An Experimental Investigation on the Erosion of a Helico-Axial Pump With Gas Presence

2020 ◽  
Author(s):  
Yi Chen ◽  
Abhay Patil ◽  
Yiming Chen ◽  
Gerald Morrison ◽  
Marisela Rojas
Keyword(s):  
Volume Fraction ◽  
Pressure Rise ◽  
Leading Edge ◽  
Oil And Gas Industry ◽  
Performance Degradation ◽  
Oil Field ◽  
Tip Clearance ◽  
Centrifugal Pumps ◽  
Impeller Blade ◽  
Axial Pump

Abstract Electrical submersible pump (ESP) technology has been widely applied in the oil and gas industry due to its high productivity. However, erosion always causes the reduction of productivity and sometimes even the failure of an ESP system. This study explores the effect of gas presence on erosion mechanism on an ESP which is composed of 4 stages of Helico-Axial Pump (HAP). A 200-hour erosion test has been performed on this ESP. During the test, the ESP was running at 3600 RPM with a liquid flow rate of 880 GPM, 20% inlet Gas Volume Fraction (GVF), and 0.24% sand concentration by weight. Performance tests were conducted every 50 hours to acquire the performance maps and monitor the performance degradation. Analysis of volume/weight loss and performance degradation is conducted to investigate pump wear. Two types of erosion are found at the impeller: the volume loss found notably at the leading edge is mainly caused by two-body impact erosion, while the tip clearance increment between the impeller housing and impeller blade tip is mainly caused by the three-body abrasive erosion. Unlike most conventional centrifugal pumps, there is no observable wear found at the trailing edge of the impeller. The presence of the gas shows a negative effect on both types of erosion. The consequence of the erosion is the performance degradation, especially at the condition with higher pressure rise. It is suggested to apply this HAP in the oil field with more gas and higher bottom hole pressure.

scholarly journals Influence of Large Relative Tip Clearances for a Micro Radial Fan and Design Guidelines for Increased Efficiency

2020 ◽  
Author(s):  
Patrick H. Wagner ◽  
Jan Van herle ◽  
Lili Gu ◽  
Jürg Schiffmann
Keyword(s):  
Pressure Rise ◽  
Leading Edge ◽  
High Sensitivity ◽  
Design Guidelines ◽  
Tip Clearance ◽  
Small Scale ◽  
Blade Tip ◽  
Dynamics Simulations ◽  
Experimental Findings ◽  
Blade Tip Clearance

Abstract The blade tip clearance loss was studied experimentally and numerically for a micro radial fan with a tip diameter of 19.2mm. Its relative blade tip clearance, i.e., the clearance divided by the blade height of 1.82 mm, was adjusted with different shims. The fan characteristics were experimentally determined for an operation at the nominal rotational speed of 168 krpm with hot air (200 °C). The total-to-total pressure rise and efficiency increased from 49 mbar to 68 mbar and from 53% to 64%, respectively, by reducing the relative tip clearance from 7.7% to the design value of 2.2%. Single and full passage computational fluid dynamics simulations correlate well with these experimental findings. The widely-used Pfleiderer loss correlation with an empirical coefficient of 2.8 fits the numerical simulation and the experiments within +2 efficiency points. The high sensitivity to the tip clearance loss is a result of the design specific speed of 0.80, the highly-backward curved blades (17°), and possibly the low Reynolds number (1 × 105). The authors suggest three main measures to mitigate the blade tip clearance losses for small-scale fans: (1) utilization of high-precision surfaced-grooved gas-bearings to lower the blade tip clearance, (2) a mid-loaded blade design, and (3) an unloaded fan leading edge to reduce the blade tip clearance vortex in the fan passage.

scholarly journals Experimental Investigations on the Inner Flow Behavior of Centrifugal Pumps under Inlet Air-Water Two-Phase Conditions

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4377 ◽  
Author(s):  
Si ◽  
Zhang ◽  
Bois ◽  
Zhang ◽  
Cui ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Flow Behavior ◽  
Bubbly Flow ◽  
Performance Degradation ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Impeller Blade ◽  
Pump Performance ◽  
Starting Point

Centrifugal pumps are widely used and are known to be sensitive to inlet air-water two-phase flow conditions. The pump performance degradation mainly depends on the changes in the two-phase flow behavior inside the pump. In the present paper, experimental overall pump performance tests were performed for two different rotational speeds and several inlet air void fractions (αi) up to pump shut-off condition. Visualizations were also performed on the flow patterns of a whole impeller passage and the volute tongue area to physically understand pump performance degradation. The results showed that liquid flow modification does not follow head modification as described by affinity laws, which are only valid for homogeneous bubbly flow regimes. Three-dimensional effects were more pronounced when inlet void fraction increased up to 3%. Bubbly flow with low mean velocities were observed close to the volute tongue for all αi, and returned back to the impeller blade passages. The starting point of pump break down was related to a strong inward reverse flow that occurred in the vicinity of the shroud gap between the impeller and volute tongue area.

Numerical Study on the Influence of Tip Clearance on Rotating Stall in an Unshrouded Centrifugal Compressor

2017 ◽  
Author(s):  
Wenying Ju ◽  
Shengli Xu ◽  
Xiaofang Wang ◽  
Xudong Chen ◽  
Shuhua Yang ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Numerical Study ◽  
Leading Edge ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Forming Process ◽  
Impeller Blade ◽  
Tip Clearance Flow ◽  
Rotating Speed ◽  
Operation Conditions

Whole annulus unsteady simulations are performed by CFD with the whole flow passage model from inlet guide vanes to volute of an unshrouded centrifugal compressor. Characteristics and development mechanism of rotating stall are analyzed including the flow field and the impeller blade load in time and frequency domain. Rotating stall with three cells is observed in both two actual operation conditions but the cell rotating speed and the forming process is different. Leading edge tip clearance leakage is a criterion to predict the formation of a spike stall in centrifugal compressors. Tip clearance flow also plays an important role in the moving of rotating instabilities and the propagation of stall cells. It can effectively slow down the stall forming and decrease the pressure load on blade by reduced the tip clearance size at the leading edge.

scholarly journals Study on Wear Properties of the Flow Parts in a Centrifugal Pump Based on EDEM–Fluent Coupling

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 431
Author(s):  
Si Huang ◽  
Jiaxing Huang ◽  
Jiawei Guo ◽  
Yushi Mo
Keyword(s):  
Centrifugal Pump ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Leading Edge ◽  
Suction Side ◽  
Pressure Side ◽  
Flow Conditions ◽  
Wear Properties ◽  
Impeller Blade ◽  
Fluid Medium

By using EDEM–Fluent codes and coupling the continuous fluid medium with a solid particle discrete element, the solid–liquid two-phase flow field in a centrifugal pump was simulated under the same inlet conditions of the particle volume fraction and three flow conditions of 0.7Qd, 1.0Qd and 1.3Qd. By introducing the Archard wear model, the wear was calculated, and the wear law was obtained for the pump flow parts such as the leading edge of the impeller blade, blade tip, blade pressure side, blade suction side, impeller shroud, hub and volute. The results demonstrate that the wear of volute is about 70% of the total wear of pump. The wear in the impeller mainly occurs in the blade leading edge, the junction of the hub and the trailing part of the blade pressure side, and the junction of the shroud and the rear part of the blade suction side. Under lower flow conditions, the wear in the impeller shroud is relatively considerable. As the flow rate increases, the wear in the blade pressure side and the hub increases significantly.

scholarly journals Origins and Structure of Spike-Type Rotating Stall

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
G. Pullan ◽  
A. M. Young ◽  
I. J. Day ◽  
E. M. Greitzer ◽  
Z. S. Spakovszky
Keyword(s):  
Pressure Rise ◽  
Leading Edge ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Suction Surface ◽  
Tip Leakage ◽  
Pressure Surface ◽  
Sequence Of Events ◽  
High Incidence ◽  
Experimental Findings

In this paper, we describe the structures that produce a spike-type route to rotating stall and explain the physical mechanism for their formation. The descriptions and explanations are based on numerical simulations, complemented and corroborated by experiments. It is found that spikes are caused by a separation at the leading edge due to high incidence. The separation gives rise to shedding of vorticity from the leading edge and the consequent formation of vortices that span between the suction surface and the casing. As seen in the rotor frame of reference, near the casing the vortex convects toward the pressure surface of the adjacent blade. The approach of the vortex to the adjacent blade triggers a separation on that blade so the structure propagates. The above sequence of events constitutes a spike. The computed structure of the spike is shown to be consistent with rotor leading edge pressure measurements from the casing of several compressors: the centre of the vortex is responsible for a pressure drop and the partially blocked passages associated with leading edge separations produce a pressure rise. The simulations show leading edge separation and shed vortices over a range of tip clearances including zero. The implication, in accord with recent experimental findings, is that they are not part of the tip clearance vortex. Although the computations always show high incidence to be the cause of the spike, the conditions that give rise to this incidence (e.g., blockage from a corner separation or the tip leakage jet from the adjacent blade) do depend on the details of the compressor.

Analytical Study on the Performance of Centrifugal Compressor Considering Running Tip Clearance

2015 ◽  
Author(s):  
Changhee Kim ◽  
Jangsik Yang ◽  
Changmin Son ◽  
Horim Lee ◽  
Yoonjei Hwang ◽  
...  
Keyword(s):  
Centrifugal Force ◽  
Leading Edge ◽  
Type A ◽  
Tip Clearance ◽  
Tip Leakage Flow ◽  
Maximum Displacement ◽  
Impeller Blade ◽  
Operating Condition ◽  
Aerodynamic Pressure ◽  
Compressor Performance

In this study, a series of aero-thermo-mechanical analyses were carried out to predict the running tip clearance and the effects of impeller deformation on the performance using two different centrifugal compressors (blade type A and B). In operation, impeller deformation due to the combination of centrifugal force, aerodynamic pressure and thermal load results in non-uniform tip clearance profile. The predicted running tip clearance leads to further findings of its impact on compressor performance. The prediction employs one-way fluid-structure interaction (FSI) method using CFX 14.5 and ANSYS. The results show that the maximum displacement occurs at the leading edge tip of the impeller blade but maximum stress takes place at the blade root of the impeller for these particular designs. The analysis also confirms the centrifugal force has dominant effect on impeller deformation at its operating condition. The predicted running tip clearance shows non-uniform profile over the entire flow passage. In particular, a significant reduction of the tip clearance height has occurred at the leading edge and the trailing edge of the impeller. Due to the reduction of the tip clearance, the tip leakage flow has decreased by 19.4% and 16.2% in the blade type A and B, respectively. Also, the polytropic efficiency of the blade type A and B at operating condition has increased by 0.72% and 1.81%, respectively. These findings confirm that the prediction of running tip clearance and its impact on compressor performance is important area for further investigation.

scholarly journals Numerical Investigation of the Characteristics of Erosion in a Centrifugal Pump for Transporting Dilute Particle-Laden Flows

2021 ◽  
Vol 9 (9) ◽  
pp. 961
Author(s):  
Rui-Jie Zhao ◽  
You-Long Zhao ◽  
De-Sheng Zhang ◽  
Yan Li ◽  
Lin-Lin Geng
Keyword(s):  
Centrifugal Pump ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Finite Size ◽  
Wall Region ◽  
Pressure Side ◽  
Centrifugal Pumps ◽  
Particle Volume ◽  
Impeller Blade ◽  
The Impact

Erosion in centrifugal pumps for transporting flows with dilute particles is a main pump failure problem in many engineering processes. A numerical model combining the computational fluid dynamics (CFD) and Discrete Element Method (DEM) is applied to simulate erosion in a centrifugal pump. Different models of the liquid-solid inter-phase forces are implemented, and the particle-turbulence interaction is also defined. The inertial particles considered in this work are monodisperse and have finite size. The numerical results are validated by comparing the results with a series of experimental data. Then, the effects of particle volume fraction, size, and shape on the pump erosion are estimated in the simulations. The results demonstrate that severe erosive areas are located near the inlet and outlet of the pressure side of the impeller blade, the middle region of the blade, the corners of the shroud and hub of the impeller adjoining to the pressure side of the blade, and the volute near the pump tongue. Among these locations, the maximum erosion occurs near the inlet of the pressure side of the blade. Erosion mitigation occurs under the situation where more particles accumulate in the near-wall region of the eroded surface, forming a buffering layer. The relationship between the particle size and the erosion is nonlinear, and the 1 mm particle causes the maximum pump erosion. The sharp particles cause more severe erosion in the pump because both the frequency of particle-wall collisions and the impact angle increase with the increasing sharpness of the particle.

scholarly journals Rotor–Stator Interaction in a Diffuser Pump

1989 ◽  
Vol 111 (3) ◽  
pp. 213-221 ◽  
Author(s):  
N. Arndt ◽  
A. J. Acosta ◽  
C. E. Brennen ◽  
T. K. Caughey
Keyword(s):  
Pressure Fluctuations ◽  
Pressure Rise ◽  
Leading Edge ◽  
Suction Side ◽  
Pressure Measurements ◽  
Vaneless Diffuser ◽  
Impeller Blade ◽  
Frequency Spectra ◽  
Vaned Diffuser ◽  
Wall Pressure Fluctuations

The interaction between impeller blades and diffuser vanes in a diffuser pump was investigated. Steady and unsteady pressure measurements were taken on the diffuser vanes, and the shroud wall of a vaned and a vaneless diffuser. Steady, unsteady, and ensemble-averaged unsteady data, as well as frequency spectra, are presented. The measurements were made for different flow coefficients, shaft speeds, and radial gaps between impeller blade trailing and diffuser vane leading edge (1.5 and 4.5 percent based on impeller discharge radius). The resulting lift on the vane, both steady and unsteady, was computed from the pressure measurements at midvane height. The magnitude of the fluctuating lift was found to be greater than the steady lift. The pressure fluctuations were larger on the suction side than on the pressure side attaining their maximum value, of the same order of magnitude as the total pressure rise across the pump, near the leading edge. Pressure fluctuations were also measured across the span of the vane, and those near the shroud were significantly smaller than those near the hub. The pressure fluctuations on the shroud wall itself were larger for the vaned diffuser than a vaneless diffuser. Lift, vane pressure, and shroud wall pressure fluctuations decreased strongly with increasing radial gap.

Unsteady Numerical and Experimental Study of Cavitation in Axial Pump

2014 ◽  
Vol 4 (1) ◽  
pp. 55-68
Author(s):  
Mohamed Adel ◽  
Nabil H. Mostafa
Keyword(s):  
Numerical Simulation ◽  
Void Growth ◽  
High Speed ◽  
Volume Fraction ◽  
Numerical Study ◽  
Three Dimensional ◽  
Axial Flow ◽  
Two Phase ◽  
Impeller Blade ◽  
Axial Pump

This paper presents an experimental and three-dimensional numerical study of unsteady, turbulent, void growth and cavitation simulation inside the passage of the axial flow pump. In this study a 3D Navier-Stokes code was used (CFDRC, 2008) to model the two-phase flow field around a four blades axial pump. The governing equations are discretized on a structured grid using an upwind difference scheme. The numerical simulation used the standard K-e turbulence model to account for the turbulence effect. The numerical simulation of void growth and cavitation in an axial pump was studied under unsteady calculating. Pressure distribution and vapor volume fraction were completed versus time at different condition. The computational code has been validated by comparing the predicated numerical results with the experiment. The predicted of cavitation growth and distribution on the impeller blade also agreed with that visualized of high speed camera.

scholarly journals Origins and Structure of Spike-Type Rotating Stall

2012 ◽  
Author(s):  
G. Pullan ◽  
A. M. Young ◽  
I. J. Day ◽  
E. M. Greitzer ◽  
Z. S. Spakovszky
Keyword(s):  
Pressure Rise ◽  
Leading Edge ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Causal Connection ◽  
Suction Surface ◽  
Stall Inception ◽  
Pressure Surface ◽  
Sequence Of Events ◽  
Experimental Findings

In this paper we describe the structures that produce a spike-type route to rotating stall and explain the physical mechanism for their formation. The descriptions and explanations are based on numerical simulations, complemented and corroborated by experiments. It is found that spikes are caused by a loss of pressure rise capability in the rotor tip region, due to flow separation resulting from high incidence. The separation gives rise to shedding of vorticity from the leading edge and the consequent formation of vortices that span between the suction surface and the casing. As seen in the rotor frame of reference, near the casing the vortex convects toward the pressure surface of the adjacent blade. The approach of the vortex to the adjacent blade triggers a separation on that blade so the structure propagates. The above sequence of events constitutes a spike. The simulations show shed vortices over a range of tip clearances including zero. The implication is that they are not part of the tip clearance vortex, in accord with recent experimental findings. Evidence is presented for the existence of these vortex structures immediately prior to spike-type stall and, more strongly, for their causal connection with spike-type stall inception. Data from several compressors are shown to reproduce the pressure and velocity signature of the spike-type stall inception seen in the simulations.

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