Pump Shaft Research Articles

A new design of the Lobe pump is based on the meshing principle of elliptical gear pairs

The paper presents a new rotor design of an external coupling Lobe pump driven by pair of elliptical gears. The new rotor is a four-tooth elliptical gear with tooth profile is a improve cylocid curve. The improve cylocid curve is the locus of the fixed point on the generation circle, when the circle a pure rolling without slipping on the elliptical centrode of the rotor. The conditions of the rotor addendum and dedendum profiles are also considered. The limited supply angle addendum and dedendum rotor profiles are determined through an iterative algorithm when the generation circle makes a pure rolling without slipping on the ellipse base of the rotor. From there, we proceed to determine the pump design parameters according to the characteristic design parameters forming the rotor profile. The flow rate of the pump is determined by the area of the pockets on a cross-section perpendicular to the pump shaft. On that basis, a Matlab program is written from the mathematical model established by the paper to calculate the rotor design. In addition, the paper also investigates the effect of the coefficient l (semi-major axis divided semi-minor axis of the elliptical centrode ) on the average flow and axis distance. Survey results show that the design at l = 0.5 flow is 52.17% larger and the axis distance is reduced by 21.43% when compared to the traditional design at l = 1. This is the advantage of the new design proposed by this study.

Strength Analysis Plastic Deformed Centrifugal Pumps

The G-3503 centrifugal pump functions to flow Diethanolamine fluid with a viscosity of 380 Cp which functions to reduce H2S and CO2 levels in natural gas. When operating, the pump shaft experiences a torque load which causes the shaft to be twisted by 80. From the exact and finite element analysis results, the shear stress that occurs on the shaft is greater than the shear stress of the shaft material. Thus, the shaft is deformed plastically. The shear stress that occurs is 164 MPa

Performance evaluation and characterization of a locally designed water pump

Voltron, a locally designed water pump, is widely used among farmers in Central Luzon of the Philippines. The study aimed to evaluate the performance of the Voltron water pump. Voltron was tested at different pump shaft speed settings of 450, 600, and 700 rpm and with different blade (impeller vanes) numbers of 6, 8, 9, and 10 using V-belts and B-section pulleys transmission. The highest pump efficiency of 62.5% was observed using an 8-vane impeller under a 700-rpm setting. Currently, farmers utilized the 8-vane impeller under a 600-rpm setting. Statistical analysis showed that there is no significant difference between the pump efficiencies on the set pump shaft speeds, but there is a significant difference in the set number of vanes. On the other hand, the effects of pump shaft speed, the head, discharge, and fuel consumption increased as rotational speed was increased. The difference is around Php 17.61 per ha per day of operation favoring the usual setting upon the computation of the fuel cost. However, the 8-vane impeller under a 700-rpm setting will be more economical in the long run as it is determined to be more efficient than the normal setting being used by the farmers.

Fatigue Failure Analysis of Pump Shaft of a Hydraulic Coke Removal System

Failure of pump shaft (P116-1) of high-pressure water pump occurred during coke removal. Shaft material (3Cr13) demonstrated yield and tensile strength of 737 and 910 MPa, respectively. Failure analysis was performed to determine the cause of failure, which was a fracture at the pump shaft located at the journal. Macroscopic, metallographic, chemical composition, hardness, SEM, and EDS analyses were used in the failure analysis. Metallographic and SEM analyses revealed that fatigue cracks are related to corrosion and geometrical shape. Fatigue crack initiation at the disconnected area of the chromium plating layer weakened fatigue resistance. Causes of incomplete chromium plating at the shaft journal and keyway should be investigated further.

Wet Modal Analyses of Various Length Coaxial Sump Pump Rotors with Acoustic-Solid Coupling

The dynamic characteristics of the rotor components were determined using a first-order modal model of the rotor components for various sump pump shaft lengths for actual working environments. By employing ANSYS-Workbench software, this paper uses a fluid-solid coupling analysis to calculate the reaction forces of the fluid on the rotor with results, which is then used in dry and wet modal analyses of the rotor parts to calculate the vibration modal characteristics with and without prestresses. The differences between the wet and dry modal characteristics were compared and investigated by ANSYS. The results show that increasing the sump pump shaft length reduces the first-order natural frequency of the prestressed rotor components. The structure also experiences stress stiffening, which is more obvious in the high-order modes. The natural frequency of the rotor in the wet mode is about 16% less than that in the dry mode for the various shaft lengths due to the added mass of the water on the surface which reduces the natural frequency. In the wet modal analysis, when the structure is in a different fluid medium, the influence of its modal distribution will also change, this is because the additional mass produced by the fluid medium of different density on the structure surface is different. Thus, the wet modal analysis of the rotor is important for more accurate dynamic analyses.

Cause analysis and Countermeasures for shaft fracture of closed pump

Two 350MW supercritical wet cooling units in a power plant, the closed water pump adopts horizontal single-stage double suction split centrifugal pump. In recent two years, the shaft of the closed pump B of 1 unit has been fractured twice. In this paper, the fracture causes of the closed pump shaft are analyzed from the aspects of closed pump operation, material analysis and micro organization, and treatment measures are taken to solve the problem.

31CrMoV9 ve 34CrAIMo5 Çeliklerinin Nitrürleme Sonrası Yüzey Pürüzlüğüne Talaşlı İmalatın Etkisi

31CrMoV9 and 34CrAlMo5 are high-performance steels used in many industrial applications in which machines and components are exposed to high surface stresses and dynamic loads. Depending on the customer needs, these steels are first machined on CNC machines and then their surfaces are hardened by nitriding. After nitriding, grinding is needed to reduce the surface roughness values of the product according to the customer demand or the need of the production. Grinding is a chip removal process that uses an a grinding wheel as the cutting tool. However, one of the major drawback for grinding process is significant amount of processing costs. For some applications, such as pump drive shaft, it is foreseen that elimination of grinding step in workflow may reduce significantly cost item for the manufacturer. In this study, the machining parameters of hydraulic pump drive shafts produced from 31CrMoV9 and 34CrAlMo5 materials were changed before nitriding process and after nitriding no grinding process was applied and surface roughness after heat treatment was measured. In the final machining process, 54 hydraulic pump drive shaft samples made of both 31CrMoV9 and 34CrAlMo5 steel material were processed and the cutting edge moving value was used as a variable parameter. Thus, it was investigated whether it is possible to remove the grinding step after nitriding. According to the measurement results, it was observed that the surface roughness of the pump shafts made of both steel materials was negatively affected after the heat treatment, but this change was limited by changing the turning conditions. Finally, by removing the grinding process from the production process, it is aimed to shorten the total production time of the products and reduce the production cost.

Accelerated testing of the friction pairs of mechanical seals made of composite material of the TiC – SiC system

Novel wear-resistant materials used in friction pairs are being developed to increase their reliability and failure-free performance in operation, reduce the environmental load and energy consumption in manufacturing processes. One of the promising functional materials for manufacturing durable and wear-resistant parts and products that undergo intensive wear in operation is a powder material of the TiC – SiC system obtained by spark plasma sintering (SPS). SPS is an energy-efficient alternative to hot pressing and environmentally-friendly procedure compared to that used in manufacturing serial friction pairs from the lead-graphite composition NAMI GS-TAF-40 for tractor industry. Prototype friction pairs made of the powder material of the TiC – SiC system have been manufactured by SPS technology using sketches of a serial friction pair of the mechanical seal of a centrifugal pump 16-08-140SP of the cooling system of D-180 diesel engine developed for a T10 tractor. The goal of the study is accelerated bench testing of the obtained experimental friction pairs. The tests were carried out on the equipment of a modular block for testing mechanical seals designed for the USI «Climate». The method of accelerated testing provided simulation of the operational tests of experimental friction pairs of mechanical seals of centrifugal pumps of the cooling system of an internal combustion engine with a 2.0 – 2.5-fold acceleration. The criterion for the applicability and evaluation of the results of accelerated tests of experimental friction pairs was the similarity of temperature conditions of the water pump seal and the compression forces of the rings in the friction pair under real diesel operation and the accelerated test modes for the increased rotational speed of the centrifugal water pump shaft. A path traveled by the point of the average radius of the «contact line of touch» of the working surfaces of the rings with allowance for test acceleration coefficient (2.0 – 2.5) was taken as a basis for assessing the reliability and durability of test objects. During accelerated testing, all the test parameters were taken into account in addition to visual inspection of the test equipment and the mechanical seal. The wear resistance of the experimental friction pairs was determined by change in the mass through intermediate measurements of the ring wear after 100 and 200 hours of testing. Accelerated bench tests revealed that a friction pair with parts made of a TiC – SiC-based composite material will provide at least 1.5- fold increase in the service life of the mechanical seal of the centrifugal pump of a D180 diesel cooling system.

Failure analysis of a broken SA564 stainless steel pump shaft

Shafts are rotating elements that are subjected to torsion and bending moments that cause failures at times leading to personal injury, capacity loss, or poor product quality if basic preventive design actions are not taken. Against this background, this paper describes the failure analysis and root cause of a broken SA564 grade stainless steel pump shaft used in a plant through visual inspection, metallography, X-ray diffraction, scanning electron microscope, chemical analysis, hardness, tensile and non-destructive tests. The results show that creep, fatigue initiation and propagation from defects in the material during the operation were the predominant factors of pump shaft failure. Moreover, the existence of voids, micro-cracks, sensitisation and creeps were also identified on the broken shaft. Overall, the studied broken shaft of the impeller failed due to fatigue, initiated at the fillet radius of the keyway due to the high cyclic stress loading.

Numerical Analysis of Rotor Dynamics of Dredge Pump Shafting

The operating condition of dredge pump is highly complicated, a technical issue is the shaft vibration problems, which has great effects on the operation safety and stability of pumps. This paper introduces a mathematical model of rotor dynamics for the dredge pump, which is used to numerically investigate critical speeds and mode shapes of the pump shaft under different bearing stiffness and damping. The effects of bearing stiffness and damping on shafting vibration characteristics are considered. The results show that the stiffness has great effect on 1st and 3rd order critical speed and the damping effect can be ignored. The stiffness has little effect on shafting axial and torsional natural frequency, but has great effect on lateral natural frequency. The analysis method of rotor dynamics dealt with in this paper can provide a foundation for the design of dredge pump shafting.

Effect of deep cryogenic treatment on C93700 bearing bush material used in submersible pumps

Bearing bush is an essential part of a rotating machine. It is inserted in a housing to support the motor shaft of a submersible pump with a radial clearance of 40 μm. This plain bearing is made of high lead tin Bronze, C93700. In the working condition the submersible pump stacked with series of impellers is assumed to be an overhanging structure as the fluid flow through the impellers is not uniform in the beginning. This imbalance leads to the misalignment between pump and motor shafts resulting in the contact of bearing bush with motor shaft, as the shaft material AISI 420 stainless steel is harder than the bearing material, wear out of latter is inevitable. Due to the continuous running of motor in this condition for long hours, the shaft comes in contact with the stator and the stator coils begin to burn implying the breakdown of pump set within 6–12 months of installation. This paper aims to improve the hardness and wear resistance of C93700 bronze through deep cryogenic treatment. The test samples of the material were treated with liquid Nitrogen at −196℃ temperature and tested for tensile strength, hardness and wear resistance. Microstructure of the samples have been examined using SEM and chemical analysis was done through EDS.

Modal Analysis of Components and Whole of Gear Pump

The vibration characteristics of Gear pump are studied to avoid the Damage of parts caused by resonance. The modal of Pump body, driving gear shaft, Driven gear shaft and Gear pump are analyzed by using the Workbench module of ansys14.0 analysis software, Statistics of the first ten natural frequencies and the maximum total deformation data, Analyze the modal shape diagram. Comprehensive analysis results, There is a big gap between the natural frequency and the working frequency, the gear pump will not resonate, The local position of the parts and the whole of the gear pump will be deformed, but will not cause damage to the gear pump, and will not affect the performance of the gear pump. Computer aided research of vibration characteristics can shorten the research period and avoid safety problems.

Wear issues of pumping units

The article presents the possibility of increasing the service life of pumping units. Particular attention is paid to the regulation of the speed of rotation of the pumping unit. There are some assumptions in the mathematical model that do not affect the final result. The factors influencing the operating mode are given. It is indicated that the speed of rotation of the pump shaft significantly affects the wear resistance of the pump blades. Thus, the regulation of the pump rotation speed will rationally increase its service life.

Failure analysis of a broken SA564 stainless steel pump shaft

Failure analysis of a broken SA564 stainless steel pump shaft

Metal structure prediction in cross-wedge rolling processes

A method of computer prediction of the size of metal grains, their disorientation, grain boundaries and dislocation density, depending on the modes of cross-wedge rolling, is considered. The regularities of the formation of the parameters of the metal structure depending on the stress state are revealed by methods of computer simulation. The stress state is described by two parameters: the average stress and the parameter of the third invariant of the stress deviator. The effect of the stress state in the deformation zone on the metal structure parameters was determined for the first time. The new method allows improvement of the quality of products by computer optimization of rolling modes. The results of determining the metal structure and parameters of the stress-strain state in the deformation zone during hot rolling of the water pump shaft of steel 45 are presented. The verification and analysis of the data of virtual experiments on the formation of the structure of structural steels in the processes of cross-wedge rolling are carried out. To analyze the output data of the simulation, the parameters for predicting the calculation of grain boundaries and grain size were used. The created computer model for predicting the characteristics of metal structures, depending on the modes of plastic deformation, provides, at minimal cost and without carrying out field experiments, finding the optimal thermodynamic and stress-strain modes of plastic flow of metal, which guarantee the highest operational properties of the products obtained.

Shape optimization and uncertainty assessment of a centrifugal pump

ABSTRACT Centrifugal pumps, being used nowadays for many applications, must be suited for a wide range of pressure ratios and flow rates. To overcome difficulties arising from the design and performance prediction of this class of turbomachinery, many researchers have proposed coupling Computation Fluid Dynamics (CFD) codes and optimization algorithms for fast and effective design procedures. However, uncertainties are present in most engineering applications such as turbomachines, and their influence on performance should be assessed. In this work, some advanced optimization techniques are applied to the blade optimization of a European Research Community on Flow, Turbulence and Combustion (ERCOFTAC)-like pump, and the robustness of the optimal profiles through an uncertainty quantification study is assessed. Two primary sources of uncertainty are considered: (i) equipment uncertainties, primarily the rotational speed of the pump shaft that also affects the flow rate; and (ii) uncertainties in the inlet turbulence quantities in CFD simulations.

Improvement of Reliability and Ecological Safety of NPP Reactor Coolant Pump Seals

The paper presents the analysis of existing designs of NPP reactor coolant pumps (RCP) rotor sealing systems. The most common design solutions of sealing units that provide the necessary tightness, reliability and service life under high pressure, temperature and sliding speeds typical for RCP, as well as trends for their improvement to increase tightness and environmental safety of activities were identified.
 Designs of impulse seals with a self-adjusting clearance are presented as the most promising assemblies for sealing pump shafts with high parameters. A computer model of impulse mechanical seal as an automatic control system is proposed. A framework for calculating impulse mechanical seals has been developed, allowing the choice of their main geometric parameters to ensure the optimal value of the mechanical clearance and the friction moment on the sealing contact surfaces. Expressions are obtained for constructing the static and flow characteristics of a impulse mechanical seal, the condition for its dynamic stability is determined. The paper presents the shaft sealing system of RCP, main nodes of which are several stages of impulse mechanical seals with a self-regulating clearance.

Aspects of Utilizing Burnishing for Reconditioning Machine Components

Abstract The paper presents exemplary application of burnishing treatment as a technological process of reconditioning machine components. Empirical research of burnishing treatment was conducted on the most common cylindrical surfaces which are widely used in machine construction, for example in drive shafts of centrifugal pumps. Experimental tests were carried out and determined the influence of burnishing technology on strengthening the surface layer of cylindrical samples made of unalloyed C45stainless steel. Burnishing was conducted by means of NK-01 roller burnisher, made in the Department of Marine Maintenance at Gdynia Maritime University. The burnishing is normally applied in manufacturing as well as reconditioning machine elements used in machine industry, metallurgic industry, power engineering industry or shipping and aviation industry where the safety and reliability of machine work is decisive.

Study of Dual Stator Induction Motor in Photovoltaic-Fuel Cell Hybrid Pumping Application

This paper discusses the modeling of hybrid Photovoltaic/Fuel cell pumping. This system comprises a photovoltaic generator and a fuel cell, two DC/DC converters, two of inverters which supply a double star induction motor (DSIM) which drives the shaft of a centrifugal pump. The evaluation of the water requirements, the total dynamic head (TDH) and the flow are of great importance to evaluate the various powers allowing the determination of the size of the pumping system. The global proposed system is sized and simulated under Matlab/Simulink Package. The obtained results under different metrological conditions show the effectiveness of the proposed hybrid pumping system.

Metallographic Analysis of Stainless Steel Inner Shaft of Centrifugal Pump

The paper focuses on the metallographic analysis of the damaged inner shaft of a centrifugal pump with a magnetic clutch. This pump was used for the pumping of viscous suspensions. The damaged part of the centrifugal pump was made of stainless steel and transmitted power from the magnetic clutch to the impeller of the pump. The pump was overhauled by the Manufacturer after ten years of routine work. Slightly worn parts of the pump, including the inner stainless steel shaft, were replaced by the Manufacturer according to the preserved documentation. The overhauled pump failed after two days of running in the original conditions. The problematic is solved by an analysis of three used inner shafts with the aid of a metallographic analysis of the microstructure of the material, using light microscopy and scanning electron microscopy, and an EDS microanalysis of the chemical composition and hardness measurements.