Comparative study of SGS models for simulating the flow in a centrifugal-pump impeller using single passage

Huang, Xianbei; Liu, Zhuqing; Yang, Wei

doi:10.1108/ec-09-2014-0193

Cited by 10 publications

(7 citation statements)

References 16 publications

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“…For example, the low speed areas caused by rotation instability near the blade pressure surfaces are captured, and the high speed areas near the blade suction surfaces and impeller outlet are resolved correctly. Moreover, under the 0.25Q0 condition, the important phenomenon, "alternate stall", is also well captured by the MST model, and the prediction results of stall cells are in agreement with those simulated by the LES method [48][49]. Again, it proves that the MST model is suitable for the computations of turbulent flows in the impeller, a core component of hydraulic rotating machineries.…”

Section: Flow In a Centrifugal Pump Impellersupporting

confidence: 68%

“…High quality hexahedral grids are adopted to discretize the domain, and the number of grids are approximately 1.60 million, which is determined on the basis of previous simulations of this flow case [48][49]. As for boundary conditions, the mass flowrate inlet condition with a low turbulence intensity is employed, while the pressure outlet condition and the no-slip wall condition are adopted.…”

Section: Flow In a Centrifugal Pump Impellermentioning

confidence: 99%

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A modified STRUCT model for efficient engineering computations of turbulent flows in hydro-energy machinery

Wang

et al. 2020

International Journal of Heat and Fluid Flow

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A modified STRUCT turbulence model (MST model) for efficient engineering computations of turbulent flows with rotation and curvature is proposed in this paper. The MST model switches between URANS and LES-like modes using a new damping function to adjust the turbulent viscosity. Compared with the original STRUCT method, the modifications are as follows:(1) the BSL k-ω model with the Spalart-Shur correction is chosen as the new baseline to improve the sensitivity to rotation and curvature; (2) a new adaptive time-scale ratio is proposed to avoid the arbitrariness of geometric averaging operation in the original method; (3) the normalized helicity is introduced into the new damping function to detect the energy backscatter phenomenon. Five classical high Reynolds number flow cases are tested. The results show that the turbulent viscosity of flow in the massively separated regions modeled by the MST model is reasonably reduced, and LES-like mode is activated, which captures more turbulent vortices and fluctuations on the URANS grids. With high efficiency and robustness, the MST model inherits the advantages of the original STRUCT method and improves the prediction accuracy of turbulent flows with rotation and curvature, which enables efficient engineering computations of the turbulence in hydraulic rotating machinery.

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Section: Flow In a Centrifugal Pump Impellersupporting

confidence: 68%

Section: Flow In a Centrifugal Pump Impellermentioning

confidence: 99%

A modified STRUCT model for efficient engineering computations of turbulent flows in hydro-energy machinery

Wang

et al. 2020

International Journal of Heat and Fluid Flow

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“…There was also alternating stall generated in the centrifugal impeller with cite-fixed stall cells and alternating distribution of the stalled blade channel. 13–15 This alternating stall pattern can be found in both the experimental and numerical cases. Based on the studies in the past, the mechanism of the undesirable flow regime at partial load was already clarified.…”

Section: Introductionmentioning

confidence: 54%

Comparative modeling and analysis of the flow asymmetricity in a centrifugal pump impeller at partial load

Tao

Wang

2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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Undesirable flow regime occurs at partial-load conditions of the centrifugal pump. Flow separates at the leading edge and pulses in the blade channel with complex stall cell transfer law. The passing capability of the blade channel becomes important when rotating stall happens. In this study, the blade channel number influence on the flow stability in a centrifugal pump impeller was studied by unsteady flow simulations after numerical-experimental verification. The 5-, 6-, and 7-blade impellers were discussed under the same partial-load flow rate condition and the same rotating speed. Results show that the internal flow pattern was strongly influenced by the blade channel number. Periodic half-blockage was observed in the 5-blade impeller. Alternating stall with three stalled and three well-behaved channels existed in the 6-blade impeller. Complex aperiodic flow pattern occurred in the 7-blade impeller with the well-behaved, half-blocked, and fully stalled passages were all observed with stall cell transfer. The different flow regime caused different pressure pulsations. In the 5-blade impeller, the inter-channel flow frequencies, which were induced by the fluid extruded from blocked channels flowed into other channels, dominated. In the 6-blade impeller, the pressure pulsations performed low-in-amplitude and high-in-frequency. The flow regime was stable even under the rotating stall. In the 7-blade impeller, the rotating stall frequency dominated. The inter-channel flow frequencies were also obvious. The stable rotating stall pattern does not strongly influence the pressure pulsation and impeller axial and radial forces. The transferring stall cell induces extra mild pressure pulsation and impeller forces. The inter-channel flow adds strong pressure pulsation and impeller forces. When centrifugal pumps are operating at partial-load conditions, the flow characters especially the inter-channel flow caused by half-channel-blockage should be checked to avoid operation instability and security.

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“…Its design flow rate, Q d , is 3.06 kg/s, and its angular rotating speed is ω = 725 r/min (revolution per minute). This is a typical pump impeller with six untwisted blades (blade number Z = 6) and widely studied by researchers [35,36]. In this case, the quarter partial-load condition Q = 0.25 Q d , which is about 0.76 kg/s, was analyzed.…”

Section: Pump Impeller Objectmentioning

confidence: 99%

Influence of Blade Leading-Edge Shape on Rotating-Stalled Flow Characteristics in a Centrifugal Pump Impeller

et al. 2020

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Rotating stall, which is a common phenomenon in turbomachinery, strongly relates to the flow rate condition. In centrifugal impellers, rotating stall was induced by the incidence angle on blade leading-edge at partial-load. The blade leading-edge shape also influences the rotating stall because of the subtle change of local flow-field. In this study, the influence of blade leading-edge shape on rotating-stalled flow characteristics was studied in a six-blade centrifugal pump impeller. The stall pattern was “alternating”: Three passages were stalled, three passages were well-behaved, and the stalled and well-behaved passages occurred alternately. The stalled flow characteristics can be studied without the interruption of stall cell movement. Four types of blade leading-edge (blunt, sharp, ellipse, and round) were numerically compared based on the initial typical impeller and the numerical–experimental verification. The numerical comparison shows that the leading-edge shape has a strong influence on the stalled flow pattern, velocity, pressure, turbulence kinetic energy, and flow-induced noise inside impellers. The blunt and sharp leading-edge impellers had a similar internal pattern; the ellipse and round leading-edge impellers were also similar in the internal flow-field. Pressure pulsation analysis showed more obvious differences among these impellers. The main frequency and the pulsation peak–peak values were completely different because of the slight leading-edge shape differences. It revealed the impact of leading-edge geometry on the transient flow-field change under the same incidence angle conditions. It also provided reference for influencing or controlling the rotating stall by blade profile design.

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Comparative study of SGS models for simulating the flow in a centrifugal-pump impeller using single passage

Cited by 10 publications

References 16 publications

A modified STRUCT model for efficient engineering computations of turbulent flows in hydro-energy machinery

A modified STRUCT model for efficient engineering computations of turbulent flows in hydro-energy machinery

Comparative modeling and analysis of the flow asymmetricity in a centrifugal pump impeller at partial load

Influence of Blade Leading-Edge Shape on Rotating-Stalled Flow Characteristics in a Centrifugal Pump Impeller

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