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Study for the Increase of Micro Regenerative Pump Head
Horiguchi, Hironori,Wakiya, Keisuke,Tsujimoto, Yoshinobu,Sakagami, Masaaki,Tanaka, Shigeo Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.3
The effect of inlet and outlet blade angles on a micro regenerative pump head was examined in experiments. The pump head was little increased by changing the blade angles compared with the original pump with the inlet and outlet blade angles of 0 degree. The effect of the axial clearance between the impeller and the casing on the pump head was also examined. The head was increased largely by decreasing the axial clearance. The computation of the internal flow was performed to clarify the cause of the increase of the pump head due to the decrease of the clearance. The local flow rate in the casing decreased as the leakage flow rate through the axial clearance decreased due to the decrease of the clearance. It was found that the larger head in the smaller clearance was just caused by the smaller local flow rate in the casing. In the case of the smaller clearance, the smaller local flow rate caused the smaller circumferential velocity near the front and rear sides of the impeller. This caused the increase of the angular momentum in the casing and the head.
Horiguchi, Hironori,Matsumoto, Shinji,Tsujimoto, Yoshinobu,Sakagami, Masaaki,Tanaka, Shigeo Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.1
The effect of symmetric and asymmetric micro regenerative pump impellers on their pressure performance was studied. The shut off head of the pump with the symmetric impeller was about 2.5 times as that with the asymmetric impeller. The computation of the internal flow was performed to clarify the cause of the increase of the head. It was found that the contribution of the angular momentum supply was larger than that of shear stress for the head development in both cases. The larger head and momentum supply in the case of the symmetric impeller were caused by larger recirculated flow rate and larger angular momentum difference between the inlet and outlet to the impeller. The larger recirculated flow rate was caused by smaller pressure gradient in the direction of recirculated flow. The decrease of the circumferential velocity in the casing was attributed to the smaller local flow rate in the casing.
Reynolds Number Effect on Regenerative Pump Performance in Low Reynolds Number Range
Horiguchi, Hironori,Yumiba, Daisuke,Tsujimoto, Yoshinobu,Sakagami, Masaaki,Tanaka, Shigeo Korean Society for Fluid machinery 2008 International journal of fluid machinery and syste Vol.1 No.1
The effect of Reynolds number on the performance of a regenerative pump was examined in a low Reynolds number range in experiment. The head of the regenerative pump increased at low flow rates and decreased at high flow rates as the Reynolds number decreased. The computation of the internal flow was made to clarify the cause of the Reynolds number effect. At low flow rates, the head is decreased with increasing the Reynolds number due to the decrease of the shear force exerted by the impeller caused by the increase of leakage and hence local flow rate. At higher flow rates, the head is increased with increasing the Reynolds number with decreased loss at the inlet and outlet as well as the decreased shear stress on the casing wall.
Ken Yoshida,Hideya Yamazaki,Satoaki Nakamura,Koji Masui,Tadayuki Kotsuma,Hironori Akiyama,Eiichi Tanaka,Nobuhiko Yoshikawa,Yasuo Uesugi,Taiju Shimbo,Yoshifumi Narumi,Yasuo Yoshioka 대한부인종양학회 2015 Journal of Gynecologic Oncology Vol.26 No.3
Objective: To assess actual rates of late vaginal stenosis and identify predisposing factors for complications among patients with previously untreated cervical cancer following high-dose-rate brachytherapy. Methods: We performed longitudinal analyses of 57 patients using the modified Dische score at 6, 12, 18, 24, 36, and 60 months after treatment, which consisted of 15 interstitial brachytherapys and 42 conventional intracavitary brachytherapys, with a median follow-up time of 36 months (range, 6 to 144 months). Results: More than half of the patients developed grade 1 (mild) vaginal stenosis within the first year of follow-up, and grade 2 (97.5%, moderate) to grade 3 (severe) stenosis gradually increased with time. Actual stenosis rates for grade 1, 2, and 3 were 97.5% (95% confidence interval [CI], 92.7 to 97.5), 60.7% (95% CI, 42.2 to 79.3), and 7.4% (95% CI, 0 to 18.4) at 3 years after treatment. Pallor reaction grade 2–3 at 6 months was only a statistically significant predisposing factor for grade 2–3 late vaginal stenosis 3 years or later with a hazard ratio of 3.48 (95% CI, 1.32 to 9.19; p=0.018) by a multivariate Cox proportional hazard model. Patients with grade 0–1 pallor reaction at 6 months showed a grade ≥2 vaginal stenosis rate of 53%, whereas the grade 2–3 pallor reaction group achieved a grade ≥2 vaginal stenosis rate at 3 years at 100% (p=0.001). Conclusion: High-dose-rate brachytherapy was associated with high incidence of late vaginal stenosis. Pallor reaction grade 2–3 at 6 months was predictive of late grade 2–3 vaginal stenosis at 3 years after treatment. These findings should prove helpful for patient counseling and preventive intervention.