Reliability Of Pumps Research Articles

The vibration origin in the electric pump of the spacecraft and methods to reduce them

The important problem for rocket-space, aviation and transport equipment fields is designing high-resource electric pumps. Electric pumps are active energy conversion devices to provide the thermal control system operation. Electric pumps failure leads to fault of the interfaced equipment, system failures and significant economic damage accidents. The most unfavorable factor for electric pump reliability is vibration. That the reason of relevance, practicability and importance to research the electric pumps vibration activity, the reasons for the appearance of vibrations and ways to control them. The paper provides the main sources of electric pump of the spacecraft vibrations as mechanical, hydrodynamic and electrical. This paper presents the recommendations of foreign and domestic authors to control each vibration source. To solve the problem of reducing the electric pump vibration activity the research of the technical level of existing developments, results, main technical solutions and technical solutions trends was produced. The main directions of further electric pump vibration activity researches leading to decreasing of vibration activity were defined on this paper.

Development of A High-Load Capacity Test Rig to Evaluate the Static Performance of Process Fluid-Lubricated Thrust Bearings

Electrical submersible pumps (ESPs) are artificial lift devices widely used in the oil and gas industry to increase production. For unconventional wells, which includes subsea applications, installation cost is an order of magnitude higher than the cost of the typical ESP, thus pump reliability is paramount. Contamination of the thrust bearing lubricant oil by process fluid due to seal failures is one of the leading causes of thrust bearing failure. While improving seal reliability can prevent thrust bearing failures, an alternative approach is to develop process-fluid lubricated thrust bearings. This research aims to characterize and study the performance of thrust bearings operating with process fluid lubrication. A component level-level test rig for testing the performance of thrust bearings in any mixture of water, sand, and air is designed, built, and commissioned. Initial tests of the PEEK and Tungsten Carbide (WC) bearings include a load capacity test to determine the hydrodynamic limit of the bearing, a hydrodynamic test to corroborate test rig stability, and a wear test to determine if the bearings can operate feasibly past hydrodynamic limits in a mixed lubrication regime. Initial results show that lubrication starvation can occur in an unpressurized chamber for low viscosity fluids that are not supplied directly to the bearing. Furthermore, the film thickness, temperature rise in the pads, and load capacity all are lower for water lubricated bearings when compared to oil lubricated bearings. Results suggest that liner material affects wear rate but not load capacity; however, operating even the WC bearings past hydrodynamic limits causes substantial wear and is not recommended as an operating mode. Polycrystalline Diamond (PCD) coated mixed lubrication bearings were also tested. These bearings, although requiring higher drive torque, sustained higher loads than the tilting pad bearings without significant wear

Study On The Reliability Improvement Of The Control Of The Main Feed Pump In The Second Circuit Of Nuclear Power Plants

There is a safety hazard in the interlock control logic of the second circuit electric main feed pump of the CPR1000 nuclear power unit. When the unit is operating at full power, if the speed of an operating pump suddenly drops below 3950 rpm or if the pump outlet pressure suddenly drops but does not reach the pump trip threshold, the standby pump cannot be automatically interlocked to start. If the standby pump is not started in time, it will cause the unit to overpower the first circuit or even trip the reactor. In this paper, the control strategy of the second circuit electric main feed pump is analysed and demonstrated, and after simulation tests, a feasible improvement plan is proposed, which effectively improves the control reliability of the second circuit electric main feed pump in nuclear power plants.

Effect of axial offset of rotor on thrust characteristics of a centrifugal pump

To ensure the reliability of multi-stage centrifugal pumps, the prediction of axial thrust is an important issue for the design of balancing device and selection of thrust bearing. However, it is known that the fluid forces acting on rotor could be sensitively affected by the geometrical relations between rotor and stator especially at the low flow rate. Among them, the effect of axial offset of rotor has not been studied sufficiently though the axial offset is easily caused by accumulation of manufacturing tolerances and assembling errors. In this study, experimental/numerical investigations on the effect of axial rotor offset in a final stage model of a three-stage centrifugal pump are carried out. The axial offset is intentionally given to shaft system to the both of discharge/suction side. As a result, the axial thrust is significantly affected by the axial offset in the flow rate range below 50% of the design. It is shown by CFD analysis that this effect of axial offset is caused by the interaction between the back flow from the diffuser and the main flow.

Study of BPF pressure pulsations reduction in centrifugal bladed machines using splitters

Presence of intensive pressure pulsations and noise on blade passing frequencies is a characteristic feature of all types of centrifugal bladed machines including pumps. Under definite conditions pressure pulsations can reduce the pump reliability and life cycle. High level of tonal noise can be inappropriate due to ecological requirements. The paper is devoted to the study of application of splitters for reduction of pressure pulsations in centrifugal pumps. 2D and 3D numerical methods are used in the study. Initial computational tests were performed with a two-dimensional formulation for a centrifugal pump with a simple volute using 2D discreet vortex method for the impeller flow and 2D acoustic-vortex approach for pressure pulsations prediction. 3D unsteady flow computations of an air model of the centrifugal pump are undertaken with the impeller having splitters. Calculations of pressure pulsations show that the use of additional blades reduces the amplitude of the first harmonic of blade passing frequency by more than three times compared to the design without splitters. It correlates with flow parameters distribution along the impeller outlet diameter that has less nonuniformity and a more balanced vorticity profile. Application of splitters reduces the amplitude of pressure pulsations by a factor of 3.

Development of High-Efficient Centrifugal Pump Through Optimization of Its Volute Tongue and Expeller Vane

Abstract Centrifugal pumps are often used for pumping liquids from one priority area to another, which require working effectively in terms of performance and reliability. The objective of this study is to enhance the hydraulic performance and reliability of a centrifugal pump based on computational fluid dynamics (CFD) optimization. The shapes of the expeller vane and volute tongue were optimized based on the following six design parameters; outer diameter, exit angle, front and rear heights, back sidewall gap, and tongue angle. The hydraulic efficiency and axial thrust were chosen as the optimization objectives. In this sense, a design of experiment (DOE) technique was utilized to generate 45 design samples. A response surface modeling (RSM) approach was employed to investigate the interaction between the parameters and objectives. The accuracy of the numerical simulation was verified by the experimental data and showed a good agreement. The optimization was found to improve the hydraulic efficiency by 2.92%, whereas the axial thrust was decreased by 7.51%.

Mathematical Modelling of Dynamic System Rotor-Groove Seals for the Purposes of Increasing the Vibration Reliability of NPP Pumps

Groove seals are considered as hydrostatic bearings capable of effectively damping rotor vibrations. In order to determine the dynamic characteristics, a model of the rotor-groove seals system is considered. The radial forces and moments in groove seals had been estimated. Expressions of joint radial-angular rotor vibrations in groove seals had been obtained. Formulas had been proposed for constructing amplitude and phase frequency characteristics. An example of calculating the dynamic characteristics of a centrifugal machine rotor model is presented. The directions of increasing the vibration reliability of NPP pumping equipment by purposefully increasing the rigidity of groove seals are determined.

Experimental and numerical investigations of cavitation evolution in a high-speed centrifugal pump with inducer

Along with the anti-cavitation performance, the high speed and the high power density, are the main trends in the development of centrifugal pumps. At present, the most effective method is to install an inducer in front of the impeller. However, the tip leakage of the inducer results in the vortex cavitation at the blade leading edge of the inducer, and the cavitating flow inside the inducer seriously interferes with the hydraulic behavior of the inducer as well as the impeller with the development of the cavitation, thus to badly affect the operational reliability of the high-speed centrifugal pump. In the present paper, the cavitating flow in a high-speed centrifugal pump with an inducer is investigated by numerical simulations and visual experiments for different cavitation numbers. A typical evolution process of the cavitation is shown, including the inception, the development and the deterioration. A general description of the pump head-drop phenomenon is made through the study of the local and global flow fields, and the relationship between the vapor distribution and the static pressure distribution along the inducer is determined to describe the evolution of the cavitation. This paper intends to provide the foundation for studying the overall cavitation state of a high-speed centrifugal pump, and designing the inducer with a better cavitation resistance.

XVI International Scientific and Engineering Conference Hermetic Sealing, Vibration Reliability and Ecological Safety of Pump and Compressor Machinery – HERVICON+PUMPS-2020

A Zahorulko1, S Hudkov1 1 Sumy State University, Sumy, UkraineE-mail: a.zagorulko@omdm.sumdu.edu.ua, s.gudkov@omdm.sumdu.edu.uaDue to the Covid-19 pandemic, the meetings of regular XVI International Scientific and Engineering Conference Hermetic Sealing, Vibration Reliability and Ecological Safety of Pump and Compressor Machinery – HERVICON+PUMPS-2020 were held online in the virtual laboratory of Sumy State University (Sumy, Ukraine) on September 8, 2020.The Conference was dedicated to the memory of its founder and permanent Chairman of the Organizing Committee, Dr., Prof., Dr.h.c. Volodymyr Martsynkovskyy. He was a well-known scientist in centrifugal pump hydrodynamics and strength, sealing technology and rotordynamics, honored worker of science and technology of Ukraine, distinguished professor of Sumy State University, doctor honoris causa of Kielce University of Technology (Poland). In 1976, Volodymyr Martsynkovskyy founded a Scientific and Technical Meeting on Sealing Technology, which, subsequently, grew into the International Scientific and Engineering HERVICON+PUMPS Conference.List of titles Organizing Committee, Program Committee, Editorial Committee, Key Reviewers, Co-Organizers, Informational Support are available in this Pdf.

Analysis and Performance Evaluation of Casting Inclusions in the Reactor Coolant Pump Casing of Nuclear Power Plant

The casting quality of the coolant pump casing of the nuclear power plant reactor is directly related to the operational reliability and safety of the nuclear main pump, and plays a key role in the integrity of the pressure-bearing boundary of the reactor primary loop. In this paper, aiming at the low impact performance of the sample during the casting process of the main pump casing of a nuclear power plant, through using failure analysis tools like fishbone diagram from multiple dimensions such as material selection, design and technology, melting analysis, pouring process, riser design, and heat treatment process, and combining with metal macro-fracture analysis and micro-electron microscopy scanning methods for cause analysis, finally, it was found that the basic reason for the low impact performance of the pump shell is that the secondary inclusions appear on the fracture of the sample during the solidification of the molten steel. Using test-retest inspection and finite element mechanics simulation analysis, the comprehensive evaluation of the impact performance of the sample was obtain, which provides an effective solution for the analysis and evaluation of casting inclusions in water pumps of nuclear power plants, and also provides an important reference for the structural optimization and equipment research and development of water pump equipment of nuclear power plants.

Optimization for a centrifugal pump transporting brine using orthogonal design based on CFD-DEM simulation

To enhance the reliability of a centrifugal pump transporting brine solutions with crystallization, the effect of impeller geometrical configurations on crystal particle behaviors was investigated by an orthogonal design based on CFD-DEM coupled method. In this work, the main impeller geometrical configurations were set as the blade inlet angle α1, blade outlet angle α2, wrap angle φ, and outlet width b2. In the meanwhile, the L9(34) orthogonal design containing 4 factors with 3 levels was applied in this study. Given the crystal particle features, CFD-DEM coupling method was utilized to study inner flow in a pump with crystal particles. Current results indicated that the blade outlet angle α2 could significantly affect the collisions between particles and blades. Moreover, a low-speed region at the blade pressure side in the optimal impeller has been reduced, declining the probability of the crystal particles adhering to the impeller.

Development of methods of gas chromatographic analysis of technological media of the main circulation pumps of a nuclear power plant

During the operation of power plant equipment, technological media are used – water, turbine oils. Diagnostics of equipment by chromatographic determination of diagnostic components (gases Н 2 , СН 4 , С 2 Н 6 , С 2 Н 4 , С 2 Н 2 , СО, СО 2 , О 2 , N 2 ), water, Ionol in these media is urgent. For this, 5 chromatographs are used. An increase in the reliability of the main circulation pumps of a nuclear power plant can be due to an increase in the reliability of its system. The influence of ultrasonic vibrations on the generation of gases in the systems oil – diagnostic gas, oil – water – diagnostic gas with the use of turbine Тп-22s is studied. Gas concentrations increase with an increase in the duration of exposure for 1600 s at a frequency of 35–125 kHz and a power of 20 W. The dependences of the concentrations Ci of dissolved gases on the irradiation time τ of technological media is expressed by the equation Сi=А∙τ+В Coefficients A, B and correlation coefficients R2 have specific values for each dissolved gas. So, 0.95≤R2≤0.995, which indicates the adequacy of the obtained equations to the experimental data. This makes it possible to determine turbine in water after irradiation and subsequent chromatographic determination of the generated dissolved gases. The technical requirements for a 5-channel chromatograph were established and its structural diagram was developed. This makes it possible to reduce the number of measurement operations and chromatographs. The thresholds for determining the diagnostic components in the corresponding technological environments have been determined: 2 ррm (Н 2 ); 1 ррm (СН 4 , С 2 Н 6 , С 2 Н 4 ); 0,5 ррm (С 2 Н 2 ); 5 ррm (СО, СО 2 ); 1,5 ppm (О 2 , N 2 ); 0.05 wt. % (Ionol); 2 g/t (water in turbine oil) 0.02 mg/dm3 (turbine in water). The basic technological scheme of the system for the main circulation pumps of the NPP has been developed. It is proposed to continuously: degassing the turbine flow; sorption purification of cooling water, analysis of turbine and cooling water by chromatography methods. This will reduce the degradation of turbine and increase the reliability of the system of the NPP main circulation pumps

Devising a method for ensuring the reliability of fire centrifugal pumps while reducing their weight and dimension characteristics by optimizing their structural elements

An algorithm for calculating the strength and reliability of centrifugal fire pump housings has been developed, aimed at determining the optimal mass-dimension parameters of centrifugal fire pumps. To this end, a method has been devised for determining the main indicators of reliability, an optimization mathematical model has been built, and an algorithm for solving the optimization problem using the Monte Carlo method has been developed. When devising a method for determining the main reliability indicators of centrifugal fire pumps, the strength and kinematic parameters have been taken into consideration, as well as an economic indicator of reliability and the costs of ensuring reliability. These indicators make it possible to establish the optimal consumption of materials for the manufacture of structural elements of centrifugal fire pumps that ensure their strength and reliability. When building the optimization mathematical model, a pump weight minimization was used as the objective function while the applied difference criterion makes it possible to take into consideration the economic indicator in the manufacture of centrifugal fire pumps and to reduce their cost. It was established that the principal indicator that affects the weight of a pump and the cost of its manufacture is the thickness of the pump housing wall. Based on the developed optimization mathematical model, the flowcharts of the algorithms have been constructed for solving it using the Monte Carlo method. The calculation results showed that the width of the PN-40 UV pump housing can be reduced by 1.18 from the rated one. Applying the optimization mathematical model in the process of designing fire centrifugal pumps makes it possible to reduce the pump weight by 9‒11 % while ensuring high reliability and reducing the cost of its production by 10 %

Study of Mechanical Performance Affecting Factors in Split Casing Pump

The need for better performance and higher comfort continually drive search for new features. In today’s applications, pumps are expected to continue continuously for a long time. So “operational reliability” is a key factor. The comprifugal pump is a fluid-carrying machine, with centrifugal energy produced by rotating air. Pumps are used for conveying fluids. Rotating power usually comes from an electric car, which is turned by the engine and the engine. There is a great demand for centrifugal pumps on the market. The construction is relatively inexpensive, durable and easy, and its high speed makes it possible to connect the pump directly to an unmatched car. The centrifugal pump provides a constant flow of fluid, and can be easily blown without causing damage to the pump. Pump reliability problems address a large amount of repair repairs and the cost of loss of access to chemical plants, refineries, and many electrical appliances. This paper describes the most common causes of pump failure, and how they can be avoided in most cases by using the appropriate types of analysis and procedure during the pump selection process. Specifically, key issues include where the pump will operate next to the best efficient point (BEP). Proper pump selection and installation avoid misalignment. This paper explains the various reasons for the failure of Split break pumps.

Dynamics characteristics analysis of the oil-free scroll hydrogen recirculating pump based on multibody dynamics simulation

The hydrogen recirculating pump is the key equipment of the hydrogen recirculating system for the fuel cell vehicles. The scroll pump is one of the preferred types of hydrogen recirculating pumps because of its unique advantages of higher efficiency and lower noise. In order to provide valuable basis for improving the reliability and durability of hydrogen pumps under oil-free high-speed conditions, this paper carried out dynamics performance research based on the theoretical method. The gas force, force and torque of moving parts were calculated. Tangential gas force is about 100 N and axial gas force is about 200 N which are much smaller than the traditional scroll compressors due to lower designed pressure ratio of hydrogen pump. Due to the exist of bearing assembly tolerances of sub-crankshafts during practical operation, the actual contact forces and dynamics characteristics were further analyzed based on multibody dynamics simulation. It is found that the rotating speed and the actual assembly tolerance have significant influence on the dynamics characteristics. The radial and tangential forces can reach 3000 N at 6000 r·min−1 which is three times than the value at 3000 r·min−1. Furthermore, the service lives of bearings were analyzed. The contact force considering assembly tolerance presented the high-frequency oscillations. When the size of clearance is increasing, the oscillation frequency is reducing, but the contact force is enlarging. The radial force on a sub-crankshaft was 30 N without assembly tolerances. It increased to 150 N and 330 N, respectively, when the assembly clearances were designed separately as 2~−14 μm and −8~−24 μm, and the corresponding bearing service life decreased by 46% and 83%.

Carbon Nanomaterials: Application and Prospects of Urban and Industrial Wastewater Pollution Treatment Based on Abrasion and Corrosion Resistance.

Environmental pollution as a result of urban and industrial wastewater has become an increasingly prominent issue. Rivers, lakes, and oceans that have become eutrophicated or polluted by suspended solids and hazardous substances in wastewater have endangered the environment. A root cause of this is the discharge of untreated urban and industrial wastewater into the ecosystem. As a solution to the pollution, wastewater treatment facilities have seen increasingly rapid development. Sewage pumps are designed to transport urban and industrial wastewater containing solid particles or hazardous substances to water treatment centers for purification and treatment. Sewage pumps are of great importance in the entire wastewater treatment system. Sewage in the environment where sewage pumps work usually contains sands, suspended particles, and plenty of saline ions. Flow passage components and sealing elements of the pump become vulnerable to abrasion and chemical corrosion, which further challenges operational stability of the pump. Research has remained focused on how to improve reliability of sewage pumps under severe conditions. Because of advances in materials science, the application of an increasing number of new materials has been witnessed, such as carbon-based composite materials and carbon nanomaterials, thanks to their fine self-lubrication performance, heat resistance, thermal and electrical conductivity, chemical stability, heat and seismic resistance, as well as plasticity. These properties contribute to enormous potential that new carbon-based composite materials and carbon nanomaterials have to offer in terms of corrosion resistance. This paper outlines application scenarios, research progress, and the prospect of new materials in sewage pumps.

Research of dependence centrifugal pump efficiency of impeller slit seal design parameters

Efficiency and resource are the two main characteristics of a centrifugal pump. In present study, the dependence of these characteristics from impeller sealing wear ring configuration was considered. Range of models with various configurations has been analyzed using numerical flow simulation. Compromise curves nave been obtained as a result. This information allows select an optimal ratio of dimensions of wear ring hydrodynamic slit seal to achieve a balance between efficiency and reliability of centrifugal pump.

Analisis Kinerja Penukar Kalor Tipe Shell and Tube untuk Pendinginan Governor

One of the elements that affect the reliability and service life of a hydraulic pump is the stability level of oil viscosity as a power successor. The stability level of oil viscosity is affected by changes in temperature. The compression and friction process that the oil receives to move the hydraulic pump will increase the oil temperature so that its viscosity level will decrease. To maintain the performance of the hydraulic pump, the oil temperature must be maintained at room temperature. In the case study at PLTA Ir. H. Djuanda, Lurah Kawi Street No.1 Jatiluhur-West Java, to cool the oil, a shell and tube heat exchanger type JPK 13699068 (single tube) is used. This research was conducted to test whether the heat exchanger is still working properly, the parameter is that the cooled oil exit temperature must be close to room temperature. The effectiveness of the heat exchanger will be tested by comparing the test results with the condition of the heat exchanger without impurity factors. The test was carried out by measuring the temperature of the HX intake oil at 44 0 C with a discharge of 0.437 kg/s, and the temperature of the HX inlet water at 28 0 C with a discharge of 0.498 kg/s. The results showed that, for the coefficient of U between 110 to 350 W/m 2 o C with a water impurity factor of 0.0001 m 2 o C/W and an oil impurity factor of 0.0002 m 2 o C/W, there was a decrease in effectiveness from an average of 74.5% to 73.7%, and there was an increase in oil temperature out of the heat exchanger from an average of 32.07 o C to an average of 32.21 o C.

Establishing the causes for low operational reliability of slurry pumps based on a system analysis

In practice, the difference between the actual and planned costs forthe maintenance of slurry pumps used at concentration and screening plants of Russian diamond mining companies is mainly represented by the costs of purchase and delivery of their new original (OEM) parts. These costs are primarily due to the premature failure of pump components. The impeller is the least reliable or fail-proof element in their design. The main cause for impeller failure is the intense abrasion of its surfaces by mechanical impurities contained in the slurry pumped. The respective comprehensive scientific research has established the critical factors affecting the weighted average service life of pump impellers used by Russian diamond mining companies. A linear regression model has also been designed, allowing to predict the service life of impellers in Russian-made slurry pumps for the processing plants of PJSC ALROSA with a high degree of probability, duly confirmed using the Fisher criterion. The results obtained are of great practical interest as they make it possible to further assess impeller operational durability and to accordingly predict the maintenance costs for the slurry pumps, depending on their specific operation conditions at Russian diamond mining companies.

Malfunctions of Aviation Hydraulic Pumps

Abstract Hydraulic pumps are among the most complex and responsible units from the point of view of aircraft flight safety. One of the most important scientific and technical problems in improving the reliability of hydraulic pumps is to understand the physical nature of the cause of damage in them and on this basis to develop measures and recommendations to ensure their reliability. The article discusses the characteristics of hydraulic piston pairs of hydraulic pumps according to the kinematics of their movement and load conditions. Selected actual damages of axial piston pumps are discussed. The paper presents a simplified 3D solid model of the cylinder-piston assembly and the mechanism for adjusting the inclination of the piston cylinder block, the axial hydraulic pump, and the model of breaking loads for selected elements of this pump. The digital solid model and element load analysis were developed in SolidWorks Simulation.