All issues
Volume 38, Issue 4
Displaying 1-4 of 4 articles from this issue
- |<
- <
- 1
- >
- >|
Technical papers
-
Nobutaka HAYASHI, Masaharu KOYAMA, Masatoshi SANO2010 Volume 38 Issue 4 Pages 215-226
Published: 2010
Released on J-STAGE: May 19, 2011
JOURNAL FREE ACCESSThe flow field during rotating stall in a radial vaneless diffuser was investigated experimentally using PIV. Experiments were conducted in a radial vaneless diffuser of an open loop centrifugal blower. Although PIV offers high spatial resolution, it is inadequate measuring method for the flow with large velocity fluctuation such as inside the turbo machinery because of its low resolution in time domain. During the experiments static pressure and instants of the frame acquisition were also recorded. Unsynchronized relation between the time instant of the frame acquisition and the pressure signal allowed to measure different phases of periodic phenomena. And the velocity data was reordered in the postprocessing procedure. As result, the velocity field of the diffuser during rotating stall is clarified precisely.View full abstractDownload PDF (264K) -
Daisuke MATSUSHITA, Yoshinori HARA, Satoshi WATANABE, Akinori FURUKAWA ...2010 Volume 38 Issue 4 Pages 227-233
Published: 2010
Released on J-STAGE: May 19, 2011
JOURNAL FREE ACCESSThe estimation of wind turbine performance over complex terrain is very difficult because the document of standard IEC61400-12 is adapted on flat or slightly complex topography. And the cost of constructing a meteorological mast becomes higher with scaling wind turbine up. Authors have proposed numerical site calibration (NSC) in order to estimate the inflow velocity at the position of wind turbine by using CFD tool for calculating flow field around the site. The present paper shows problems on the procedure of NSC where a commercial nonlinear CFD tool and the method is improved to obtain more accurate result. It is clarified that the wind turbine performance, which is estimated with the calculated wind speed on the meteorological mast by the improved method has a good result for annual energy production.View full abstractDownload PDF (115K) -
Tomoyasu TSUYUKI, Kenji SHINGAI, Kiyohito TANI2010 Volume 38 Issue 4 Pages 234-239
Published: 2010
Released on J-STAGE: May 19, 2011
JOURNAL FREE ACCESSThe draft tube of bulb turbines, which is a diffuser to convert kinetic energy into static pressure by decelerating the flow, plays an important role in turbine efficiency. The flow in draft tubes is characterized by the swirl flow at the runner outlet. In order to estimate the effect of swirl intensity on the total pressure loss in the draft tube of the bulb turbine, full-model simulations that include whole hydraulic components are compared to results obtained from the model test. The simulation results show the swirl intensity is an effective parameter for prediction of turbine efficiency. In addition, using the relation between the swirl intensity and the total pressure loss obtained from full-model simulations, single-passage simulations of the runner are able to predict the efficiency of the bulb turbine with the draft tube.View full abstractDownload PDF (135K) -
Naoto SAKAI2010 Volume 38 Issue 4 Pages 240-247
Published: 2010
Released on J-STAGE: May 19, 2011
JOURNAL FREE ACCESSIn the present paper, a 3-dimensional numerical study of partial admission stages of a steam turbine is described. Three models : Q3-D model only on mean diameter, 3-D model without tip clearances and disk cavities, and 3-D model with tip clearances and disk cavities, are applied and their results are compared with experimental results of a single stage air turbine. The mechanism of loss generation in partial admission stages is discussed by comparison with full arc admission stages. Tip leakage flow plays more significant role in partial admission stages.View full abstractDownload PDF (148K)
Review
- |<
- <
- 1
- >
- >|