Effect of Blade Outlet Angle on Unsteady Hydrodynamic Force of Closed-Type Centrifugal Pump with Single Blade

Nishi, Yasuyuki; Fukutomi, Junichiro

doi:10.1155/2014/838627

Cited by 18 publications

(6 citation statements)

References 15 publications

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“…Previous studies have confirmed that the clearance flow in the sidewall gaps, sensitive to the clearance size, is able to influence the pump performance (Engeda, 1995; Shukla and Kshirsagar, 2007; Li, 2012; Wu et al , 2014; Cao et al , 2015). Moreover, experiments and simulations also indicate that the clearance flow contributes substantially to the rotordynamic forces, especially the radial force and axial thrust on the impeller (Adkins and Brennen, 1988; Uy and Brennen, 1999; Park and Morrison, 2009; Will et al , 2012; Nishi and Fukutomi, 2014; Liu et al , 2014). The above clearance flow effect is derived from the interaction between the clearance flow in the sidewall gap and the main flow in the volute casing and impeller.…”

Section: Introductionmentioning

confidence: 99%

Pressure fluctuation characteristics in the sidewall gaps of a centrifugal dredging pump

Cao

Xiao

Wang

et al. 2017

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Purpose The purpose of this paper is to study the pressure fluctuation characteristics in the sidewall gaps of a centrifugal dredging pump in detail and discover the excitation sources. Design/methodology/approach An unsteady numerical simulation with shear–stress transport–scale-adaptive simulation (SAS-SST) model was conducted for a centrifugal pump considering the sidewall gaps. The numerical codes were validated by a model test carried out in China Water Resources Beifang Investigation, Design and Research Co., Ltd. Fast Fourier transform was used to obtain the frequency components of the pressure fluctuation. Findings Pressure fluctuation characteristics inside the pump were analyzed for a condition near the design point. In the sidewall gaps, the circumferential, radial and axial distribution of the pressure fluctuation amplitude follow different laws. The non-axisymmetrical distribution of pressure fluctuation in the sidewall gaps shows that the unsteady flow in the volute casing which has a non-axisymmetrical geometry imposes an evident effect on the flow field in the sidewall gaps and the interaction between the main flow and the clearance flow cannot be neglected. There are several frequency components appearing as the dominant frequencies at different locations in the sidewall gaps, but the relatively stronger pressure fluctuations are all dominated by the rotating frequency. It indicates that the rotating impeller, which originally makes the shrouds rotate, is the primarily excitation source of the pressure fluctuations in the sidewall gaps. Originality/value The pressure fluctuation characteristics in the sidewall gaps of centrifugal pumps were first comprehensively analyzed. Unsteady flows in the sidewall gaps should be considered during the design and operation of centrifugal pumps.

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Section: Introductionmentioning

confidence: 99%

Pressure fluctuation characteristics in the sidewall gaps of a centrifugal dredging pump

Cao

Xiao

Wang

et al. 2017

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“…Multi-stage pump is composed of multiple single-stage impellers, and the research results on axial forces in single-stage pumps can be used as a reference for multi-stage pumps. Nishi and Fukutomi 16 studied the effect of the change in outlet placement angle of single-vane closed centrifugal pumps on axial forces, and the result shows that at large flow rates, the time average value of the axial forces in the front and rear pump chamber increased with the increase of impeller vane outlet angle. Kazakov and Pelinskii 17 carried out an experimental study on axial force of submersible well pump, it was found that the pump axial force increased with the seal gap increased.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the axial force distribution characteristics of multistage pumps and its correlation with hydraulic property

Chen

Lihuan

Zhipeng³

et al. 2022

Advances in Mechanical Engineering

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As the centrifugal pump is running, the fluid usually flows into the impeller along pump shaft, and the fluid flows out radially by the force of the impeller. The force is mutual, so the impeller is also subjected to the reaction force of the fluid, but the distribution of this force on the blades is uneven. In addition, the front and rear shrouds of the impeller are asymmetric, which are the main causes of axial force. This paper adopts numerical calculation method studying the mechanism of axial force of impeller at all stages of multistage pump at various working conditions, and exploring the formation mechanism of shroud pressure differential force and blade twisting axial force and its variation laws of similarities and differences, analyzing the steady state and transient characteristics between axial force and hydraulic property of double-casing multistage pump. The results show that the rotational angular velocity of the fluid in the front and rear pump chamber at each stage impeller is distributed along the axial direction in three regions, the regions are pump body boundary layer, core region, and impeller boundary layer. The working surface and back surface of the blade twist have the high and low axial force area, and its distribution is staggered, at the same number of stages, the greater the flow rate, the smaller the blade twisting axial force. The shroud pressure differential force with the increase of impeller stages presents a linear increasing trend, conforms to the principle of linear superposition of cover pressure differential force. The total axial force pulsation of multi-stage pump is related to the number of secondary impeller blades, its primary frequency coincides with the secondary impeller blade frequency, increasing the flow rate can reduce the multi-stage pump axial force pulsation amplitude. The pulsation period of single-stage impeller head and efficiency are related to the number of impeller blades, the smaller the number of impeller stages, the stronger the pressure dynamic, and static interference effect of the impeller inlet and outlet. Rotation of the secondary impeller causes dynamic and static interference, which is the main reason for the pulsation of the axial force coefficient in double-casing multistage pumps, the pulsation intensity is related to the periodic generation and shedding of the blade vortex. The results of the study can be used as a reference for optimizing the axial force of double-casing multistage pumps.

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“…Aoki [3] measured the transient pressure distribution on the impeller blade of an open single-blade centrifugal and obtained the impeller's dynamic and static radial force. Nishi [4] studied the radial force of a single blade centrifugal pump by a numerical simulation and experiment, analyzed the influence of the blade outlet angle and blade outlet width on the radial force, and found that increasing the blade outlet width can reduce the mean value of radial force under small flow conditions. Meng [5] and Al [6] studied the radial force of a centrifugal pump with guide vanes and found that the asymmetry of pressure in each flow channel of the impeller was the main reason for the radial force of the impeller.…”

Section: Introductionmentioning

confidence: 99%

Research on Influence of Rotation Center Eccentricity on Radial Force of Single-Blade Centrifugal Pump

Wang

Tan

Shi

et al. 2022

Water

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To estimate the influence of the rotation center eccentricity of the single-blade centrifugal pump impeller on the radial force on it, and to explore the effective radial force balance method, a single blade pump with a power of 2.2 kW is analyzed. The accuracy of Numerical Simulation Methods are verified by tests of external characteristics (under three rotation-speeds of 1470 r/min, 2000 r/min, and 2940 r/min) and pressure distributions. There are five models with different rotation center coordinates (model a with (0,1), model b with (−1,0), model c with (0,−1), model d with (1,0), and model e with (0,0.5)) which are analyzed. The results show that the radial force of model c and model d reduced by 8.1% and 9.8%, respectively, which means the offset of the center of the impeller to the positive direction of the x-axis and the negative direction of the y-axis can effectively reduce the radial force. At the eccentricity of the impeller (2,−2), the radial force under all operating conditions is reduced, most obviously at 1.0 Qd, which is about 17%. The study may prove helpful to designers and pump manufacturers to find a path forward for an optimal eccentricity to minimize the radial force.

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Effect of Blade Outlet Angle on Unsteady Hydrodynamic Force of Closed-Type Centrifugal Pump with Single Blade

Cited by 18 publications

References 15 publications

Pressure fluctuation characteristics in the sidewall gaps of a centrifugal dredging pump

Pressure fluctuation characteristics in the sidewall gaps of a centrifugal dredging pump

Analysis of the axial force distribution characteristics of multistage pumps and its correlation with hydraulic property

Research on Influence of Rotation Center Eccentricity on Radial Force of Single-Blade Centrifugal Pump

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