Publication: Anti-vortex device efficiency for pump sump using hydraulic physical model
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Date
2024-07-01
Authors
Wahidah, Nur Rizzuan
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Abstract
Pump sump design is very crucial in order to optimize pump inflow and pump
efficiency. The pump may become damaged as a result of the vortex that forms around
the pump sump suction area. The vortex may change particle velocity and increase
impeller erosion. A vortex is a special form of fluid motion, with unstable and
nonlinear characteristics. There are two types of vortices that occur at a pump station
inlet: a submerged vortex and a free surface vortex. The free surface vortex has a great
impact on the project, which will reduce the effective water flow section at the inlet of
the pump station and reduce the flow capacity. To increase pump efficiency, a
phenomenon called vortex generation near the pump entrance in the sump during intake
needs to be managed. In this study, a pump sump model is equipped with five
variations of an anti-vortex device (AVD) types at five different water level in order to
assess how the anti-vortex device design affects the efficiency of vortex management
in the intake flow. According to the ANSI/HI standard, the sump that produced vortex
must be eliminated and the swirl angle in the flow must not be greater than 5°. All
AVD variations used in this study were successful in removing the free surface vortices
(FSV) at high water level (853.5 mm, 638.5 mm and 463.5 mm) but the majority of
them occurred at low water level (400 mm and 370 mm). This can be avoided by
placing modification of an anti-vortex device (AVD) which are back wall fillet and
Floating-Anti Vortex Device (F-AVD) near the intake pipe in the pump sump. The
function of Floating Anti-Vortex Device (F-AVD) is to prevent and eliminate the
formation of vortices and swirl in the water flow during low water level. Proved that
after placing the back wall splitter and F-AVD, the swirl angle is reaching less than 5° which achieve the lowest swirl angle reading (2.3°). As opposed to a case where there is no AVD, the application of back wall splitter and F-AVD greatly improves
performance in swirl angle reduction and vortex suppression.