Performance Of Centrifugal Pump Research Articles

Study on Impeller Optimization and Operation Method of Variable Speed Centrifugal Pump with Large Flow and Wide Head Variation

The benefits of variable speed centrifugal pumps include high stability, a broad operating range, and adjustable input power. In water distribution systems, the pump units are increasingly using variable speed technology. The energy-saving features and operational stability of the pump station are directly impacted by the hydraulic performance and the operation strategy. In this study, CFD numerical analysis and model tests were adopted to design and evaluate the hydraulic performance of the variable speed centrifugal pump with large flow and wide head variation in Liyuzhou Pump Station. Under the premise of ensuring the wide head variation, the optimized centrifugal pump met the requirements of hump margin and efficiency in the high head zone and the cavitation margin in the low head zone. The test results demonstrated that the operational range of the variable speed centrifugal pump was successfully widened by reasonable hydraulic parameters selection and impeller optimization. The safe and efficient operational range of the variable speed unit was determined by means of taking the performance requirements of the pump’s maximum input shaft power, cavitation characteristics and pressure fluctuation into consideration. The scientific and reasonable operational path to meet the various operation needs was also investigated and determined for the pump station’s actual operation needs. A high efficiency, safe operation, and a simplified control logic were achieved by using the operational path, which makes it a reasonable potential guide for hydraulic design and operational optimization of variable speed centrifugal pumps with large flow and wide head range.

IMPROVING THE PERFORMANCE INDICATOR OF CENTRIFUGAL PUMPS

This article is devoted to the research and development of methods to improve the performance of centrifugal pumps. Centrifugal pumps are key elements in various industrial and technical systems, ensuring efficient transportation of liquids. This article reviews the operation of centrifugal pumps, shows the scheme of the pumping part of the centrifugal type equipment, the scheme of the cantilever type centrifugal pump and describes their main components. Further, the factors affecting pump performance, including fluid viscosity and operating conditions, are analyzed, and methods for improving performance are described in detail, including design optimization, the use of new materials and modern technologies, as well as speed control and monitoring of pump condition. The advantages and disadvantages of centrifugal pumps are noted, the concept of what the operation of this equipment is based on is given, and the fields of application of centrifugal pumps are considered. In order to improve the operation of pumps, the article includes a table showing the existing problems in the operation of the pumps described by the author, the correction of which will lead to positive results, namely, an increase in quantitative and qualitative performance indicators. Further, in the article, a color diagram is shown, which shows the share distribution, that is, the percentage of damage to the structural elements of centrifugal pumps. To improve the reliability and efficiency of operation of centrifugal pumps, the article discusses in detail two ways to solve this task. The first way to solve the problem is the development and manufacture of new, namely more advanced pumps in design, which most often requires significant financial costs, and the second way was noted the modernization of already functioning equipment, which allows you to reduce your own costs and thereby ensure the implementation of energy saving programs. Based on the analysis and the examples considered, it is concluded that an increase in the performance of centrifugal pumps can lead to a significant improvement in efficiency and cost reduction. Keywords: centrifugal pump, productivity, performance indicators, optimization, materials, control.

Numerical investigation of axial force of a centrifugal pump in the reverse mode

This paper numerically investigates the hydraulic performance and axial force of a low specific speed centrifugal pump in the turbine mode using the k - ω SST model. Numerical results are validated against the experimental data in the literature and a good agreement is observed. Results show that the rotation factor increases by flowrate, since the head, which is directly proportional to the transferred circumferential momentum, increases by the flowrate in the turbine mode. Moreover, values of rotation factors on both sides varies in radial direction due to geometrical parameters and, they reduce where larger axial gaps are present. Additionally, the pressure distributions on the hub and shroud sides are correlated with rotation factors on these areas. Interestingly, the axial position of the impeller plays an important role in the axial force of the PAT. By applying impeller movement of 5 mm from its original position, the point of zero axial force has shifted to higher flowrates and the maximum axial force is reduced 50%. Finally, with 10 mm movement of the impeller, the axial force exhibits distinct behavior so that its direction is preserved and, the returned magnitude is almost constant in the working range by 60% decrease in the maximum axial force.

Visual experimental study on cavitation performance of double-suction centrifugal pump

In this paper, the cavitation test results of double-suction centrifugal pump are further “visualized” and verified by using high-speed photography technology to photograph the development process and flow field of impeller inlet cavitation. By optimizing the impeller inlet parameters, the key geometric factors affecting the cavitation performance of the double suction pump were determined. The experimental results show that by optimizing the inlet parameters of the double-suction pump and combining the visualization test verification of cavitation, on the basis of ensuring the wide and efficient efficiency of the double-suction centrifugal pump, the optimization scheme of the experimental design greatly improves its cavitation performance, and provides a new design idea and reference for guiding the development and design of products with high cavitation performance.

The influence of ring clearance on the performance of a double-suction centrifugal pump

Due to the complex structure of a double-suction pump's suction chamber, the flow in the pump's cavity is often ignored in numerical simulations because of difficulties in structured hexahedral meshing. However, the wear ring clearance interlinking the pump chamber leads the fluid at the impeller inlet directly to the impeller area. This significantly impacts the pump's internal flow field, so the influence of the clearance on the internal flow of a double-suction pump cannot be ignored. This paper develops four three-dimensional double-suction pump models with different wear ring clearances to investigate their influence on pump performance, and structured hexahedral meshes were used for all the computational domains. The clearances varied from 0.2 to 0.5 mm in 0.1 mm increments. The influences of the clearance on the energy loss, external characteristics, and internal flow field distribution of the pump were simulated via a verified computational fluid dynamics method. The results show that the wear ring leakage decreases with the flow rate and increases with wear ring clearance. The increase in backflow leads to an internal flow disorder inside the impeller, resulting in a decreased head and efficiency. Energy loss is mainly caused by increasing the turbulence entropy production with an increasing wear ring clearance. Also, the low-pressure region in the pump cavity expands to the volute with increasing clearance, and the impeller outlet pressure decreases. This study's research on wear ring clearance provides a reference for the design and application of double-suction centrifugal pumps.

Optimization method investigation for centrifugal pump performance based on 3D inviscid inverse design

Centrifugal pump is widely used in many important fields such as large hydropower station, urban central heating, aerospace engineering, etc. It has high requirements for cavitation performance and hydraulic performance in actual use. This study centers around on a pipeline pump with a specific speed of 360, reconstructs the impeller in TURBOdesign, takes important parameters of the impeller as the input conditions for optimization, aims at enhancing the blade’s minimum pressure and curtailing the flow losses in the blade channel and progressively optimize the meridional-blade loading based on the inviscid flow which was carried out by using genetic algorithm. The optimization leverages genetic algorithm, progressively optimizing the impeller using meridional and blade loading. By analyzing the effects of meridional and blade loading parameters on cavitation and hydraulic performance, it is found that the optimized models’ NPSH are much better than the original one. It’s approved that this optimization method is valid.

Effect of Blade number on the Energy Dissipation and Centrifugal Pump Performance Based on the Entropy Generation Theory and Fluid–Structure Interaction

Effect of Blade number on the Energy Dissipation and Centrifugal Pump Performance Based on the Entropy Generation Theory and Fluid–Structure Interaction

Design optimization of a domestic centrifugal pump using Taguchi Method

This study focuses on optimizing the design of a domestic centrifugal pump through the Taguchi method, aiming to enhance its performance. Experimental data on pump performance, including total head, efficiency, and suction specific speed, were collected and analyzed. The effects of three design parameters—impeller diameter, blade angle, and volute tongue angle—were investigated using ANOVA. The analysis revealed that impeller diameter had the most significant influence on pump performance, followed by volute tongue angle and blade angle. Optimal performance was achieved with a 55 mm impeller diameter, 25° blade angle, and 20° volute tongue angle. These findings provide valuable insights for engineers seeking to improve centrifugal pump performance, highlighting the importance of impeller diameter in particular. By optimizing design parameters, significant enhancements in pump performance can be achieved, leading to more efficient and effective domestic centrifugal pumps.

Assessment of the derating methods for centrifugal pump performance handling non-Newtonian fluids

Oil and Gas applications commonly require the displacement of a huge amount of processing fluids. In most cases, these fluids consist of solid rock particles transported by water, e.g. kaolin or bentonite powder, which show non-Newtonian behavior. For this kind of fluid positive displacement pumps are usually recommended, but where high flow rates have to be guaranteed, centrifugal pumps are installed. Since most of the manufacturers provided the performance curves only with water, choosing the appropriate centrifugal pump to handle mineral slurries may be very challenging. Since the viscosity of this kind of fluids varies with the imposed stress and rheology, pumping this type of fluids can lead to a considerable variation in the pump head, and thus, overall efficiency is difficult to-be-predicted. Several reliable methods to predict the centrifugal pump performance in handling high-viscous Newtonian fluids can be found in literature, e.g. the well-known Hydraulic Institute method. Nevertheless, no general practical correlations are provided for non-Newtonian fluids. Previous experimental investigations on centrifugal pumps reported high-performance instabilities at low flow rates when non-Newtonian fluids are considered. Further investigations are needed to define which parameters in the pump fluid interaction have to be considered in the derating process. In this work, an assessment of the prediction quality of the existing derating methods from the literature is carried out. For this purpose, the data obtained from previous experimental investigations on a small commercial centrifugal pump handling mixtures of water and kaolin are considered.

Improving flow and noise performances of centrifugal pump in dishwasher through impeller design optimization

Noise and performance are critical factors in the customer's selection of dishwashers. The centrifugal pump, which circulates water for washing dishes, dominantly influences the performance and noise of a dishwasher. This study aims to improve the performance and reduce the noise of a centrifugal pump by modifying its impeller design. Priorly, the flow and noise characteristics of the target pump were experimentally characterized. Then, the flow performance of the pump was predicted using a virtual pump performance tester based on the computational fluid dynamics techniques to solve the three-dimensional unsteady incompressible Reynolds Averaged Navier-Stokes equations. The noise radiation generated by the impeller was predicted using the Ffowcs Williams-Hawkings equation. The results were validated by comparing the predicted with the measured. The Response Surface Method, where the blade inlet and outlet angles at the hub and shroud locations were used as design variables, was applied to improve the flow and noise performance of the pump. The optimized impeller design increased the pump flow rate by 17.5% and reduced the flow noise level by 3.5 dB at the same flow rate, as per the fan law predictions.

Transient Hydraulic Performance of a Prototype Pump during Starting and Stopping Periods

In order to meet different operational requirements, existing low specific speed centrifugal pumps may have to be run at high speeds. Therefore, it is crucial to understand the transient performance of such centrifugal pumps during high speed starting and stopping. However, there are currently no experiments on the starting and stopping of low specific speed centrifugal pumps. In this paper, transient hydraulic performance experiments during starting and stopping had been carried out on an atypical open impeller centrifugal pump with a rated flow rate of 6 m3/h using an updated test rig. The correlation of speed, flow, head and shaft power with time was obtained for four flow ratios of 0.353, 1.022, 1.654 and 2.343 operating conditions. It was found that the fluctuation of the shaft power curve was the strongest during the starting process, and there was a significant impact phenomenon. The corresponding impact shaft power from small to large flow rates were 0.167 kW, 0.409 kW, 0.234 kW and 0.215 kW, and the shaft power impact phenomenon was the most obvious under rated operating conditions. During the stopping process, the speed, flow rate and head all remain stable for a small period of time, and the time required to decrease to 0 is longer than the time required to reach a stable state during starting. During stopping, the shaft power will instantly decrease, accompanied by varying degrees of fluctuations.

Optimization Research on the Space-V-Type Biomimetic Surface Grooves of a Marine Centrifugal Pump

The biomimetic surface with Space-V grooves can effectively reduce flow resistance and noise. Our investigation was in order to further enhance the drag reduction and noise reduction performance of a marine centrifugal pump with Space-V-groove-shaped biomimetic surfaces. A regression equation was established with response surface methodology between the total sound pressure level and the height (h), width (s), and spacing (b) of the biomimetic groove structure. The interaction effects of various parameters on the total sound pressure level were analyzed, and the parameter range was determined at the lowest total sound pressure level. The hydraulic performance and interior noise of the model before and after optimization were compared. The results showed that the total sound pressure level initially decreased and then increased with increasing groove height. Similarly, with an increase in groove width, the total sound pressure level decreased at first, then increased. When the height of the bionic groove is 0.5–0.7 mm, the groove width is 0.4–0.7 mm, the groove spacing is 0.7–1.3 mm, and the total sound pressure level of the centrifugal pump is the smallest, which is 180–182 dB. On the other hand, the total sound pressure level increased as groove spacing increased. Through the use of an optimized Space-V groove model, under rated working conditions, the model head is increased by 0.27 m and the efficiency is increased by 1.21%. In addition, the optimized model has excellent drag and noise reduction performance, with the drag reduction rate of 3.73% and noise reduction rate of 1.81%, which are, respectively, increased by 0.87% and 0.45% compared with before optimization. The performance of centrifugal pumps for ships can be greatly improved.

Unsteady Cavitation Analysis of the Centrifugal Pump Based on Entropy Production and Pressure Fluctuation

A numerical method using combined detached-eddy simulation (DES) and a cavitation model considering the rotation effect is used for unsteady cavitation flow field of the centrifugal pump. A closed-type pump test system was established to obtain the pump performance and pressure pulsation characteristics under different flow rates and cavitation condition, which provide boundary conditions and verification of calculations. Based on the calculation results of the unsteady flow field of the centrifugal pump cavitation, the entropy generation analysis of the flow field and an analysis of the pressure fluctuation characteristics were carried out. Then, we tried to reveal the relationship between cavitation and the deterioration of the centrifugal pump performance and the generation of the unstable operation excitation force. The internal energy loss is mainly concentrated in the impeller, volute, and pump cavity area, which accounts for more than 85% of the total entropy generation. The characteristic frequency of a Strouhal number of about 0.333 appears at the volute tongue due to the cavitation flow spread downstream.

Effect of Trimmed Rear Shroud on Performance and Axial Thrust of Multi-Stage Centrifugal Pump With Emphasis on Visualizing Flow Losses

Abstract Multi-stage centrifugal pumps are frequently used in high-lift applications and consume considerable energy, but suffer from poor performance and large axial force. The rear shroud of impeller is trimmed for reducing axial thrust, but this degrades performance. This study analyzes performance degradation and optimizes performance and axial force. Experiments and simulations are conducted on different ratios of rear shroud to front shroud (λ). Total pressure losses are calculated, and flow losses are visualized using the entropy generation method. Both measured and simulated performances decrease as the rear shroud is trimmed. Designs with different λ meet the head coefficient requirement of 1.1. However, λ of 0.86 has the best efficiency of 42.7%, λ of 0.83 reaches 42.5%, λ of 0.8 shows the lowest efficiency of 39.9%. Efficiency in the middle channel improves as the rear shroud is trimmed, but this cannot offset increased losses in the impeller and rear side chamber. Entropy production is exacerbated in the axial passage between impeller and rear side chamber due to the collision between impeller-driven flow and pressure-driven backflow. When λ is reduced by 0.03, axial thrust drops by 7%. To compromise between performance and axial thrust, λ should be designed at 0.83.

Transient numerical investigation on hydraulic performance and flow field of multi-stage centrifugal pump with floating impellers under sealing gasket damage condition

Multi-stage centrifugal pumps with floating impellers provide a convenient means of adjustment to meet diverse head requirements. These pumps utilize sealing gaskets to minimize leakage losses and restrict impeller axial motion. However, the impact of sealing gasket breakage on hydraulic performance and internal flow remains uncertain. To investigate this, a novel dynamic mesh simulation method is proposed to enable simultaneous axial motion and rotation of the impeller. Validation of numerical simulations with experiments is performed. Transient hydraulic performance is influenced by impeller axial motion, with a lagging flow field response. Head coefficient and efficiency curves exhibit asymmetric triangular functions with higher fluctuations compared to impeller with fixed axial position. At the design condition, with the impeller floating, the head coefficient ranges from 0.7 to 1.9, while the efficiency ranges from 29.7% to 60.1%. Among the various loss ratios, the hydraulic loss ratio exhibits the highest magnitude, followed by the leakage loss ratio, with the shroud friction loss ratio being the smallest. Entropy production reveals the significant influence of impeller oscillation on local flow loss. The axial motion of the impeller causes drastic velocity and pressure fluctuations in both time and space.

Influence of Dynamic and Static Interference on the Internal Flow and Vibration and Noise Characteristics of Marine Centrifugal Pump

To improve the overall performance of marine centrifugal pumps (MCPs), their vibration and noise performances were optimized using the hydraulic design of the volute casing parameters considering a constant hydraulic performance at a specific speed of 66.7. Numerical simulations of the full flow field, vibration, and noise were conducted for each of five volute base circle diameters. The impact of dynamic and static disturbances on the flow and vibration and noise characteristics were investigated. These results provide some theoretical and technical support for the design and application of MCPs. The flow pattern inside the volute becomes more uniform as the D3 increases, but the pressure pulsation decreases. The total vibration levels of the inlet flange, outlet flange, and pump base decreased by 8.3%, 7.9%, and 12.3% respectively. The sound pressure of the flow noise at each characteristic frequency showed a different degree of decreasing trend.

Analysis of Cavitation Flow Performance in Centrifugal Pump Using OpenFOAM

In order to explore the cavitation mechanism and cavitation cloud development process of centrifugal pump, OpenFOAM7.0 open-source software was used to simulate the unsteady cavitation gas-liquid two-phase flow of IS125 centrifugal pump under different flow conditions. Based on the flow field simulation results, the relationship between the flow rate of the centrifugal pump and the NPSHr was predicted and compared with the experimental data. The comparison showed that it is feasible to use OpenFOAM software to simulate the cavitation flow of centrifugal pump under design condition. Under the design condition, when NPSHa was different, the distribution of cavitation clouds in each blade channel was asymmetric. With the decrease of NPSHa, cavitation clouds continue to develop downstream in the impeller channel and appear on the blade pressure surface. Regardless of whether cavitation occurred in the centrifugal pump, the pressure coefficient showed periodic pulsation, and the pulsation number of the impeller in a rotation cycle was equal to the number of blades of the impeller. The research results can provide an effective open-source software calculation method for centrifugal pump performance prediction.

REVIEW AND CRITICAL ANALYSIS OF THE CURRENT STATE AND WAYS TO IMPROVE REGULATED POWER SUPPLIES AND AUTOMATIC CONTROL SYSTEMS FOR ELECTRIC CENTRIFUGAL PUMPING UNITS IN INTERMITTENT OPERATION OF OIL WELLS

Link for citation: Kladiev S.N. Review and critical analysis of the current state and ways to improve regulated power supplies and automatic control systems for electric centrifugal pumping units in intermittent operation of oil wells. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 203-215. In Rus. Relevance. At present efforts are being made to convert low- and medium-flow oil wells to cyclical or short-term operation in order to reduce the excess pumping capacity that resulted from the reduction of well flow that is caused by reduced reservoir pressure during long-lasting exploitation of the deposit. The need for such a conversion requires justification for the use of more complex configurations of regulated power supply sources and automatic control systems of centrifugal pump units electric drives in automated process control systems. The local low-level automatic control systems for a mechanized electric drive method for lifting an oil-containing liquid from the well to the surface, namely the installation of variable-speed AC electric drives consist of ground-based devices and special submersible equipment. The ground-based devices are control stations with AC voltage and frequency converters with built-in telemetry units, external sine filter, step-up transformer. The special submersible equipment includes asynchronous induction electric motor, power cable, submersible telemetry unit, process sensors, centrifugal pump. The power supply of such a unit is provided from the external electric three-phase network of 6 kV through a reducing transformer substation of 6/0,4 kV. In the continuous mode of operation of oil pumping plants the electric pumps and other equipment, operate in quasi-static modes. Unregulated electric drive, as well as the open-loop controlled electric drive does not allow for smooth acceleration to the nominal performance of pumping equipment for pumping oil out of well in difficult conditions and its smooth regulation when reducing the well flow because of reducing oil flow to the slaughter. Therefore, the main way of smoothly reducing the excess performance of the submersible centrifugal pump is the periodic activation mode, which includes pumping the oil mixture out of the well and stop – for its accumulation and recovery of formation pressure. The introduction of cyclical technology shows that it is impossible to use the open-loop system of regulated electric drive everywhere, where acceptable quality indicators of transition comparable with the quality of closed-loop control systems are objectively unattainable. Due to the fact that the amount of pressure at the well intake created by a centrifugal pump, necessary to lift the well fluid to the surface, depends on the square of the rotation speed of the pump working stages, the operating pump productivity range Qmin... Qmax (m3/day) is obtained by varying the motor stator winding voltage (80…100) % from the nominal voltage value by using AC voltage controller with a phase control mode. If the stator voltage value is less than 80 % of Unom then the well fluid is not lifted to the surface and does not flow out of wellhead equipment. Therefore, when a frequency converter with Unom/fnom=const is used, the supply voltage and frequency of the motor should be varied in the same range. The price for using cyclic operation is a decrease in the reliability of submersible pumps. It is necessary to use special designs of submersible electric motors, improve power supply systems and synthesize closed-loop control systems of automatic control of electric drive of submersible pump. The purpose of the study is the review and critical analysis of the current state and ways to improve regulated power supplies and automatic control systems for electric centrifugal pumping units in intermittent operation of oil wells. Object: systems of power supply and automatic control of centrifugal pump units in intermittent operation of oil well, telemetry systems, energy-efficient submersible motors and centrifugal pump designs. Methods: methods of the theory of the automatic control system for developing the concept of operation of low flow of wells, analysis and synthesis of open and closed loop control systems of electric submersible centrifugal pumping units. Results. The paper introduces the scientific problem of development, implementation, models and methods of identification of technological processes, complexes and integrated control systems of oil extraction by electric drive method, taking into account the influence of a long submerged cable, low flow of wells and difficult operating conditions. The author proposed scientifically based technical solutions in the form of a structure of a power channel of an electromechanical system with a frequency-regulated induction motor, long submersible cable and indirect method of measuring state variable from ground-based measurements at load changes and measurement channel characteristics.

Next Generation Development of Hybrid Continuous Flow Pediatric Total Artificial Heart Technology: Design-Build-Test.

To address the unmet clinical need for pediatric circulatory support, we are developing an operationally versatile, hybrid, continuous-flow, total artificial heart ("Dragon Heart"). This device integrates a magnetically levitated axial and centrifugal blood pump. Here, we utilized a validated axial flow pump, and we focused on the development of the centrifugal pump. A motor was integrated to drive the centrifugal pump, achieving 50% size reduction. The motor design was simulated by finite element analysis, and pump design improvement was attained by computational fluid dynamics. A prototype centrifugal pump was constructed from biocompatible 3D printed parts for the housing and machined metal parts for the drive system. Centrifugal prototype testing was conducted using water and then bovine blood. The fully combined device ( i.e. , axial pump nested inside of the centrifugal pump) was tested to ensure proper operation. We demonstrated the hydraulic performance of the two pumps operating in tandem, and we found that the centrifugal blood pump performance was not adversely impacted by the simultaneous operation of the axial blood pump. The current iteration of this design achieved a range of operation overlapping our target range. Future design iterations will further reduce size and incorporate complete and active magnetic levitation.

Evaluation of Various Turbulence Models and Large Eddy Simulation for Stall Prediction in a Centrifugal Pump

Rotational stall is an unstable flow phenomenon that reduces the performance of centrifugal pumps, usually occurring under partial load conditions. It causes instability in the flow resulting in intense vibrations and noise under certain flow conditions. In this study, the one-equation Wray–Agarwal (WA) turbulence model, which was recently developed, is employed to numerically simulate the internal flow field of a centrifugal pump under the deep stall condition. The aim of this study is to examine the prediction accuracy for stall by using the WA turbulence model. The method based on computational fluid dynamics (CFD) has been widely applied for investigation of complex flow patterns in pumps by solving Reynolds-averaged Navier-Stokes (RANS) equations. Particle image velocimetry (PIV) experimental results were compared with simulations predicted using the WA, renormalization group (RNG) k−ε, shear stress transport (SST) k−ω, and realizable k−ε turbulence models and large eddy simulations (LES). The comparisons indicated that the WA turbulence model can accurately predict the flow separation and has a good agreement with the PIV data. The WA model adds a cross-diffusion term and a blending function to the eddy viscosity R equation, so that this model could be expressed as a one-equation k−ω model or one-equation k−ε model as needed by using the switching function. The results show the strong potential of the WA model for accurately computing the stall in rotating fluid machinery. The outcomes of the study are useful in development and optimization of fluid machinery with a low calculation cost and a high accuracy.