Effect of Tip Clearance on Helico-Axial Flow Pump Performance at Off-Design Case

Neng-qi, Kan; Liu, Zongku; Shi, Guangtai; Liu, Xiaobing

doi:10.3390/pr9091653

Cited by 11 publications

(6 citation statements)

References 26 publications

(25 reference statements)

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“…Kan et al [18] numerically applied the k-omega turbulence model to simulate the helical axial pump type. The effect of the clearance area between the casing and blade tip region on the characteristics of the internal flow was observed through investigating the pressure streamline in the pump and TKE.…”

Section: Introductionmentioning

confidence: 99%

Evaluation and Investigation of Hydraulic Performance Characteristics in an Axial Pump Based on CFD and Acoustic Analysis

Al-Obaidi

2024

Processes

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In this work, the internal flow behaviour and characteristic pressure fluctuations of an axial pump with varying water conditions are analysed. The impact of tip vortex flow on the pattern of turbulent flow is simulated numerically by the application of the CFD technique and experimentally using an acoustics analysis method. The numerical CFD data are verified with an experimental test model for accuracy and reliability. Based on the results, the difference in pressure in the internal flow and at the surfaces of the blade can be impacted through tip leakage vortex regions, which leads to changes in internal flow. Subsequently, the flow in the clearance and tip leakage vortex regions is changed. Moreover, the results reveal that the suction wall upstream is more unsteady near the surface due to more mixing, secondary flow, and tip leakage vortices. Pressure fluctuation occurs near the tip of the blade, caused by the increasing vortex flow velocity and hence raising the turbulent kinetic energy (TKE). Using different monitoring points at the blade impeller reveals high values of the pulsation amplitude. Owing to the region of clearance backflow under low-water conditions, the axial pump displays larger fluctuations in pressure near the tip blade area. Because the leakage flow leaves the gap at a high flow rate, shear layers are formed quickly between the main flow and the leakage flow. Near the end wall, there is a negative-vorticity-induced vortex. Moreover, as the flow rate increases, the pump’s amplitude decreases along with its main frequency. For the low-water flow, the results reveal that there is an important clearance backflow because the axial pump has large clearance.

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Section: Introductionmentioning

confidence: 99%

Evaluation and Investigation of Hydraulic Performance Characteristics in an Axial Pump Based on CFD and Acoustic Analysis

Al-Obaidi

2024

Processes

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“…Zhang et al (Zhang et al, 2017) artificially analyzed the wear characteristics of the axial-flow pump with sewage as the medium, and the research results showed the relationship between the solid volume fraction and the sweep Angle of the pressure/suction surface and the particle diameter. In order to reveal the influence of tip clearance on the flow characteristics and pressurization performance of spiral axial flow pump, Kan et al (Kan et al, 2021) analyzed the flow characteristics and energy characteristics of spiral axial flow pump and found that tip clearance increased the possibility of cavitation and had a great influence on the pressurization performance of spiral axial flow pump. The damage of axial flow pump impeller in sandy water was predicted and analyzed by Hua (Hua et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Analysis of internal flow characteristics and entropy generation of low head bulb tubular pump

et al. 2023

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To study the internal flow characteristics and energy characteristics of a large bulb perfusion pump. Based on the CFX software of the ANSYS platform, the steady calculation of the three-dimensional model of the pump device is carried out. The numerical simulation results obtained by SST k-ω and RNG k-ε turbulence models are compared with the experimental results. Finally, SST k-ω is selected for subsequent calculation. With the help of the flow line diagram and turbulent kinetic energy table of the whole flow channel of the pump device, the flow components of the pump device under different working conditions are analyzed, and the pressure and velocity distribution at the impeller and guide vane are analyzed by pressure cloud diagram and velocity cloud diagram. It is found that there are three high-pressure areas in the impeller and guide vane section, and the high-pressure regions are mainly distributed in the middle of the impeller channel. As the head decreases, the pressure at the impeller and guide vane positions decreases gradually, and the flow rate increases. Based on the entropy production principle, the wall entropy production and the distribution of mainstream entropy production at the impeller and guide vane parts are analyzed.

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“…Yang et al [18,19] studied the internal flow characteristics and pressure pulsation characteristics inside the impeller and guide vanes of a vertical axial flow pump at different flow rates, and analyzed the internal flow characteristics at the inlet and outlet under different deflection angles based on the k-omega model, finding that the uniformity of the outlet flow velocity and the pressure pulsation are periodic with the increase in the deflection angle. Kan et al [20] used the k-omega turbulence model to numerically calculate a helical axial flow pump and revealed the influence of the clearance between the blade tip and the casing on the internal flow characteristics by analyzing the pump's pressure, streamline, and turbulent kinetic energy. Feng et al [21] used numerical methods to study the influence of the clearance between the blade tip and the casing on the pressure fluctuation of an axial flow pump, and proposed a new method based on pressure statistics to determine the pressure fluctuation of all grid nodes in the pump.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Complex Three-Dimensional Flow Structure in the Circulation Pump of the Flow-Making System Based on Delayed Detached Eddy Simulation

et al. 2023

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As the core component of the flow-making system, the circulating pump has differences in its internal flow structure under different operating conditions, which affects the flow quality of the environmental simulation test area and the authenticity of marine environmental simulation. To explore the internal flow characteristics and outlet evolution characteristics of the circulating pump, this paper uses the DDES (delayed detached eddy simulation) method for numerical simulation. This paper combines BVF (boundary vorticity flow) diagnosis and the limit streamline method to analyze the evolution characteristics of the unstable flow area on the blade surface; it uses the Q criterion to identify the vortex structure inside the pump and analyze its evolution and development laws. Additionally, a quantitative analysis of the flow state of the circulating pump using flow uniformity indexes is performed. The results show that the surface of impeller blades is uniform under 1.0 QN. At 0.7 QN, the evolution process of the blade suction surface BVF is periodic, with a corresponding period of about 2/9 T (0.02 s). At 1.0 QN, the strength and scale of the separated vortices inside the guide vanes are minimized compared to other flow rates, and the scale and strength of the vortices show a decreasing trend along the outer normal direction. The evolution period of the separation vortex on the pressure surface of the guide vane is about 1/3 T (0.033 s) under 1.1 QN and the evolution period of the suction surface of the guide vane is about 2/3 T (0.067 s) under 0.7 QN. The flow uniformity indexes value downstream of the pump outlet under 1.0 QN are very close to the ideal value; with a corresponding value of Ϛi = 0.023, θ¯ = 89.94°, γ = 0.95, λ = 97.9%, the outflow can be approximately regarded as axial uniform flow. The research results can provide theoretical support for the further optimization design of circulating pumps and lay the foundation for the implementation of real systems.

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Effect of Tip Clearance on Helico-Axial Flow Pump Performance at Off-Design Case

Cited by 11 publications

References 26 publications

Evaluation and Investigation of Hydraulic Performance Characteristics in an Axial Pump Based on CFD and Acoustic Analysis

Evaluation and Investigation of Hydraulic Performance Characteristics in an Axial Pump Based on CFD and Acoustic Analysis

Analysis of internal flow characteristics and entropy generation of low head bulb tubular pump

Analysis of the Complex Three-Dimensional Flow Structure in the Circulation Pump of the Flow-Making System Based on Delayed Detached Eddy Simulation

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