巻号一覧
39 巻, 6 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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斉藤 純夫, 高橋 正旭, 永田 佳未, 出嶌 京太原稿種別: 論文
2011 年 39 巻 6 号 p. 323-331
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーWater hammer pumps can effectively use the water hammer phenomenon in long-distance pipeline networks that include pumps and allow fluid transport without drive sources, such as electric motors. The results of experiments that examined the effect of the geometric form of water hammer pumps by considering their major dimensions have been reported. In addition, a paper has also been published analyzing the water hammer phenomenon numerically by using the characteristic curve method for comparison with experimental results. However, these conventional studies have not fully evaluated the pump performance in terms of pump head and flow rate, common measures indicating the performance of pumps. Therefore, as a first stage for the understanding of water hammer pump performance in comparison to the characteristics of typical turbo pumps, the previous paper experimentally examined how the hydrodynamic characteristics were affected by the inner diameter ratio of the drive and lifting pipes, the form of the air chamber, and the angle of the drive pipe. To understand the behavior of the components attached to the valve chamber and the air chamber that affects the performance of water hammer pumps, the previous study also determined the relationship between the water hammer pump performance and temporal changes in valve chamber and air chamber pressures according to the air chamber capacity. For the geometry of components attached to the drain valve, another major component of water hammer pumps, this study experimentally examines how the water hammer pump performance is affected by the length of the spring and the angle of the drain pipe.抄録全体を表示PDF形式でダウンロード (202K) -
山田 和豊, 古川 雅人, 福島 久剛, 茨木 誠一原稿種別: 論文
2011 年 39 巻 6 号 p. 332-339
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーThe objective of the present paper is to identify vortical and separated flow structures in a transonic centrifugal compressor impeller with splitter blades at an off-design condition. Steady state single passage RANS and time-accurate full annulus DES calculations are used to investigate the flow field inside the centrifugal impeller. In order to clearly show distinctive flow structures in the unsteady flow field at the off-design condition, the time-averaged flow field from the DES calculation is investigated by being compared with the RANS result. It is observed that a horseshoe vortex is generated in front of the splitter blade tip due to a reversed flow inside the impeller near the casing, being integrated with leading-edge separation vortex, tip leakage vortex and secondary flow vortex out of the full blade to form one large-scale vortical flow structure.抄録全体を表示PDF形式でダウンロード (197K) -
（定常流条件下での二次元デバイスの効果）船﨑 健一, 田中 望, 柴 孟宏, 谷光 玄行, 浜辺 正昭原稿種別: 論文
2011 年 39 巻 6 号 p. 340-348
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーThis study aims at the development of a new method to increase aerodynamic loading of low-pressure turbine airfoils for modern aeroengines to a great extent for the sake of drastic reduction of their airfoil counts. This study proposes a twodimensional device on the airfoil suction surface to suppress the separation bubble that causes large aerodynamic loss, especially at low Reynolds number condition. This paper describes experimental investigations on aerodynamic performance of the airfoils with the device under steady-state flow conditions. The main objective of this paper is to show how and to what extent the device without any other disturbances affects the suction surface boundary layer accompanying separation buble. It turns out from the detailed experiments that the device on the airfoil surface can effectively suppress the separation bubble, resulting in significant improvement of cascade aerodynamic performance.抄録全体を表示PDF形式でダウンロード (178K) -
(子午面形状の影響)金子 雅直, 辻田 星歩原稿種別: 論文
2011 年 39 巻 6 号 p. 349-357
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーA single stage ultra micro centrifugal compressor constituting ultra micro gas turbine is required to operate at high rotational speed in order to achieve the pressure ratio which establishes the gas turbine cycle. As a consequence, the relative Mach number of the flow in the impeller passage increases and then the shock wave which causes the loss by the interaction with the boundary layer on the blade surface can be induced. In addition, the restriction of processing technology for the downsizing of impeller not only relatively enlarges the size of tip clearance but also makes it difficult to process the impeller with the three-dimensional blade. Therefore, it is important to establish the design technology for the impeller with two-dimensional blade which possesses the sufficient aerodynamic performance and enough strength to bear the centrifugal force caused by the high rotational speed. In this study, the flow in two types of impeller with the two-dimensional blade which have different meridional configuration was analyzed numerically. The computed results clarified the effects of the meridional configuration on the loss generation in the impeller passage.抄録全体を表示PDF形式でダウンロード (211K) -
川崎 聡, 木村 俊哉, 内海 政春, 須田 一志原稿種別: 論文
2011 年 39 巻 6 号 p. 358-365
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーIn this study, numerical investigation of coolant flow across the angular contact ball bearing in a rocket turbopump was performed to evaluate pressure loss of the bearing. The results show that the pressure loss tendencies against the bearing revolution speed were significantly different between the flow directions. It was mainly caused by the flow separation behind the ball and centrifugal force effect of swirl flow made by bearing revolution. Furthermore, we get a simplified pressure loss model of the bearing and it can approximately estimate the difference of the pressure losses between the flow directions.抄録全体を表示PDF形式でダウンロード (182K) -
重光 亨, 福富 純一郎, 岡本 慎司, 久保 慧史原稿種別: 論文
2011 年 39 巻 6 号 p. 366-372
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーFluid machineries for fluid food have been used in wide variety of field i.e. transportation, filling and improvement of the quality of fluid food. Although, flow conditions of it are quite complicated because fluid food is different from water. Therefore, the design method based on the internal flow conditions is not conducted. In this research, turbo-pump having small number of blade number was used to decrease shear loss and keep wide flow passage. In this paper, performance and internal flow conditions of turbo-pump using low viscous fluid were clarified by experimental and numerical analysis results.抄録全体を表示PDF形式でダウンロード (169K) -
下川 海, 岩本 俊介, 大熊 九州男, 廣渡 光太朗, 渡邉 聡, 古川 明徳, 松下 大介原稿種別: 論文
2011 年 39 巻 6 号 p. 373-379
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーA two dimensional Darrieus-type turbine has been proposed for hydropower utilization of extra-low head less than 2m. Though a hydro turbine system consists of an intake, runner section and draft tube for higher efficiency operation, it was found in previous study that a draft tube and side-wall casings of runner section could be removed with improving turbine performance by installation of an inlet nozzle. In the present paper, first, effects of inlet nozzle width and positions on turbine performance are experimentally examined considered at first. After clarifying the optimum inlet nozzle, performances of four 4 bladed Darrieus-type turbine with the simplified geometry are investigated and are discussed in terms of flow rate variation and self-starting characteristics.抄録全体を表示PDF形式でダウンロード (166K)
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