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39 巻, 4 号
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論文
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重光 亨, 福富 純一郎, 名定 亮一, 岡本 慎司原稿種別: 論文
2011 年 39 巻 4 号 p. 208-215
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーMini turbo-pumps which have a diameter smaller than 100 mm are utilized in many fields. It is desirable that the mini turbo-pump design is as simple as possible due to the limitation of the precision for manufacture. But the design method for the mini turbo-pump is not established. Therefore, we started the research of the mini turbo-pump for the purpose of development of high performance mini turbo-pump with simple structure. It is clarified from the numerical results that head and efficiency decrease drastically with the increase of the tip clearance and the flow condition near the tip region is influenced by the leakage flow from the blade tip. In the present paper, the performance of the mini turbo-pump is shown and the internal flow condition is clarified with the results of the numerical flow analysis. Furthermore, the effects of the tip clearance on the performance are investigated and high performance rotor design for mini turbo-pump would be considered.抄録全体を表示PDF形式でダウンロード (167K) -
佐藤 利行, 鶴田 浩史, 渕脇 正樹, 田中 和博原稿種別: 論文
2011 年 39 巻 4 号 p. 216-223
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーCavitation creates three major issues which are degradation in pump, pump vibrations/noises and erosion. In order to avoid cavitation, design change and improvement of process conditions have been considered as normal design practice. Many researchers have been trying to analyse the detail of cavitation mechanism including behavior of vortex cavitation, however it has not been clarified yet. On the other hand, CFD is very useful for comprehending cavitation phenomena and CFD code has always been developed. It is well-known that there are three types of cavitation in a double-suction volute pump. These are called as vortex cavitation, reverse flow vortex cavitation and cloud cavitation. In this paper, the behaviors of vortex cavitation in the double-volute suction pump will be analyzed by using CFD.抄録全体を表示PDF形式でダウンロード (199K) -
橋本 圭佑, 川口 清司, 竹田 知弘原稿種別: 論文
2011 年 39 巻 4 号 p. 224-231
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーThe fan heater used for industry and residence has become smaller, lighter, and more silent as the result of improvement. However there are problems that the fan heater size is large, and the noise is high due to air pressure loss of heat exchangers. Therefore we have been developing the centrifugal type fan with the function of heat exchanger. The features of this new type fan heater are that the fan heater size is very small and silent because the fan and the heat exchanger are in one body. This paper described the effects of the flow between fan blades on the distribution of Nusselt number on the blade surface of fans with different diameter. The heat transfer characteristics and the flow patterns in the fans with different diameter were clarified by calculating the flow in the fan, and measuring the local heat transfer coefficient on the blade surface.抄録全体を表示PDF形式でダウンロード (175K) -
髙橋 直彦, 三浦 治雄, 成田 光裕, 真柄 洋平原稿種別: 論文
2011 年 39 巻 4 号 p. 232-237
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーIn order to evaluate the rotor stability of a high pressure compressor, the forward eigen modes need to be distinguished from the backward eigen modes, and the frequencies and the damping ratios need also to be identified with a good accuracy. In this paper, a complex expression is introduced for the rotor motion and a directional frequency response functions that enable the separation of those modes in the frequency domain is derived. Curve fitting is also introduced for the frequency response functions to determine the frequencies and damping ratios based on system identification methods, such as prediction error methods. These techniques were applied to a stability evaluation for the low pressure gas operation, in which condition the stability mainly depends on the bearing property. Finally, the bearing coefficients are estimated by using an optimization method.抄録全体を表示PDF形式でダウンロード (116K) -
（翼先端外側の速度変動場）塩見 憲正, 木上 洋一, 瀬戸口 俊明原稿種別: 論文
2011 年 39 巻 4 号 p. 238-248
発行日: 2011年
公開日: 2013/05/31
ジャーナル フリーIn order to clarify the inlet flow fields of a semi-opened propeller fan with bellmouth at low flow-rate region, especially the flow fields outside of blade tip, the experimental investigation was carried out using hot-wire anemometer. The axial and tangential velocity component including the radial velocity component were measured using a single I-type hot-wire probe. FFT analysis was done to search the periodical fluctuation with frequency different from the one for rotor rotating. And, the distributions of velocity fluctuations on meridional plane were shown to obtain the flow structure at low flow-rate. As a result, it was confirmed that two types of periodical fluctuations without rotor rotating frequency, which are similar to rotating stall, occur. One has a frequency of approximately 7 Hz at φ=0.210 near rear portion of open area, and the other has as frequency of 10 Hz at φ=0.180 near front portion of open area. It is also found that the flow condition largely changes near these flow-rates.抄録全体を表示PDF形式でダウンロード (193K)
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