Effects of flow pattern on hydraulic performance and energy conversion characterisation in a centrifugal pump

Li, Xiaojun; Chen, Bo; Luo, Xianwu; Zhu, Zuchao

doi:10.1016/j.renene.2019.11.049

Cited by 106 publications

(32 citation statements)

References 34 publications

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“…The convergence study provides us reference values for choosing the time step and fundamental element size, and proper damping coefficients to obtain convergent results. To verify the accuracy of the present numerical results, they were compared with published experimental [35], analytical [36], and other numerical results [34,37,38]. The force components were determined through performing Fourier analysis on the steady state part of the force histories.…”

Section: Convergence Study and Validationmentioning

confidence: 92%

Numerical Analysis of Combined Wave Radiation and Diffraction on a Floating Barge

Stankovic

et al. 2020

Water

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A two-dimensional boundary element method (BEM) based on the potential flow theory is adopted to study the combined wave radiation and diffraction by a single barge. The wave-body interaction problems are simulated using a mixed Euler-Lagrangian scheme, with fully nonlinear boundary conditions. The numerical schemes are verified through comparing with existing results, which show that both the wave runups on the barge and hydrodynamic forces can be calculated with sufficient accuracy. Cases of a single barge subjected to sway motion and regular waves are studied. The real contribution of this study is the outcomes of the spectral analysis conducted for test cases when wave radiation effects are considered in addition to pure wave diffraction. The cases of sway motion with the same frequency as incident wave are simulated first. It is found that sway motion will reduce the overall horizontal force when the frequency is lower than a critical frequency. After that, the higher the frequency, the bigger the horizontal force increasing effect. When the frequency of sway motion is lower than that of incident wave, in terms of the magnitude of the horizontal force, sway motion of the body will always make the resultant force larger than that of pure diffraction case.

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Section: Convergence Study and Validationmentioning

confidence: 92%

Numerical Analysis of Combined Wave Radiation and Diffraction on a Floating Barge

Stankovic

et al. 2020

Water

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“…The generation and development of the vortices in the impeller channels could have prevented the upstream liquid from flowing downstream, which was responsible for the unstable dynamic pressure. Li et al [34] propose that the motion of the vortices in the impeller channels considerably impacts pump hydraulic performance. The occurrence and development of unstable flow, which include backflows, rotating stalls and other types of unstable flow under partial load conditions in the centrifugal pump, could result in the generation and intensification of noise as well.…”

Section: Of 22mentioning

confidence: 99%

Investigation of the Noise Induced by Unstable Flow in a Centrifugal Pump

Liu

Zeng

et al. 2020

Energies

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In order to investigate the mechanism and the characteristics of the noise induced by unstable flow in a centrifugal pump, the internal flow characteristics in the pump were numerically researched, and the acoustic pressure fluctuations at the pump inlet and outlet were experimentally investigated. Obvious corresponding relationships between the flow instabilities, the cavitation and the noise were established. It was found that the rotating stall, the backflow, the hump, the occurrence of unstable flow and the cavitation in such a centrifugal pump were effectively detected through the noise, which could help to provide fundamental information on flow instabilities and guarantee safe and steady operating conditions for the system. The recirculation and prewhirl regions in the pump upstream pipe, which were caused by the backflow and the rotation of the impeller, presented the circumferential movement with a spiral shape, causing apparent broadband fluctuations at low frequency band of the acoustic pressure. The backflow and rotating stall could also result in broadband fluctuations of the pump outlet noise, which was distributed from 100 Hz to 150 Hz. Meanwhile, the broadband fluctuations of the pump outlet acoustic pressure distributed in the low frequency range, which was produced by the occurrence of cavitation, moved to the lower frequency band as the flow rate increased. The enhanced broadband fluctuations of the pump inlet and outlet noise distributed from 1 kHz to 6 kHz were caused by the coupling between the cavitation-induced noise and the system-produced noise. The broadband fluctuations of the pump inlet noise distributed between 6 kHz and 9 kHz were regarded as the typical frequency band of cavitation in the centrifugal pump.

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“…It is well known that pumps have huge energy consumption, and wall roughness has an important effect on pump efficiency [11][12][13][14][15][16]. In the process of using the double-channel sewage pump, the abrasion of the wall surface caused by the impurities in the transport medium and the damage of the blade surface caused by erosion will cause the change of the wall roughness, and roughness Ra is one of the important factors affecting the performance of the pump.…”

Section: Introductionmentioning

confidence: 99%

Influence of Critical Wall Roughness on the Performance of Double-Channel Sewage Pump

Zhang

Wang

et al. 2020

Energies

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The numerical method on a double-channel sewage pump was studied, while the corresponding experimental result was also provided. On this basis, the influence of wall roughness on the pump performance was deeply studied. The results showed that there was a critical value of wall roughness. When the wall roughness was less than the critical value, it had a great influence on the pump performance, including the head, efficiency, and shaft power. As the wall roughness increased, the head and efficiency were continuously reduced, while the shaft power was continuously increased. Otherwise, the opposite was true. The effect of wall roughness on the head and hydraulic loss power was much smaller than that on the efficiency and disk friction loss power, respectively. With the increase of wall roughness, mechanical efficiency and hydraulic efficiency reduced constantly, leading to the decrement of the total efficiency. With the increase of flow rate, the effect of wall roughness on the head and efficiency gradually increased, while the influence on the leakage continuously reduced. The influence of the flow-through component roughness on the pump performance was interactive.Energies 2020, 13, 464 2 of 20 Literature OverviewIn the past years, many scholars studied the effect of wall roughness on the flow in pipes, fans, compressors, microchannels. In order to study the effect of wall roughness in turbulent pipe flow, Hemeida [17] developed an equation for estimating the thickness of the laminar sublayer in turbulent pipe flow of pseudoplastic fluids and found that the turbulent pipe flow could be divided into two regions: smooth wall and rough wall turbulence. The roughness Reynolds number was used to determine the smooth wall turbulence and rough wall turbulence regions. Kandlikar [18] studied the roughness effects at microscale-reassessing Nikuradse's experiments on liquid flow in rough tubes, and found that Nikuradse's work was revisited in light of the recent experimental work on roughness effects in microscale flow geometries. Li et al. [19] studied the influence of the internal surface roughness of the nozzle on cavitation erosion characteristics of submerged cavitation jets from the aspects of erosion intensity and erosion efficiency; it could be concluded that excessive smooth surface was not conducive to the formation of cavitation bubbles, leading to an attenuated intensity of cavitation erosion, while excessive rough surface caused much energy dissipation and led to divergent jets, resulting in a significant reduction of erosion intensity. According to the experimental results, there existed an optimum inner surface roughness value to achieve the strongest aggressive cavitation erosion capability for submerged cavitating jets. Tang et al. [20] analyzed the existing experimental data in the literature on the friction factor in microchannels. The friction factors in stainless steel tubes were much higher than the theoretical predictions for tubes of conventional size. This discrepancy resulted from the large rel...

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Effects of flow pattern on hydraulic performance and energy conversion characterisation in a centrifugal pump

Cited by 106 publications

References 34 publications

Numerical Analysis of Combined Wave Radiation and Diffraction on a Floating Barge

Numerical Analysis of Combined Wave Radiation and Diffraction on a Floating Barge

Investigation of the Noise Induced by Unstable Flow in a Centrifugal Pump

Influence of Critical Wall Roughness on the Performance of Double-Channel Sewage Pump

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