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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,Ueno, Yoshinori,Takahashi, Koutaro,Miyagawa, Kazuyoshi,Tsujimoto, Yoshinobu Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.2
Dynamic characteristics of the clearance flow between an axially oscillating rotational disk and a stationary disk were examined by experiments and computations based on a bulk flow model. In the case without pressure fluctuations at the inlet and outlet of the clearance, parallel and contracting flow paths had an effect to stabilize the axial oscillation of the rotating disk. The enlarged flow path had an effect to destabilize the axial oscillation due to the negative damping and stiffness for outward and inward flows, respectively. It was shown that the fluid force can be decomposed into the component caused by the inlet or outlet pressure fluctuation without the axial oscillation and that due to the axial oscillation without the inlet or outlet pressure fluctuation. A method to predict the stiffness and damping coefficients is proposed for general cases when the device is combined with an arbitrary flow system.
Study on the Development of Two-Stage Centrifugal Blood Pump for Cardiopulmonary Support System
Hironori Horiguchi,Tomonori Tsukiya,Takeshi Nomoto,Toratarou Takemika,Yoshinobu Tsujimoto 한국유체기계학회 2014 International journal of fluid machinery and syste Vol.7 No.4
In the cardiopulmonary support system with an ECMO (extracorporeal membrane oxygenation), ahigher pump head is demanded for a blood pump. In order to realize a blood pump with higher pump head, higher anti-hemolysis and thrombosis performances, astudy on the development of unprecedented multistage blood pump was conducted. In consideration of the applicationof the blood pump for pediatric patients, a miniature two-stage centrifugal blood pump with the impeller’s diameter of40mm was designed and the performance was examined in experiments and computations. Some useful knowledge for a design of the blood pump with higher anti-hemolysis and thrombosis performances was obtained.
Hironori Horiguchi,Shinichiro Hata,Yutaro Wada,Julien Richert,Yoshinobu Tsujimoto 한국유체기계학회 2019 International journal of fluid machinery and syste Vol.12 No.4
Rotordynamic fluid forces and a mechanism of their occurrence were examined in experiments and computations for a closed type centrifugal impeller in whirling motion. The rotordynamic fluid force on a front shroud was a main component of the rotordynamic fluid force. In a clearance between the front shroud and a casing, velocity disturbances were caused by an eccentricity of the impeller and a squeeze effect due to the whirling motion of the impeller. Appling the Bernoulli equation to disturbed swirling flow in the clearance in a relative coordinate fixed on the whirling motion, the pressure disturbance which generated the rotordynamic fluid force could be reasonably explained.
Study on the Development of Two-Stage Centrifugal Blood Pump for Cardiopulmonary Support System
Horiguchi, Hironori,Tsukiya, Tomonori,Nomoto, Takeshi,Takemika, Toratarou,Tsujimoto, Yoshinobu Korean Society for Fluid machinery 2014 International journal of fluid machinery and syste Vol.7 No.4
In the cardiopulmonary support system with an ECMO (extracorporeal membrane oxygenation), a higher pump head is demanded for a blood pump. In order to realize a blood pump with higher pump head, higher anti-hemolysis and thrombosis performances, a study on the development of unprecedented multistage blood pump was conducted. In consideration of the application of the blood pump for pediatric patients, a miniature two-stage centrifugal blood pump with the impeller's diameter of 40mm was designed and the performance was examined in experiments and computations. Some useful knowledge for a design of the blood pump with higher anti-hemolysis and thrombosis performances was obtained.
Hironori Horiguchi,Tomonori Tsukiya,Toratarou Takemika,Takeshi Nomoto,Yoshinobu Tsujimoto 한국유체기계학회 2015 International journal of fluid machinery and syste Vol.8 No.1
In cardiopulmonary support systems with a membrane oxygenation such as a percutaneous cardiopulmonary support (PCPS) or an extracorporeal membrane oxygenation (ECMO), blood pumps need to generate the pressure rise of approximately 200mmHg or higher, due to the high hydraulic resistances of the membrane oxygenation and of the cannula tubing. In order to realize the blood pump with higher pressure rise, higher anti-hemolysis and thrombosis performances, the development of novel centrifugal blood pump composed of two-stage has been conducted by the authors. In the present paper, effective attempts to decrease the wall shear stress and to suppress the stagnation are introduced for the prevention of hemolysis and thrombosis in blood pumps. The hemolysis test was also carried out and it was clarified that the decrease of wall shear stress is effective as a guideline of design of blood pumps for improving the anti-hemolysis performance.
Horiguchi, Hironori,Tsukiya, Tomonori,Takemika, Toratarou,Nomoto, Takeshi,Tsujimoto, Yoshinobu Korean Society for Fluid machinery 2015 International journal of fluid machinery and syste Vol.8 No.1
In cardiopulmonary support systems with a membrane oxygenation such as a percutaneous cardiopulmonary support (PCPS) or an extracorporeal membrane oxygenation (ECMO), blood pumps need to generate the pressure rise of approximately 200mmHg or higher, due to the high hydraulic resistances of the membrane oxygenation and of the cannula tubing. In order to realize the blood pump with higher pressure rise, higher anti-hemolysis and thrombosis performances, the development of novel centrifugal blood pump composed of two-stage has been conducted by the authors. In the present paper, effective attempts to decrease the wall shear stress and to suppress the stagnation are introduced for the prevention of hemolysis and thrombosis in blood pumps. The hemolysis test was also carried out and it was clarified that the decrease of wall shear stress is effective as a guideline of design of blood pumps for improving the anti-hemolysis performance.
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.
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.
Song, Bingwei,Horiguchi, Hironori,Ma, Zhenyue,Tsujimoto, Yoshinobu Korean Society for Fluid machinery 2010 International journal of fluid machinery and syste Vol.3 No.1
Severe flexural vibration of the rotor shaft of a Francis turbine runner was experienced in the past. It was shown that the vibration was caused by the fluid forces and moments on the backshroud of the runner associated with the leakage flow through the back chamber. The aim of the present paper is to study the self-excited rotor vibration caused by the fluid force moments on the backshroud of a Francis turbine runner. The rotor vibration includes two fundamental motions, one is a whirling motion which only has a linear displacement and the other is a precession motion which only has an angular displacement. Accordingly, two types of fluid force moment are exerted on the rotor, the moment due to whirl and the moment due to precession. The main focus of the present paper is to clarify the contribution of each moment to the self-excited vibration of an overhung rotor. The runner was modeled by a disk and the whirl and the precession moments on the backshroud of the runner caused by the leakage flow were evaluated from the results of model tests conducted before. A lumped parameter model of a cantilevered rotor was used for the vibration analysis. By examining the frequency, the damping rate, the amplitude ratio of lateral and angular displacements for the cases with longer and shorter overhung rotor, it was found that the precession moment is more important for smaller overhung rotors and the whirl moment is more important for larger overhung rotors, although both types of moment due to the leakage flow can cause self-excited vibration of an overhung rotor.