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 光太郎 廣瀬 智水 古屋 興二

出版者

社団法人 可視化情報学会

雑誌

可視化情報学会論文集 (ISSN:13465260)

巻号頁・発行日

vol.26, no.7, pp.62-68, 2006 (Released:2006-07-31)

参考文献数

11

被引用文献数

2 2

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医療用輸液ポンプでは点滴法により流量を計測する場合がある.点滴筒は液滴体積が出口径によって決定されるという仮定の下に設計され,医師や看護士は滴落下時間間隔から視覚的に輸液状況を確認できる反面,精度の面からは液滴体積は液体の物性に依存し,さらにサテライト滴をも形成するため,常に設計通りの体積の液滴が落下するとは限らない.これまでも多くの研究者らによって研究がなされてきたが,液滴形成には局所的高速現象が含まれていることから断片的な挙動観察が多く,実験による系統的な観察例は多くない. 本研究は安定した薬液の輸液システム開発をはじめ,様々な分野での応用が期待される液滴制御の基礎的研究として,種々なる条件下での液滴形成過程を高速度ビデオカメラにより観察した.主として液滴分離時に生じる諸現象を含む液滴形成機構と物性および流量との関係を調べ,さらに液滴形成に及ぼす液滴形成部出口形状の影響についても議論した.

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

佐藤 光太郎 納富 昭光 太田 勇 中島 裕輔

出版者

一般社団法人日本建築学会

雑誌

学術講演梗概集. D-1, 環境工学I, 室内音響・音環境, 騒音・固体音, 環境振動, 光・色, 給排水・水環境, 都市設備・環境管理, 環境心理生理, 環境設計, 電磁環境 (ISSN:13414496)

巻号頁・発行日

vol.2008, pp.1223-1224, 2008-07-20