巻号一覧
39 巻, 2 号
選択された号の論文の7件中1～7を表示しています
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論文
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姜 東赫, 有本 悠祐, 米澤 宏一, 堀口 祐憲, 川田 裕, Chunill Hah, 辻本 良信2011 年 39 巻 2 号 p. 65-78
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーThe purpose of the present research is to suppress cavitation instabilities by using a circumferential groove. The circumferential groove was designed based on CFD so that the tip leakage vortex is trapped by the groove and does not interact with the next blade. Experimental results show that the groove can suppress rotating cavitation, asymmetric cavitation and cavitation surge. However, weak instabilities with higher frequency occurred in a wide range of cavitation number. From the analysis of pressure pattern similar to that for rotor-stator interaction, it was found that the higher frequency components are caused by the interaction of backflow vortices with the inducer blades.抄録全体を表示PDF形式でダウンロード (369K) -
（騒音との相関に関する考察）船﨑 健一, 高橋 友恵, 谷口 英夫, 山田 和豊原稿種別: 論文
2011 年 39 巻 2 号 p. 79-86
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーIt is quite usual that the small axial flow fan used for PCs is installed in narrow space. In such a case the fan performance and flow field are supposed to be different from those of design conditions. In addition, influences that obstacles upstream and downstream of the fan give to the fan performance are not well understood. In this study, we measure the flow field and performance of a PC cooling fan used under realistic conditions. Furthermore, we compare calculated results with the experimental results.抄録全体を表示PDF形式でダウンロード (165K) -
斉藤 純夫, 高橋 正旭, 永田 佳未原稿種別: 論文
2011 年 39 巻 2 号 p. 87-94
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーRecently, as global-scale problems, such as global warming and energy depletion, have attracted attention, the importance of future environmental preservation has been emphasized worldwide, and various measures have been proposed and implemented. This study focuses on water hammer pumps that can effectively use the water hammer phenomenon and allow fluid transport without drive sources, such as electric motors. An understanding of operating conditions on water hammer pumps and an evaluation of their basic hydrodynamic characteristics are significant for determining whether they can be widely used as an energy-saving device in the future. However, conventional studies have not described the pump performance in terms of pump head and flow rate, common measures indicating the performance of pumps. As a first stage for the understanding of water hammer pump performance in comparison to the characteristics of typical turbo pumps, previous study focused on understanding the basic hydrodynamic characteristics of water hammer pumps and experimentally examines how the hydrodynamic characteristics are affected by the inner diameter of the drive and lifting pipes and the angle of the drive pipe. This paper proposes the effect of air volume in air chamber that affects the hydrodynamic characteristics and operation conditions of the water hammer pump.抄録全体を表示PDF形式でダウンロード (198K) -
鈴木 正己原稿種別: 論文
2011 年 39 巻 2 号 p. 95-102
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーTwo dimensional numerical analysis of Darrieus turbine is carried out with an Unsteady Reynolds-Averaged Navier- Stokes (URANS) equation and a structured mesh configuration using overset grid approach. It is confirmed that the calculations are in agreement with the experimental results for the tip speed ratio more than two at which the maximum power coefficient is obtained by the experiment. It is possible to solve the flow field around the turbine by the URANS in reasonable calculation time and the result practical enough is obtained in the flow field where the tip speed ratio is comparatively high and the separation is small.抄録全体を表示PDF形式でダウンロード (190K) -
江尻 英治, 岡田 克彦原稿種別: 論文
2011 年 39 巻 2 号 p. 103-111
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーTwo-dimensional flow around an automotive torque converter stator was investigated computationally using a generalpurpose computational fluid dynamics code. Two turbulence models for the main stream and three methods of treating the flow near the blade wall were used. The computation results were compared with experimental data obtained by PIV using a two-dimensional linear cascade in a circulating water channel. The results showed that the standard k-ε model employing the wall function as a boundary condition on the wall was not able to predict accurately the separated flow near the leading edge on the blade suction surface. A second-order nonlinear k-ε model using a low Reynolds number type of handling method near the wall gave the closest results to the measured data for the velocity vector field and total pressure loss coefficient. All the computed results for the turning angle showed tendencies similar to the experimental data with little discrepancy in absolute values.抄録全体を表示PDF形式でダウンロード (394K) -
重光 亨, 福富 純一郎, 名定 亮一, 梶 兼輔原稿種別: 論文
2011 年 39 巻 2 号 p. 112-118
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーMini turbo-pumps having a diameter smaller than 100 mm are employed in many fields. Further, the needs for mini turbo-pumps would become larger with the increase of the application of them for electrical machines. It is desirable that the mini-turbo pump design is as simple as possible due to restriction to make precise manufactures. But the design method for the mini turbo-pump is not established because the internal flow condition for these small-sized fluid machineries is not clarified and conventional theory is not conductive for small-sized pumps. Three types of rotors with different outlet angles are prepared for an experiment and a numerical analysis. The performance tests are conducted with these rotors in order to investigate the effect of the outlet angle on rotor performance and internal flow condition of mini-turbo pumps. It is clarified from the numerical results that rotor performance of each type of rotors shows almost the same results, however pump performance of the rotor with large blade outlet angle becomes lower than that with small blade outlet angle. In the present paper, the detailed performance of the mini turbo-pump is shown and the internal flow condition is clarified with the results of the experiment and the numerical flow analysis. Furthermore, the causes of the pump performance decrease of the rotor with the large blade outlet angle are considered.抄録全体を表示PDF形式でダウンロード (144K) -
百崎 晋平, 宇佐見 聡, 渡邉 聡, 古川 明徳, 大熊 九州男原稿種別: 論文
2011 年 39 巻 2 号 p. 119-125
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーAn application of contra-rotating rotors, in which a rear rotor is in tandem with a front one and these rotors rotate in the opposite direction to each other, has been proposed for higher specific speed axial flow pump. Then the superiority of efficiency and cavitation performance of contra-rotating type has been clarified from experimental comparison with the conventional type in addition to the difficulty of high performance design of it. In the present study, the possibility of performance improvement of contra-rotating axial flow pump by rotational speed controls of front and rear rotors were experimentally investigated. The substantial improvement of pump efficiency was achieved from the partial to the over flow rate by the rotational speed control of rear rotor and was achieved at the lower flow rates by that of front rotor.抄録全体を表示PDF形式でダウンロード (138K)
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