Investigation on the Horn-Like Vortices in Stator Corner Separation Flow in an Axial Flow Pump

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Chaoyue Wang ◽  
Fujun Wang ◽  
Yuan Tang ◽  
Benhong Wang ◽  
Zhifeng Yao ◽  
...  
Keyword(s):  
Guide Vane ◽  
Pressure Fluctuations ◽  
Axial Flow ◽  
Maximum Amplitude ◽  
Separation Flow ◽  
Suction Surface ◽  
Corner Separation ◽  
Axial Flow Pump ◽  
Velocity Moment ◽  
Flow Pump

Abstract Stator corner separation flow existing in the guide-vane domain has significant effects on the characteristics of an axial-flow pump. The objective of this paper is to investigate the vortical structures in stator corner separation flow. Transient numerical simulation with a proof experiment was conducted for an axial-flow pump. Structural features of the vortices and their effects on velocity moment attenuation and pressure fluctuations in the guide-vane domain were analyzed. Horn-like vortices are found in the stator corner separation flow. A full cycle of the horn-like vortex evolution, “inception-growth-development-decay,” is presented. During this transit process, the vortex tube is gradually elongated and deformed, which forms an oblique separation line on the vane suction surface. High velocity moment always exists in the flow passages of the guide-vane domain, and the uniformity of main flows is gradually reduced. Meanwhile, periodic pressure fluctuations arise. The maximum amplitude of pressure fluctuations in the flow passages occurs in the region where the horn-like vortex cores at the “growth” stage lie in, which is approximately 3.39 times higher than that in the vaneless region between the impeller and guide-vane. The dominant frequency of pressure fluctuations in the flow passages is approximately 0.75 times the rotating frequency, which is close to the frequency of the full cycle of the horn-like vortex evolution. Horn-like vortices have remarkable effects on the flow fields, and more attention should be paid to them.

On the Vortical Characteristics of Horn-Like Vortices in Stator Corner Separation Flow in an Axial Flow Pump

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Chaoyue Wang ◽  
Fujun Wang ◽  
Lihua Xie ◽  
Benhong Wang ◽  
Zhifeng Yao ◽  
...  
Keyword(s):  
Deformation Mechanism ◽  
Pressure Fluctuation ◽  
Vortex Tube ◽  
Axial Flow ◽  
Separation Flow ◽  
Decomposition Approach ◽  
Corner Separation ◽  
Swirling Strength ◽  
Axial Flow Pump ◽  
Flow Pump

Abstract The phenomenon of horn-like vortex in stator corner separation flow in an axial flow pump was first reported by Wang et al. (2020, “Investigation on the Horn-Like Vortices in Stator Corner Separation Flow in an Axial Flow Pump,” ASME J. Fluids Eng., 142(7), p. 071208), and the associated external features were preliminarily presented. However, internal vortical characteristics of horn-like vortices, including the distributions of swirling strength, the deformation mechanism of vortex tube and the correlation with pressure fluctuation surge, are not revealed. In this paper, the newly developed vorticity decomposition approach is introduced, and thus more novel quantitative results are provided for the physics of horn-like vortex evolution in an axial flow pump. First, the distributions of absolute swirling strength, relative swirling strength and Liutex spectrum are presented to outline the vortical features of the horn-like vortex fields. Second, the deformation mechanism of the horn-like vortex tube is revealed. It is found that the horn-like vortex spatial evolution can be described by the deformation terms (Liutex stretching term, Liutex dilatation term, and curl term of the pseudo-Lamb vector) controlling the Liutex transport process. These terms constantly act on the horn-like vortex tube in an almost independent way, causing its continuous deformations in the transit process. Third, the quantitative correlation between horn-like vortex transit and pressure fluctuation surge is given. It is proved that periodic vortex transit can cause severe pressure fluctuation that is much larger than that induced by rotor–stator interaction. From multiple perspectives, a clearer evolution process of the horn-like vortex is outlined, which is conducive to controlling the corner separation flows and improving the stability of large-capacity and low-head pumping stations.

scholarly journals Effect of Guide Vanes on Flow and Vibroacoustic in an Axial-Flow Pump

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Guoping Li ◽  
Eryun Chen ◽  
Ailing Yang ◽  
Zhibin Xie ◽  
Gaiping Zhao
Keyword(s):  
Guide Vane ◽  
Spectral Characteristics ◽  
Pressure Fluctuations ◽  
Axial Flow ◽  
Coupled Model ◽  
Sound Field ◽  
Pump Design ◽  
Flow Discharge ◽  
Axial Flow Pump ◽  
Flow Pump

An effect of guide-vane numbers on pressure fluctuations and structural vibroacoustics induced by unsteady flow is performed by a hybrid numerical method. A 3D flow field is simulated in axial-flow pump with four impeller blades, in which three diffuser models with 5, 7, and 9 vanes are devised to match, respectively. A full scale structural vibroacoustics coupled model is solved using LMS acoustics software. The results show that the blade-passing frequency (BPF) is dominated frequency of the vibration acceleration of pump, which is consistent with frequency spectral characteristics of pressure pulsation. The unsteady pressure fluctuating becomes strong as the flow discharge decreases from 1.0Qv to 0.6Qv, the circumferential unsteady behavior of which is more severe due to flow nonuniformity induced by the suction elbow at partial operation. Generally, the pressure fluctuating increases slightly when the flow discharge increases from 1.0Qv to 1.3Qv. Moreover, pressure fluctuations amplitude on the pump with 9-vane diffuser is small relative to other two models and the vibrating accelerating and radiation sound field at BPF are also slight relatively, which indicates that appropriate guide-vane numbers contribute to suppress pressure fluctuations and vibroacoustics in axial-flow pump. The conclusions in the present paper can provide theoretical guidance for low vibration pump design.

The Effect of the Thickness and Angle of the Inlet and Outlet Guide Vane on the Performance of Axial-Flow Pump

2016 ◽  
Author(s):  
Sang-Won Kim ◽  
Youn-Jea Kim
Keyword(s):  
Numerical Analysis ◽  
Numerical Study ◽  
Guide Vane ◽  
Axial Flow ◽  
Inlet Guide Vane ◽  
Guide Vanes ◽  
Pump Performance ◽  
Blade Thickness ◽  
Axial Flow Pump ◽  
Flow Pump

An axial-flow pump has a relatively high discharge flow rate and specific speed at a relatively low head and it consists of an inlet guide vane, impeller, and outlet guide vane. The interaction of the flow through the inlet guide vane, impeller, and outlet guide vane of the axial-flow pump has a significant effect on its performance. Of those components, the guide vanes especially can improve the head and efficiency of the pump by transforming the kinetic energy of the rotating flow, which has a tangential velocity component, into pressure energy. Accordingly, the geometric configurations of the guide vanes such as blade thickness and angle are crucial design factors for determining the performance of the axial-flow pump. As the reliability of Computational Fluid Dynamics (CFD) has been elevated together with the advance in computer technology, numerical analysis using CFD has recently become an alternative to empirical experiment due to its high reliability to measure the flow field. Thus, in this study, 1,200mm axial-flow pump having an inlet guide vane and impeller with 4 blades and an outlet guide vane with 6 blades was numerically investigated. Numerical study was conducted using the commercial CFD code, ANSYS CFX ver. 16.1, in order to elucidate the effect of the thickness and angle of the guide vanes on the performance of 1,200mm axial-flow pump. The stage condition, which averages the fluxes between interfaces and is accordingly appropriate for the evaluation of pump performance, was adopted as the interface condition between the guide vanes and the impeller. The rotational periodicity condition was used in order to enable a simplified geometry to be used since the guide vanes feature multiple identical regions. The shear stress transport (SST) k-ω model, predicting the turbulence within the flow in good agreement, was also employed in the CFD calculation. With regard to the numerical simulation results, the characteristics of the pressure distribution were discussed in detail. The pump performance, which will determine how well an axial-flow pump will work in terms of its efficiency and head, was also discussed in detail, leading to the conclusion on the optimal blade thickness and angle for the improvement of the performance. In addition, the total pressure loss coefficient was considered in order to investigate the loss within the flow paths depending on the thickness and angle variations. The results presented in this study may give guidelines to the numerical analysis of the axial-flow pump and the investigation of the performance for further optimal design of the axial-flow pump.

Interactional Effects of Inlet Guide Vane and Blade Angle on Hydraulic Performance Characteristics of a Submersible Axial-Flow Pump

2018 ◽  
Author(s):  
Youn-Sung Kim ◽  
Hyeon-Seok Shim ◽  
Kwang-Yong Kim
Keyword(s):  
Stokes Equations ◽  
Guide Vane ◽  
Incidence Angle ◽  
Axial Flow ◽  
Performance Characteristics ◽  
Inlet Guide Vane ◽  
Computational Domain ◽  
Blade Angle ◽  
Axial Flow Pump ◽  
Flow Pump

This study aims to evaluate effects of blade pitch and inlet guide vane (IGV) angle on the performance characteristics of a submersible axial-flow pump. According to the results of the previous study, the efficiency at the design and over-load conditions were significantly affected by the angle of IGV due to change in the incidence angle. To investigate the interactional effects of IGV and blade angle are analyzed using three-dimensional Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model. The hexahedral grids are used in the computational domain and a grid-dependency test is performed to obtain an optimal number of the grids. In this study, combinations of three different blade angles and two different IGV angles are tested. Adjusting angle of IGV increases the total pressure of the pump with a blade pitch increase, which can increase the efficiency of the pump in operating range.

scholarly journals Performance analysis of axial flow pump on gap changing between impeller and guide vane

2013 ◽  
Vol 52 (3) ◽  
pp. 032011
Author(s):  
W J Wang ◽  
Q H Liang ◽  
Y Wang ◽  
Y Yang ◽  
G Yin ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Guide Vane ◽  
Axial Flow ◽  
Axial Flow Pump ◽  
Flow Pump

scholarly journals Improvement of the Efficiency of the Axial-Flow Pump at Part Loads due to Installing Outlet Guide Vanes Mechanism

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Fan Yang ◽  
Hao-ru Zhao ◽  
Chao Liu
Keyword(s):  
Prediction Model ◽  
Flow Rate ◽  
High Efficiency ◽  
Guide Vane ◽  
Axial Flow ◽  
Hydraulic Performance ◽  
Operating Conditions ◽  
Ann Model ◽  
Axial Flow Pump ◽  
Flow Pump

In order to investigate the influence of adjustable outlet guide vane on the hydraulic performance of axial-flow pump at part loads, the axial-flow pump with 7 different outlet guide vane adjustable angles was simulated based on the RNG k-ε turbulent model and Reynolds time-averaged equations. The Vector graphs of airfoil flow were analyzed in the different operating conditions for different adjustable angles of guide vane. BP-ANN prediction model was established about the effect of adjustable outlet guide vane on the hydraulic performance of axial-flow pump based on the numerical results. The effectiveness of prediction model was verified by theoretical analysis and numerical simulation. The results show that, with the adjustable angle of guide vane increasing along clockwise, the high efficiency area moves to the large flow rate direction; otherwise, that moves to the small flow rate direction. The internal flow field of guide vane is improved by adjusting angle, and the flow separation of tail and guide vane inlet ledge are decreased or eliminated, so that the hydraulic efficiency of pumping system will be improved. The prediction accuracy of BP-ANN model is 1%, which can meet the requirement of practical engineering.

Influence of tip clearance on pressure fluctuations in an axial flow pump

2016 ◽  
Vol 30 (4) ◽  
pp. 1603-1610 ◽  
Author(s):  
Jianjun Feng ◽  
Xingqi Luo ◽  
Pengcheng Guo ◽  
Guangkuan Wu
Keyword(s):  
Pressure Fluctuations ◽  
Axial Flow ◽  
Tip Clearance ◽  
Axial Flow Pump ◽  
Flow Pump

PIV Measurements and CFD Analysis in an Axial-Flow Pump

2007 ◽  
Author(s):  
Fang-Ping Tang ◽  
Chao Liu ◽  
Ji-Ren Zhou ◽  
Hua Yang ◽  
Li Cheng
Keyword(s):  
Flow Rate ◽  
Outer Part ◽  
Axial Flow ◽  
Operating Conditions ◽  
Design Flow ◽  
Separation Flow ◽  
Mean Velocity ◽  
Piv Measurements ◽  
Axial Flow Pump ◽  
Flow Pump

In this study, an axial flow pump impeller without guide vanes is experimentally investigated. The impeller used in the experiments consists of four blades. The particle image velocimetry technique and a five-hole probe have been used. Measurements of flow velocities in the outer part of the impeller have been made. PIV measurements have been realized in 12 meridian planes between blade-to-blade for design and off-design operating conditions. The meridian velocity is obtained with phase averaged method and the total circumferential mean velocity is obtained with an arithmetical average over the 12 circumferential data. The calculation is based on the CFX-TASC flow CFD code solving the three-dimensional Reynolds-averaged Navier-Stokes equation with RNG k–ε model of turbulence. The paper focuses on the comparisons of the results. Difference for the flow field between numerical and experimental results is small at large and design flow rate, while big difference occurs at small flow rate. It indicates that the numerical model is not suitable for separation flow.

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