Experimental and numerical investigation on the effect of tip leakage vortex induced cavitating flow on pressure fluctuation in an axial flow pump

Shen, Xi; Zhang, Desheng; Xu, Bin; Shi, Weidong; Esch, B.P.M. van

doi:10.1016/j.renene.2020.09.004

Cited by 53 publications

(11 citation statements)

References 44 publications

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“…This leads to serious flow separation, and other unstable flow phenomena in the device. Usually, this kind of flow phenomena is the cause of the system vibration and noise, and may further affect the unit's stability and safety (Xi et al 2021). Therefore, it is of great importance to carry out the research on transition process to provide certain theoretical guidance for engineering design and practical operation.…”

Section: Introductionmentioning

confidence: 99%

“…Thanapandi and Prasad (1995) studied the transient laws of running speed, flow rate and water head at the moment of start-up and shutdown of a centrifugal pump by using the line method. Xi et al (2021); Wang et al (2010) studied the onedimensional transition process of the pump system, and discussed the closing law of the valve behind the pump and the optimization process of the air valve arrangement scheme. Kim et al (2015) calculated the hydraulic transient process in a pump station after a power failure based on the characteristic line method, and applied numerical analyses of water hammer for a pump-pipeline system with an air chamber.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Flow Evolution and Energy Loss Mechanism in Accidental Shutdown Process of a Large Submersible Mixed-Flow Pump System

2023

JAFM

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To investigate the accidental shutdown process for a large vertical and submersible mixed-flow pump unit in a drainage pumping station, a three-dimensional numerical method for this transition process was proposed according to the angular momentum balance theorem and rigid body rotation technology. We obtained the transient performance curves of the unit and the internal flow characteristics of the full flow channel. In addition, we also analyzed the energy loss distribution of the through-flow components during this progress based on the entropy production theory. The results show that the whole runaway process needs to go through four stages: the pump mode, the pump braking mode, the turbine mode, and the stable runaway mode. The pressure amplitude changes greatly in impeller and guide vanes, and the main fluctuation frequency is the blade frequency. There are higher harmonic frequencies in the dynamic rotor-stator interface. As the rotating speed increases in turbine mode, the negative pressure area near the impeller blade's trailing edge gradually increases. The entropy production method can be used to determine the location, intensity of energy loss during the transient process. If the rotating speed exceeds the allowed value in the runaway turbine mode, the interaction between blade tip vortex and hub vortex rope may cause loss of stability.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flow Evolution and Energy Loss Mechanism in Accidental Shutdown Process of a Large Submersible Mixed-Flow Pump System

2023

JAFM

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“…Axial flow pump devices with low head are widely used in flood control, irrigation, and regional water diversion projects [1,2]. Tubular axial flow pump devices are mounted with the motor inside a passage, which has the advantages of a straight passage profile and small civil work.…”

Section: Introductionmentioning

confidence: 99%

Energy Characteristics of Full Tubular Pump Device with Different Backflow Clearances Based on Entropy Production

Meng

Pei

2021

Applied Sciences

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In this study, the entropy theory was used as the evaluation standard of energy dissipation, and the effect of backflow clearance (the gap between motor rotor and motor shell) on energy characteristics of a full tubular pump was investigated by 3D unsteady flow simulation. The calculated results validated through testing shows that backflow clearance produces additional head loss and the rotation of the motor rotor requires more shaft power. The additional energy losses lead to a significant decline in the efficiency of tubular pump device. Under design conditions, the total dissipation of backflow clearance, rear guide vane, and outlet passage decreases with the increase of clearance radius, but that of the impeller decreases first and then rises with the increase of clearance radius. In addition, the increase of the clearance radius leads to disorderly flow pattern in the impeller. The total dissipation rate on the impeller suction side and near the impeller inlet increases with the increase of backflow clearance radius, but that on the impeller suction side decreases with the increase of backflow clearance radius. The total dissipation rate of the suction side of the guide vane and the wall of the outlet passage decreases with the increase of backflow clearance radius. This work can provide an intuitive analysis of the energy dissipation caused by backflow clearance and reference for engineering applications of full tubular pump.

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“…Based on the simplified R-P equation, the connection between local gas concentration and its effect on cavitation is modeled, and the mass source terms in the original Schnerr-Sauer (S-S) cavitation model are modified. Xi et al [16] simulated the cavitating flow and pressure fluctuation in the tip region based on the delayed detached eddy simulation (DDES). e high-speed photography and transient pressure measurements were employed to capture the cavitation structures and pressure fluctuation.…”

Section: Introductionmentioning

confidence: 99%

Numerical Research of the Submerged High‐Pressure Cavitation Water Jet Based on the RANS‐LES Hybrid Model

Yang

Shi

Tan

et al. 2021

Shock and Vibration

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The submerged high-pressure water jet has the characteristics of high velocity, strong turbulence, and severe cavitation. In order to reveal the formation mechanism of shear cavitation in the submerged high-pressure water jet and to grasp the turbulent structure and velocity distribution characteristics in the jet, the prediction ability of different turbulence models is studied first. The models represent the RANS model and RANS-LES hybrid model which are used to simulate the same cavitation jet, and the results are compared with the experimental results. The most reasonable model is then used to investigate the submerged high-pressure cavitation jet with different cavitation numbers. It is found that the calculation accuracy for small-scale vortexes has a great influence on the prediction accuracy of cavitation in the submerged jet. Both the DDES model and the SBES model can effectively capture the vortexes in the shear layer, and the SBES model can obtain more turbulence details. The result of the simulation under different cavitation numbers using the SBES model agrees well with the experimental result. Under the condition with low cavitation number, an intensive shear layer is formed at the exit of the nozzle, and small-scale vortexes are distributed along the shear layer. Mass transfer rate is relatively high in the region with a stronger vortex, which confirms that the low pressure in the vortex center is the main reason for the generation of cavitation in the shear layer. With the decrease of the cavitation number, the cavitation intensity increases obviously, while the nondimensional velocity along the radial direction changes little, which follows an exponential function.

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Experimental and numerical investigation on the effect of tip leakage vortex induced cavitating flow on pressure fluctuation in an axial flow pump

Cited by 53 publications

References 44 publications

Flow Evolution and Energy Loss Mechanism in Accidental Shutdown Process of a Large Submersible Mixed-Flow Pump System

Flow Evolution and Energy Loss Mechanism in Accidental Shutdown Process of a Large Submersible Mixed-Flow Pump System

Energy Characteristics of Full Tubular Pump Device with Different Backflow Clearances Based on Entropy Production

Numerical Research of the Submerged High‐Pressure Cavitation Water Jet Based on the RANS‐LES Hybrid Model

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