Journal of Power and Energy Systems
Online ISSN : 1881-3062
ISSN-L : 1881-3062
Volume 3, Issue 2
Displaying 1-7 of 7 articles from this issue
Papers
  • Shin'ya OBARA, Abeer Galal El-Sayed
    2009 Volume 3 Issue 2 Pages 321-332
    Published: 2009
    Released on J-STAGE: March 12, 2009
    JOURNAL FREE ACCESS
    A bioethanol reforming system (FBSR) with a sunlight heat source is developed as a potential fuel supply system for distributed fuel cells. The temperature distribution of a catalyst layer in the reactor is not stable under conditions of unstable solar radiation and unstable outside air temperature; therefore, it is thought that the inversion rate of a reforming reaction will decrease. In this paper, heat transmission analysis was used in the catalyst layer of the reforming component of an FBSR, and temperature distribution, inversion rate, and process gas composition were investigated. Based on the results, the relationship between weather conditions and a hydrogen-generating rate was determined. When solar insolation was unstable, it turned out that the efficiency of the reforming component is reduced. Fluctuations of the solar insolation over a short period of time affect the hydrogen generating rate of an FBSR. Moreover, the amount of hydrogen production of an FBSR was simulated using meteorological data from a day in March and a day in August in a cold region (Sapporo). The analysis showed that efficiency of the reforming component exceeded 40% for both of the days.
    Download PDF (883K)
  • Jun MANABE, Katsuhiko YAMAKAMI, Satoshi HIRAOKA, Toshinari KAWAI
    2009 Volume 3 Issue 2 Pages 333-346
    Published: 2009
    Released on J-STAGE: May 12, 2009
    JOURNAL FREE ACCESS
    A lifecycle management program, for turbine balance of plant of light water reactor units which had been operated for more than 20 years but still having a long intended residual life time, was proposed and implemented from the view point of system and equipment supplier. Here would be introduced the program executed for several utilities. The program consists of unit surveillance analyzing both operation and inspection data, degradation assessment for the equipment and prospecting for the future by planning the proper measures for the issues based on both technology and economy. The program is introduced exampling the generating power affected by main steam pressure reduction derived from the scale adhesion and degradation of equipment. Multidisciplinary optimum design for the replacement of the feedwater heaters, one of the items of the planning, is introduced. Additionally would be introduced the new concept maintenance support program, mainly applied to the units already replaced their principal machines and auxiliaries, configured with both the condition based maintenance system monitoring the trend of parameters of a component and the diagnosis of malfunctions ascertaining the equipment by analyzing and synthesizing operation parameters.
    Download PDF (827K)
  • Hironobu KATAOKA, Yusuke SHINKAI, Akio TOMIYAMA
    2009 Volume 3 Issue 2 Pages 347-355
    Published: 2009
    Released on J-STAGE: July 07, 2009
    JOURNAL FREE ACCESS
    Experiments on two-phase swirling flow in a separator are carried out using several swirlers having different vane angles, different hub diameters and different number of vanes to seek a way for improving steam separators of uprated boiling water reactors. Ratios of the separated liquid flow rate to the total liquid flow rate, flow patterns, liquid film thicknesses and pressure drops are measured to examine the effects of swirler shape on air-water two-phase swirling annular flows in a one-fifth scale model of the separator. As a result, the following conclusions are obtained for the tested swirlers: (1) swirler shape scarcely affects the pressure drop in the barrel of the separator, (2) decreasing the vane angle is an effective way for reducing the pressure drop in the diffuser of the separator, and (3) the film thickness at the inlet of the pick-off-ring of the separator is not sensitive to swirler shape, which explains the reason why the separator performance does not depend on swirler shape.
    Download PDF (1597K)
  • Tetsuya FUNATSU, Hiroaki NATSUME
    2009 Volume 3 Issue 2 Pages 356-367
    Published: 2009
    Released on J-STAGE: August 27, 2009
    JOURNAL FREE ACCESS
    A pumped storage hydroelectric generation (PSHG) has been studied as alternative peak power source of the oil-fired power generation in Indonesia. However, because there is no surplus base load electricity even in the night, the economic advantage can not be found. The possibility of solar thermal power generation (STPG) is investigated to restrain the increase of fuel consumption by the existing peak power source. The optimum system simulation and the analysis of economy and environmental impact by a multiobjective optimization method provide the following results. The optimum aperture area and thermal storage capacity of STPG are found by the simulation based on the climate and the solar condition in West Java. PSHG with STPG as the power source of storage pump shows lower generation cost and CO2 emission than PSHG with existing oil fired peak power sources. Even if the fuel switch from oil to gas is supposed in future, PSHG with STPG will achieve the lower generation cost and CO2 emission than PSHG with the oil/gas fired combined cycle by sharing the peak electricity supply with the oil/gas fired combined cycle in an appropriate ratio. Furthermore, if the crude oil price hike in future is considered, PSHG with STPG may be the optimal solution for the peak electricity supply of Java-Bari grid.
    Download PDF (382K)
  • Jun MANABE, Jiro KASAHARA
    2009 Volume 3 Issue 2 Pages 368-381
    Published: 2009
    Released on J-STAGE: August 27, 2009
    JOURNAL FREE ACCESS
    This paper introduces the development of the current model Moisture Separator Reheater (MSR) for nuclear power plant (NPP) turbines, commercially placed in service in the period 1984-1997, focusing on the mist separation performance of the MSR along with drainage from heat exchanger tubes. A method of predicting the mist separation performance was devised first based on the observation of mist separation behaviors under an air-water test. Then the method was developed for the application to predict under the steam conditions, followed by the verification in comparison with the actual results of a steam condition test. The instability of tube drainage associated with both sub-cooling and temperature oscillation might adversely affect the seal welding of tubes to tube sheet due to thermal fatigue. The instability was measured on an existing unit to clarify behaviors and the development of a method to suppress them. Both methods were applied to newly constructed units and the effectiveness of the methods was demonstrated.
    Download PDF (1313K)
  • Hironobu KATAOKA, Yusuke SHINKAI, Akio TOMIYAMA
    2009 Volume 3 Issue 2 Pages 382-392
    Published: 2009
    Released on J-STAGE: September 01, 2009
    JOURNAL FREE ACCESS
    Pressure drop and liquid film thickness in air-water swirling flows in a one-fifth scale model of the steam separator are measured for a wide range of gas and liquid volume fluxes. Numerical simulations based on one-dimensional single-fluid and two-fluid models are also carried out to examine the feasibility of predicting the pressure drop and film thickness in swirling flows. The pressure drop in a single-phase swirling flow is about five times as large as that in a non-swirling flow due to the increase in the frictional pressure drop. The pressure gradient and liquid film thickness in a two-phase swirling annular flow at the inlet of the pick-off-ring of the separator are well evaluated by using a standard one-dimensional two-fluid model, provided that the interfacial and wall frictions in an ordinary two-phase annular flow are multiplied by appropriate constant values.
    Download PDF (636K)
  • Zheng ZHANG, Shigeo HOSOKAWA, Kosuke HAYASHI, Akio TOMIYAMA
    2009 Volume 3 Issue 2 Pages 393-404
    Published: 2009
    Released on J-STAGE: September 07, 2009
    JOURNAL FREE ACCESS
    Numerical simulations based on a three-dimensional two-way bubble tracking method are carried out to predict bubble motions in a square duct with an obstacle and in a two-by-three rod bundle with a grid spacer. Comparisons between measured and predicted bubble motions demonstrate that the two-way bubble tracking method gives good predictions for trajectories of small bubbles in the upstream side of the grid spacer in the rod bundle geometry. The predicted bubble trajectories clearly show that bubbles are apt to migrate toward the rod surface in the vicinity of the bottom of the grid spacer. Analysis of forces acting on the bubbles confirms that pressure gradient force induced by the presence of the spacer is the main cause of the bubble lateral migration toward the rod surface. Motions of steam bubbles at a nominal operating condition of a pressurized water reactor (PWR) are also predicted by using the bubble tracking method, which indicates that steam bubbles also migrate toward the rod surface at the upstream side of the spacer due to the spacer-induced pressure gradient force.
    Download PDF (3099K)
feedback
Top