Numerical Simulation on Hydraulic Characteristics of Nozzle in Waterjet Propulsion System

Wang, Chuan; He, Xiaoke; Cheng, Li; Luo, Can; Xu, Jing; Chen, Kun; Jiao, Weixuan

doi:10.3390/pr7120915

Cited by 20 publications

(14 citation statements)

References 31 publications

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“…It is necessary to verify the independence of the centrifugal pump grid [21][22][23]. Generally speaking, if the geometry model is correctly meshed, the Reynolds-Average Navier-Stokes-based turbulence simulation result will not fluctuate significantly as the number of model grids increases.…”

Section: Methods Validationmentioning

confidence: 99%

Numerical Study on the Influence of Inlet Guide Vanes on the Internal Flow Characteristics of Centrifugal Pump

Lin

et al. 2020

Processes

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In order to make the centrifugal pump run efficiently and stably under various working conditions, the influences of the incoming vortex flow in the inlet pipe on the main flow in the impeller is studied numerically, based on the k − ω SST turbulence model. Some guide vanes with different offset angle were added to change the statistical characteristic of the internal flow in the inlet pipe of the centrifugal pump. Both contour distributions of internal flow and statistical results of external performance are obtained and analyzed. The results show that the existence of vanes can divide the large vortex because of the reversed flow from the rotating impeller at low flow rate conditions into small vortices, which are easier to dissipate, make the velocity and pressure distribution more uniform, improve the stability of the flow in the impeller, reduce the hydraulic loss, and improve the hydraulic performance of the pump. The pump with vanes of offset angle 25° has a small pressure pulsation amplitude at each monitoring point. Comparing with the performance of the original pump, the head increased by around 2% and efficiency increased by around 2.5% of the pump with vanes of offset angle 25°.

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Section: Methods Validationmentioning

confidence: 99%

Numerical Study on the Influence of Inlet Guide Vanes on the Internal Flow Characteristics of Centrifugal Pump

Lin

et al. 2020

Processes

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“…With the rapid development of computer technology, numerical simulation is increasingly widely used in the fluid flow [27][28][29][30][31][32][33]. Guelich et al [34] studied the effect of wall roughness on the efficiency Energies 2020, 13, 464 3 of 20 of centrifugal pumps.…”

Section: Literature Overviewmentioning

confidence: 99%

“…In terms of roughness, the total pressure loss value was reduced by 23.1% compared to the smooth blade. Han et al [26] used numerical methods to study the influence of blade surface roughness on the internal flow field and characteristic parameters of the compressor under the compressor-level environment and found that the blade roughness had a significant effect on the main performance parameters of the compressor; with the blade roughness with the increase of the compressor, the performance degradation of the compressor stage was intensified, and the energy loss of the internal airflow was increased, especially the energy loss of the airflow near the middle and upper part of the leading edge of the impeller was severe, and the temperature of the blade end wall was increased.With the rapid development of computer technology, numerical simulation is increasingly widely used in the fluid flow [27][28][29][30][31][32][33]. Guelich et al [34] studied the effect of wall roughness on the efficiency Energies 2020, 13, 464 3 of 20 of centrifugal pumps.…”

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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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“…Centrifugal pumps are widely applied in a variety of fields, such as industrial plants, agricultural irrigation, the petroleum and chemical industries, aeronautics and astronautics [1][2][3]. Due to the current energy crisis and restrictions on environmental noise levels, centrifugal pumps that operate with low noise, high efficiency, high rotating speed and high reliability have become increasingly important.…”

Section: Introductionmentioning

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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Numerical Simulation on Hydraulic Characteristics of Nozzle in Waterjet Propulsion System

Cited by 20 publications

References 31 publications

Numerical Study on the Influence of Inlet Guide Vanes on the Internal Flow Characteristics of Centrifugal Pump

Numerical Study on the Influence of Inlet Guide Vanes on the Internal Flow Characteristics of Centrifugal Pump

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

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

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