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Takafumi SASAKI, Jun-ichi IKEDA, Kazushige KIKUTA, Yukio HISHINUMA, Ta ...
Article type: Article
Session ID: K-1814
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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In the heat treatment of silicon wafer, temperature control of the wafer surface is very important. This paper investigates the rapid radiative heating characteristics of the silicon wafers arranged in a row in the vertical heating furnace by the experiment and the numerical simulation. In present test, a wafer pitch was changed from 54 mm to 216 mm. The results showed that the maximum difference of surface temperature decreased with increase of a pitch of the silicon wafer. The maximum temperature difference was about 5℃, when a wafer pitch was 108mm and ramp-up ratio was 150℃/min. Simulation and experimental result agreed very well.
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Katsufumi UCHIYAMA, Fumi TAKAHATA, Nao KOBAYASHI, Masanobu UJIHIRA, Mi ...
Article type: Article
Session ID: K-1815
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Internal temperature equalization of cortical bone and cancellous bone by microwave irradiation were investigated. Equality of heating velocity and internal temperature in femoral head of bovine and diaphysis of bovine femur was measured, and experimental model to control temperature and time by microwave irradiation was determined. Insert head of optical fiber thermometer into the hole of bovine's bone (femur diaphysis and femoral head). And measured temperature after heated in microwave oven. As bone was heated from inside by using microwave irradiation, the bone was heated more rapidly and faster than regular thermal process method. Moreover, humidifying the surface of bone resulted temperature of entire bone to keep close temperature of inside of bovine's bone (femur diaphysis and femoral head). Results show that the thermal processing method using microwave irradiation seems to be effective for disinfections if equality of temperature is improved further.
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Hiroyuki YAMAMOTO, Takashi YOSHIDA, Toshihiko IKEDA, Masaharu MATSUBAR ...
Article type: Article
Session ID: K-1816
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The duct with a sharp 180-degree turn is widely used for heat exchanger. We present numerical calculations of flow and thermal fields in two-dimensional duct with a sharp turn. The effects of the Reynolds number on the characteristics of the flow and heat transfer are studied. At Re=1200 the flow has steady solution, then at Re=1300 the flow becomes unsteady and the pressure loss decreases.
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Ken OGISO
Article type: Article
Session ID: K-1817
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Duality of heat conductor and heat insulator inherent in heat exchanger performance is considered from the view point of entropy generation rate. And, by defining the appropriate index number of entropy generation rate, it is clarified that the PARADOX, pointed out by A. Bejan, can be cleared.
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Masahumi KATSUTA, Sang-Chul BAE, Takahiro YABE, Shigeo ASAHI
Article type: Article
Session ID: K-1818
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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MH refrigeration system is a system which is applied energy conversion mechanism with hydrogenation reaction of metal hydride (MH) to the refrigeration. In this study, optimum operating condition of the system was verified through the measurement of basic characteristic value of MH through a trial manufacture of system demonstration equipment. Furthermore, the system was modeled with prameters such as heat source temperature and hydrogen filling quantity, to evaluate the system performance and operating conditions in simulation. From the result of demonstration equipment operating experiment and numerical calculation of the above, the guideline necessary for the optimum design of MH refrigeration system was achieved.
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Masaya NISHIWAKI, Masanori TAKEUCHI, Niro NAGAI, Shigenobu MIYAMOTO, H ...
Article type: Article
Session ID: K-1819
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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This paper presents new snow-melting system using the geothermal and solar energy. Snow was melted by the geothermal energy collected by building piles with circulating water. The road concrete panels with circulating water collected solar energy and it was storied into the ground. It was found that solar energy was enough to melt the snow after a long period of continues operation.
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Takahiro NAKAYA, Yoshiro TOCHITANI
Article type: Article
Session ID: K-1820
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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For liquid-liquid direct-contact heat transfer with evaporation, a method for nucleation in a dispersed-phase drop is studied experimentally. The evaporation of the water drop in silicone oil stops during the evaporation, because the unvaporized water drop separates from the vapor bubble. In order to continue the evaporation, the nucleus must be supplied again. It is known that a charged-drop in oil with uniform electric field collides with an electrode plate by turns and exchange the charge, and shuttles between two electrode plates. If the nucleus can be supplied on the electrode plate, evaporation is initiated in the collision. The effectiveness of this method has been verified experimentally. It is clarified that the electrode plate surface scratched by an abrasive paper is effective for giving the nucleus. The effect of the degree of superheat of the silicone oil on relative frequency of initiation of evaporation is also shown.
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Tomoaki SATO, Masahiko YAMASHITA, Yoshinori TAKAISHI, Kosei OGUCHI
Article type: Article
Session ID: K-1821
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The concentration dependence of nucleate boiling heat transfer coefficients for HFC-134a and POE oil systems has experimentally been investigated. A horizontal Pt wire (φ 0.1mm) is used for higher ranges of heat flux between 0.02 and 0.3MW・m^<-2>, and a horizontal Nickel-Chromium rod (φ 1.0mm) is used for lower ranges of heat flux of 0.02 MW・m^<-2>. Heat transfer coefficients for HFC-134a/POE systems have been obtained at temperatures of 4 and 9℃ for oil concentrations from 0 to 32 mass%. The present results show that the change in oil-concentration dependence of the heat transfer coefficient due to lower or higher heat flux is not recognized, and the heat transfer coefficient for the systems decreases with increasing oil-concentration as a whole.
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Masayuki SATO, Koichi MURAKAMI, Shinfuku NOMURA, Hiroshi OGAWA
Article type: Article
Session ID: K-1822
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The connection between the behavior of coalescent bubble generated from local heated upper wall and boiling characteristics in an inclined channel with rectangular cross section was studied experimentally and analytically. The channel was submerged at an inclination angle θ from horizontal (2・≦θ≦20・) in saturated water. The height of the channel H (3≦H≦7mm)and the heat flux were changed. The analytical model of bubble behavior was constructed and the method for prediction of the heat flux at the occurrence of burnout was proposed.
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Eitaro TANAKA, Kiyoshi KAWAGUCHI, Tadayoshi TERAO, Masahiko SUZUKI
Article type: Article
Session ID: K-1823
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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In recent years, calorific power of computer chip has been increasing, thus high performance cooling unit is desired. Further, it is desired that it's performance dose not depend on any posture of chip. We developed the cooling unit that complied with the demands. It has the boiling part that enabled to supply refrigerant to boiling part with sintering metal, and the condensation part that enabled to spread high temperature vapor of coolant without clogging.
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Tetsu FUJII, Mitsuo TASHIRO, Osamu MAKISHI
Article type: Article
Session ID: K-1824
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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This paper deals with an experimental study of free convection condensation of steam-air mixture on a vertical tube. The experiment is made using copper tube of 4mm in outer diameter. The range of concentration of air is 0.1〜0.9. Condensation rate is measured as well as overall heat transfer rate. The convection heat flux is obtained by subtracting the condensation heat flux from the heat flux at the cooling surface. The newly proposed equations in the previous paper for predicting condensation mass flux, convective heat flux at the liquid-vapor interface and heat flux at the cooling surface correlate the respective experimental results within the error of several percents.
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Hitoshi SUTO, Yoshiaki KANEKO, Koji MATSUBARA, Mutsuo KOBAYASHI
Article type: Article
Session ID: K-1825
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Large eddy simulation (LES) and direct numerical simulation (DNS) were carried out for flow and scalar transfer of a round jet. Simulated domain includes transitional and established fields. In LES, Smagorinsky model was used as subgrid scale (SGS) model. Validity of the simulation was examined through comparison between existing experimental literatures and computational results with and without SGS model. Instantaneous structures of vortices and temperature field for Reynolds numbers Re=1200 and 10000 were found to have similarity regardless of Reynolds number.
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Nobuaki ISHIBASHI, TOMOHARU Yoshino, Yasutaka NAGANO
Article type: Article
Session ID: K-1826
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Direct numerical simulation (DNS) of a fully developed turbulent rotating channel flow with heat transfer has been performed using the spectral method, where we show how the rotation affects the velocity and thermal fields. In the rotating channel flow, turbulence energy is transported from the pressure side to the suction side by the action of pairs of streamwise vortices generated in the center of channel by the rotational effect. In the thermal field, temperature variance decreases on the pressure side and increases on the suction side. And, in the case of the higher rotation number at a low Reynolds number, turbulence is enhanced on the pressure side and suppressed on the suction side, which leads to relaminarization.
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Masahiro SHIOJI, Kiyoshi KAWASAKI, Kenichi IKESHIMA, Hideki KATSUYAMA, ...
Article type: Article
Session ID: K-1827
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The instantaneous velocity distributions in a free jet are measured using cross-correlation of high-resolution particle images, which contributes to evaluate the production- and dissipation-rates of turbulence kinetic energy. The obtained velocity vectors show that eddies having various sizes interact with each other. Also, the turbulence structure in a jet is discussed based on the balance of turbulence energy.
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Tomoya HOURA, Tooru MATSUO, Yasutaka NAGANO
Article type: Article
Session ID: K-1828
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Characteristics of turbulent boundary layer flows with adverse pressure gradients (APGs) differ significantly from those of canonical boundary layers. We have experimentally investigated the effects of APG on the mean velocity and temperature profiles in a thermal boundary layer developing on the uniformly heated plate. It is found that, in the APG boundary layer, the conventional thermal law of the wall does not hold in the fully turbulent region. Moreover, turbulent Prandtl number decreases in the fully turbulent region. These findings indicate that heat transfer is greatly enhanced under the APG conditions.
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Dai Nagano, Ichiro Ueno, Hiroshi Kawamura
Article type: Article
Session ID: K-1829
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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A large number of terrestrial experiments have been conducted on Marangoni convection in a liquid bridge to date. The attainable size of the bridge and thus the attainable Marangoni number are seriously limited in the terrestrial experiments. In the present study, a series of experiments was performed in a low temperature environment in order to suppress the evaporation of fluid, while realizing a large temperature difference between the both ends of the bridge to attain a high Marangoni number in spite of a small size of the bridge. Special attention was paid upon the flow field up to for beyond the critical Marangoni number. It was found that the flow field could be categorized into eight regimes; from steady to turbulent-like flows. After the pulsating and rotating oscillatory flows emerged, the flow exhibited another types such as, chaotic and turbulent convections. They were distinguished by applying the Fourier analysis and the pseudo-phase-space reconstruction from the time series of the surface temperature.
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Takanobu YAMADA
Article type: Article
Session ID: K-1830
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Thermal fluctuation phenomenon is often observed in a enclosed cavity where hot and cold walls are located in a line, and causes a periodical location exchange of hot and cold flow cells. Since it only exists in limited area of some Rayleigh numbers, it is not easy to clarify the fluctuation mechanism and detailed characteristics of its heat transfer effect. This study tried to find the conditions for the occurrence of the fluctuation with experiments and then to analyze the mechanism numerically. As the results, thermal fluctuation phenomenon appeared in the range of inclined angle, 45°〜150° and most typical fluctuation existed at the inclined angle of 90° and in Raleigh numbers of (1〜7)×10^5. And the frequency of fluctuation tended to be divided into two area to each inclined angle of the cavity.
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Masanori SUKO, Naozo HATTARI
Article type: Article
Session ID: K-1831
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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An experimental investigation was conducted on the transition region of natural convection along a vertical cylinder immersed in water. Temperature fluctuation in the thermal boundary layer was measured from the transition to the turbulent region by using a thermocouple. Frequency analysis for the output of thermocouple revels that, the temperature fluctuation at the beginning of transition has some frequency before its periodicity fades before long with increasing (Gr^*_x Pr)_e. Moreover, move of vortices from the transition region to the turbulent flow is also noticed.
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Takafumi NAKAGOMI, Naozo HATTORI
Article type: Article
Session ID: K-1832
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Natural convection in .a vertical councentric pipe annulus is investigated numerically for laminar flows at the modified Grashof numbers Gr^*=10^2〜10^5. In numerical calculations the thermal entrance region for Prandtl numbers of 0.01,7.0,50 is examined at the diameter ratios d _i/d_0=0.2,0.5,0.8. From the results obtained acorrelation equation is presented for thermal entrance length x/b.
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Masaru ISHIZUKA
Article type: Article
Session ID: K-1833
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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This paper describes the effects of the outlet vent size and the distance between the outlet vent location and the power heater position on the flow resistance in natural-air-cooled electronic equipment casings. An experiment was carried out using a simple model casing simulated for the practical natural-air-cooled casing which is composed of 4 side walls, a top plate and bottom plate witch has an inlet opening. A power heater to served as a power dissipation unit was placed at its open bottom. An outlet opening was set on one of the side walls. The opening area, the height of the outlet and the heater location were varied. The experimental results were analyzed using the flow resistance coefficient K which was related to the distance between the outlet vent and the power healer position and the heat removal from the outlet vent, and K values were plotted against a pair of Reynolds numbers Re ard the outlet vent porosity β which is defined as the ratio of outlet vent open area to the top surface area of the casing.
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Yushi KAMIYA, Kazuyuki NARUSAWA, Morimasa HAYASHIDA, Hitoshi ROPPONGI, ...
Article type: Article
Session ID: K-1901
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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This paper covers our investigation into a decline in FC productivity resulting from hydrogen fuel containing CO. Here, we had several investigations into CO poisoning on dependence of the type of catalyst electrodes between Pt and Pt+Ru alloy. The results are summarized as follows: 1) The actual process of poisoning was scrutinized by focusing on adsorption of CO molecules. 2) The investigation into the relationship between the CO concentration and the poisoning was carried out. If the FC underwent at a high CO concentration, no significant improvement could be expected by operating at increased pressure. The effect of the operating temperature is almost the same between two types of FCs. 3) Some formulas to predict the performance were derived theoretically and empirically.
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Takuro IWASHITA, Jun MACHIDA, Jin KUSAKA, Yasuhiro DAISHO
Article type: Article
Session ID: K-1902
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Fuel cell is expected as the future power generation source. However, the formation method of hydrogen as the fuel of fuel cell is not established. In this study, equilibrium calculation was performed for the purpose of investigating the steam reformation characteristic of various fuels, methanol, natural gas and octane. In calculations the effects of temperature and S/F (Steam/Fuel) on hydrogen formation were examined by considering the amount of hydrogen and byproduct formation, and the enthalpy before and after the reformation.
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Masayuki KUNIMATSU, Tatehiro SHIMIZU, Toshio SHUDO, Yasuo TAKAGI
Article type: Article
Session ID: K-1903
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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A direct methanol fuel cell system (DMFC) consists of simple and compact equipment, and is suited for automobile use. The relatively low power output and efficiency of a DMFC are due to the low activity of methanol and the penetration of methanol through the electrolyte membrane. It is very important to improve the power output and thermal efficiency of a DMFC. This research investigated the characteristics of polarization in a DMFC using a reference electrode. Influences of cell temperature and methanol solution concentration were also analyzed.
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Kouhei TSUTSUI, Yoshio YOSHIOKA
Article type: Article
Session ID: K-1904
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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NO exhausted from diesel engine generators can be removed by non-thermal plasmas generated by discharge devices. Here we tried to control the NO concentration in a certain level at the exit of the system independent of the engine output power. It was demonstrated that NO concentration at the exit of the system could be controlled in the given values by adjusting the supply power to the discharge reactor..
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Shigeru ABE, Junya TANAKA, Koji KOREMATSU
Article type: Article
Session ID: K-1905
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Diesel Particulate Filter (DPF) is studied as an effective method for removing PM in exhaust gas from the diesel engine. However, it is not possible that DPF removes very small PM which is noxious for the human body, from its principle. Our goal of this study is the development of scrubber system which can remove small PM. In the current stage, the conclusion of this paper that 53% of PM which has passed DPF could be removed is got.
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Hitoshi NAGANO, Junya TANAKA, Koji KOREMATSU
Article type: Article
Session ID: K-1906
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The environmental pollution caused in association with Dioxins has been one of the most pressing themes among environmental issues in Japan. We detect Dioxins in the exhaust gas of a diesel engine and discuss their formation mechanism by several experiments.
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Yoshinori KANEDA, Ali MOHAMMADI, Yoshiyuki KIDOGUCHI, Kei MIWA
Article type: Article
Session ID: K-1907
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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A non-thermal dielectric barrier plasma reactor with a high NO_2/NO_X conversion was developed for soot oxidation using NO_2 gas obtained from plasma assisted oxidation of NO in diesel exhaust. Newly developed reactor operates at a relatively low discharge voltage and input power due to unique electrode configuration. Effect of reactor geometry on plasma intensity was clarified measuring induced electric energy and analyzing active gas component such as ozone. Maximum NO_2/NO_X conversion ratio was obtained at an energy density level in which ozone concentration peaks.
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Makoto NAGAOKA, Kazuhiko SUGA, Nariaki HORINOUCHI
Article type: Article
Session ID: K-1908
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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This paper presents discussions on predicting turbulent flows in simple model of engine intake port-valve-cylinder with three port-curvature ratios. The low-Reynolds-number linear k-ε, cubic nonlinear k-e and k-ε-A_2 turbulence models are applied to the flow field computation. The results suggest that the nonlinear eddy viscosity modelling of turbulence is very successful for predicting mass flow rate and in-cylinder velocity distributions.
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Yasuhiro Shutoh, Akihiko AZETSU
Article type: Article
Session ID: K-1909
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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For internal combustion engine, it will be a indispensable technology to make stratified mixture, but it is difficult to evaluate the non-uniformity quantitatively including the scale of distribution. We examined the quantification of stratified air-fuel mixture when charged different composition from each intake valve using 4-valve optical engine. We used oil mists as tracers for stratification and it is charged from only one side of intake valves. Particle images were photographed with laser sheet illumination. The intensity and the scale of stratification were evaluated from coefficient of variation and auto-correlation function.
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Hiroshi TOKITOU, Kyungnam KO, Masataka ARAI
Article type: Article
Session ID: K-1910
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Behavior of spray impinging on a recessed-wall was experimentally investigated as a new concept of impingement diesel spray. The spray injected through a diesel nozzle impinged vertically on the center of the circular recess. Spray height and spray path penetration were measured at various timings on high speed photographs of the spray, which was injected by a single shot injection system into a high pressure chamber. The spray impinged on the recessed-wall was more rebounded from the recess compared with the spray impinged on a flat wall. When the spray width at the wall location was wider than the recess diameter, the spray after impingement expanded along the wall. Conversely, the spray width was narrower than the recess diameter, the spray after impingement was rebounded with rolling up motion. It resulted in the formation of the spray having more homogeneous structure. Also, for increasing the spray height, it was necessary that the value of Ws/Dr should be around 0.5.
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Ryo YUYAMA, Takemi CHIKAHISA, Yukio HISHINUMA
Article type: Article
Session ID: K-1911
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Quick mixing of fuel and air is one of the most essential factors to improve combustion and emissions in diesel engines. The paper investigates local diffusion phenomena with focusing on scales of the diffusion in turbulent jets. Analysis was made with entropic concept proposed in the previous paper; it analyses homogeneity degree and scales of the heterogeneity in a picture. The result shows the effectiveness of the entropic analysis method for identification of scales of heterogeneity and diffusion intensity. The result of the experiment shows that the diffusion intensity is the highest at the vicinity of the nozzle exit, and the heterogeneity scale is the smallest. The heterogeneity scale increases gradually along the spray axis towards downstream, with containing smaller scales inside of the large clouds. In the downstream region, small-scale structure diffuses and becomes unclear, while large scale structure remains clearly.
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Tatsumi KITAHARA, Masaru OTSUBO, Kotaro FUJISAKI
Article type: Article
Session ID: K-1912
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The influences of the overlay on the seizure resistance of the crosshead-pin bearing for large size two-stroke diesel engines were evaluated by using a dynamic load bearing apparatus. The major results are: (1) The seizure resistance of the aluminum-tin bearing plated with the tin-copper overlay using the tin bonding layer is significantly higher than that of the conventional lead-based overlay plated white metal and aluminum-tin bearings; (2) Increasing copper content in the tin-copper overlay is effective in improving the seizure resistance. If the copper content becomes too high, however, the running-in property is degraded, thereby causing the seizure resistance to decrease; and (3) Increasing the overlay thickness is advantageous for improving the running-in property, and thereby raising the seizure resistance. If the overlay becomes too thick, however, seizure occurs within the overlay, thereby causing the seizure resistance to decrease.
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Yasuo HARIGAYA, Michiyoshi SUZUKI, Masaaki TAKIGUCHI
Article type: Article
Session ID: K-1913
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The variation of oil film thickness on a piston ring of diesel engine is analyzed by using thermo-hydrodynamic lubrication. The oil film temperature is calculated by using unsteady state 2-D energy equation considering the viscous dissipation. The effects of oil film temperature and viscosity on oil film thickness are discussed and the calculated thickness is compared with the measured one. As a result, the calculated values agree approximately with the measured values. The minimum oil film thickness calculated by the present method is thinner than that with viscosity estimated by liner temperatures.
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Mitsuhiro SOEJIMA, Yoshito EJIMA, Kenji UEMORI
Article type: Article
Session ID: K-1914
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Friction and wear characteristics of cam and follower lubricated with soot contaminated oils were examined with a cam-follower test rig. Changes in friction force and amount of wear were measured during the course of the tests. The influence of the soot was examined by mixing the exhaust gas soot or the carbon black into the oils blended with the dispersant and ZnDTP and/or MoDTC additives. Results are summarized as follows. (1) The friction fluctuated and gradually increased with elapse of time in case of soot contaminated oils. (2) Under the coexistence of ZnDTP and MoDTC, however, it became a gradual decrease lower in friction even if mediated with the soot. (3) The wear rate became the smallest as if the anti-wear effect of ZnDTP was kept due to the MoDTC. (4) Such characteristics were not always reproduced by the carbon black contamination.
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Masayuki SHIMA, Tatsuhiro JIBIKI, Eriya YAMAMOTO, Tatsuya ITO, Yoshio ...
Article type: Article
Session ID: K-1915
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Effect of soot on wear of valve and valve sheet insert is investigated under the dry and lubricated conditions. Specimens used are stelite#12 for valve, SUH3 and three kinds of Fe base sintered alloys for valve sheet insert. Experiments are conducted with three types of test. One is a crossed cylinder point contact impact-sliding wear test for basic test. The other two are the tests using actual valve and valve sheet insert, that is, an impact test and a micro slip test induced by explosion force. The main results are as follows. (1) Under the dry condition, soot between the contacting surfaces decreases wear of seating surfaces. (2) Under the lubricated condition, soot increases the wear compared to the lubricating oil without soot. (3) Agglomerated soot has a load carrying capacity and makes seating surfaces deform plastically.
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Mitsuhiro SOEJIMA, Yoshito EJIMA, Masataka KAWASAKI
Article type: Article
Session ID: K-1916
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Regarding a rolling cam follower system, the frictional losses in the valve train have been measured with a cam-tappet test rig. In particular, the influences of oil property and its deterioration on losses have been examined by the use of an oil contaminated with soot kinds and other oils. Further the friction of a needle roller follower was measured. Followings were made obvious. (1) The friction loss is remarkably reduced by the use of the roller tappet but the total loss of the valve train is approximately half as much as that with the flat tappet. (2) Little difference was observed among the different oils tested. (3) The friction loss is not always reduced by the use of the needle roller.
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Masaaki TAKIGUCHI, Naoki IIJIMA, Ikuma TAKAHASHI
Article type: Article
Session ID: K-1917
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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This paper was aimed at clarifying the ring collapse phenomena through the experimental study. The oil film thickness and fluttering of second ring with taper face were measured in the operating engine under various engine speeds. The measurement of second land pressure also carried out. As the results, It is found out that the oil film thickness of second ring greatly increases just after compression top dead center and that the larger blow-by gas flow through the second ring at the same time during high engine speed range. It is because of the ring collapse allowing the second ring loses the contact with the liner wall.
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Nobuyuki KAWAHARA, Eiji TOMITA, Hiroshi KAMAKURA
Article type: Article
Session ID: K-1918
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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A fiber optical heterodyne interferometry system was developed to obtain high temporal resolution temperature histories of unburned gas in an SI engine non-intrusively. The effective optical path length of the test beam changes with the gas density and corresponding changes of the refractive index. Therefore, the temperature history of the gas can be determined from the pressure and phase shift of the interference signal. The Fiber optical heterodyne interferometry has the advantage of resisting mechanical vibration. The resolution of the temperature measurement is approximately 0.5 K, and is dependent upon both the sampling clock speed of the A/D converter and the length of the test section. This optical heterodyne interferometry system may also be used for other applications that require gas density and pressure measurements with a fast response time, or a transient temperature record.
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Hirokazu Fukushima, Ichiro Asano, Shigeo Nakamura
Article type: Article
Session ID: K-1919
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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It is getting more difficult to quantify particulate emissions with a conventional gravimetric method, because the amount of particle gets lower and lower. In order to overcome this issue, a new technique has been developed that can measure very low mass particulate matter (PM) and analyze volatile organic fraction (VOF), soot and sulfate mass in 4 minutes using vaporization, oxidization and deoxidization method. In this paper, principle and experimental results are described. Furthermore, using this technique, the possibility of compensation for error factors at PM collection is also discussed.
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Yuyin ZHANG, Tomoaki ITO, Keiya NISHIDA
Article type: Article
Session ID: K-1920
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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A dual-wavelength laser absorption-scattering (LAS) technique was developed by use of the second harmonic (532nm) and the fourth harmonic (266nm) of a pulsed Nd: YAG laser as incident light and dimethylnaphthalene (DMN) as the test fuel. By applying this technique, imaging was made of DMN sprays injected into a high-temperature and high-pressure constant volume vessel by a single-hole nozzle and a common rail injection system for D.I. Diesel engine. The line-of-sight optical thickness of both fuel vapor and droplets in the sprays was obtained from the sprays images. The quantitative information of the distributions of the vapor concentration and droplets density was further deconvoluted using the onion-peeling model.
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Eiji MURASE, Kenjiro NAKAMA, Shunji TOYODA, Jin KUSAKA, Yasuhiro Daish ...
Article type: Article
Session ID: K-1921
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The mixture formation process of a direct injection gasoline spray, which plays an important role of combustion and emission formation processes, was investigated to visualize liquid and vapor phase by the use of scattering and LIF. In the present study, the charge condition including density and temperature in the constant volume bomb was changed to investigate the effect of surroundings on mixture formation. Moreover, OH radical of spray combustion was also visualized by LIF. As a result, the injected spay behavior into high pressure and temperature field and these combustion characteristics were made clear.
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Kenjiro NAKAMA, Eiji MURASE, Shunji TOYODA, Jin KUSAKA, Yasuhiro DAISH ...
Article type: Article
Session ID: K-1922
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Various spray models were investigated to explain fuel spray formation and fuel mixing processes in DI engines. Based on TAB model, spray formation of the swirl injector that is currently used in conventional gasoline DI engines was modeled to an agreement with experimental results. As the results, the structure and the behavior of calculated swirl spray well agree with experimental results at different ambient conditions.
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Makoto YAMAKADO, Motoyuki ABE, Yuzo KADOMUKAI, Hiromasa KUBO, Yasunaga ...
Article type: Article
Session ID: K-1923
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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We have developed a mass producible battery-voltage-driven fuel injector for direct-injection gasoline engines. The injector has a dual-coil structure that enables the injector to operate at the battery voltage, thus eliminating the need for either voltage step-up circuitry or current control circuitry. Deviation in battery voltage and changes in harness resistance are fully compensated through opening-coil energization-time control. In addition, with this control method, the injector can be used with a wide range of fuel pressures. In this paper, the design concept and the dynamic characteristics of the battery-voltage-driven fuel injector with a dual-coil structure and the opening-coil energization-time control method is discussed in detail.
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Hideki OKITA, Masafumi KOUNO, Masataka ARAI, Kenji AMAGAI
Article type: Article
Session ID: K-1924
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Combustion characteristics of diesel spray impinging on a wall were investigated. Ambient temperature was varied from 500 to 620℃. Especially, the experiments for ignition position, ignition delay and flame area were performed to understand the effect of impingement distance. As the result, the ignition position reached to wide area under the conditions of high ambient temperature and short ignition delay. In that case, it seemed that complete combustion state was achieved. On the other hand, when the combustion was to be complete and ignition position was near a wall, the flame area became large. A model of the flame developing process was proposed to explain the effect of impingement distance on ignition position, ignition delay and flame area.
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Tomomi KANEKO, Takemi CHIKAHISA, Yukio HISHINUMA
Article type: Article
Session ID: K-1925
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The authors have been interested in a relationship between flame length of unsteady jet and NOx emission. It was predicted by their simple simulation that NO of unsteady jet flame is mainly formed in the region vicinity of the spray tip, where unsteady structure of species-concentration is dominant. Because of this fact they predicted that NO emission index has a peak, and beyond the peak low NO combustion may be accomplished. The purpose of the paper is to confirm the prediction experimentally. The result shows a tendency agreeing with the prediction, however the change is much smaller than the prediction. The paper presents a plan of the experimental system and shows a limited result of the experiment, although more data is necessary for the clear conclusion.
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Eiji Hayakawa, Kazumitsu Kobayashi, Takashi Matsuura, Seiichi SHIGA, H ...
Article type: Article
Session ID: K-1926
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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This paper presents a study on the effect of injection rate on the performance and emissions in a direct injection gasoline engine. Five kinds of swirl injectors were utilized; their static injection rates were 600, 700, 800, 900 and 1000cc/min at the injection pressure of 7MPa. The BSFC is shown to have its optimum at lower rate of dynamic injection rate 10.7×10^<-2>cm^3/ms which is attributable to the combustion efficiency variation due to the behavior of droplet concentration. Two other factors of mechanical efficiency and cycle efficiency determining the thermal efficiency are discussed in comparison with the results of port injection operation.
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Kunihiko SUZUKI, Kazuie NISHIWAKI
Article type: Article
Session ID: K-1927
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Turbulent propagating flame during flame growth period in an SI engine was visualized by a laser-light sheet technique. The time histories of fractal dimension of the wrinkling flame front were analyzed. The results show that the fractal dimension increases during flame the growth period and that the fractal dimension develops faster at higher engine speeds.
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Makoto IKEGAMI, Takuji ISHIYAMA
Article type: Article
Session ID: K-2001
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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A computer simulation code is developed to predict the engine performance of a spark-ignition engine, taking the occurrence of knocking into consideration. In this simulation, time-evolution is solved based on mass and heat flow during the cycle. Knocking is described by using the Livengood-Wu function giving ignition delay data estimated by Nishiwaki and the coworkers. Results of prediction show reasonable degree of reproduction of actual tendency of in-cylinder processes over a range of engine running. The developed code will be a useful tool for improving the engine performance.
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Hiroki MUNE, Junya TANAKA, Koji KOREMATSU
Article type: Article
Session ID: K-2002
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The deposits are produce on the combustion chamber wall, when the engine is operated for a long time. The deposits on the combustion chamber wall adsorb the fuel during the intake and compression stroke, and discharge it during the expansion and exhaust stroke. This phenomenon increases HC emission from the spark-ignition engine. In this paper, how the deposit on the piston surface artificially produced affects the emission of HC, is clarified experimentally. The result of the measurement shows that the HC discharge from the deposit is important under the cold-start.
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Hozumi KITAHARA, Junya TANAKA, Koji KOREMATSU, Makoto MIYANISHI
Article type: Article
Session ID: K-2003
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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High concentration of nitrogen oxide is detected in the exhaust gas during the cranking process of internal combustion engines. In this paper, the mathematical model which estimates the generation of nitrogen oxides in the cranking process is developed. The calculated results show that the high concentration of nitrogen oxide has been obtained when the rotational speed of the engine is low. The experimental results can be explained by our mathematical model.
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