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Yasushi MUTO, Shintaro ISHIYAMA, Seiya YAMADA, Iwao MATSUMOTO, Chiharu ...
Article type: Article
Pages
397-398
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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This paper describes a design of the gas-turbine system in a 600MW HTGR closed cycle helium gas turbine power plant. Design of turbine, compressors and generator are given. A horizontal gas turbine arrangement adopted is shown which can solve rotor dynamics and remote replacement problems.
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Osamu BABA, Kazuhiko KUNITOMI, Tatsuo IYOKU, Haruyoshi MOGI
Article type: Article
Pages
399-400
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The HTTR (High Temperature Engineering Test Reactor) is a graphite-moderated and helium-cooled reactor with 30 MW in thermal output and outlet gas temperature of 850℃ for rated power operation and 950℃ for high temperature operation. It was successfully constructed, and its power up operation has been carried out since September 1999 according to a rise to power test program. At present (May 2000), the 9 MW operation was almost finished without any major problem. The rise to power test program was designed to confirm basic performance of the HTTR such as core physics, radiation shield performance, thermal performance, fuel integrity and so on. Also, it includes commissioning tests by the Science and Technology Agency (STA). This paper describes contents of the rise to power test program and preliminary results of the 9MW operation.
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Hirofumi OHASHI, Tetsuo NISHIHARA, Tetsuaki TAKEDA, Shoji KATANISHI, K ...
Article type: Article
Pages
401-402
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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JAERI has carried out the R&D on hydrogen production system using high-temperature nuclear heat supplied from HTGR to progress in the utilization of nuclear energy without CO_2 emissions. Some technologies required from the viewpoint of economy, controllability and safety should be developed and demonstrated to commercialize the HTGR hydrogen production system. JAERI has constructed a 30-MWt HTGR, named HTTR, of which first criticality was attained in 1998. A hydrogen production system by means of a steam reforming of nature gas is planned as the first nuclear heat utilization system coupling with HTTR as a demonstration test facility. Prior to coupling of the steam reforming system with the HTTR, an out-of-pile test, which is an approximately 1/30 scale system of the HTTR steam reforming system and simulates key components downstream from an intermediate heat exchanger, is under construction to confirm safety, controllability and performance of the HTTR steam reforming system. This report describes the development items and the demonstration test program for the HTGR hydrogen production system.
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Tetsuo NISHIHARA, Koichi MORIYAMA
Article type: Article
Pages
403-404
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The high temperature gas cooled reactor can supply hot helium gas whose temperature is about 950℃ for not only power generation but also process heat in the chemical industry. JAERI has conducted the conceptual design on the HTTR steam reforming hydrogen production system. This system can achieve the hydrogen production rate of 410m^3/h per process heat of 1MW and it is competitive to the conventional plant. Furthermore thermal transients of helium gas induced by some troubles in the hydrogen production plant can be mitigated passively by using the steam generator integrated with radiator so that this system can continue normal operation.
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Tetsuaki TAKEDA, Jin IWATSUKI, Masuro OGAWA
Article type: Article
Pages
405-406
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Permeation of hydrogen isotope through a high-temperature alloy as used heat exchanger and reformer tubes is an important problem in the hydrogen production system connected to be the high-temperature engineering test reactor (HTTR). The objective of this study is to investigate an effect of mutual permeation process of hydrogen (H_2) and deuterium (D_2) on an amount of permeated D_2 through tubes. From the results obtained in this experiment, when the partial pressure of D_2 was kept at 100Pa in the tube inside and the one of H_2 was lower than 10kPa in the tube outside, the amount of permeated D_2 in the case of mutual permeation was larger than the one in the case of ordinary permeation. On the other hand, when the partial pressure of H_2 was larger than 10kPa, the amount of permeated D_2 decrease with increasing the partial pressure of H_2 in the tube outside. This paper described a permeability of hydrogen and deuterium for Inconel 600 and effectiveness of mutual permeation on the amount of permeated D_2.
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Kenichiro Sugiyama, Satoshi Nishimura, Izumi Kinoshita, Nobuya Abe
Article type: Article
Pages
407-408
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In order to clarify a fragmentation mechanism of molten drops, we carried out a series of experiments of dropping a molten Al drop (around 3 g) and a molten Cu drop (around 5 g) into a sodium pool through argon gas. The molten Al drop was dropped under the condition that the instantaneous contact interface temperature was sufficiently lower than the boiling point of Na. The molten Cu drop was dropped under the condition that the instantaneous contact interface temperature was sufficiently lower than the melting point of Cu and the boiling point of Na. It is concluded under the condition of instantaneous contact interface temperatures sufficiently lower than the boiling point of Na and the melting point of the drop that fragmentation is internally caused by the thermal interaction between the molten drop with an initial temperature higher than the boiling point of Na and the sodium entrapped within its drop.
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Hideki NARIAI, Yutaka ABE, Yukihiro HAMADA, Daisuke TOCHIO
Article type: Article
Pages
409-410
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The thermal detonation model is proposed to describe the vapor explosion. Based on the model, the vapor explosion is triggered by the vapor film collapse and the following atomization. The present study examines the effect of the temperature of hot liquid and cold water on the trigger condition from vapor film collapse to atomization by using the experimental result of small scale single droplet experiment and large scale experiment.
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Kiyofumi MORIYAMA, Yu MARUYAMA, Hideo NAKAMURA, Kazuichiro HASHIMOTO, ...
Article type: Article
Pages
411-412
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A new molten core model was developed to simulate the pre-mixing process of steam explosions in severe accidents at light water reactors. The phenomena considered here involves disintegration of a molten core jet dropping into a coolant pool and mixing of the melt droplets with the coolant. The model consists of a jet, particles and a pool of molten core, and also coupled with a two-phase flow code ACE-3D which solves the surrounding coolant flow field. The basic capability of the presentmodel in handling the phenomena considered was tested by simulating a molten metal jet breakup experiment. The calculation result showed that the model can reproduce the phenomena observed in the experiment well.
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Masami KATO, Hideo NAGASAKA, Yuri S. Vasiliev, Aleksandoer A. Kolodesh ...
Article type: Article
Pages
413-414
Published: July 31, 2000
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Fuel coolant interaction (FCI) phenomena when molten corium falls into water pool on containment floor during a sever accident of LWR were experimentally investigated in COTELS Test A. In the tests, about 60kg of mixture of UO_2,Zr ZrO_2 and SS was poured into water pool. In most tests conducted, measured pressure in the test vessel reached the first peak value in about 0.5 s, then it gradually approached the final quasi-steady state pressure within 10 s. No violent steam explosion was observed in any tests. Most of poured corium was broken up and the first peak pressure was well correlated by the corium particle size. The observed final quasi-state pressure was larger than that evaluated by the initial stored energy in corium due to non-condensible gas generation by oxidation of metallic components in the corium. The non-dimensional first peak pressure was well correlated by one non-dimensional parameter not only for COTELS data but also for FARO data.
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Yu MARUYAMA, Kiyofumi MORIYAMA, Hideo NAKAMURA, Kazuichiro HASHIMOTO, ...
Article type: Article
Pages
415-416
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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An analytical code, CAMP, is being developed at JAERI for thermo-fluiddynamic analysis of molten core in the lower plenum of the reactor pressure vessel. This code is mainly used for the evaluation of initial and boundary conditions for ex-vessel interactions between molten core and coolant. The experiments, where molten alumina was poured into a water-filled lower head experimental vessel, were analyzed with CAMP code. It was found that thermal responses of the experimental vessel were qualitatively reproduced by using models on vessel deformation, subsequent gap formation between solidified alumina and the vessel, and water penetration into the gap. The validation of low Reynolds number two-equation turbulence model, recently incorporated into CAMP code, is also in progress with experiments for natural convection of internally heated fluids with high Rayleigh number.
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Kenji YONEBAYASHI, Niroshi NISHIURA, Jun UCHIDA, Toshihiko KANAO, Naoy ...
Article type: Article
Pages
417-418
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The phenomena of natural convection boiling on the outer surface of a heated hemispherical vessel surrounded by a thermal insulation structure were investigated experimentally in the subscale test facility that modeled shapes of the reactor vessel and the structure surrounding the reactor vessel in the domestic PWR. The objective were to measure the rate of boiling heat transfer, to observe the behavior of the boiling-induced two-phase motion in the annular channel formed between the hemispherical vessel and the insulation structure. Measurements of the local boiling heat fluxes and the local wall superheats showed a spatial variation of the nucleate boiling heat transfer.
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Isao SAKAKI, Masami KATO, Hideo NAGASAKA, Vladimir S. ZHDANOV, Aleksan ...
Article type: Article
Pages
419-420
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Test B/C in COTELS project was performed to investigate fuel coolant interaction and molten core concrete interaction (MCCI) under water injection onto molten debris. After 60kg UO_2 corium mixture was melted in electric melting furnace, the corium was fallen into concrete trap. The molten corium in the trap was re-heated to simulate decay heat. When subcooled water was injected onto the molten debris, steam explosion was not observed. Debris was cooled after water injection and MCCI was suppressed. In 6 tests out of 10 tests, particulate debris bed was formed above continuous ingot debris. Large amount of smallest diameter particles was obtained due to the entrainment of molten corium, decomposed concrete and oxidation of metallic components in corium associated with MCCI generated gas. This favorable cooling was attributed to the existence of remaining porosity inside corium due to simulation of falling process, water ingression via eroded concrete side wall clearance and channels, and the interruption of further concrete floor erosion due to the existence of pebble bed, decomposed from concrete, below the debris.
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Tomoyuki Matsumoto, Kenichi Satou, Hiroaki Suzuki, Ryoichi Hamazaki, T ...
Article type: Article
Pages
421-422
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Masao OGINO, Takashi HASHIMOTO
Article type: Article
Pages
423-424
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Since the hydrogen combustion behavior in a multi-compartment vessel was a key issue to the containment vessel integrity during a severe accident, NUPEC developed an analytical hydrogen combustion model and incorporated in to MELCOR, which could evaluate mechanistically the hydrogen combustion behavior to track the flame front propagation in a multi-compartment vessel. The new model was validated under the homogeneously pre-mixed gas conditions using the results of the GRS/Battelle multi-compartment hydrogen combustion test. Following to the above work, using the tests results, simulating transient severe accident conditions from NUPEC large-scale combustion test facility, scenario oriented test analyses were carried out to validate the new model extensively. It was clarified that the MELCOR code replaced with the new combustion model could analyze sufficiently the combustion behavior at low flame velocity as well as the deflagration behavior at high flame velocity in a multi-compartment vessel.
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Kazuichiro HASHIMOTO
Article type: Article
Pages
425-426
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In a severe accident of a light water reactor (LWR), the reactor cooling system piping might be subjected to thermal loads from high temperature steam generated in the degraded reactor core, and decay heat of deposited fission products, in addition to an internal pressure load. In the Wide Range Piping Integrity Demonstration (WIND) Project which is performed at Japan Atomic Energy Research Institute (JAERI) the fission product (FP) aerosol behavior in reactor piping and the piping integrity under severe accident conditions are investigated. The FP aerosol behavior is being investigated using cesium iodide as simulant material, and deposition and revaporization tests are being performed. Thermal and structural responses of the reactor cooling system piping under high temperature and high pressure conditions are being investigated in piping integrity tests. This paper describes the overview and major results of WIND Project.
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Atsushi WATANABE, Takashi HASHIMOTO, Kazuya YAMADA, Masahiko Osaki
Article type: Article
Pages
427-428
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Three kinds of tests have been carried out to confirm the integrity of containment penetrations under accidnet management (AM) conditions and to investigate its failure criteria beyond AM conditions and to demonstrate fission product (FP) aerosol trapping effects along the leakage path of its degraded penetrations. Tests were carried out using the actual containment penetrations in a BWR plant. Cesium iodide (CsI) was selected as a representative species of a FP aerosol. All prototypical containment penetrations were intact under AM conditions (200℃, 0.8MPa). Temperature not pressure governed the penetration failure, and the failure temperature was much higher (over 70℃) than the temperature of AM conditions. Total leak area estimated from the test was about 1/10 time smaller than the used in current severe accident (SA) analysis codes. Aerosol trapping effect of the leakage path were evaluated as a decontamination factor (DF) in all cases and the total DF in actual plant was estimated to be about 400.
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Seiichi YOKOBORI, Hideo NAGASAKA, Atsushi WATANABE, Toshimi TOBIMATSU, ...
Article type: Article
Pages
429-430
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Fission product (FP) removal tests by containment spray, simulating accident management (AM) condition, were carried out. Tests were conducted by using almost full-height simulation test facility with a scaling ratio of 1/720 in volume. A system integral tests simulating both BWR low pressure vessel failure sequence and PWR LOCA sequence were successfully accomplished during about 10 hours. After spray initiation, aerosol concentration decreased rapidly in the entire region of drywell.
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Kuwahara Fujio, Hidenobu Kitamura, Hideaki Motoyama, Akira Nakayama
Article type: Article
Pages
431-432
Published: July 31, 2000
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A one dimensional model based on the two energy equation model designed for a porous medium has been adopted to investigate transport of heat and mass within a monolithic catalytic reactor. Sample calculations were carried out for a commercial three-way catalysis consisting of honeycomb monolith with micro-channels. Transient thermal responses and species concentrations at the exit were predicted reasonably well by the model
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Katsunori HANAMURA
Article type: Article
Pages
433-434
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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An experimental study on autothermic reforming in a porous catalyst has been performed. In the system, a mixture of methane or methanol, steam and air is introduced into the porous catalysts, where the flow direction reverses regularly. By the reciprocating-flow system, the product gas enthalpy is effectively regenerated into an enthalpy increase in the mixture through the porous media, which provides heat storage. A part of fuel is oxidized by air and the residual part is effectively converted into hydrogen. The endothermic reaction heat for the production of hydrogen is supplied directly from the exothermicity released by combustion.
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Noriyuki KOBAYASHI, Yugo ARAKI, Masanobu HASATANI, Sachio TANAKA
Article type: Article
Pages
435-436
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A combustor of a fuel-vaporizing type has the merits in turn down ratio, combustion load capacity and combustion controllability. The burner of the boiler, however, consumes the electric power for fuel vaporizer during combustion. The purpose of this study is to develop a power saving type-home water boiler. We manufactured a burner and a boiler in which radiant heat can reflux from flames upstream through large-porous ceramic plate enough to evaporate fuel. The plate has a role of flame stabilizer as well. As a result of experimental study on the combustion characteristics, it is found that this burner provides high turndown ratio, uniform temperature distribution and fine combustion controllability. The reflux rate of radiant heat from frames is estimated to be less than 2% of the combustion load.
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Kuniyasu OGAWA, Mitsuhiro BECK, Hiromi HASEGAWA, Katsumi HASHIMOTO, Sh ...
Article type: Article
Pages
437-438
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A new method to measure local heat flux distribution from capsule surface in packed bed of ice thermal storage capsule using magnetic resonance imaging (MRI) was developed. In this method, local heat flux distribution from a capsule was calculated from freezing rate of water in the capsule cooled by brine below 0℃ in a time interval. By applying this method to packed bed, heat flux distributions from capsule surfaces in packed bed were measured, and axial velocity distributions of brine through packed bed were obtained by phase method in MRI techniques. Based on these results, it was found that heat exchange effectiveness of brine through channel was lower than that through other area. In addition, time-variations of overall heat transfer coefficient of packed bed at different flow rates were obtained.
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Shigeo KIMURA
Article type: Article
Pages
439-440
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A simple one-dimensional theory about the heat transfer through a conductive partition separating porous medium and Newtonian fluid reservoirs at different temperatures has been developed. In the present study we assume that the porous reservoir has a higher themperature than that of fluid reservoir. According to the theory a unique nondimensional parameter σ is identified as a single parameter to govern the convection-conduction conjugate problem. The parameter is defined by σ=(1.323B)^<2/3>, where B is the Bejan number defined by B=(k_pRa^<1/2>_H)/(kRa^<1/4>_C), where k_p, k, Ra^<1/2>_H and Ra^<1/4>_C are the porous medium thermal conductivity, reservoir fluid thermal conductivity, Darcy-modified Rayleigh number based on the partition height, and the fluid reservoir Rayleigh number based on the partition height respectively. The present one-dimensional theory is well compared with Bejan's results for average partition temperature and the overall Nusselt number.
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Hirofumi TANIGAWA, Hidekazu KOSHINO, Takashi MASUOKA
Article type: Article
Pages
441-442
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Koichi ICHIMIYA, Yoshio YAMADA
Article type: Article
Pages
443-444
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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This paper describes the numerical heat transfer and flow characteristics of a slit-type impinging jet in a flow passage partially filled with a porous medium. The porous medium is a dispersed matter. Numerical calculation was performed in the three kinds of the constructions and in various thicknesses of the porous medium. The working fluid was herium and the temperature dependency of its thermalconductivity and kinematic viscosity was consiered. Velocity, temperature and density distributions in a flow passage were obtained. Additionally, Nusselt numbers on the impingement surface were evaluated
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Hideo MORI, Toshihiko ISHIDA, Yoshinori AOKI, Tomohide NIIMI
Article type: Article
Pages
445-446
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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REMPI (Resonantly Enhanced Multiphoton Ionization) is a powerful optical tool for measurements of highly rarefied gas flows because of its high sensitivity and ability to measure nonequilibrium among translational and internal energy, thus it will be a powerful tool for measurements of reflected molecules in gas-surface interaction experiments. In this paper, we proposed the temperature measurement technique by 2R+2 N_2-REMPI for measurements of rarefied gas flows in gas-surface interaction experiments. To propose a method of Boltzmann plot using the spectral lines of both O and P branches, electronic transition dipole moments in Honl-London factors are determined experimentally form the relative line strength of O and P branches. Then an effect of an experimental noise on a rotational temperature measured by the Boltzmann plot becomes smaller because the number of the lines used for the plot increases.
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Naoki KURIMOTO, Yukinori SAKIYAMA, Shu TAKAGI, Yoichiro MATSUMOTO
Article type: Article
Pages
447-448
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The rotational temperature distribution in the interaction region of a supersonic free jet and a vertical plate, which is a plate fixed vertically to the centerline of the free jet, is measured experimentally by electron beam fluorescence method. The source gas is cold N_2 and the pressure ratio is 520. It is found from the distribution that there is a bow-like shockwave in front of the vertical plate and the relaxation of the rotational temperature is carried out approximately to the stagnation temperature. This result is in good agreement with that of the numerical simulation by DSMC method.
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Toshihiko ISHIDA, Shuichi ADACHI, Masaki YOSHIDA, Tomohide NIIMI
Article type: Article
Pages
449-450
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In this study, the flow fields of a single supersonic free-jet and two interacting parallel supersonic free-jets are studied by flow visualization using PLIF (Planer Laser Induced Fluorescence) of nitric oxide seeded in N_2 test gas. An experimental apparatus has been constructed for visualization including an ArF excimer laser as an excitation resource and a high sensitive CCD camera with a ultraviolet bandpass filter as a detection system. The flow fields are visualized in the plane including the centerlines of orifices. It is found that a back flow seems to appear on the symmetrical plane near the orifice wall when two parallel jets interact.
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Takashi SUZUKI, Kouji KURATANI, Yasufumi OGURI, Masatake YOSHIDA
Article type: Article
Pages
451-452
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The distribution of luminous intensity of radicals, CH and C_2 were measured under atmospheric pressure and high combustion pressure. From the experiment with the premixed laminar burner, it could be confirmed that the radical luminescence distribution and the distribution of radical luminous intensity ratio could be measured. And it was found that the luminous intensity of CH radical was greater than that of C_2 radical and the value of luminous intensity ratio became small as the mixture became rich. From the experiment with the combustion chamber, it was also found that the luminous intensity became strong as the combustion pressure rose and the value of luminous intensity ratio became large as the combustion pressure rose.
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Seizo KATO, Naoki MARUYAMA
Article type: Article
Pages
453-454
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A combined LIF (Laser Induced Fluorescene) intensity and lifetime technique is proposed to measure simultaneously local density, temperature and pressure in rarefied gas flow fields. The theoretical principle is firstly introduced, taking account of the hyperfine structure broadening effect, and then its experimental verification is carried out. As a result, the present LIF measurement technique is found to be attractive.
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Seiji YOSHIDA, Yoji KUROSAWA, Takeshi YAMAMOTO, Mitsuo GOMI, Kazuo SUZ ...
Article type: Article
Pages
455-456
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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This study deals with aerodynamics phenomena in a swirl type combustor that has two swirlers. The Particle Image Velocimetry (PIV) technique has been used to get the velocity filed of swirling flow without combustion. It is revealed that high turbulence area occurs at a boundary of recirculation region at downstream of swirler and an interaction region of two swirling flows.
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Hiroyasu YAMASHITA, Takashi SUGANUMA, Norihiko YOSHIKAWA
Article type: Article
Pages
457-458
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A planar imaging technique of laser-induced fluoresecence is applied to the measurements of nitrogen monoxide in methane-air stoichiometric premixed laminar flames of small scale. Laser sheets of P_11(36.5) excitation line at 225.178nm is used. Intensity maps of fluorescence lines about 247nm are recorded through an interference filter (246.8nm, FWHM 14.6nm) by an intensified CCD camera. This specific excitation line can provide an approximately linear relation between fluorescence intensity and concentration of nitrogen monoxide in temperature range of 1000 - 2000K. Relative concentration maps are obtained. Temperature is determined computing the equations of fluorescence intensity and data of energy levels. The results of this thermometry are compared with those of Rayleigh scattering method. The Rayleigh scattering intensity for the methane-air stoichiometric flame is inversely proportional to the absolute temperature. The comparison gives a good agreement. This LIF measurement techniques demonstrate a possibility of application to practical measurements of larger size industrial burner for evaluating NO_x emission levels.
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Yoshinori NAGASE, Ryouji OHSUKA, Shigeo KOTAKE, Yasuyuki SUZUKI, Masaf ...
Article type: Article
Pages
459-460
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Tomokazu MINAMI, Yuichi MURAI, Koichi FUJIMOTO, Fujio YAMAMOTO
Article type: Article
Pages
461-462
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A peculiar two-phase convection is generated when an object is inserted in a free rising bubbly flow. This paper is concerned with an experimental method to elucidate the bubble behavior around several types of the object based on flow visualization and image processing techniques. Experimental results show the following points; 1) area of single-phase region behind the object depends sensitively on the shape of the object, 2) when many objects are arranged, the single-phase region expands behind the most downstream object.
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Norihiko YOSHIKAWA, Yoshiyuki SHOUGENNJI, Konstantinos Kontis
Article type: Article
Pages
463-464
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A non-intrusive, high spatial and temporal resolution thermal imaging system based on the fluorescence properties of a dysprosium-doped yttrium-alminum-garnet (Dy^<3+> : YAG) thermographic luminescent material has been developed. The solid surface of a test piece is excited by the third harmonic 355nm beam of a pulsed Nd : YAG laser. The resulting fluorescence emission intensities of 456nm and 496nm peaks in the spectra are acquired using an image-intensified charged coupled device camera. The correlation of the ratio of the acquired peak intensities with temperature is obtained measuring the fluorescence of the test piece in an electric furnace with thermocouple calibration. Temperature measurements of a test piece heated by an impinging jet flame demonstrate the feasibility of this technique for general heat transfer studies involving significant unsteadiness and transient phenomena.
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Tomoaki SATO, Yoshinori TAKAISHI, Kosei OGUCHI
Article type: Article
Pages
465-466
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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This paper reports experimental saturated liquid densities for the mixtures of HFC-134a and polyalkyleneglycol (PAG) oil. The saturated liquid density is measured by the method using spherical floats made of glass. The experiments have been conducted for temperatures 258-353K, densities 960-1330kg・m^<-3> and oil-concentrations 0-50 mass% including pure HFC-134a. We have found that the change in saturated liquid density for the mixtures due to temperature tends to become smaller with increasing oil-concentration.
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Hitoshi SAI, Hiroo YUGAMI
Article type: Article
Pages
467-468
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Surface microstructured selective emitters for thermophotovoltaic (TPV) applications were fabricated on a Si wafer with electron beam lithography and wet etching process. It was predicted from the period of the surface structure that selective emission was observed around 2.0μm. Reflectance, transmittance spectra at room temperature and emittance spectra at elevated temperatures were measured. Selective emission due to the resonance effect between the microstructured surface and the electromagnetic field was clearly observed. Numerical calculations by rigorous coupled wave analysis (RCWA) were also carried out to estimate spectral properties of microstructured emitters. Numerial results at room temperature showed a good agreement with the experimental results.
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Eiji KINOSHITA, Seiichi TANABE, Shintaro IWASHITA, Toshiaki YANO, Shui ...
Article type: Article
Pages
469-470
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Yoshitoki SEO, Kentarou NONAKA, Masayasu HATAZAWA, Sadayoshi KORENAGA
Article type: Article
Pages
471-472
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The heat transfer characteristics of a coupling thermoacoustic sound wave generator is described. When two sound wave generators are combined and operated, the heat transfer characteristics of each of the sound wave generators show results different from those obtained when they are operated independently. The sum of heat transferred by sound wave, Q_<MA>, is the largest for the closed ends connected-type sound wave generator when the stack positions of the two sound wave generators are the same. When frequency, f, is 134Hz, the maximum sum of Q_<MA> is 10% greater than that of two sound wave generators that are independently driven. The stack position where the temperature of hot heat exchanger, T_H, is the lowest does not agree with the optimum stack position in which the sound wave generators are independently operated. It is confirmed that the lowest T_H in the coupling sound wave generator is 50℃ lower than that in the sound wave generators that are independently operated.
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Osamu SATO, Hiroyuki KITSUNAI, Minoru SHIMIZU
Article type: Article
Pages
473-474
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Carbon deposition on specimens exposed to electron beams in an electron-microscope chamber, which is offer used to measure the size of ULSI patterns on silicon wafers, is very serious problem. We measured the increase of aluminum wiring-line width on wafers due to carbon deposition by directly spreading oils on the wafers. This method indicated that, linewidth increase varied from 1 to 200 nm. This method is a useful way to estimate carbon deposition since it is highly sensitive and does not get contaminated.
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Koichi SUZUKI, Masaomi KOYANAGI, Hiroshi KAWAMURA
Article type: Article
Pages
475-476
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In subcooled pool boiling of water under microgravity obtained by a parabolic flight of aircraft, coalesced bubbles did not detach from the heating surface until the heating surface was burned out and the heat flux was 200∿400 percent higher than the widely accepted predictions. The microgravity duration was about 20 seconds and the level was 0.01∿0.04g. According to the observed bubble behaviors, same pool boiling was performed with attached bubbles on the heating surface on the ground. The burnout heat fluxes obtained were well agreed with those under the microgravity. An effect of heating period on the burnout heat flux was investigated in the ground experiment with bubble holder. The burnout heat fluxes decreased rapidly with heating period over about 20 seconds and became constant for long heating period. The constant burnout heat fluxes were roughly coincident with those calculated by the conventional predictions.
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Y. Takata, S. Hidaka, J. M. Cao, M. Masuda, T. Ito, T. Watanabe, M. Sh ...
Article type: Article
Pages
477-478
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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We have developed a superhydrophilic metallic surface by sputtering process. By exposing the surface to ultraviolet ray, the contact angle decreases to zero under UV illumination. We applied this surface to enhancement of boiling heat transfer. Heat transfer characteristic of pool boiling has been investigated using TiO_2-sputtered copper surface. Experiments have been conducted both for TiO_2-coated and non-coated surfaces and it is found that the maximum heat flux of TiO_2-coated surface is almost double to non-coated surface and temperature at the minimum heat flux of TiO_2-coated surface is much higher than of non-coated one.
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Masanori Monde, Yuhichi Mitsutake, Hirofumi Arima, Masakazu Murashige
Article type: Article
Pages
479-480
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Critical heat flux (CHF) in two-phase thermosyphon can be improved about 8 times by inserting a tube into the thermosyphon and controlling a flow situation near its exit, where a counter-current flow of vapor and liquid always takes place. The critical heat flux can be improved by the counter-current flow there. The present experiment has been made to elucidate an effect of inserted tube on CHF by inserting either a rod or tube, which is extruded into a vapor space and then through which the vapor only flows out. For the case of the inserted rod, the CHF is gradually decreased with increasing the rod diameter and is found to be predicted by a method of maximum falling film liquid rate. For the case of the inserted tube, the CHF is also gradually decreased until a tube diameter, beyond which the CHF is again increased approaching the CHF for natural convection flow in annular channel.
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Hirofumi ARIMA, Masanori MONDE, Yuhichi MITSUTAKE, Kouji KAWAMURA
Article type: Article
Pages
481-482
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Experimental study is carried out to measure heat transfer coefficient of ammonia-water mixture on a horizontal heated surface, which is one of the nonazeotropic binary mixtures. The nonazeotropic binary mixtures have variable boiling and dew points, depending on the mixture components and concentrations. It is expected to have a higher coefficient of performance as a result of decreasing the thermodynamically irreversible loss, when there is a relevant concentration. Therefore, ammonia-water mixture is used as working fluid in small temperature difference power generation cycles and absorption refrigeration cycles. However, few experiments were carried out in the world for measuring heat transfer coefficient for ammonia-water mixture. Heat transfer coefficient was measured and compared with existing correlations prediction and a revised correlation can be proposed.
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Hiroyasu OHTAKE, Yoshihiro TERUYA, Yasuo KOIZUMI, Munehiko YOKOGAWA
Article type: Article
Pages
483-484
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Recently, the dry/semi-dry cutting without cutting oil is proposed for ecology. The establishment of high heat removable technology is required in the future cutting. In this study, as a proposal of the high heat removable technology, the boiling heat transfer in mist cooling was investigated experimentally. Furthermore, the estimation of the cooling in the cutting was examined by using the heat conduction model. The required cooling rate was 5×(10)^3W/m^2K to suppress the heating due to the cutting. The cooling rate was achieved by the boiling heat transfer in the mist cooling for 4l/hr in liquid flow rate and 70 Nl/min in air flow rate. The cooling rate in the mist cooling was related to forming liquid film on a heated surface in the present experimental range.
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Koichi IRISA, Wataru NOGIMORI, Sinji ANDO, Yoshihiro NARUSE
Article type: Article
Pages
485-486
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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We have investigated the advantageous condition to the actuator as a principle using thermal bubble by electric micro heater. A micro heater has been investigated occurrence situation of a thermal bubble by various heating energy and time. As a result, it has been observed that it becomes better if the input voltage to the heater is high and heater size is small as a trend. We have been also carried out driving possibility of actuator array that adapts to a micro pump using the examined condition. The micro actuator has been driven at responsiveness of 0.8Hz and it's displacement was 35μm.
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Takaharu TSRUTA, Hisashi MATENO
Article type: Article
Pages
487-488
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Tetsu FUJII, Mitsuo TASHIRO, Osamu MAKISHI
Article type: Article
Pages
489-490
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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An experimental study is presented on free convection laminar film condensation of steam-air mixture on a vertical tube. The test tube used is of about 220mm height and about 6mm outer diameter. The range of concentration of air is 0.1∿0.9. The average heat flux values or average heat transfer coefficients obtained have been about 2.5 times larger than the corresponding values from the two-phase boundary layer theory for a vertical flat surface. The enhanced values are quantitatively explained by the curvature effect upon the vapor boundary layer, which is analogically derived from single phase free convection heat transfer.
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Yosio UTAKA, Hideyuki SONODA
Article type: Article
Pages
491-492
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The steam condensation on the thin tubes was investigated. It was expected that the surface tension instability of the condensate appeared under the case when the vapor condensed on the thin tubes. The wettable surface of the stainless steel tube was prepared by using the wetting coating agent of titanium oxide. The wavy shaped condensate film appeared for the tubes having the diameter of 0.5mm and 0.2mm, while the smooth surface of condensate was observed for 1.0mm in diameter. It was clarified that although the distance between the neighboring convexes coincided with the analysis of Rayleigh for relatively low heat flux, it increased with increasing heat flux.
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Toshiyuki KOBAYASHI, Kiyonori OZEKI, Mamoru ISHIKAWA, Tomio HIGO, Chik ...
Article type: Article
Pages
493-494
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In order to assemble a high performance fin-tube type heat exchanger, one of the most effective ways is improving the heat transfer performance of the tubes. In the present study we carried out the local condensational heat transfer and pressure drop experiments with refrigerant R410A. Two kinds of test tubes were used in the experiments horizontally, i.e. an asymmetric herringbone tube (AH) and a spirally grooved tube (SG), both having 7.00mm O.D. and 500mm long. With the double-tube test section, the experiments were carried out under the mass velocity of 172 and 257kg/m^2s, the inlet pressure of 2.63MPa. Comparing the case with SG, it is found that the condensational heat transfer coefficient with AH is 1.1 to 3.0 time higher, especially 3.0 times in average quality x=0.9,however the pressure drop increases as the average quality becomes high.
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Taiki NAKAMRA, Shigeo KIMURA, Atsushi OKAJIMA, Takahiro KIWATA
Article type: Article
Pages
495-496
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The effect of time varying temperature at boundaries transmitting in the solid and solidification processes can be observed in fields of engineering and geophysical phenomena. This paper describes a response of ice formation to the time-varying cooling temperature. In the present study, a box filled with distilled water is used for the experiment. We measured transient solidification processes in the box for the constant bottom wall temperature, but varying the cooling temperature. We demonstrate that a simple one-dimensional analysis can explain well various response characteristics of ice layer growth.
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