In this study, computational fluid dynamics (cfd) software and detached eddy simulation turbulence model were used to simulate butterfly valves with different designs. The effects of shaft diameters on the value and the fluctuation of valve disk torque were studied, and the physical reason was discussed. The simulation results were verified by comparing with the experimental data. The findings revealed that with the closing of the valve, the hydraulic torque of the valve disk first increases and then decreases. Meanwhile, the torque decreases gradually with the increase of the shaft diameter. The variation of torque is caused by the change of pressure on both sides of the valve disk. The result also indicates that the fluctuation of torque is induced by the flow separation phenomenon occurs on the valve disk. The fluctuation is significant for the valve opening from 20% to 60%. The strength of the torque fluctuation is greater for the smaller shaft diameter. This study provides a theoretical basis for the design and optimization of butterfly valves.
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http://dx.doi.org/10.1115/1.4047795 | DOI Listing |
Folia Microbiol (Praha)
October 2024
Clinic of Medical Microbiology, Gülhane Training and Research Hospital, University of Health Sciences, Ankara, 06010, Türkiye.
J AAPOS
October 2024
Division of Ophthalmology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois; Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois. Electronic address:
RSC Adv
April 2024
University of Yamanashi, Graduate Faculty of Interdisciplinary Research Japan.
In this study, we established the control and design theory of an autonomously driven dispenser at a steady rotation speed and proposed a dispenser-integrated multiplex enzyme-linked immunosorbent assay (ELISA) device. In establishing the theory of the dispenser, we estimated the flow rate in the dispenser and the applied pressure onto the passive valves, so that the suitable burst pressure of the valves and flow rate could be designed. The dispenser-integrated multiplex ELISA device has the potential to perform flow control for executing an ELISA of 6 samples/standards per chip or 18 samples/standards per compact disk by just steadily rotating a chip.
View Article and Find Full Text PDFScand Cardiovasc J
December 2023
Research Unit of Internal Medicine, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland.
Objectives: Patients receiving transcatheter aortic valve implantation (TAVI) are elderly with multiple comorbidities and at increased risk of perioperative cerebrovascular events. Retinal vasculature represents a surrogate of central nervous system circulation and is noninvasively achievable by retinal imaging. The aim of this study was to evaluate the applicability of retinal angiography of microvascular complications and association to cerebral ischemic events during TAVI.
View Article and Find Full Text PDFJ Vis
October 2023
Department of Human Movement Sciences, Institute of Brain and Behavior Amsterdam, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
Objects in one's environment do not always move at a constant velocity but often accelerate or decelerate. People are very poor at visually judging acceleration and normally make systematic errors when trying to intercept accelerating objects. If the acceleration is perpendicular to the direction of motion, it gives rise to a curved path.
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