著者

高橋 政行 中村 慎策 佐藤 光太郎 横田 和彦

出版者

一般社団法人 ターボ機械協会

雑誌

ターボ機械 (ISSN:03858839)

巻号頁・発行日

vol.43, no.6, pp.336-347, 2015 (Released:2018-01-11)

参考文献数

8

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The system environments of the axial flow fan are various. The axial flow fans are often used under unsuitable operating condition. Especially, the cases where the obstacles are distributed in upstream of the fan to downsize are increasing, in recent high density design of equipment. An attempt is made to clarify the influence of the obstacle on the flow characteristics of axial-flow fans. In this study, a blockage disk is installed upstream of a test fan which is a typical cooling axial-flow fan. Blockage disks with various diameters are set up. The performance curves of axial-flow fan with blockage disks are measured. In addition, flow instabilities with a cell structure are demonstrated on typical condition. The main objects of the present study are : to evaluate the performance degradation when obstacles are installed in upstream of the test fan, to elucidate causes of positive slope for the performance characteristics curves and reverse flow, to clarify the generation mechanism of flow instabilities when the blockage disks which are larger than diameter of the test fan are installed.

著者

佐藤 理那 鶴 若菜 横田 和彦

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会関東支部総会講演会講演論文集

巻号頁・発行日

vol.2019, 2019

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<p>Hyperloop is a next-generation transportation system plan that is currently being developed which is a railroad running in a tube with reduced pressure. In this research, we aim to understand the behavior of the capsule and to investigate the running stability by numerical analysis of the flow field inside the Hyperloop tube. In this study, the tube is moved at high speed in numerical calculation and the internal flow field is examined. Calculation is performed considering compressibility in non-steady computation. In addition, each parameter was calculated from the relational expression of the shock wave whose Mach number was changed and given as a condition. In the process of calculation, we changed the total pressure applied and verified in which condition shock waves occur in the tube. Also, we investigated the effects on the capsule due to the changed Mach number and the change in the speed, and made it a basic research to examine the running stability of the Hyperloop.</p>

著者

中村 みずき 白神 優理子 横田 和彦 浜野 幸一

出版者

日本共産党中央委員会 ; 1998-

雑誌

議会と自治体

巻号頁・発行日

no.231, pp.22-33, 2017-07

著者

姜 東赫 佐藤 光太郎 横田 和彦

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.17-00038-17-00038, 2017 (Released:2017-06-25)

参考文献数

15

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The present study investigates a swirl flow instability induced by a rotating cylinder between coaxial two disks as a model of a vaneless diffuser at zero flow rate. To begin with, the experiment and three-dimensional finite volume simulation were performed. The rotating cylinder was used to produce the swirl flow. Small vortices were generated from the cylinder surface. They were combing and forming one croissant-shaped toroidal vortex (CTV), which was rotating around the cylinder. Small vortices were separating from the CTV and flowing away from the cylinder. In order to investigate the cause of the swirl flow instability, a 2D stability analysis for an annular vortex street was performed. The annular vortex street became less unstable for the larger radial location and the fewer number of vortices. This implies that the vortices could be forming into one vortex as their radial locations increased. In order to validate the stability analysis, the vortex simulations were carried out. The vortices generated from the cylinder surface were forming into one cell as their radial locations increased. In order to validate the stability analysis and vortex simulation, the 2D finite volume simulation was performed. The vortices were generated from the cylinder surface. They were combining and forming one cell, which was rotating around the cylinder. The vortices were separating from one cell and flowing away from the cylinder. The frequencies of vortex rotation agreed in the experiment, the two and three-dimensional simulations. Therefore, it is considered that the 2D vortex transforms to the 3D CTV, similarly the Tayler vortex. Furthermore, all the results indicate that the 2D swirl flow instability causes the CTV, and the vortices combining to and separating from the CTV.

著者

井口 亮 伊藤 基之 玉野 真司 横田 和彦 秋野 詔夫

出版者

一般社団法人日本機械学会

雑誌

年次大会講演論文集 : JSME annual meeting

巻号頁・発行日

vol.2004, no.2, pp.319-320, 2004-09-04

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The purpose of this research is to develop a new technique for the turbulent drag reduction as the passive control. The pressure loss of three kinds of seal fur (Ribbon, Spotted and Harp seals) and an electret nonwoven fabric surfaces was measured in the channel flow using the water and glycerol-water (40 wt%). The data was compared with those of smooth and riblet surface. The drag reduction could be obtained for all kinds of seal fur surfaces; it was estimated to be 11.5 % on ribbon seal, 9.5 % on spotted seal and 3.5 % on harp seal for glycerol-water, while the drag reduction was not achieved for the electret nonwoven fabric surface.

著者

佐藤 光史 横田 和彦 内田 久則 吉田 宗紀 大宮 東生 大場 正己 阿曽 弘一 藤田 芳邦 矢島 義忠 真崎 義彦

出版者

北里大学

雑誌

北里医学 (ISSN:03855449)

巻号頁・発行日

vol.11, no.5, pp.493-498, 1981-10-31

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30頭の雑種成犬を用い,血管吻合による同種膵移植実験を行なった。15頭のdonorとして用いるイヌに気管内挿管による全身麻酔を施行し,腹部正中切開で開腹した。門脈ならびに腹腔動脈,上腸間膜動脈を含め全膵を摘出し,門脈ならびに腹腔動脈より4℃乳酸加リンゲル液を用い膵を灌流した。15頭のrecipient犬も全身麻酔下で腹部正中切開で開腹し腹腔内に膵移植を施行した。donorの門脈をrecipientの下大静脈に,donorの腹腔動脈と上腸間膜動脈の起始部をrecipientの腎動脈分岐より下の大動脈に吻合した。空腸はRoux-en Y脚とし,主膵管と副膵管をそれぞれ空腸と吻合し,さらに胆嚢空腸吻合,胃空腸吻合を施行した。recipientの死因は膵炎,術後腹腔内出血,血管吻合部血栓による膵壊死が多かった。9日以上生存したイヌは6頭であり,免疫抑制剤を用いなかったrecipient 5頭の平均生存日数は12.8±3.4 (M±SD)日であった。血管吻合,膵管空腸吻合による膵移植実験は可能性があり,臨床応用にとっても良い方法であると考えている。