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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Water engineering : Experimental study on effects of vortex-prevention devices for suppressing air entrainment inside su...
Experimental study on effects of vortex-prevention devices for suppressing air entrainment inside surface intake facility
Author : KOHSEI TAKEHARA(1), NOBUYUKI HISASUE(2) & YASUHIDE TAKANO(3)
ABSTRACT
In the hydro-electrical power station, water in the reservoir is taken into the electrical power generator through an intake
facility. In the common intake facilities, the free surface flow merges into the closed pipe flow, which leads to the
electrical power generator. Air entrapment by the intake vortices inside the surface intake facilities causes the
deterioration of power generation, the destruction of blade in a turbine, and so on. It is very important for the hydroelectrical
power station to suppress the air entrapment by the intake vortices. To suppress the air entrapment by the
vortices, vortex-prevention devices have been proposed and some of them have been used in hydro-electrical power
stations. Those vortex-prevention devices are effectively suppress the air entrapments in a certain hydraulic condition.
However, the hydraulic properties of flow structure by those vortex-prevention devices are still unclear.
In this research, the effects of the vortex-prevention devices in the surface intake facilities are investigated
experimentally by using the particle tracking velocimetry (PTV). The vorticity distribution is evaluated by the Moving
Least Square (MLS) method, which can accurately evaluate the vorticity from the randomly distributed velocity vectors
obtained by the PTV. Three types of the surface intake facilities were tested to evaluate the effects of the vortexprevention
devices. The average velocity distribution, the turbulent properties distribution, the average vorticity
distribution and statistics property distribution of vorticity are calculated from the obtained velocity distributions. The
results show that the vortex-preventing devices effectively stabilize the flow in the dead water region. As a result, airentrapment
by surface vortex is suppressed by the vortex-preventing devices.
File Size : 1,572,565 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Water engineering
Date Published : 20/08/2015
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