Numerical Study of Pressure Fluctuation and Unsteady Flow in a Centrifugal Pump

Liu, Bai; Zhou, Lian; Chen, Han; Zhu, Yong; Shi, Weidong

doi:10.3390/pr7060354

Cited by 51 publications

(33 citation statements)

References 34 publications

(38 reference statements)

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“…By comparing the pressure at the outlet with different time steps, it was found that small variations exist among the results when using different time steps. Based on this study on the influence of time steps on the solution, 1/60 T (4.54 × 10 −4 s) is selected as the time step for computational efficiency without compromising accuracy [17,18]. The numerical setup is described in Table 3.…”

Section: Calculation Methodsmentioning

confidence: 99%

“…And 60 (17) where , and denote the pressure difference, velocity difference, and height difference obtained when the water flow through the pump, M is the torque, and QF is the flow conditions of the self-priming pump. In the analysis and presentation of results, the head and flow conditions are converted into the dimensionless parameters given below [24]: 60 (18) .…”

Section: Hydraulic Performance Of the Pumpmentioning

confidence: 99%

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Numerical and Experimental Study of a Vortex Structure and Energy Loss in a Novel Self-Priming Pump

et al. 2019

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The self-priming pump as an essential energy conversion equipment is widely used in hydropower and thermal power plants. The energy losses in the internal flow passage of the pump directly affect its work efficiency. Therefore, it is important to improve the internal flow characteristic of the pump. In the present work, a novel self-priming pump which starts without water is proposed; this pump can reduce the energy consumption as well as the time needed to start its operation. The spatial structure of the vortices in the pump is investigated by employing the Q criterion with the numerical solution of the vorticity transport equation. Based on the morphology, the vortices can be separated into three categories: Trailing Edge Vortex (TEV), Leading Edge Vortex (LEV) and Gap Leakage Vortex (GLV). Generally, the morphology of the TEV is more disorderly than that of LEV and GLV, and the intensity of TEV is significantly higher than that of the other two vortices. To determine the magnitude and distribution of energy loss in the pump, entropy production analysis is employed to study the influence of blade thickness on energy characteristics of the pump. It is found that with an increase in the flow rate, the location of energy loss transfers from the trailing edge to the leading edge of the blade, and viscous entropy production (VEP) and turbulence entropy production (TEP) are the dominant factors which influence the energy conversion in the pump. More importantly, employing the blade with a thin leading edge and a thick trailing edge can not only significantly reduce the impact of incoming flow under over-load condition (flow rate higher than the design condition) but can also increase the efficiency of the pump. Thus, an increase in thickness of the blade from the leading edge to the trailing edge is beneficial for improving the pump performance. The results of this paper can be helpful in providing guidelines for reducing the energy loss and in improving the performance of a self-priming pump.

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Section: Calculation Methodsmentioning

confidence: 99%

Section: Hydraulic Performance Of the Pumpmentioning

confidence: 99%

Numerical and Experimental Study of a Vortex Structure and Energy Loss in a Novel Self-Priming Pump

et al. 2019

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“…In process machinery, pumps, valves, pipes, absorption tower, fluid-bed and other devices which involve complex flow or heat transfer are indispensable [1][2][3][4][5][6][7][8][9][10][11][12][13]. Among them, the valve is an important controlling device for opening and closing pipelines, adjusting the flow direction and regulating the transmission of the medium [14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis to the Effect of Guiding Plate on Flow Characteristics in a Ball Valve

et al. 2020

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When internal flows go through a valve with a small opening degree, high-speed jet flows are induced, which causes the erosion of the valve core and affects the stability of the flow field. Setting guiding plates in the valve behind the valve core has the function of reducing the adverse effect of high-speed jet flows. In this work, numerical simulations were carried out to investigate the effect of the guiding plate on flow and resistance coefficient, velocity and pressure distributions and flow stability downstream of the valve. The number of guiding plates was changed from 0 to 3 and the opening degree was varied from 0 to 100% at intervals of 10%. A guiding plate with holes in it plays the role of bypassing and guiding flow. Under the action of the guiding plate, the flow coefficient obviously decreases, the gap flow between the valve core and the valve wall in the top of the valve are modified, and the gap flow even disappeared in the valve with 3 guiding plates. It was found that setting the guiding plate can improve the performance of the ball valve, reducing the internal erosion and increasing the stability of valve downstream flow efficiently.

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“…For example, Boncinelli, et.al [6] analyzed the effects of the meridional channel geometries and the blade turning angles of a bowl-type diffuser for a low specific-speed pump to achieve an optimal configuration. Bai, et.al [7] investigated the effect of diffuser vane numbers on the performance of a centrifugal pump with a diffuser and concluded that a lower number of diffuser vanes is beneficial to obtain a good pump stability. It should be stated that some critical geometrical parameters of the diffuser are not mentioned, such as the wrap angles and the vane positions of the diffuser.…”

Section: Introductionmentioning

confidence: 99%

Effect of space diffuser on flow characteristics of a centrifugal pump by computational fluid dynamic analysis

Liu

Yang

et al. 2020

PLoS ONE

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Achieving an optimal configuration of the diffuser is indispensable for high pump performances. In this work, a numerical study on diffuser configuration is conducted for a high pump performance using a computational fluid dynamics code, and the effects of the wrap angle and the relative position of the diffuser vane to the impeller on pump performances are included. The results indicate that the modified diffuser with a suitable wrap angle may improve the pump hydraulic efficiency and the head by approximately 4% and 8%, respectively, while a suitable position of the diffuser vane can enhance the pump head by more than 4%. Meanwhile, the pressure recovery coefficient and the local Euler head of the diffuser are adopted to evaluate the diffuser performance. For a high pump performance, the local Euler head of the diffuser has a peak value at the leading edge with the change rate of zero along the meridian streamline, meaning that no blade loading at the leading edge of the diffuser guarantees a better match between the impeller and the diffuser.

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Numerical Study of Pressure Fluctuation and Unsteady Flow in a Centrifugal Pump

Cited by 51 publications

References 34 publications

Numerical and Experimental Study of a Vortex Structure and Energy Loss in a Novel Self-Priming Pump

Numerical and Experimental Study of a Vortex Structure and Energy Loss in a Novel Self-Priming Pump

Numerical Analysis to the Effect of Guiding Plate on Flow Characteristics in a Ball Valve

Effect of space diffuser on flow characteristics of a centrifugal pump by computational fluid dynamic analysis

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