Modern submersible pumps are high performance aggregates for long-term operation, which find application in open-pit mining. Dewatering of groundwater to run an open-pit mine with various conditions for submersible pumps often leads to short-term performance based on different circumstances in the well as well as in the general operation. These result in high maintenance and energy costs and decreases the drawdown in open-pit mining. To ensure a long-time performance, a proper selection of submersible pump and motor is required. It is also necessary to consider the geometry of different deep wells in order to take into account the initial conditions of the pumps. This paper shows recommendations for long-term operation of high-performance submersible pumps due to the conditions of the mining industry. Therefore, a holistic consideration of the aggregate takes place to receive recommendations, which minimize the rate of pump failures and increase the efficiency of the dewatering process. These recommendations are based on various failures found during an investigation. Furthermore, this paper recommends different methods to prevent these failures, for instance clogging and erosion through particles in the well. These recommendations are linked to the research of different submersible motor pumps from various manufacturers in different wells in German open-pit mines with short-term operation caused by several circumstances.

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.

The performance of multi-stage Electrical Submersible Pumps (ESPs) under different flow conditions and its life span with sand production are commonly predicted by the Computational Fluid Dynamics (CFD) simulations. The mesh generation methodology and optimum grid number are usually validated by pump water catalog curves. Then, the validated mesh geometry is adopted in high viscosity, multiphase flow, and sand erosion simulations to study the effects including but not limited to: discrete phase bubble diameter, turbulence model, body forces, and erosion models. However, the mesh validation by pump water curves is not enough in complex flow conditions, especially in the erosion simulations. Different from the pump hydraulic performance simulation, the accuracy of the erosion simulation can be affected by mesh boundary and inner layer grid thickness, especially for small particles. In addition, the mesh-type (hexahedral and tetrahedral) and size of the inner domain can also significantly affect the particle trajectory. A comprehensive mesh independent study is conducted for water, oil, and gas-liquid conditions of a mixed type ESP in this paper. Then the near-wall inflation layer thickness and inner domain grid size effect to ESP erosion simulation are well analyzed. The mesh generation methodology can be applied to other turbomachinery simulations to improve accuracy.

Fluctuating pressures can induce vibration in the Electric Submersible Pump (ESP) and severely affect the pump components. The installation depths of ESP systems are varying from a few meters to several hundred meters. Once installed ESPs are not accessible for diagnostic measurement and maintenance activity, so it becomes necessary to obtain detailed information of mean and fluctuating pressures to attain an optimal pressure distribution inside the pump. In this paper the results obtained from an experimental investigation of stage-wise pressure pulsation at Best Efficiency Points at various speeds are presented. Tests were conducted on a five stage ESP having impellers of 121 mm diameter and 14 mm width at outlet with impeller of 8 vanes and a diffuser-return channel of 6 vanes which delivers 7 lps (litres per second) and develop 60 m total head at various speeds. Unsteady pressure signals were captured by mounting piezoresistive transducers at each stage of ESP. Captured pressure signals were converted into frequency domain to analyze the characteristics of pressure pulsation. The results have indicated that the maximum amplitude of pressure pulsation was obtained at the highest operating speed setting of 60 Hz at stage 4. The normalized frequency at which this amplitude was maximum was highest at stage 2 at all the speeds.

High speed rotating pump is the current trend in pump’s development and application, which has the advantages of compact size and energy-saving features. The electrical submersible pump, typically called an ESP, is an efficient and reliable artificial-lift method for lifting moderate to high volumes of fluids from wellbores, which have been wildly used for oil or groundwater extraction. To verify the similarity of pump performance under different rotating speeds, a typical ESP is selected as the model pump. By employing the numerical simulation and performance testing methods, the external performance characteristics and internal flow fields under different rotating speeds of the pump are studied. The entire computational domain is established by two stages ESP, and then meshed with the high-quality structured grid based on the Q-type and Y-type block topology. Grid sensitivity analysis is carried out to determine the appropriate mesh density for mesh independent solution. SST k-ω turbulence model with standard wall function in conjunction with Reynolds-Averaged Navier-Stokes (RANS) equations is used to solve the steady flow field. The results show that the increase in the rotating speed could increase the ESP’s head significantly. ESP’s external characteristics under different speeds meet the similar conversion rule quite well. In addition, the flow field distributions in the main flow components of the pump have great similarity at different rotating speeds. The experimental test results for a prototype show good agreement with the simulation results, including the pump’s head, efficiency and axial force. This paper provides a data set for further understanding of the effects of rotating speeds on ESP’s performance and inner flow fields.

Sand production is one of the most serious problems of electrical submersible pumps (ESPs). It is important to predict erosion rate and pump life under sand flow condition. However, erosion experiments on centrifugal pumps are difficult, expensive and time-consuming. Besides, the erosion on pump blades and shrouds are hard to be quantified. It is difficult to measure or scan the thickness of an inside flow channel. Therefore, computational fluid dynamic (CFD) method is a convenient way to forecast erosion failures of the pump. Although various erosion simulations were carried out for simple geometries, including pipelines, elbows, tees, and etc., erosion simulation methodology in a turbomachinery geometry should be carefully evaluated. Therefore, the effect of different turbulence models and rebound models are investigated in a 3-stage mixed type ESP by ANSYS Fluent Discrete Phase Model (DPM) simulations. The erosion rate is calculated and particle impact parameters are extracted by a User Define Function (UDF). Preliminary erosion simulation methodology recommendations were given in this study.

This paper presents a study of the effects of blade pitch angle and inlet guide vane (IGV) angle on the performance of a submersible axial-flow pump. To analyze the interaction effects between the IGVs and the rotor blades, both steady and unsteady three-dimensional Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model were solved. Hexahedral meshes were used in the computational domain and a grid-dependency test was performed to obtain an optimal number of grid nodes. The performance curves obtained by numerical simulation showed good agreement with experimental data. The results show that the fluctuation of hydraulic efficiency and head coefficient increased significantly under overload conditions as the IGV setting angle increased. Additionally, both the steady and unsteady performance characteristics were shown to be quite dependent on the combination of IGV angle and blade pitch angle, because the relative velocity at leading edge played an important role in the performance under overload conditions.

To better understand the workings of submersible tubular pumping system and to enable future improvements, the pressure fluctuation and unsteady flow characteristics due to the complex rotor-stator interactions need to be properly delineated. High-frequency pressure measurements coupled with CFD simulations have been invoked in this study to elucidate the unsteady flow in different components of a submersible tubular pumping system at different discharges. The focus is on the impeller and guide vane, where the unsteady interaction is the strongest. The pressure pulsation distributions of different characteristic cross sections such as impeller exit, middle of guide vane, and exit of guide vane were quantified. In addition, the flow characteristics and the turbulent kinetic energy inside the impeller, guide vane, and bulb unit were obtained at the different time steps. The results show that the pressure pulsation frequency obtained by simulation was in agreement with the experimental results, including the critical points around the impeller and the guide vanes. The complementary two-prong approach is thus proven to be a powerful duo in researching and advancing a convoluted pumping system.

This paper presents a numerical study of flow pattern recognition inside the rotating impeller of electrical submersible pump (ESP) using the transient multiphase CFD simulations. Based on the previous experimental facility for visualizing flow patterns in an ESP, the entire flow domain is constructed. The high-quality structured mesh comprising hexahedral grids is generated using multi-block technique in ANSYS ICEM. Mesh independence is confirmed by comparing numerical results with catalog curves. For transient two-phase simulation, the realized RNG k-ε turbulence model with volume of fluid (VOF) and Eulerian multiphase models is successfully implemented in ANSYS Fluent solver. The sliding mesh technique is applied to interfaces where rotating and stationary parts interact. By incorporating the same boundary conditions as experimental study, two different cases with fixed liquid flow rates and varying gas flow rates are selected to conduct CFD simulations. The comparison of numerical results against experimental visualizations shows that the two-fluid Eulerian model is superior to VOF model in simulating gas/liquid flow in a rotating ESP. The single-phase simulation results match catalog curves of ESP, which validates the numerical methodology. For gas-liquid simulations, the simulated flow patterns with Eulerian model agree well with visualization experiments. The distinct flow patterns prevailing inside the rotating ESP impeller are captured by CFD simulations, including dispersed bubble flow, bubbly flow, and intermittent flow.

Electrical submersible pump (ESP) is one of the most widely used artificial lift methods in the petroleum industry. It is crucial to study the wear in ESP stages with sand production, which can severely reduce pump performance and life span. Usually, experiments and simulation studies were conducted for simple flow geometry such as direct impingement and pipe elbow. Various erosion equations and models were developed for different material and affecting factors. However, the predictions of these erosion models for complex flow geometry need to be evaluated in order to make a proper selection. This study will compare the wear patterns and erosion rates of six different erosion models in three ESPs by using commercial Computational Fluid Dynamics (CFD) software ANSYS Fluent. The results will offer engineers a brief guidance of erosion model selection for complicated flow domain. In this paper, stages of three ESPs, DN1750, TE2700 and Flex31, are modeled. For each pump, the flow domain of two stages are selected and high-quality structured meshes, comprising around 1.2 to 1.8 million hexahedral grids per stage, are generated by ICEM or Turbogrid. Six erosion models, Ahlert (1994), Haugen (1995), Zhang (2007), Oka (2007), Mansouri (2014) and DNV (2015), are simulated under pump best efficiency point. Among six selected erosion models, Ahlert (1994) gives a much higher wear rate than others, while DNV predicts lowest, Besides, the impact angle functions show that all models, except Haugen (1995), assume steel to be a ductile material. Furthermore, the erosion pattern, location, and distribution of all three pumps are different, which indicates different solid particle handling capabilities and failure reasons of radial type and mixed type ESPs.

Laser Doppler velocimetry (LDV) and high-speed imaging techniques were used in a transparent model of a fourstage, mixed-flow commercial electric submersible pump (ESP) to characterize the flow through a range of inlet gas volume fractions (GVF) from 0 to 30%. Measurements demonstrate the presence high turbulence levels in the wake of the impeller blades, and recirculation cells at low flow rates. In gas-liquid conditions, the bubble size varied within a pump stage, as break-up occurred at the impeller tip, and coalescence was dominant in the diffuser, especially at low flow rates because of recirculation. At moderate-to-high inlet GVF, the first impeller acted as a mixer and the flow patterns at the stage level alternated between bubbly and radially separated flows, as short gas slugs propagated through the stages. The flow patterns at the stage level did not depend on the pump inclination, but the inlet conditions did, with worse performance induced by slugging flows for the horizontal setup.

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.

Understanding and predicting the effect of viscosity change on an Electrical Submersible Pump (ESP) performance is of great significance to the oil and gas operators. The purpose of this research is to investigate the flow behavior inside a mixed flow type pump operating with fluids of different viscosities using Computational Fluid Dynamics (CFD) with the goal to establish additional terms for the pump affinity laws to scale pump performance including the effects of viscosity. Several sets of fluids of different viscosities and densities are simulated under various operating conditions. The effect of viscosity on the performance of the impeller and diffuser is discussed. Changes in the pump performance due to fluid viscosity are characterized using the dimensionless flow coefficient, head coefficient and rotational Reynolds number. The result, which can be regarded as the modified pump affinity laws for viscosity flows, was obtained based on the relationships between dimensionless coefficients. The modified affinity laws agreed well with the CFD results. Further study was conducted to validate the relationships using previously published test data for a semi axial pump design (Specific Speed, N s : 3869) tested with fluid viscosity ranging from 1 cp to 1020 cp and in-house testing of a split vane impeller pump ( N s : 3027) and a helicoaxial pump ( N s : 5281) using 1cp and 5 cp viscosity fluid. The modified affinity laws accurately models the performance dependence upon viscosity. As with the standard affinity laws, a pump’s functional relationship varies with each pump design. Yet the modified affinity laws produce a single common curve for all operating conditions and viscosities for a specific pump.

Electric submersible pumps utilize grooved-rotor seals to reduce leakage and break up contaminants within the pumped fluid. Additionally, due to their decreased surface area (when compared to a smooth seal), grooved seals decrease the chance of seizure in the case of rotor-stator rubs. Despite their use in industry, the literature does not contain measurements for smooth-stator/circumferentially-grooved-rotor liquid annular seals. This paper presents test results consisting of leakage measurements and rotordynamic coefficients for a smooth-stator/circumferentially-grooved-rotor liquid annular seal. Both static and dynamic performance for the grooved seal are investigated for various imposed pre-swirl ratios, static eccentricities, axial pressure drops, and running speeds. The grooved seals′ static and dynamic performance are compared to those of a smooth seal with identical length, diameter, and radial clearance. Results show that adding grooves reduces leakage at lower speeds (less than 5 krpm) and higher axial pressure drops, but does little at higher speeds. The grooved seal’s direct stiffness is generally negative, which would be detrimental to pump rotordynamics. Furthermore, increasing pre-swirl increases the magnitude of cross-coupled stiffness and increases the whirl frequency ratio. When compared to the smooth seal, the grooved seal has smaller effective damping coefficients, indicative of worse stability characteristics.

In the petroleum industry, during the production and transportation of oil, multiphase flow occurs, due to the usual mixture of the crude oil, water and gas. This type of flow can be simplified, for study purposes, as a two-phase one, in which the gas is one phase, and a mixture of oil and water is the other. Separation of gaseous and liquid phases at the wellhead level is done by a separator and has innumerous advantages, including avoiding or at least reducing typical problems of multiphase flows such as intermittent flow, severe slugging and hydrates deposition. Another advantage is to increase the efficiency of the submersible centrifugal pumps or other artificial lift process used. A recurrent problem found in exploration and production of oil and gas is the range of the fluid viscosities encountered during exploration and extraction of petroleum, which can greatly vary with the temperature or the composition of the oil being extracted. Thus, it is necessary to understand how this parameter affects the performance of the equipment used. In addition, installation and maintenance of separators are hampered by the large size of this type of equipment. Therefore, a prior distribution system is here proposed, aiming to distribute the flow in more than one branch, in order to decrease the general size of the separation equipment needed, while maintaining the flow rate and separation efficiency. This distribution system has a cyclonic chamber, in which the flow enters through two nozzles tangentially oriented with the wall of the chamber, which performs a pre-separation due to the centrifugal field, and divides the flow into four outlets. This work presents a numerical study on the height influence of the cyclonic chamber in a distribution system. The transient beginning of the flow is analyzed, with the stability of the film being study. This work is focused on the behavior of the liquid phase in this proposed distribution system, so that only single-phase liquid flow at the inlet of the distribution system is considered. A validation was done through comparison with experimental data obtained in a test rig, in which was used one wire mesh sensor with 12 wires in order to evaluate the thickness of the liquid film over time. In addition, different heights and viscosities are studied in order to evaluate their influence on the flow. The parameters investigated are the film thickness, velocity and turbulence kinetic energy fields and flow rates at the outlets, focusing on the stability of the film and the transient effects associated with the beginning of the flow. In order to perform this study, the commercial software ANSYS-CFX 15.0 was used, with a hybrid mesh, for four different heights and two inlet velocities.

Generally, artificial lifts to pump crude oil having a high viscosity from wellbores using an electrical submersible pump (ESP) are not efficient. The present study consists of a numerical approach to understand the effect of fluid viscosity and surface roughness of the flow passage on the performance of an ESP. A three-dimensional numerical analysis was carried out using Reynolds-averaged Navier-Stokes equations at different off-design conditions. The standard k-ε turbulence model was used for the steady incompressible flow. Water and crude oils having different viscosities were used as working fluids and numerical analyses were made by varying surface roughness of the flow passage. Although there was a sharp drop in the efficiency with the increase in surface roughness, but the combined effect of viscosity and surface roughness showed an increase in efficiency up to a certain fluid viscosity.

In order to meet the requirement of coal mine flooding emergency rescue, a high power, high head and small volume high-speed wet submersible pump is designed. The high speed rescue pump applies the wet motor and pump integrated structure to achieve the best effect . When high speed rescue pump works, the temperature rise of the motor is high, which may cause the damage of the whole unit if the heat which produced by motor can not be taken away fully. The design of the cooling circuit is critical for the performance of the high speed rescue pump. This paper gives two design methods of the cooling circuit of high speed rescue pump. The design performance parameters: Capacity Q = 200m 3 /h, Head H = 50m, Rotate speed n = 6000r/min, Power P = 600kW. Two cooling circuits contains the normal and reverse one, which are based on theoretical deduction, numerical simulation and experimental verification. First and foremost, two theoretical models of cooling circuit are established by the theory of convective heat transfer .The heat balance and distribution are calculated by theoretical derivation. Then, both three-dimensional models of the circuit are built by CREO and simulated by ANSYS. The method of flow-heat coupling is used to simulate the whole inner flow field of the high speed rescue pump at different running conditions by considering the transformation of thermal performance parameter of cryogenic fluid caused by temperature change. In the simulation ,the information , such as temperature , flow field, pressure distribution of the whole cooling circuit together with temperature and velocity in the gas gap where temperature changed greatly, the convective heat transfer between fluid and motor ,and the flow rate of the cooling fluid are also gained. The analysis results show that: from the comparison of the pressure distribution of the two cooling forms, under the same inlet and outlet liquid condition ,the minimum and maximum pressure value of the reverse circuit are much higher than the corresponding value ,which means the reverse cooling method is better than the normal method as the aspect of cavitation performance. The temperature rise of reverse cooling circuit with the value 1.5K is smaller than the value of the normal cooling circuit. As the key part of the cooling circuit, the motor gas gap has a significant influence on the performance of the circuit. The velocity and temperature distribution is given to study the law of the flow and thermal field in the gap which can supply an intuitive understanding of the key part. At last, an experiment of a model pump is carried out on the test table validated the reliability of the reverse cooling circuit. It can be also concluded that the cooling circuit can satisfy with mode demand of the working condition of the high speed rescue pump.

This study presents the hydrodynamic analysis and optimization for a single-channel submersible pump impeller. The numerical analysis involved the use of the shear stress transport turbulence model to solve three-dimensional Reynolds-averaged Navier-Stokes equations. The optimization process was based on a radial basis neural network model and was conducted by considering two design variables to control the area from the inlet to the outlet of the impeller. The hydrodynamic performance of the pump impeller was optimized by selecting the efficiency as the objective function. The objective function was numerically assessed via Latin hypercube sampling at design points selected in the design space, and the optimization yielded a maximum increase in efficiency of approximately 1% in terms of the design flow rate, as compared to the initial design. The performance curve for the efficiency was also improved in the high flow rate region. Further details of the internal flow fields between the reference and optimum designs are also analyzed and discussed in this work.

In many places lifting systems represent central components of wastewater systems. Pumping stations with a circular wet-pit design are characterized by their relatively small footprint for a given sump volume as well as their relatively simple construction technique [1]. This kind of pumping stations is equipped with submersible pumps. These are located in this case directly in the wastewater collection pit. The waste water passes through the pump station untreated and loaded with all kind of solids. Thus, the role of the pump sump is to provide an optimal operating environment for the pumps in addition to the transportation of sewage solids. Understanding the effects of design criteria on pumping station performance is important to fulfil the wastewater transportation as maintenance-free and energy efficient as possible. The design of the pit may affect the overall performance of the station in terms of poor flow conditions inside the pit, non-uniform und disturbed inflow at the pump inlet, as well as air entrainment to the pump. The scope of this paper is to evaluate the impact of various design criteria and the operating conditions on the performance of pump stations concerning the air entrainment to the pump as well as the sedimentation inside the pit. This is done to provide documentation and recommendations of the design and operating of the station. The investigated criteria are: the inflow direction, and the operating submergence. In this context experiments were conducted on a physical model of duplex circular wet pit wastewater pumping station. Furthermore the same experiments were reproduced by numerical simulations. The physical model made of acrylic allowed to visualize the flow patterns inside the sump at various operating conditions. This model is equipped with five different inflow directions, two of them are tangential to the pit and the remaining three are radial in various positions relative to the pumps centerline. Particles were used to enable the investigation of the flow patterns inside the pit to determine the zones of high sedimentation risk. The air entrainment was evaluated on the model test rig by measuring the depth, the width and the length of the aerated region caused by the plunging water jet and by observing the air bubbles entering the pumps. The starting sump geometry called baseline geometry is simply a flat floor. The tests were done at all the possible combinations of inflow directions, submergence, working pump and operating flow. The ability of the numerical simulation to give a reliable prediction of air entrainment was assessed to be used in the future as a tool in scale series to define the scale effect as well as to analyze the flow conditions inside the sump and to understand the air entrainment phenomenon. These simulations were conducted using the geometries of the test setup after generating the mesh with tetrahedral elements. The VOF multiphase model was applied to simulate the interaction of the liquid water phase and the gaseous air phase. On the basis of the results constructive suggestions are derived for the design of the pit, as well as the operating conditions of the pumping station. At the end recommendations for the design and operating conditions are provided.

Submersible tubular pump is a kind of horizontal pump with low head and large discharge, which uses the structure of postpositive tubular type with motor and pump coaxial. Nowadays, more and more urban pumping stations need to have the function of irrigation and drainage. In the plain areas, the head of many pumping stations are very low, even only about one meter. Considering the efficiency and practicability, the reversible submersible tubular pump is chosen to realize the function of irrigation and drainage. Research on three-dimensional flow field in a submersible tubular pumping system using numerical simulation based on the Reynolds time-averaged Navier-Stokes equations and the RNG k -ε turbulent model. By using this method, the performance of pumping system such as head, shaft power and efficiency are predicted based on the calculation of different operating conditions. For verifying the accuracy and reliability of the calculation results, a model test was conducted. The comparison of simulation results and the experiment data shown that the calculation performances close agreement with the experiment results in the high efficiency area, but in the condition of large discharge and small discharge, deviations were existed between the two results. Combining with the numerical simulation and experimental, which can provide more evidences for the hydraulic performance prediction and optimization design of pumping system.