The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Jamshid H Karimov - One of the best experts on this subject based on the ideXlab platform.
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effects of blood Pump orientation on Performance in vitro assessment of universal advanced ventricular assist device
Artificial Organs, 2020Co-Authors: Takuma Miyamoto, Yuichiro Kado, Anthony R Polakowski, David J Horvath, Barry D Kuban, Kiyotaka Fukamachi, Jamshid H KarimovAbstract:An advanced ventricular assist device (VAD), which is under development in our institution, has specific features that allow changes in the axial rotor position and Pump Performance by intraPump pressure difference. However, Performance could be influenced by the Pump orientation because of the effect of gravity on the rotor position. The purpose of this study was to evaluate the effects of Pump orientation on the Pump Performance, including pulse pressure and regurgitant flow through the Pump when the Pump was stopped. Bench testing of the VAD was performed on a static or pulsatile mock loop with a pneumatic device to simulate the native ventricle. The Pump Performance, including pressure-flow curve, pulsatility, and regurgitant flow, was evaluated at several angles, ranging from -90 degrees (inlet pointed upward) to +90 degrees (inlet pointed downward) at Pump speeds of 2000, 2500, 3000, and 3500 rpm. The Pump Performance was slightly lower at +90 degrees at all rotational speeds, compared with -90 degrees . The pulse pressure on the pulsatile mock loop (80 bpm) was 50 mm Hg without Pump support, remained at 50 mm Hg during Pump support, and was not changed by orientation (-90 degrees , 0 degrees , and +90 degrees ). When the Pump was stopped, the regurgitant flow was near 0 L/min at all angles. Pump orientation had a minor effect on Pump Performance, with no effect on pulse pressure or regurgitant flow when the Pump was stopped. This indicates that the effect of gravity on the rotor assembly is insignificant.
Takuma Miyamoto - One of the best experts on this subject based on the ideXlab platform.
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effects of blood Pump orientation on Performance in vitro assessment of universal advanced ventricular assist device
Artificial Organs, 2020Co-Authors: Takuma Miyamoto, Yuichiro Kado, Anthony R Polakowski, David J Horvath, Barry D Kuban, Kiyotaka Fukamachi, Jamshid H KarimovAbstract:An advanced ventricular assist device (VAD), which is under development in our institution, has specific features that allow changes in the axial rotor position and Pump Performance by intraPump pressure difference. However, Performance could be influenced by the Pump orientation because of the effect of gravity on the rotor position. The purpose of this study was to evaluate the effects of Pump orientation on the Pump Performance, including pulse pressure and regurgitant flow through the Pump when the Pump was stopped. Bench testing of the VAD was performed on a static or pulsatile mock loop with a pneumatic device to simulate the native ventricle. The Pump Performance, including pressure-flow curve, pulsatility, and regurgitant flow, was evaluated at several angles, ranging from -90 degrees (inlet pointed upward) to +90 degrees (inlet pointed downward) at Pump speeds of 2000, 2500, 3000, and 3500 rpm. The Pump Performance was slightly lower at +90 degrees at all rotational speeds, compared with -90 degrees . The pulse pressure on the pulsatile mock loop (80 bpm) was 50 mm Hg without Pump support, remained at 50 mm Hg during Pump support, and was not changed by orientation (-90 degrees , 0 degrees , and +90 degrees ). When the Pump was stopped, the regurgitant flow was near 0 L/min at all angles. Pump orientation had a minor effect on Pump Performance, with no effect on pulse pressure or regurgitant flow when the Pump was stopped. This indicates that the effect of gravity on the rotor assembly is insignificant.
Hirokuni Hiyama - One of the best experts on this subject based on the ideXlab platform.
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Pumping Effect in an Axially Vibrating Choke Nozzle : Pump Performance
Jsme International Journal Series B-fluids and Thermal Engineering, 1995Co-Authors: Hiroyuki Hashimoto, Akio Ihara, Rokuro Sato, Hideo Watanabe, Hirokuni HiyamaAbstract:A newly developed Pumping system is presented. The Pumping effect was experimentally obtained using a vibrating choke nozzle in a stationary liquid. The relation-ship between Pump Performance and the input vibration conditions was investigated. By the flow visualization of inflow and outflow bubbles, the flow mechanism in the actual Pump operation was investigated. It has been confirmed that this Pumping effect can be utilized in actual Pump machinery.
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Pump Performance and Hemolytic Property of a Vibration Pump as a Ventricular Assist Device.
Transactions of the Japan Society of Mechanical Engineers. B, 1991Co-Authors: Masanori Aoki, Hiroyuki Hashimoto, Shin-ichi Nitta, Taroh Sonobe, Hirokuni HiyamaAbstract:In order to study the possibility of using a vibration Pump as a ventricular assist device, the Pump Performance and hemolytic property of the Pump were evaluated. As a result, it was shown that the Pump Performance varied with the length and elasticity of the suction tube. The tested vibrating Pump under discussion met the Pump Performance requirements of a ventricular assist device. The hemolytic property of the tested vibration Pump was determined using goat blood. As a result, it was shown that the tested Pump compared favorably with the conventional roller or centrifugal Pumps with respect to hemolysis.
H M Abdalla - One of the best experts on this subject based on the ideXlab platform.
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Centrifugal Pump Performance Enhancement by Blade Shape Modification
Volume 2B: Turbomachinery, 2017Co-Authors: A. Farid Ayad Hassan, H M AbdallaAbstract:The effect of impeller blades shape modification on the centrifugal Pump Performance has been investigated numerically. Impeller blades’ shape have been modified by new technique called “bladelet”. This technique has been called the “bladelet” after the name of the aeroplane winglet because of the great similarity between them in shape and function. The shapes of the blade trailing edge greatly affect the Performance of the turbomachines. So, the purpose of the blade tilting (bladelet) is to decrease the recirculating flow at the Pump trailing edge due to the high pressure difference and enhance the hydraulic Performance of the centrifugal Pump. The bladelet technique has two main geometrical parameters: radial position RBL and bladelet inclination angle θBL. 3-D validated numerical simulation model has been carried out using commercial software, ANSYS® CFX, to study the effect of the bladelet technique and its different parameters on the Pump Performance at different flow rates. In this study nine cases with different bladelet parameters have been numerically simulated in order to check its effect on the centrifugal Pump Performance. These nine cases have been chosen by considering the geometrical constrain of the bladelet parameters. The results of these nine cases have been compared with the basic impeller (the same impeller but without bladelet) at the same operating condition in order to discuss the effect of the bladelet parameters variation on the centrifugal Pump Performance. It was found that the use of the bladelet technique decrease the pressure difference between the pressure and the suction side at the blade trailing edge. This decrease in pressure difference at the blade trailing edge decreases the flow recirculation at the impeller outlet from pressure side to suction side. Also, bladelet technique improves the hydraulic efficiency at the part-load operating zone. In addition, the bladelet has a regression effect on the Pump head for some cases with high inclination angle and low radial position. However, the bladelet technique increases the impeller blades’ overlap.
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effect of semi open impeller side clearance on the centrifugal Pump Performance using cfd
Aerospace Science and Technology, 2015Co-Authors: Farid A Ayad, H M AbdallaAbstract:Abstract Centrifugal Pumps (CP) are probably among the most often used machinery in industrial facilities as well as in common practice. Compared to other types of rotating Pumps, CP yield higher efficiency. In aerospace application, reducing the weight of the CP impeller has the advantage of reducing mechanical stresses and enable using the CP at the high number of revolutions. In order to minimize the impeller weight the requirements to study and develop the CP with semi-open impeller appear. The present paper is devoted to revealing more details about the impact of CP side clearance on its Performance. This is done by numerically investigating the influence of the variation of the CP side clearance width (0:0.2 impeller width) on the CP Performance parameters at different flow rates (0:5 L/s). These CP Performance parameters include the Pump head, efficiency, slip factor, blade loads and the internal flow structure. The numerical simulation has been compared with own experimental results and a published empirical formula to verify the numerical solution. The CFD results show an acceptable agreement with the results of the experimental work and the empirical formulas. It has been shown that the impeller side clearance has a great regression effect on the centrifugal Pump Performance.
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Study of the Effect of Impeller Side Clearance on the Centrifugal Pump Performance Using CFD
Volume 7A: Fluids Engineering Systems and Technologies, 2015Co-Authors: A. Farid Ayad, H M AbdallaAbstract:Centrifugal Pumps (CP) are probably among the most often used machinery in industrial facilities as well as in common practice. Compared to other types of rotating Pumps, CP yield higher efficiency. In aerospace application reducing the weight of the CP impeller has the advantage of reducing mechanical stresses and enable using the CP at high number of revolution. In order to minimize the impeller weight the requirements to study and develop the CP with semi-open impeller appears. Using this type of impeller results in clearance between the impeller blades and the casing which degrade the centrifugal Pump Performance. The impact of this side clearance has not been deeply investigated in open literature.The present paper is devoted to reveal more details about the impact of CP side clearance on its Performance. This is done by numerically investigating the influence of the variation of the CP side clearance width (0:0.2 impeller width) on the CP Performance parameters at different flow rates (0:5 Liter/s). These CP Performance parameters include the Pump head, efficiency, slip factor, blades loads and the internal flow structure.3-D steady numerical simulation has been carried out using commercial software, ANSYS® CFX. The computational domain consists of four zones: inlet, side gab, impeller and volute with outlet. They are defined by means of the multi-reference frame technique. The impeller is situated in the rotating reference frame, while the inlet, side gab and outlet zones are in the fixed reference frame, and they are related to each other through the “frozen rotor” interface. The meshes of four computational domains are generated separately after performing mesh sensitivity analysis. The boundary conditions are set as total pressure at inlet and the mass flow at outlet. A no-slip condition is imposed at the wall boundary defined at the blade and casing. A turbulent, incompressible flow solver has been adapted using SST k–ω turbulent model.The numerical simulation has been compared with own experimental results and a published empirical formulas to verify the numerical solution. The CFD results show an acceptable agreement with the results of the experimental work and the empirical formulas. It has been shown that the impeller side clearance have a great regression effect on the centrifugal Pump Performance. An explanation to the Performance regression has been proposed based on the flow field feature. Performance regression could be attributed to the drop in the pressure difference between the impeller inlet and outlet. And the redistribution of the velocity inside the impeller channel and the side clearance.Copyright © 2015 by ASME
Masud Behnia - One of the best experts on this subject based on the ideXlab platform.
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seasonal Performance rating of heat Pump water heaters
Solar Energy, 2004Co-Authors: G L Morrison, T N Anderson, Masud BehniaAbstract:Seasonal Performance evaluation methods for water heaters are reviewed and an experimental method for rating air-source heat Pump water heaters is presented. The rating method is based on measured heat Pump Performance during heat-up operation of particular products rather than a generic simulation model of heat Pump Performance. The measured Performance is used in a correlation model of the heat Pump unit in an annual load-cycle system Performance simulation based on the TRNSYS simulation package.
