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Volume 39, Issue 10
Displaying 1-7 of 7 articles from this issue
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Technical papers
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Norimasa SHIOMI, Yoichi KINOUE, Toshiaki SETOGUCHIArticle type: Technical papers
2011 Volume 39 Issue 10 Pages 577-586
Published: 2011
Released on J-STAGE: March 13, 2014
JOURNAL FREE ACCESSIn order to develop the low specific speed diagonal flow fan with good performance, low specific speed（Ns=670（min-1, m3/min, m））diagonal flow fan was designed using a quasi-three-dimensional aerodynamics design method, the fan test was carried out, and the internal flow fields were measured by the use of 5 hole Pitot tube and hotwire anemometer with a slant hotwire probe. From the result of fan test, the test fan designed showed a good performance at the design point. From the results of internal flow measurement, mean velocity distributions for meridional and tangential velocity near design flowrate were similar distributions of design condition. From the phase-lock averaged velocity distributions, it is also found at all measurement flowrate that there exists the region with low meridional velocity and high tangential velocity in blade passage.View full abstractDownload PDF (225K) -
Ryo KAGAYA, Masaru SHONAI, Yuhei FUJIMURA, Koji NAKAGAWAArticle type: Technical papers
2011 Volume 39 Issue 10 Pages 587-593
Published: 2011
Released on J-STAGE: March 13, 2014
JOURNAL FREE ACCESSIn this study, two horizontal axis wind turbines with delta-wing were tested. The starting torque coefficient reached half the value of Savonius wind turbine and the power coefficient of one model reached the level of Dalius wind turbine. To examine these characteristics, torque coefficient was estimated by using wind tunnel data of delta-wing. Adding to this, to analyze the flow around the turbine, visualization by surface tuft method and numerical simulation were conducted. The result showed that the leading edge separated vortex which is characteristic phenomena of delta wing has little effect on the starting torque coefficient.View full abstractDownload PDF (200K) -
Yumeto NISHIYAMA, Takayuki SUZUKI, Koichi YONEZAWA, Hiroshi TANAKA, Pe ...Article type: Technical papers
2011 Volume 39 Issue 10 Pages 594-605
Published: 2011
Released on J-STAGE: March 13, 2014
JOURNAL FREE ACCESSPhase resonance was studied by using a centrifugal compressor for vacuum cleaner. It was found from experiments and CFD that pressure fluctuation at the volute outlet becomes the maximum when the rotational speed of the mode caused by the rotor-stator interaction agrees with the sound velocity. A simple one-dimensional theory is presented to explain the phase resonance in turbomachinery.View full abstractDownload PDF (233K) -
Yuji KANEMORI, Kazuhiko MOTOZAKIArticle type: Technical papers
2011 Volume 39 Issue 10 Pages 606-615
Published: 2011
Released on J-STAGE: March 13, 2014
JOURNAL FREE ACCESSThe submerged vortex should be eliminated to decrease the vibration. It is necessary to increase the pump flow rate while preventing the occurrence of vortices with submerged vortex breaker. The pump discharge quantity should be increased without changing the shape of the sump construction, because the sump design is frequently beyond the control of the pump designer. In this study, the pump performance test is conducted with several types of suction bells. The influence of suction bell shape on the behavior of vortex and pressure fluctuation and vibration is studied, and it is found that the submerged vortex can be controlled with the multi suction bells. A pump flow rate with an ordinary bell can be increased with the application of multi suction bells. It is confirmed that the submerged vortex can be controlled to decrease the pressure fluctuation and the vibration.View full abstractDownload PDF (284K) -
Masami SUZUKI, Kazumasa AMEKUArticle type: Technical papers
2011 Volume 39 Issue 10 Pages 616-623
Published: 2011
Released on J-STAGE: March 13, 2014
JOURNAL FREE ACCESSComputational fluid dynamics（CFD）modeling and experiments have both advantages and disadvantages. Doing both can be complementary, and more effective understanding of the phenomenon can be expected. It is useful to utilize CFD as an efficient tool for the turbomachinery and can complement uncertain experimental results. However the CFD simulation takes a long time for a design in general. It is necessary to reduce the calculation time for many design conditions. In this paper, it is attempted to obtain the more accurate characteristics of a wind turbine in yawed flow conditions for a short time, using a few grid points. It is discussed for the reliability of the experimental results and the CFD results.View full abstractDownload PDF (141K) -
Hidechito HAYASHI, Kyohei NAKAMURA, Souichi SASAKI, Seiji SHIRAHAMA, A ...Article type: Technical papers
2011 Volume 39 Issue 10 Pages 624-631
Published: 2011
Released on J-STAGE: March 13, 2014
JOURNAL FREE ACCESSThe flow characteristics of the turbo fan with a rectangular casing are investigated with experiments and simulations. The length of the casing is varied. It is cleared that the performance of the fan is not influenced with length of the rectangular casing. The pressure on the casing varies with the section geometry, but the pressure out of the impeller varies mainly with the distortion of the net flow. When the net flow out of the impeller increases, the pressure decreases at the outlet of the fan. The discrete frequency noise from the fan is mainly generated by the interaction of the distorted net flow and the blades.View full abstractDownload PDF (160K) -
Akiyasu TAKAMI, Shinya OKUHARA, Manabu TAKAO, Toshiaki SETOGUCHIArticle type: Technical papers
2011 Volume 39 Issue 10 Pages 632-637
Published: 2011
Released on J-STAGE: March 13, 2014
JOURNAL FREE ACCESSA unique twin impulse turbine has been proposed in order to enhance the performance of wave energy plant. This turbine system uses two impulse turbines to make a unidirectional flow and their flow direction in the plant is different each other. The one is suitable to inhalation in the plant and another one is for exhalation. However, characteristics of the twin turbine have not been clarified to date. The performances of a unidirectional impulse turbine under steady flow conditions were investigated experimentally by using a wind tunnel with large piston/cylinder in this study. Then, efficiency of the twin impulse turbine has been estimated by a quasi-steady analysis using experimental results.View full abstractDownload PDF (106K)
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