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

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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Investigation of rotating stall for a centrifugal pump impeller using various SGS models

Journal of Hydrodynamics ◽

10.1016/s1001-6058(16)60733-3 ◽

2017 ◽

Vol 29 (2) ◽

pp. 235-242 ◽

Cited By ~ 13

Author(s):

Pei-jian Zhou ◽

Fu-jun Wang ◽

Zheng-jun Yang ◽

Jie-gang Mou

Keyword(s):

Centrifugal Pump ◽

Rotating Stall ◽

Pump Impeller ◽

Centrifugal Pump Impeller

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An Impact of Various Shroud Bleed Slot Configurations and Cavity Vanes on Compressor Map Width and the Inducer Flow Field

Journal of Turbomachinery ◽

10.1115/1.4007513 ◽

2013 ◽

Vol 135 (4) ◽

Cited By ~ 8

Author(s):

Subenuka Sivagnanasundaram ◽

Stephen Spence ◽

Juliana Early ◽

Bahram Nikpour

Keyword(s):

Flow Field ◽

Incidence Angle ◽

Pressure Ratio ◽

Leading Edge ◽

Operating Conditions ◽

Choked Flow ◽

Recirculating Flow ◽

Heavy Duty Diesel ◽

Compressor Map ◽

The Impact

This paper describes an investigation of map width enhancement and a detailed analysis of the inducer flow field due to various bleed slot configurations and vanes in the annular cavity of a turbocharger centrifugal compressor. The compressor under investigation is used in a turbocharger application for a heavy duty diesel engine of approximately 400 hp. This investigation has been undertaken using a computational fluid dynamics (CFD) model of the full compressor stage, which includes a manual multiblock-structured grid generation method. The influence of the bleed slot flow on the inducer flow field at a range of operating conditions has been analyzed, highlighting the improvement in surge and choked flow capability. The impact of the bleed slot geometry variations and the inclusion of cavity vanes on the inlet incidence angle have been studied in detail by considering the swirl component introduced at the leading edge by the recirculating flow through the slot. Further, the overall stage efficiency and the nonuniform flow field at the inducer inlet have been also analyzed. The analysis revealed that increasing the slot width has increased the map width by about 17%. However, it has a small impact on the efficiency, due to the frictional and mixing losses. Moreover, adding vanes in the cavity improved the pressure ratio and compressor performance noticeably. A detail analysis of the compressor with cavity vanes has also been presented.

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An Impact of Various Shroud Bleed Slot Configurations and Cavity Vanes on Compressor Map Width and the Inducer Flow Field

Volume 7: Turbomachinery, Parts A, B, and C ◽

10.1115/gt2011-45629 ◽

2011 ◽

Cited By ~ 1

Author(s):

Subenuka Sivagnanasundaram ◽

Stephen Spence ◽

Juliana Early ◽

Bahram Nikpour

Keyword(s):

Flow Field ◽

Incidence Angle ◽

Pressure Ratio ◽

Leading Edge ◽

Operating Conditions ◽

Choked Flow ◽

Recirculating Flow ◽

Heavy Duty Diesel ◽

Compressor Map ◽

The Impact

This paper describes an investigation of map width enhancement and a detailed analysis of the inducer flow field due to various bleed slot configurations and vanes in the annular cavity of a turbocharger centrifugal compressor. The compressor under investigation is used in a turbocharger application for a heavy duty diesel engine of approximately 400hp. This investigation has been undertaken using a CFD model of the full compressor stage which includes a manual multi-block structured grid generation method. The influence of the bleed slot flow on the inducer flow field at a range of operating conditions has been analysed, highlighting the improvement in surge and choked flow capability. The impact of the bleed slot geometry variations and the inclusion of cavity vanes on the inlet incidence angle have been studied in detail by considering the swirl component introduced at the leading edge by the recirculating flow through the slot. Further, the overall stage efficiency and the non-uniform flow field at the inducer inlet have been also analysed. The analysis revealed that increasing the slot width has increased the map width by about 17%. However, it has a small impact on the efficiency due to the frictional and mixing losses. Moreover, adding vanes in the cavity improved the pressure ratio and compressor performance noticeably. A detail analysis of the compressor with cavity vanes has also been presented.

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Improvement of Suction Performance of Centrifugal Pump Impeller : Effects of Leading Edge Extension of Every Other Blade and Splitting of the Impeller

Bulletin of JSME ◽

10.1299/jsme1958.23.361 ◽

1980 ◽

Vol 23 (177) ◽

pp. 361-367 ◽

Cited By ~ 1

Author(s):

Yasuo TAKAMATSU ◽

Kusuo OOKUMA ◽

Ryo NAKAMURA ◽

Akinori FURUKAWA

Keyword(s):

Centrifugal Pump ◽

Leading Edge ◽

Pump Impeller ◽

Suction Performance ◽

Edge Extension ◽

Centrifugal Pump Impeller ◽

Leading Edge Extension

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Flow Field Analysis and Nearfield Acoustic Signature Reduction of a Stationary Fan Blade Array

Journal of Fluids Engineering ◽

10.1115/1.4049116 ◽

2020 ◽

Author(s):

Syed Qasim Zaheer ◽

Peter Disimile

Keyword(s):

Flow Field ◽

Vortex Shedding ◽

Leading Edge ◽

Pressure Side ◽

Validation Data ◽

Array Configuration ◽

Blade Cascade ◽

Fan Blade ◽

The Impact ◽

Blade Leading Edge

Abstract A highly cambered and loaded stationary fan blade cascade of an in-service centrifugal fan is analyzed in this research work at flow conditions corresponding to design point operation of subject fan. The configuration of enclosed blade cascade includes upstream and downstream ducts. A preliminary analysis of flow variables and nearfield acoustic spectra is carried out experimentally which then provided boundary conditions and validation data for an extensive numerical analysis using Embedded Large Eddy Simulation turbulence model in ANSYS Fluent 19.0 ® environment. The comprehensive analysis of flow field and nearfield aeroacoustics of blade array configuration reveals vortex shedding from blade leading edge and its interaction with pressure side surface of adjacent blade becomes one of major source in the aeroacoustics signature of blade array. The vortex shedding frequency and the frequency of upstream turbulence interaction with blade leading edge are identified. A novel method of placing rectangular cavity on pressure side of blade array to suppress the impact of impingement of leading-edge vortex via cavity acoustic wave is explored. The numerical results reveal a reduction in noise by 6dB encouraging the efficacy of this method as a passive technique to reduce aeroacoustics signature of researched blade array configuration.

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

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650919851921 ◽

2019 ◽

Vol 234 (2) ◽

pp. 237-247 ◽

Cited By ~ 1

Author(s):

Ran Tao ◽

Zhengwei Wang

Keyword(s):

Flow Regime ◽

Centrifugal Pump ◽

Channel Flow ◽

Pressure Pulsation ◽

Rotating Stall ◽

Pressure Pulsations ◽

Pump Impeller ◽

Partial Load ◽

Load Conditions ◽

Centrifugal Pump Impeller

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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Measurements of Rotating Stall Inside a Centrifugal Pump Impeller

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2005-77313 ◽

2005 ◽

Cited By ~ 2

Author(s):

D. A. Johnson ◽

N. Pedersen ◽

C. B. Jacobsen

Keyword(s):

Centrifugal Pump ◽

Marked Change ◽

Rotating Stall ◽

Velocity Measurements ◽

Pump Impeller ◽

Pressure Transducers ◽

Design Load ◽

Measured Flow ◽

Flow Through ◽

Centrifugal Pump Impeller

Velocity measurements have been obtained in a centrifugal pump with a volute. The measurements have been obtained between the blade passages of a shrouded impeller and in the volute region using laser Doppler velocimetry (LDV). Complimentary measurements have been obtained with pressure transducers circumferentially mounted on the volute. The flow through the impeller is measured at both design load and at several off-design conditions including severe off-design conditions. Results show that flow behaviour at design conditions Qd is well behaved. At reduced flow off-design conditions (0.25Qd) the measured flow pattern was altered significantly showing alternating stable stationary stalled and unstalled passages. Spectral analysis of the data from the LDV probe and the pressure probes showed a marked change in the spectrum as the stall phenomena occurs. This result is in contrast with previous researchers who have reported partially stalled flow passages or rotating stall conditions where the stall pattern rotated relative to the impeller with a regular frequency.

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