slurry could be formed by cooling the emulsion without ice adhesion to a cooling wall because of the emulsion's structural feature. However, it was found that propagation of supercooling dissolution of the emulsion hardly occurred. In this study, the AC voltage was applied to the emulsion to promote propagation of its supercooling dissolution without ice nucleus charging. And then, influences of the magnitudes of applied AC voltage and frequency on the propagation rate of supercooling dissolution were clarified.
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Masato NISHIZAKI, Shokichi HANADA, Makoto TAGO, Atushi SASAKI
Article type: Article
Session ID: G0601-2-1
Published: September 12, 2009
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In this study, we devised a downhole heat exchanger with multi-pipes of a new type unlike the conventional method, and we considered the heat extraction performance of this method by numerical calculation. We found that the heat extraction rate increases although the temperature of the flowing heat extraction media in the heat exchanger falls with increasing gross flow rate of heat extraction media. In addition, the heat extraction rate of the heat exchanger with multi-pipes is larger than the heat extraction rate of a triple u-tube heat exchanger.
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Keigo SANO, Makoto TAGO, Kouji MORITA, Masahiro SUGAWARA
Article type: Article
Session ID: G0601-2-2
Published: September 12, 2009
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Various heat exchangers are used to harness geothermal energy that is renewable energy. A coaxial heat exchanger is one of them, and it is composed of an inner pipe and an outer pipe. In the case where multiple heat exchangers are buried in stratum, heat transfer phenomenon must be analyzed in three-dimensions by the influence of heat extraction. In the present study, the heat transfer characteristics when three heat exchangers are buried, and the temperature change of the stratum around the coaxial heat exchangers are measured by numerical simulation.
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Keita IZUMI, Shuichi TORII, Yasushi KOITO, Toshio TOMIMURA
Article type: Article
Session ID: G0601-2-3
Published: September 12, 2009
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In this study, the single plate model of the plate heat exchanger is made and the performance of the plate in the presence of the blocks of the separate herringbone plate and plover pattern plate is examined. The aim of the present study is to consider the effect of the plate shape and pitch of the blocks on the overall heat transfer coefficient and frictional pressure drop and to obtain the optimum one. The overall heat transfer coefficient and frictional pressure drop were obtained by measuring temperature and pressure drop between inlet and outlet of the channel, respectively. The results of the separate herringbone plate and plover pattern plate were compared with the herringbone and flat plate.
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Kotaro MATSUMOTO, Naotake HIRAO, Makoto KOMURA
Article type: Article
Session ID: G0601-2-4
Published: September 12, 2009
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A new heat exchanger for Stirling engine has been proposed. It was already examined in terms of its specific power under actual load. Here, other basic performances are evaluated so as to verify the data and to make a further progress. Pressure drop between inlet and outlet is measured experimentally. Temperature differences between inlet and outlet during constant volume heating are also discussed. And a series of results is discussed qualitatively.
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Tomohiro YAMAGUCHI, Kouhei KASAI, Hiroshi YAMAZAKI, Hiroshi NOMURA, Ya ...
Article type: Article
Session ID: G0601-2-5
Published: September 12, 2009
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Experimental researches have been conducted to improve the regeneration performance of regenerator of the α type Stirling engine. The attention was mainly paid to the pressure losses and actual heat transfer, which have effects on the performance of Stirling engine operations. On the report, we use two type different mesh in wire net and experimentally found characteristics of flow and heat transfer, inhibiting fluid leak between inside wall of regenerator and outer circumference of the wire nets.
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Yuta ABE, Hidehiko NODA
Article type: Article
Session ID: G0601-3-1
Published: September 12, 2009
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The heat pipe can transfer the heat only from the lower position to the upper position in the gravitational field. The natural cold heat storage system is developed by making use of the characteristics of the heat pipes. The experiments have been conducted in the field, paying attention to the effect of the amount of the working fluid in the heat pipe on the figure of the manufactured ice surrounding the heat pipe. It is cleared that the heat pipe can manufacture the ice cylindrically, but excessive working fluid obstructs the ice generation.
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Niro NAGAI, Kensuke SUZUKI, Yoshitaka MAEKAWA, Yoshikazu MAEGAWA
Article type: Article
Session ID: G0601-3-2
Published: September 12, 2009
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This research aims to develop snow melting system around water tank for fire-protection by using heat pipe. Water in a water tank installed underground is heated by underground heat source, 10〜15 ℃. Heat is transported from water to snow melting panel by heat pipes, which melts snow. The experimental results obtained for two years show that this system can melt the snow around the steel lid in winter season preferably. The numerical simulation using only weather data was found to predict temperature variations of the whole system with good agreements to the experimental data. Therefore, this simulation software can be used for designing this snow-melting system.
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Fumiyoshi KIMURA, Masashi KUROTANI, Kenzo KITAMURA
Article type: Article
Session ID: G0601-3-3
Published: September 12, 2009
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Experimental investigation has been carried out on natural convection of water induced around heated, horizontal square cylinders. Main concerns were the flow and heat transfer characteristics of high-Rayleigh number flows. The flows around the square cylinder and the surface temperatures were visualized with dye and liquid crystal thermometry, respectively. The results showed that the ascending flows along the vertical side surface begin to separate three-dimensionally from the upper surface of the square cylinder when the modified Rayleigh numbers, Ra^*_d, exceed Ra^*_d =2×10^6. The local heat transfer coefficients were also measured. The results showed that the coefficients of the upper surface are increased, in particular, in the region behind the three-dimensional separation.
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Satoshi FUJITA, Noriyuki NAKAMURA, Hirochika TANIGAWA, Jiro FUNAKI, Ka ...
Article type: Article
Session ID: G0601-3-4
Published: September 12, 2009
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In this study, the authors numerically investigates the flow and thermal characteristics of the three-dimensional thermal convection in a cubic cavity heated below in the gravitational field, concerning about spatially-averaged kinetic energy, Nusselt number and flow structure. The authors assume incompressible fluid with a Prandtl number Pr = 7.1 (water) and a Rayleigh number Ra = 0 -- 3.0×10^5 . In addition, the authors investigate the relationship between the Rayleigh number and the vibrational frequency about the oscillatory thermal convection caused at the high Rayleigh number. The obtained results are as follows. The values of the kinetic energy and the Nusselt number decrease at the boundary of the steady thermal convection and the oscillatory thermal convection. Also, the increasing rates of the kinetic energy and the Nusselt number to Ra show different features.
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Hisanobu KAWASHIMA, Kyohei YAMAZAKI, Tetsuya OKAMOTO, Tsuneaki ISHIMA
Article type: Article
Session ID: G0601-3-5
Published: September 12, 2009
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A perpendicular heating board with staggered circular holes was used to investigate the characteristics of the forced convection heat transfer. The multi-thermocouple was used to measure the temperature distributions in the thermal boundary layer along the wall in order to estimate the local heat transfer coefficient. The validity of the temperature measurement technique was confirmed by comparing under the condition of the natural convection with the theoretical result. The local heat transfer coefficients on the multi-holes board increased, and then heat transfer becomes like as in turbulence flow because the holes caused the turbulence when the fluid passed over the holes.
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Yuta EGAWA, Kenishiro TAKEISHI, Tsuyoshi KITAMURA
Article type: Article
Session ID: G0601-3-6
Published: September 12, 2009
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This paper describes new experimental data of film cooling performance with swirling coolant flow taken in a steady turbulent flow in a low-speed wind tunnel. The film cooling effectiveness distribution on the wall was measured by pressure sensitive paint (PSP) technique, and above the wall was measured by K-type thermocouples. The experiment was conducted about a circular cooling hole and a shaped cooling hole. For a circular cooling hole, the coolant jet penetration is inhibited by swirl. And the coolant jet slant in the lateral direction, but film cooling effectiveness distribution on the wall behind a cooling hole is higher value over a wide range. Additionally, kidney shape of the temperature contour was disappeared. For a shaped cooling hole, coolant diffuse at the downstream. Thus, lateral averaged effectiveness at the downstream indicated 50% higher than non-swirling case.
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Shin-ya OBARA
Article type: Article
Session ID: G0601-4-1
Published: September 12, 2009
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Masatake ONODERA, Takahiro OHMURA
Article type: Article
Session ID: G0601-4-2
Published: September 12, 2009
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In order to investigate the radiation heat characteristics of thermal insulations, we have developed a new apparatus to measure the diffusive reflectance and transmittance at a temperature range from room temperature to 1000 ℃ in the wavelength range from 1.28 to 25 pm. In this study, the diffusive transmittances of thermal insulation (Alumina-silica blanket) were measured. Those diffusive transmittances were less 1% without vertical transmission angle. Furthermore, the attenuation coefficient to the surface density was obtained by using the hemispherical transmittance calculated from the diffusive transmittance in the wavelength range from 2 to 10 μm. Alumina-silica blanket has two attenuation coefficients; one is about 40.3 m^2/kg in the surface density range below 0.05 kg/m^2, the other is about 14.2 m^2/kg in the surface density range above 0.05 kg/m^2.
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Masanori MONDE, Yuhichi Mitsutake, Masataka Kosaka
Article type: Article
Session ID: G0601-4-3
Published: September 12, 2009
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A previous procedure to measure thermal diffusivity and thermal conductivity simultaneously using an inverse solution for one-dimensional unsteady heat conduction can be simplified by improving the inverse solution and then clearing the issue left in previous one. The new procedure does not need any time when the temperature change starts at a sensor position and can simply choose a time duration during which the measured temperature change becomes larger than the required accurate temperature change. The measurement is usually completed within 3 minutes until the temperature rise at the thermocouple position reaches a certain temperature level which makes its error level reduce lower than one percent. This method has merit being independent of surface condition except for the requirement of two or three sensing positions in the material. The accuracy of the estimated values is also similar to the error level of sensor at the position.
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Masashi NODA, Hidehiko NODA, Susumu TAKAHASHI
Article type: Article
Session ID: G0601-4-4
Published: September 12, 2009
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A conventional absorption refrigerator uses H_2O-LiBr as an absorption solution. It needs a heat source with a temperature of around 110℃ or more for driving energy. Furthermore, it is difficult to manufacture the brine under the freezing point of water, since the refrigerant is water. The new absorption refrigerator which can manufacture the cold heat below zero degree C and can be driven by the heat source of the temperature below the boiling temperature of water is developed by using H_2O-LiBr-1,4-dioxane as the working fliud. This paper describes the properties of the new working fluid which are needed to design the new cycle of the absorption refrigerator.
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Yoshiro TOCHITANI, Kuniaki NAKANO
Article type: Article
Session ID: G0601-4-5
Published: September 12, 2009
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On the water/silicone oil interface that becomes unstable by applying electric field, bridging phenomena caused by water column in the oil is studied experimentally. The phenomena are photographed by use of a high speed video camera, and observed in detail. As a result, it is shown that the water droplets dispersed in the oil plays an important role for the bridge formation and hold-up of the water droplets in oil is caused by the difference between rise and fall velocities of the droplets.
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Shigeki HIRASAWA, Harsha BADARINARAYAN, Kazutaka OKAMOTO, Toshio TOMIM ...
Article type: Article
Session ID: G0601-4-6
Published: September 12, 2009
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We analyzed temperature distribution and plastic deformation flow during friction stir spot welding (FSSW) process with the elastic-plastic deformation model using the particle method. Calculation results indicate that temperature distribution is axisymmetric and the temperature below the rotation tool is 300 ℃ at 0.7 s when the diameter of the tool is 8 mm and the rotation speed is 2500 rpm. Plastic flow is upward near the outside of the pin of the rotation tool. Then the flow is downward below the shoulder of the tool. And the flow is upward at the outside of the shoulder to cause a burr. Mixing of the metal below the concave shoulder is strong.
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Y. Aoyama, Hidetugu Yagi, Kazuo Ono, Masahumi Jinno, Hideki Motomura
Article type: Article
Session ID: G0601-5-1
Published: September 12, 2009
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Restricted gas region close to substrate is strongly heated by plasma, which is generated in open-air by microwave excitation through coaxial-cable plasma torch. The torch is constructed with thin central electrode-column which is surrounded by outer cylindrical metal tube, that is coaxial-cable, and the tip does not poke, or slightly does, out of the cross section of the end of outer cylinder. Heated plasma-spot emerges in the clearance between the tip of electrode and substrate which is placed in parallel close to the end cross section of torch. Temperature change is measured in the reverse of substrate, the other surface of which is heated by plasma.
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Naomi MATSUMOTO, Takashi USAMI, Takeo YAMAMOTO, Masaya SUGIMOTO, Seiji ...
Article type: Article
Session ID: G0601-5-2
Published: September 12, 2009
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The variation of heat flux from the arc with magnetic flux density was theoretically considered under the DC magnetic field imposed perpendicularly to the arc. To simplify the theoretical model, two-dimensional heat flow was transformed into one-dimensional heat flow. Experiment was carried out to measure the heat flux distribution using a specially designed calorimeter. The comparison of experimental result with theoretical predictions confirmed the validity of the assumptions used in the theoretical model.
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Shinfuku NOMURA, Masanao KAGEURA, Hiromichi TOYOTA, Shinobu MUKASA
Article type: Article
Session ID: G0601-5-3
Published: September 12, 2009
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In-liquid plasma has been expected as an advanced technology of generating plasma in a liquid by a high frequency(HF) or a microwave(MW) irradiation. In this study, 27.12MHz HF plasma is generated in pure water as well as in air. The phase difference of voltage and current waveforms before and after plasma ignition, and the self-bias voltage are investigated by using an oscilloscope. The electrical property of plasma as an equivalent circuit can be explained from the difference of the phase difference qualitatively. The self-bias voltage became positive with pressure increase when the electrode made of a tungsten rod is used. As pressure increases, the electron supply into the plasma changes from a secondary electron discharge to thermionic emission.
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Shinobu MUKASA, Shunichi FUJITA, Shinfuku NOMURA, Hiromichi TOYOTA, Fu ...
Article type: Article
Session ID: G0601-5-4
Published: September 12, 2009
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Since in-liquid plasma can be used in a liquid as a chemical reactor, it has an advantage in a treatment technology of a waste liquid and fuel gas production. The purpose of this research is to examine the basic characteristic of in-liquid plasma. In this research, a spectroscope is used for measuring the emission spectra of the in-liquid plasma. In-liquid plasma is generated by applying high-frequency (HF) irradiation of 27.12MHz into a pure water. As for the distribution of the emission intensities, of the emission intensities H and 0 are high in the vicinity of the plasma, where that of OH becomes high in the upper area of the plasma. Electron temperature has a distribution, and becomes the highest at the center of the plasma at 10kPa. The change of the electron temperature in the vertical direction is bigger than that in the horizontal direction. The electron temperature decreases with pressure increases.
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Minoru SUZUKI
Article type: Article
Session ID: G0601-5-6
Published: September 12, 2009
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The imploding detonation of a propane-oxygen mixture was applied to generate underwater shock wave in a water pipe of 60mm inner diameter. We investigated imploding detonation waves in an approximately cone-shaped combustion chamber having a maximum inner diameter of 400 mm. The experimental results show that maximum pressure at the water pipe exit was 690 times higher than the initial gas pressure. We found that we could generate the water pressure more than 500MPa in a pipe repeatedly.
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[in Japanese], [in Japanese]
Article type: Article
Session ID: G0601-6-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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In an attempt to investigate the combustion enhancement effects of hydrogen addition on burning of ethanol spray, we observed the combustion characteristics of ethanol spray in hydrogen-air mixtures using a constant volume combustion vessel. The hydrogen volume fraction of 0 - 10% were tested with varying the initial pressure in the range of 0.1 - 0.5 MPa. The peak overpressures and the positive impulses increase with increasing the hydrogen volume fraction, and the pressure profiles become more stable. Also, it was found that the lag between the ignition time and the overpressure peak tend to increase up to a maximum value with increasing the hydrogen volume fraction due to increase of the amount of burnt ethanol, and then decrease. In case of the hydrogen volume fraction of 10 %, the combustion characteristics are almost the same as those of the hydrogen-air mixture. These results imply that appropriate hydrogen addition should be needed for the use of hydrogen as an auxiliary fuel.
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Takamitsu YOSHIMOTO, Tomohisa KAGEYAMA, Toshimi TAKAGI
Article type: Article
Session ID: G0601-6-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The characteristics and stability of the hydrogen diffusion flame have been investigated as for a clean energy in the future. The objective of the present study is to get further understanding lifting/blow-off of the hydrogen diffusion flame and present clearer understandings of the processes for flame holding. The species of the fuels are the pure hydrogen and the dilute hydrogen which is formed with putting nitrogen gas into the fuel of hydrogen. The parameters of the experiment are selected as fuel velocity, co-flowing air velocity, equivalent ratio, nozzle inner diameter, concentration of the fuel and so on. The stability limit and flame behaviors are investigated with increasing the spout fuel velocity or the co-flowing air velocity. The inside temperatures of the flame are measured for researching the structure of the flame.
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Kimitake KUDO, Hiroyuki TORIKAI, Akihiko ITO
Article type: Article
Session ID: G0601-6-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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A vortex ring is easily produced by pushing fluid through a circular orifice. If the vortex ring interacts with a diffusion flame, a local extinction occurs. In order to use a vortex ring for fire fighting, we have investigated the characteristics of the air vortex ring extinguishment of a methane-air jet diffusion flame. From the blowout experiments, we calculated probability of the vortex ring blowout and measured displacement speed of the vortex ring. As a result, when the air vortex ring impacts with the flame base zone of the jet diffusion flame at the displacement speed enough to generate a local extinction, the whole flame can be extinguished.
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Takumi METOKI, Hiroyuki TORIKAI, Akihiko ITO
Article type: Article
Session ID: G0601-6-4
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Basically, the filling gas in a soap bubble dose not diffuse into the surrounding air, and the soap bubble can keep the filling gas concentration constant until its bursting. If the soap bubble is filled with an extinguishing gas, it can be used as a fire extinguishing ball. In order to clarify the extinguishment characteristics and mechanisms, we have performed blowout experiments of a methane-air jet diffusion flame by using the nitrogen-filled soap bubble and visualized the blowout processes by schlieren method. As a result, when the nitrogen-filled soap bubble contacts at the thermal boundary of the flame base of the jet diffusion flame, the soap liquid film ruptures and the extinguishing gas is supplied to the flame. Then the local extinction occurs at the flame base, and the rest flame lifts off. Finally, the whole flame is blown out.
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Daichi NISHIOKA, Mariko NAKAMURA, Jun HAYASHI, Fumiteru AKAMATSU
Article type: Article
Session ID: G0601-6-5
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Coaxial jet spray flames of kerosene and oxygen are studied experimentally in the pressure range 0.1-1.0 MPa. The flame temperature is measured by a two color method. The soot production region and soot volume fraction are measured by laser induced incandescence (LII). The results of the temperature measurements show high temperature regions near the burner. The flame temperature decreases drastically along the central axis and a minimum temperature point appears. This point moves upstream with an increase in ambient pressure, because fuel spray penetration reduces and vaporization of droplets occurs further upstream. The LII measurements show that soot concentration decreases around the central axis up to 0.5 MPa and increases above 0.7 MPa. This is because the fuel vapor concentration distributions change with an increase in ambient pressure due to the change in droplet dispersion. These results show that the behavior of droplets changes as pressure increases and affects flame structure and soot production.
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Odi Akhyarsi, Mohamad Farid, Susumu Noda
Article type: Article
Session ID: G0601-6-6
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The characteristics of flame appearance, temperature profile, and NO_x emission resulting from gaseous and liquid fuels furnace combustion are investigated through a series of experiments. Numerical simulations are also conducted, for several cases, to support the experimental data. Three fuels are examined; hydrogen, propane, and a liquid fuel Jet-A (C_<12>H_<23>). The combustion is generated in two 840-mm long furnaces with diameters of 95 mm and 182 mm, respectively. Combustion air is introduced into the furnace through two coaxial air nozzles, which generate air velocity differences ΔUa. The flame appearance, temperature profile, and emission index of NO_x (EINO_x) are found to depend strongly on the furnace diameter D. This result implies that the furnace volume can characterize gaseous and liquid fuels combustion. The temperature measurements reveal that larger values of D and ΔUa lead to lower temperatures at the flame and post-flame regions. It is also found that the EINO_x can be scaled with a parameter DU_f ΔUa well. The normalized EINO_x is inversely proportional to the parameter, being attributable to the effects of dilution and flame stretch.
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Kazui FUKUMOTO, Yoshifumi OGAMI
Article type: Article
Session ID: G0601-7-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The aim of our research is to build a model which can evaluate the amount of combustion products by using the chemical equilibrium method with a few chemical reactions. This paper presents the combustion model based on chemical equilibrium combined with an eddy dissipation concept model (CE-EDC); the model is validated by simulating a CH_4-air turbulent diffusion flame. The obtained results were compared with Sandia Flame D. An advantage of the CE-EDC model is that any combustion products are obtained without using detailed chemical mechanisms. The results obtained by the CE-EDC model are in good agreement with the reference data. With the combustion model built in this paper, the combustion products can be calculated without detail chemical mechanisms, and the accuracy of present model is in the same order of the EDC model.
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Muneaki Inagaki, Ken-ichi Miyata, Yo-ichiro Koike, Makoto Takahashi, J ...
Article type: Article
Session ID: G0601-7-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Effects of asymmetric and radial multi jets on the combustion and heat transfer characteristics in a divided chamber combustor are examined by measuring pressure histories and visualizing flow patterns in the main chamber. Diameter and arrangement of 40 nozzles, uniformly equipped on a hemi-circular sub-chamber, are varied in the manner that multiple radial jets produce various types of flow patterns in the main chamber before the main chamber mixture ignites. To examine the combustion characteristics pressure histories in the combustor are measured, whereas visualization of model water flows induced by the asymmetric multi jets is made to obtain flow characteristics before ignition. Based on the results obtained, the interrelation between the flow pattern and the combustion and heat transfer properties are considered and some key factors will be examined to introduce intense asymmetric flow fields in the divided chamber combustor.
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Yosuke SUENAGA, Michio KITANO, Hideki YANAOKA
Article type: Article
Session ID: G0601-7-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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A micro-combustor that was able to form the cylindrical flames of a few millimeters in the diameter was designed and developed. A cylindrical premixed flame and diffusion flame are formed by supplying rich mixture and air. The extinction limits and the temperature in the combustion chamber were measured, and the heat loss ratio and the space heating rate were evaluated. The obtained results are summarized. (1) The temperature in the combustion chamber exceeds adiabatic flame temperature corresponding to the equivalence ratio, φ_<all>, evaluated from all supplied fuel and air. (2)Even thoughφ_<all> is lower than lean flammability limits, the flame can be formed. (3)The heat loss ratio decreases as the combustion intensity increases. However, the heat loss ratio increases when equivalence ratio of rich mixture exceeds a certain value.
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Shin-ichi INAGE, Kazuki ABE, Tomoya MUROTA
Article type: Article
Session ID: G0601-7-4
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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This paper proposes a unified model that includes preferential diffusion effect of hydrogen. As hydrogen has a larger diffusion coefficient than methane and oxygen, the mass fraction of hydrogen varies in a curved premixed flame. This phenomenon is well known as preferential diffusion effect of hydrogen. To simulate combustion phenomena of multi component fuel which includes large quantities of hydrogen accurately, preferential diffusion effect should be considered on the combustion model. On this paper, a simple model of the diffusion process of fuel in the premixed gas was evaluated analytically and results were applied to the author's combustion model. Results were compared with the experimental data by Kido and Nakahara and were in good agreement.
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Daisuke SHIMOKURI, Satoru ISHIZUKA, Kazuhiro ISHII, Hidemi TOH
Article type: Article
Session ID: G0601-7-5
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Recently, it was found that the high frequency oscillatory combustion occurred in large size (8 and 12-inch) tubular flame burners under some conditions, and which frequency is in accordance with tangential - radial coupled modes of natural frequency. In this paper, to research the oscillatory combustion in a tubular flame burner, pressure fluctuations in the 8-inch tubular flame burner have been determined at three different locations, at the injection slit, at the axial center of the burner, and at the near of the burner exit. Results showed that pressure fluctuations in the tubular flame burner propagate upstream injection slits, that is, premixture is subject to pressure fluctuation before ejected into the tubular flame burner. Results further indicated that amplitude of pressure fluctuation is the largest at the axial center position of tubular flame burner. Thus, high frequency oscillatory combustion can be considered to predominantly occur at the axial center position of the tubular flame burner.
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Takurou KURIHARA, Yasuo YAMAMOTO, Tomohiko FURUHATA, Masataka ARAI, Ma ...
Article type: Article
Session ID: G0601-7-6
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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In order to develop effective final treatment system of waste plastics, thermal gasification characteristics of plastics compounds containing flame retardant were investigated. Polypropylenes (PP) which contained Al(OH)_3 or (NH_4PO_3)_n as a flame retardant were decomposed and burned under constant temperature condition in an image furnace while changing O_2 concentration from 0% to 21%. Mass reduction during thermal decomposition was measured by an electric-micro balance. The gas components produced by the thermal decomposition and combustion process were analyzed with a gas analyzer. It was found that HC concentration for PP was the highest at 10% oxygen concentration when the ambient temperature Τ_a was 1073K. CO_2 concentration for PP contained 20wt% Al(OH)_3 was higher than PP under 21% oxygen concentration.
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Hitoshi WAKAMATSU, Toshihiko MINE, Satoshi TADAKUMA
Article type: Article
Session ID: G0601-8-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Ash deposition characteristics in oxy-fuel combustion were investigated by using the portable device for monitoring ash deposition installed in the combustion test facility. The ash deposition tests and ash deposit analyses were conducted for two types of bituminous coal with different ash components. In comparison to air combustion tests, the result was obtained that the ash particle shape and size had no difference between oxy-fuel and air combustion. The distribution of metal element in ash for oxy-fuel combustion was almost same to air combustion. The results show that ash deposits properties in oxy-fuel combustion are equal to those in air combustion in bituminous coal firing.
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Toshiyuki TOMODA, Fumiteru AKAMATSU
Article type: Article
Session ID: G0601-8-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Combustion behavior of pulverized coal using blending coal has been observed with Pyroprobe. Produced gas emission behavior has been investigated by high-speed continuous analysis with FTIR. The following results are acquired. (1) Blending coal can improve combustion rate of coal inferior to of the combustion rate, and it changes depending on mixture rate. (2) Blending coal shows homogeneous combustion behavior such as the single coal. (3) Burnout time of blending coal is not proportional to the mixture ratio, and it tends to become longer. Furthermore, even if it is the same fuel ratio, burnout time of blending coal become longer than single coal.
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Toshio TOMIMURA, Yasushi KOITO, Shuichi TORII, Kenichi YANAGI, Takahar ...
Article type: Article
Session ID: G0601-8-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The void slab is one of the lightweight insulating concrete slabs in a novel building material. In the void slab, a lot of polystyrene foam blocks are placed between lattice truss beams. In this study, concerning such void slabs, a series of numerical calculations have been carried out to predict relation between the slab structure and measured results by the fire resistance tests. Based on a one-dimensional model, a transient temperature change in the void slab for a given specific condition is numerically calculated using a network method. From comparison between the calculated and measured results, the present simple simulation method is shown fairly effective to simulate the fire resistance test of the void slab.
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Yuta DAIROKUNO, Daiichi FUKUSHIMA, Motohiro OSHIMA, Masanori TERASAKA, ...
Article type: Article
Session ID: G0601-8-4
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Nanoparticles have novel characteristics by quantum size effect. To produce homogeneous particles size and high purity particles continuously, many nanoparticles production methods have been proposed. In this paper, novel nanoparticles synthesis technique is proposed. The technique is applied FS-CVD method to the flame synthesis. In this method, the liquid precursors are supplied directly to a vacuum chamber through an injector and vaporized by flash boiling. So, the characteristics of nanoparticles are controlled by the atmosphere condition and the burner flame characteristics in this method. However, the burner flame characteristics are not examined at the low pressure ambient condition. In this experiment, the formation range of the burner flame and the flame characteristics by changing equivalent ratio and supply flux was examined.
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Satoshi TADAKUMA, Toshihiko MINE, Hitoshi WAKAMATU
Article type: Article
Session ID: G0601-8-5
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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As the flue gas composition in oxy-fuel combustion is mainly CO_2, the correct gas emissivity data are needed to design oxy-fuel combustion furnace. Therefore the gas emissivity has been measured in the complete combustion area from AAP (After air port) using oxy-fuel combustion test furnace. In the case of LPG combustion, ratio of oxy-fuel combustion to air combustion for gas emissivity without ash was 2.4, and this value was almost same to the value calculated by the existing engineering theory. In the case of coal combustion, ratio of oxy-fuel to air for gas emissivity with ash particles was 1.6, and the absorption coefficient of particulate layers of oxy-fuel was almost same to that of air.
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Yuzuru NADA, Shou MIZOGUCHI, Susumu NODA
Article type: Article
Session ID: G0601-8-6
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The effect of heat loss on the flammability limit is investigated in a liquid fuel HiTAC. Mixtures of air and N_2 are used as oxidizers. Preheated temperatures of the oxidizers are up to 1023K. The fuel is kerosene. Cooling tubes are installed inside the furnace to investigate the effect of heat loss. Heat losses removed through the cooling tubes are up to 2.3kW. The flammability limit is determined on the basis of the CO concentration which is measured at the exit of furnace. The increase in heat loss shifts the flammability limit to higher preheated temperature and O_2 concentration conditions. The flammability limits occurred in the different heat loss conditions are evaluated on the basis of the flamelet model. The evaluated flammability limits are in good agreement with the experimental results.
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