Journal of Power and Energy Systems
Online ISSN : 1881-3062
ISSN-L : 1881-3062
Volume 5, Issue 3
Displaying 1-19 of 19 articles from this issue
Papers
  • Weerin WANGJIRANIRAN, Bundhit EUA-ARPORN
    2011 Volume 5 Issue 3 Pages 209-217
    Published: 2011
    Released on J-STAGE: April 12, 2011
    JOURNAL FREE ACCESS
    This paper investigates the impacts of renewable energy deployment on the overall cost and emission for power production. A scenario-based energy accounting model with an integrated environmental database, i.e. Long-range Energy Alternative Planning system (LEAP), has been applied. The “reference scenario” is derived by the most-likely projection of Thailand power generation system, based on the national power development plan (PDP). Biomass will take the majority on renewable energy for power generation (RE-power). The “RENW scenario” will be set alternatively with more optimistic prospective on renewable energy progress. It is assumed that all of the incoming proposals of RE-power in the PDP are able to accomplish commissioning. Solar and bio-energy will play much more important role for the future domestic supply for Thailand power sector. The results indicates that the incremental cost of RE-power is not significantly affect to the cost of entire power system. On the other hand, RE-powers should not be considered as a single dependable option for the GHG mitigation target in power sector. However, the early RE-power project implementation will multiply the contribution of GHG mitigation in the long run.
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  • Toshio SHINOKI, Kenji OTA, Yuichi SONO, Yuki OKUHIGASHI, Jiro FUNAKI, ...
    2011 Volume 5 Issue 3 Pages 218-228
    Published: 2011
    Released on J-STAGE: April 12, 2011
    JOURNAL FREE ACCESS
    In the present study, we examine the dominant chemical reactions and the optimal conditions, assuming the design of ethanol-steam-reforming reactors. Experiments are performed for two catalysts, Cu/ZnO/Al2O3 and Ru/Al2O3. Using a household-use-scale reactor with well-controlled temperature distributions, we compare experimental results with chemical-equilibrium theories. As a result, the Cu/ZnO/Al2O3 catalyst shows rather high performance at low-reaction-temperature T, which suggests that the Cu/ZnO/Al2O3 catalyst promotes the ethanol-steam-reforming and the water-gas shift reactions, but does not promote the methanation reaction. On the other hand, high-reaction-temperature-type catalysts, such as Ru/Al2O3, promote all the three at high T. Furthermore, we specify the effect of the steam-carbon molar ratio S/C on the hydrogen concentration CH2 and the effect of T on CH2 for each catalyst.
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  • Wei LIU, Tamai HIDESADA, Kazuyuki TAKASE, Hiroki HAYAFUNE, Satoshi FUT ...
    2011 Volume 5 Issue 3 Pages 229-240
    Published: 2011
    Released on J-STAGE: April 12, 2011
    JOURNAL FREE ACCESS
    For a steam generator with straight double-walled heat transfer tubes that will be used in a sodium cooled faster breeder reactor, clarification of flow instability in heat transfer tubes is one of the most important research themes. As the first step of the research, thermal hydraulics experiments with water were performed under high pressure condition in JAEA with using a circular tube. Pressure drop, heat transfer coefficients and void fraction data were derived. This paper summarizes the pressure drop characteristics under 15MPa. Several two-phase flow multipliers were checked and then, it was found that both Chisholm two-phase flow multiplier and homogeneous model can predict the present experimental data in high accuracy. A sudden decrease of the pressure drop was observed when flow pattern shifts from bubbly and churn flows to annular flow. The reason for this decrease is tried to be interpreted.
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  • Daniela FONTANI, David JAFRANCESCO, Paola SANSONI, Luca MERCATELLI, Fr ...
    2011 Volume 5 Issue 3 Pages 241-248
    Published: 2011
    Released on J-STAGE: April 12, 2011
    JOURNAL FREE ACCESS
    Possible modifications for a solar simulator Yamashita YSS-200 were studied and experimented with the aim of allowing the test of concentration photovoltaic cells (CPV cells). Three different solutions were simulated and compared, using Zemax and TracePro, finally selecting the most suitable one. The modification consisted in a supplementary optical system that was externally added to the existing layout. The auxiliary system was easily demountable, thus allowing a rapid restoring of the original configuration. The selected optical system was realised and suitable optical tests verified that it satisfied the requirements on irradiance level and irradiance uniformity. Spectral measurements confirmed that the employed materials did not significantly modify the spectral distribution of the light emitted by the solar simulator.
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  • Toru TAKAHASHI, Eiichi KODA, Yoshinobu NAKAO
    2011 Volume 5 Issue 3 Pages 249-262
    Published: 2011
    Released on J-STAGE: April 12, 2011
    JOURNAL FREE ACCESS
    It is necessary to maintain or improve the thermal efficiency of actual thermal power generation plants from the viewpoint of environmental problems. When the thermal efficiency decreases, it is crucial to identify the performance deterioration factors by appropriate energy management. However, it is difficult to understand the internal state of such plants sufficiently and to determine performance deterioration factors only from operation data. In particular, investigating the performance deterioration factors is very difficult in gas turbine combined cycle (GTCC) power plants because the performance changes markedly depending on atmospheric conditions. Therefore, we develop a method based on heat and mass balance analysis to calculate the immeasurable quantity of state and the component performance values in GTCC power plants, and to correct them to the values under standard conditions using the performance function obtained from long-term operation data. From the results, we can identify the main factors affecting the thermal efficiency deterioration of GTCC power plants using this method.
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  • Akira SATOU, Yu MARUYAMA, Hideo NAKAMURA
    2011 Volume 5 Issue 3 Pages 263-278
    Published: 2011
    Released on J-STAGE: April 12, 2011
    JOURNAL FREE ACCESS
    A new model for the occurrence of the net vapor generation was developed to improve the predictive capability of best-estimate thermal hydraulic codes for transient void behavior under fast transient condition such as reactivity initiated accident (RIA). As a conventional model widely used in various codes is based on the experimental data obtained from steady boiling experiments, it did not well represent transient thermal-hydraulic phenomena near the heating surface. By analyzing our results of RIA simulation experiments previously performed at both low (atmospheric) and high (up to 7MPa) pressure, it was clarified that the concept of vapor condensation in the model needed to be improved. A new model for the net vapor generation was developed by using the thickness of thermal boundary layer as a characteristic length of vapor condensation. The new model was introduced into TRAC-BF1 code and was applied to the analyses for the high pressure experiments, confirming that the predictive capability of the modified code was improved.
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  • Tomoaki UCHIYAMA, Kenji KAWAGUCHI, Toshio WAKABAYASHI
    2011 Volume 5 Issue 3 Pages 279-294
    Published: 2011
    Released on J-STAGE: April 12, 2011
    JOURNAL FREE ACCESS
    The purpose of this study is to investigate the effects of the difference between analytical methodologies for seismic probabilistic safety assessment (PSA), especially the difference in the probability of system failures and core damage sequences. We selected two methods, upper bound approximation (UBA) using minimal cut sets and direct quantification using Monte Carlo simulation (DQFM) for comparison. The former is often used in PSA for both internal and external event. The latter is developed in Japan Atomic Energy Agency (JAEA) as a part of SECOM2, a system reliability analysis code for seismic PSA, and expanded to divide the core damage state into different core damage sequences. The result showed that there is a significant difference between UBA method and DQFM method.
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  • Takashi OGIHARA, Takayuki KODERA, Hiroshi MATSUO
    2011 Volume 5 Issue 3 Pages 295-301
    Published: 2011
    Released on J-STAGE: April 12, 2011
    JOURNAL FREE ACCESS
    A light rail vehicle (LRV) powered by a large Mn-type lithium ion battery (LIB) module was developed to run on a local railroad in Japan. A 60 kWh LIB module weighing 640 kg was used, and the relationship of running time with voltage, current, and consumed electric power was investigated in detail. The LRV was run while the LIB module was discharged between 660 V and 600 V. On a single charge, the LRV could run for 40 km by consuming around 40 kWh of energy. The running performance of the LRV with the LIB module was equivalent to that of an LRV powered electrically via an overhead contact wire. However, electrical power consumption of the LRV improved by 22% after charging the LIB with regenerative energy. The lifecycle of the LIB were examined by performing rechargeable tests. The initial capacity of the LIB was maintained at greater than 90% at 3 C (state of charge: 20%) after 3000 cycles.
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  • Qiusheng LIU, Katsuya FUKUDA, Yongwei YANG
    2011 Volume 5 Issue 3 Pages 302-315
    Published: 2011
    Released on J-STAGE: April 12, 2011
    JOURNAL FREE ACCESS
    Carbon dioxide (CO2) ocean sequestration technologies, such as dissolution into seawater, are important to mitigate global warming. In this study, solution processes of CO2 gas in seawater and synthetic seawater were experimentally and theoretically studied under various pressures and temperatures to evaluate the transport process of CO2 in seawater. The solubilities of CO2 in seawater and synthetic seawater were measured by a change in pressure due to absorption at temperatures ranged from 277 K to 333 K near atmospheric pressures, and ranged from 277 K to 298 K at pressures of 1 MPa, 2 MPa, and 3 MPa. It was obtained that the solubilities of CO2 increase with an increase in pressure, but decrease with an increase in temperature. The solubility of CO2 in synthetic seawater decreases with an increase in salt concentration. An empirical correlation for solubility of CO2 in seawater at various temperatures and pressures was obtained based on the experimental data. In the theoretical analysis for the solution of single CO2 bubble in seawater, the single CO2 bubble was assumed to be stationary and surrounded by infinite liquid seawater. The rate of solution of bubble in liquid is affected strongly by various parameters, such as solubility, diffusion coefficient, bubble radius, and temperature.
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  • Ikuo KINOSHITA, Toshifumi NRIAI, Akio TOMIYAMA, Dirk LUCAS, Michio MUR ...
    2011 Volume 5 Issue 3 Pages 316-329
    Published: 2011
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    This paper describes the effects of liquid properties on countercurrent flow limitation (CCFL) in a PWR hot leg. CCFL experiments were conducted in a 1/15th scaled-down model of the hot leg using air/water and air/glycerol-water solutions as working fluids. The experimental results revealed that an increase in the liquid viscosity did not change the zero liquid penetration point but did increase the slope of the CCFL curves on the Wallis diagram, which indicated that the increase in liquid viscosity from that of water did not affect the interfacial drag force but did influence the wall friction force. Numerical simulations of the experiments were carried out using a two-fluid model implemented in the CFD software FLUENT 6.3.26, and it was confirmed that the two-fluid model simulations properly evaluated the effects of liquid viscosity on the CCFL characteristics in the hot leg. Numerical simulations were also carried out to compare a low viscosity liquid to water. The predicted CCFL characteristics for low viscosity liquid showed no significant difference from those for water, which indicated that the decrease in liquid viscosity from that of water affected neither the interfacial force nor the wall friction force.
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  • Peyman NADERI, Tayebe MOHAMMADI
    2011 Volume 5 Issue 3 Pages 330-342
    Published: 2011
    Released on J-STAGE: August 25, 2011
    JOURNAL FREE ACCESS
    In this paper a strategy is introduced for distributed generation (DG) structure by using battery package and SPWM method for bi-directional AC/DC convertor. In proposed structure, a battery pack is connected to the power network via an AC/DC converter and a filter block. Active power direction has been controlled by a fuzzy controller for battery charge/discharge, considering battery state of charge (SoC). Also, a method has been introduced for islanding detection and isolated operation of DG system. Finally, simulation results, shows the effectiveness of proposed method.
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  • Sidik PERMANA, Mitsutoshi SUZUKI, Yusuke KUNO
    2011 Volume 5 Issue 3 Pages 343-359
    Published: 2011
    Released on J-STAGE: August 30, 2011
    JOURNAL FREE ACCESS
    Material attractiveness analysis on isotopic plutonium compositions of fast breeder reactors (FBR) has been investigated based on figure of merit (FOM) formulas as key parameters as well as decay heat (DH) and spontaneous fission neutron (SFN) compositions. Increasing minor actinide (MA) doping gives the significant effect to increase Pu-238 composition. However, the compositions of Pu-240 and Pu-242 become less with increasing MA doping. DH and SFN compositions in the core regions similar to the DH and SFN compositions of MOX-grade. Material attractiveness based on FOM1 formula shows all isotopic plutonium compositions in the blanket regions as well as in the core regions are categorized as high attractive material. Adopted FOM2 formula can distinguishes the material attractiveness levels which show the plutonium compositions in blanket regions as high attractiveness level and its composition in the core regions as low level of material attractiveness. MA doping is effective to reduce the material attractiveness level of blanket regions from high to medium and it requires much more MA doping rate to achieve low level of attractiveness (FOM<1) based on adopted FOM1 formula. Low material attractiveness level can be obtained by 4 % or more doping MA based on adopted FOM2 formula which considers not only DH composition effect, but also SFN composition effect that gives relatively higher contribution to material barrier of plutonium isotopes.
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  • Tomoaki UCHIYAMA, Kenji KAWAGUCHI, Toshio WAKABAYASHI
    2011 Volume 5 Issue 3 Pages 360-375
    Published: 2011
    Released on J-STAGE: August 30, 2011
    JOURNAL FREE ACCESS
    The purpose of this study is to investigate the effects of the consideration of simultaneous occurrence of seismically induced events in Nuclear Power Plants (NPPs) such as failures of components due to seismic stress, seismically induced fire, and seismically induced internal flooding in seismic probabilistic safety assessment(PSA). The seismic risk is estimated in terms of the Core Damage Frequency (CDF) and the CDF is comprised of occurrence frequencies of accident sequences. In this study, two analytical methods, upper bound approximation (UBA) using minimal cut sets (MCSs) and direct quantification of fault tree using Monte Carlo simulation (DQFM) are selected for comparison. The results showed that the simultaneous occurrence of seismically induced events should be reasonably considered to assess the intersection and the union of these events. In addition, the Great Eastern Japan Earthquake and the Tsunami damaged NPPs on the Pacific Coast of Eastern Japan on March 11, 2011 will be examined in this study.
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  • Shin'ya OBARA, Manabu OKUDA, Ryouhei SHIMIZU, Masahito KAWAI, Kazuhiro ...
    2011 Volume 5 Issue 3 Pages 376-387
    Published: 2011
    Released on J-STAGE: November 02, 2011
    JOURNAL FREE ACCESS
    When the mixed fluid of gas and water is pressurized and cooled to a given pressure and temperature, the generation of a gas-hydrate occurs. By heating, a very high pressure is obtained from the dissociated gas from the gas-hydrate. The purpose of this study is to investigate the operation of a high-pressure gas engine generator for distributed power supplies using the high pressure obtained though the dissociation of a gas-hydrate. A gas-hydrate functions as a working fluid and as a form of energy storage. However, until now, an actuator that uses the dissociation inflation characteristics of a gas-hydrate has not been examined. Therefore, the generation rate of CO2 hydrate and the quantity to be stored from the dissociation expansion energy of CO2 hydrate were investigated. As a result, when 1 m3 of water was used to generate CO2 hydrate for 480 minutes, the result was that electric power corresponding to approximately 45% of the daily power consumption (4.5 kWh of generator outputs) of an individual house can be stored.
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  • Shuji HIRONAKA, Yuki FUJISAWA, Saki MANABE, Gen INOUE, Yosuke MATSUKUM ...
    2011 Volume 5 Issue 3 Pages 388-399
    Published: 2011
    Released on J-STAGE: November 16, 2011
    JOURNAL FREE ACCESS
    The gas-lift method is expected as a method with the small running cost in order to recover the methane hydrate from the seabed. The methane gas injection makes the upward flow of the sea water, and it is necessary to establish the model able to estimate the sea water flow rate to the injected gas. Since the intended system is too large to conduct the experiment and multi-dimensional direct numerical simulation, this paper focuses on the calculation of the multi-phase flow in the one-dimension with the proper model equation for external forces. A drag force coefficient between gas and liquid is derived considering the liquid flow by the surrounding hydrostatic pressure. As a result, calculation with the proposed equation fairly agrees with the gas-lift experiment, compared with results with the other proposed model equations.
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  • Michitsugu MORI, Yasushi TAKEDA
    2011 Volume 5 Issue 3 Pages 400-405
    Published: 2011
    Released on J-STAGE: November 25, 2011
    JOURNAL FREE ACCESS
    Time-of-flight ultrasonic flowmeters have been widely used these days in industry. It is however in suspicion if its high accuracy is traceable to the national standard. It was made clear why traceability cannot be guaranteed from a fluid mechanical point of view. The main reason is a difference of flow configuration between the flow standard and the measurement position on-site. The concept of ‘Facility Factor’ is introduced and it is concluded that the ‘Profile Factor’ is not sufficient for correcting the meter reading. It is discussed that measurement of velocity profile on-site is essentially required.
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  • Tomohiko ISE, Satoshi ONOE, Toshihiko ASAMI, Iwao KAWASHIMA, Tadashi M ...
    2011 Volume 5 Issue 3 Pages 406-413
    Published: 2011
    Released on J-STAGE: December 01, 2011
    JOURNAL FREE ACCESS
    A split-type herringbone-grooved journal gas bearing has been developed to support the high-frequency rotations of a practical rotor for a micro machine such as a palmtop gas turbine generator currently in development. For this particular application, the critical mass of the rotor and the operable clearance of the journal and thrust bearings are designed to rotate at over 14 kHz ( 840,000 rpm ). The test journal bearing and rotor have a radial clearance of 0.008 mm and a mass of 0.0042 kg. The roundnesses of the test journal bearing under the processed and reassembled conditions were measured using a 3-D coordinate measuring machine and compared to verify the repeatability of the bearing assembly; the difference in the measured roundness between each condition was about 0.003 mm, which includes axial assembly error. A rotational test of the rotor supported by the bearings was performed on a test rig. In this bearing, the maximum rotational frequency of the rotor reached 13.4 kHz ( 804,000 rpm ). Therefore, the operational stability of the system was verified.
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  • Koichi HATA, Naoto KAI, Yasuyuki SHIRAI, Suguru MASUZAKI
    2011 Volume 5 Issue 3 Pages 414-428
    Published: 2011
    Released on J-STAGE: December 05, 2011
    JOURNAL FREE ACCESS
    The transient turbulent heat transfer coefficients in a short vertical Platinum test tube were systematically measured for the flow velocities (u=4.0 to 13.6 m/s), the inlet liquid temperatures (Tin=296.93 to 304.81 K), the inlet pressures (Pin=794.39 to 858.27 kPa) and the increasing heat inputs (Q0 exp(t/τ), exponential periods, τ, of 18.6 ms to 25.7 s) by an experimental water loop comprised of a multistage canned-type circulation pump with high pump head. The Platinum test tubes of test tube inner diameters (d=3 and 6 mm), heated lengths (L=66.5 and 69.6 mm), effective lengths (Leff=56.7 and 59.2 mm), ratios of heated length to inner diameter (L/d=22.16 and 11.6), ratios of effective length to inner diameter (Leff/d=18.9 and 9.87) and wall thickness (δ=0.5 and 0.4 mm) with average surface roughness (Ra=0.40 and 0.45 µm) were used in this work. The surface heat fluxes between the two potential taps were given the difference between the heat generation rate per unit surface area and the rate of change of energy storage in the test tube obtained from the faired average temperature versus time curve. The heater inner surface temperature between the two potential taps was also obtained by solving the unsteady heat conduction equation in the test tube under the conditions of measured average temperature and heat generation rate per unit surface area of the test tube. The transient turbulent heat transfer data for Platinum test tubes were compared with the values calculated by authors’ correlation for the steady state turbulent heat transfer. The influence of inner diameter (d), ratio of effective length to inner diameter (Leff/d), flow velocity (u) and exponential period (τ) on the transient turbulent heat transfer is investigated into details and the widely and precisely predictable correlation of the transient turbulent heat transfer for heating of water in a short vertical tube is given based on the experimental data and authors’ studies for the transient critical heat fluxes (CHFs) of subcooled water flow boiling in a short vertical tube caused by exponentially, ramp-wise and stepwise increasing heat inputs. The correlation can describe the transient turbulent heat transfer coefficients obtained in this work for the wide range of the temperature difference between heater inner surface temperature and average bulk liquid temperature, ΔTL, of 10 to 160 K with d=3 to 6 mm, Leff/d=9.87 to 18.9, u=4.0 to 13.6 m/s and τ=18.6 ms to 25.7 s within ±15 % difference.
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  • Jun TAO, Li-li TONG, Xue-wu CAO
    2011 Volume 5 Issue 3 Pages 429-440
    Published: 2011
    Released on J-STAGE: December 05, 2011
    JOURNAL FREE ACCESS
    Cavity flooding is an important severe accident management measure for in-vessel retention of a degraded core by external reactor vessel cooling in advanced PWRs. A code simulation study on the natural circulation flow in the gap between the reactor vessel wall and insulation material under cavity flooding condition is performed by using a detailed mechanistic thermal-hydraulic code package RELAP 5. By simulating of an experiment carried out for studying the natural circulation flow for APR 1400 shows that the code is applicable for analyzing the circulation flow under this condition. Molten corium pool in vessel lower plenum imposes highest heat load on the vessel lower head wall in large-break loss of coolant accident. The analysis results show that heat removal capacity of the natural circulation flow in AP1000 is sufficient to prevent thermal failure of the reactor vessel under this bounding heat load. By sensitivity analysis, some insights are provided for increasing the thermal margin between the heat source in the corium pool of the reactor lower plenum and the heat transfer from the lower vessel wall to the coolant in the gap by improvement of the vessel/insulation configurations.
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