Investigation on Stall Characteristics of Centrifugal Pump with Guide Vanes

Abstract

Stall usually occurs in the hump area of the head curve, which will block the channel and aggravate the pump vibration. For centrifugal pumps with guide vanes usually have a clocking effect, the stall characteristic at different clocking positions should be focused. In this paper, the flow field of the centrifugal pump under stall conditions is numerically simulated, and the rotor–stator interaction effects of the centrifugal pump under stall conditions are studied. The double-hump characteristic is found in the head curve by using SAS (Scale Adaptive Simulation) model. The hump area close to the optimal working condition is caused by hydraulic loss, while the hump area far away from the optimal working condition point is caused by the combined action of Euler’s head and hydraulic loss. The SAS model can accurately calculate the wall friction loss, thus predicting the double-hump phenomenon. The pressure fluctuation and head characteristics at different clocking positions under stall conditions are obtained. It is found that when the guide vanes outlet in line with the volute tongue, the corresponding head is the highest, and the pressure fluctuation is the lowest. The mechanism of the clocking effect in the centrifugal pump with guide vanes is obtained by simplifying the hydrofoil. It is found that when the downstream hydrofoil leading edge is always interfered with by the upstream hydrofoil wake, the wake with low energy mixes the boundary layer with low energy, which causes small-pressure pulsation. The results could be used for the operation of centrifugal pumps with guide vanes.

Comparative Analysis of the Hydrodynamic Performance of Dual Flapping Foils with In-Phase and Out-of-Phase Oscillations

“…As shown in Figure 15, the graph shows that at a flow rate of 0.84 m 3 /s, the internal flow field under the corresponding operating conditions shows strong instability, which poses a significant threat to the safety, stability, and reliability of the bionic pumping device. Previous studies show that the humping phenomenon leads to the instability of the device [34][35][36][37]. Hence, the pumping device with the out-of-phase oscillation is more reliable compared with the in-phase oscillation.…”

“…At the same time, the maximum head is smaller when the dual flapping foil is used to push water in the out-of-phase oscillation, which can meet the demand of ultra-low head conditions. the instability of the device [34][35][36][37]. Hence, the pumping device with the out-of-phase oscillation is more reliable compared with the in-phase oscillation.…”

Double-Tongue Worm Shell Structure on Plastic Centrifugal Pump Performance Study

“…After calculation, the volute base circle diameter is 270 mm, the volute inlet width is 50 mm, and the tongue placement angle is 15 • . The area of section VIII of the volute is 8.772 cm 2 . UG is used to create a three-dimensional model of the calculation domain of each part of the centrifugal pump, as shown in Figures 3 and 4…”

Numerical Study on the Hysteresis Effect of Volute Pump with Stay Vanes Based on Vortex Dynamics

“…Statistics show that the energy consumption of pumps presents nearly 22% of the world's motor energy consumption, among which the energy consumption of centrifugal pumps is about in the range between 70% and 80% [4][5][6]. To meet the energy saving and longterm operation demands, the hydraulic losses and internal flow structures associated with the pump operating conditions should be focused on [7][8].…”