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Suction Performance and Cavitation Instabilities of Turbopumps with Three Different Inducer Design
Tatsuya Morii,Yohei Tanaka,Satoshi Watanabe,Satoru Ohashi,Yasushi Matsunaga 한국유체기계학회 2019 International journal of fluid machinery and syste Vol.12 No.2
In the present study, the suction performance and the cavitation instabilities in turbo-pumps with three different inducers designed with different design incidence angle are experimentally investigated in the wide range of operating flow rate. Three inducers L with the lowest design incidence angle, M with the moderate one and H with the largest one are used in combination with identical main impeller. As a result, the total head of pump with inducer H is confirmed to be the largest especially at large flow rates, while the shaft power is almost the same, resulting in the best efficiency with the inducer H. The suction performance is the best with inducer H at large flow rates and is the best with inducer L at low flow rates. Two kinds of instabilities, the cavitating whirling vortex and the surges are mainly observed for the all both inducers, but they are limited at low flow rates. The occurrence ranges of these instabilities in terms of the operating flow rate is the widest with inducer H. However, those in terms of the shockless flow rate ratio is similar for the all three inducers: This fact can contribute to establish some guideline to the pump operation avoiding serious flow instabilities.
Kawamura, Ken-ichi,Watanabe, Kensuke,Nigara, Yutaka,Kaimai, Atsushi,Kawada, Tatsuya,Mizusaki, Junichiro The Korean Ceramic Society 1998 The Korean journal of ceramics Vol.4 No.2
The total conductivity and oxygen permeation in (Ce1-xZrxO2)0.9(CaO)0.1 solid solutions were measure das a function of temperature and oxygen partial pressure. Empirically, σ at given x and T was expressed essentially by σ=σo2+σeo Po2-1/4, where σo2 and σeo are constant. Applying a standard defect model in which major defects are Cace", Cece' and Vo in ideal solution, we can assign σo2 as the oxide ion conductivity decreases while the electronic conductivity increases with the increase in Zr content. Using the oxide ion and electronic conductivities thus determined, the oxygen permeation flux was calculated for respective Po2 and T conditions at which the measurements were made. The calculated values were found to agree with the observed ones.
Oe Shin,Yamato Yu,Hasegawa Tomohiko,Yoshida Go,Kobayashi Sho,Yasuda Tatsuya,Banno Tomohiro,Arima Hideyuki,Mihara Yuki,Ushirozako Hiroki,Yamada Tomohiro,Ide Koichiro,Watanabe Yuh,Haruo Niwa,Matsuyama Y 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.3
Study Design: Retrospective cohort study.Purpose: This study aimed to investigate how participation in sporting activity affects patient-reported outcome (PRO), including Neck Disability Index (NDI), in males and females.Overview of Literature: Previously, our study reported that factors with a negative influence on the NDI in females were a lack of sporting activities. However, it was still unclear why it affected poor scores of NDI.Methods: The subjects were 473 volunteers. They were divided into two groups (activity and non-activity) according to participation or non-participation in sporting activities using a self-filled questionnaire. The evaluation items were height, weight, grip strength, bone density, Hospital Anxiety and Depression Scale (HADS) score, standing radiographic parameters, PRO (evaluated by EuroQol-5 dimension [EQ-5D], Oswestry Disability Index [ODI]), and NDI.Results: There were 101 males in the non-activity group and 69 in the activity group and 178 females in the non-activity group and 125 in the activity group. For the males, the evaluation items with significant influence were cervical lordosis (non-activity group:activity group, 17°:22°) and T1 slope minus cervical lordosis (10°:6°, <i>p</i> <0.05). For the females, the evaluation items with significant influence were sagittal vertical axis (28:14 mm), HADS (10.4:8.4), EQ-5D (0.79:0.86), ODI (17:12), and NDI (12:9, <i>p</i> <0.01). HADS and PRO in the females were significantly correlated with the EQ-5D (−0.40), ODI (0.43), and NDI (0.55).Conclusions: Males who participated in sporting activities had better cervical spine alignment but no effect on PRO. Females with sporting activities had better spinal global alignment and less mental stress. It is suggested that sporting activity in females might be associated with PRO because HADS highly correlates with PRO.