Pump Shaft Research Articles

Strength analysis of the intermediate shaft of the hypocycloidal fuel pump

Diesel engines are currently characterized by very high injection pressure. The high pressure allows to achieve better parameters of the fuel atomization process, thus contributing to the improvement of the engine’s ecological parameters. Achieving such a high pressure is possible thanks to the use of reciprocating positive displacement pumps, enabling the fuel pressure to be increased up to 3000 bar. A common feature of currently produced pumps is the drive of the pressing sections through the camshaft, which is lubricated using fuel. For this reason, cam-driven pumps are very sensitive to the quality of the fuel used, and one of its disadvantageous features is also the generation of lateral force on the piston of the section. For this reason, the authors of the article have developed a pump solution, using a hypocycloid drive, in which the disadvantages of traditional cam-driven pumps have been eliminated. The hypocycloid mechanism used has a separate lubrication system, and due to the generated rectilinear motion only the force parallel to the direction of the movement works on the piston. An important problem in the construction of a hypocycloid pump is the high loads of cooperating elements. The intermediate pump shaft is considered to be the most loaded element due to the complex state of stress. The article presents the methodology and results of simulation tests. Stress states have been determined for the position of the shaft in which it takes the highest load. As a result, it was recognized that the pump shaft was designed properly and despite the high force acting on the piston section, it is possible to ensure its long-term and reliable operation.

Investigating the Fuel Type Influence on Diesel CR Pump Performance

The paper presents an experimental investigation on a three-plunger radial pump for diesel common rail injection systems.The effort is aimed at highlighting the influence on the pump torque demand due to the use of an unconventional fluid, focusing the attention on a pump model typically adopted in the field of light duty diesel engines.Pump performances have been measured on a fuel injection system test-bed. A relatively wide operation range of the pump has been considered, in terms of fuel delivery pressure and pump shaft regime, providing torque demand at each operating point. Once the experimental characterization has been completed for the standard fuel (ISO 4113 reference fuel), a Waste Cooking Oil (WCO) biodiesel fuel has been tested, at the same pump operation conditions. In the present study, the influence of such alternative fuel on pump operation has been investigated. After the description of the experimental set-up, results have been presented and discussed, highlighting the influence of the fuel type in terms of torque demand.

Fluid-dynamic analysis of an in-line water piston pump

The paper focuses on the analysis of inline water piston pumps, by means of simulation of the fluid-dynamic behaviour and experimental characterization. These pumps are commonly used on the car wash systems, industrial washes systems and fire protection systems. They possess a robust architecture, made of a typical rod-crankshaft mechanism, which transforms the circular motion of the pump shaft in the reciprocating displacement of the piston. The pump analyzed in the paper, in particular, moves three pistons, shifted one another of 120°; each piston sucks from a tank and delivers water to a hydraulic line via automatic, spring loaded, poppet valves. The shaft, rod and other movable components are lubricated with mineral oil; the three ceramic pistons are isolated from this environment using opportune seals and work with water. This pump is robust and durable but suffers of some problems: the instantaneous pressure trend within each piston is ideally a square wave: the pressure is equal to the tank pressure during suction, while it is equal to the delivery pressure during the delivery phase. Instead, non –ideal behaviour of the poppet valves, leakages, fluid properties make the pressure trend more critical: during the pressure transient between the two high and low levels, pressure peaks and de-pressurization till aeration and cavitation occurrence may happen. These phenomena generate vibrations and noise and can damage the pump components. In order to study this, a lumped parameter fluid dynamic model of the pump has been realized, later compared with experimental results coming from the test rig to validate it. The model has been used to explore the dynamic pump behaviour in several operating conditions (various speed values and delivery pressure levels), calculating the flow irregularity, the pressure and forces instantaneous trends. The design characteristics of the poppet valves have been explored, in particular the spring characteristics, to discuss the trend of the previous variables.

A New Structural Dynamic Model for Pump Mechanical Seals Vibration Analysis Incorporating Squeeze Motion of O-Ring Seals and General Dynamic Motion of the Pump Housing and the Pump Shaft

New models are developed for flexibly mounted stator (FMS) and flexibly mounted rotor (FMR) mechanical seals that incorporate the radial reaction force components produced by supporting O-rings due to relative squeezing motion across the O-rings. Supporting data come from tests done in relation to O-ring supports for ball bearing races. The reaction-force model is linear but a nonlinear function of excitation frequency. The model accounts for the axial displacement doz of the O-ring from the mass center of the seal stator (FMS configuration) or seal rotor (FMR configuration), which couples the radial and pitch–yaw motion of the model's stiffness and damping matrices. Greens' coned-face-seal model is used to define the reaction moment arising across the seal faces via stiffness and damping matrices. The damping matrix does not coincide with Green's. His is constant; the matrix developed here contains terms that are harmonic at twice theprecession frequency. When averaged over one precession cycle, the new average damping matrix coincides with Green's result. When the averaged damping matrix is used, the resultant model is linear. However, because of the viscoelastic reaction-force and reaction-moment models used for the O-ring coefficients, most of the stiffness and damping matrices are strong functions of the assumed precession frequency. The new FMR model contains a skew-symmetric stiffness matrix due to the O-ring damping terms. In rotordynamics, skew symmetric stiffness matrices due to internal damping in the rotor can lead to rotordynamic instabilities.

Cause Analysis of Booster Pump Shaft Cracking in Nuclear Power Plant

The cracking Booster pump shaft is carried out macroscopic examination, crack analysis, metallographic examination, chemical composition analysis, mechanical properties (tensile, impact) analysis, and combined with the pump shaft installation and operation, determine the direct cause of shaft cracking is crevice corrosion, the root cause include O ring in booster pump machine seal sleeve does not meet the requirement, O ring installation damage, and the clearance between pump shaft and machine seal sleeve is too small. According to the root cause of the pump shaft cracking, relevant corrective actions have been formulated, such as changing model of O ring in booster pump machine seal sleeve, change the clearance between pump shaft and machine seal sleeve, increase anti-corrosion coating or protective sleeve on pump shaft etc.

Study of volute cutwater diameter on the structural strength of pump rotor

Based on the Workbench platform, temperature and pressure loads are applied to the rotor system (impeller, pump shaft and impeller nut) in high temperature hot water circulating pump when the medium temperature is 150 ° C. The corresponding boundary conditions are defined, and steady-state thermal analysis and static analysis are carried out. The temperature distribution, the equivalent stress and the total deformation of the rotor system is discussed in detail when the volute cutwater diameter is 214mm, 216mm and 218mm. The results show that the deformation of impeller, pump shaft and impeller nut has the maximum value when cutwater diameter is 216mm. With the increasing of cutwater diameter, the minimum temperature and maximum equivalent stress of the impeller decreases gradually. There is an obvious stress concentration in the shaft shoulder which is from bearing fitting section to the maximum shaft diameter.

Failure analysis on premature fracture of boric acid recycle pump shaft in 1000 MW nuclear power plant

Abstract Boric acid recycling pump is used to maintain the circulation of boric acid solution for the need of nuclear safety protection. In a boric acid recycling pump, the pump shaft is an important component. As it is exposed to relatively harsh work environment, the pump shaft may encounter severe failures. In this paper, premature fracture of the pump shaft, happened after the pump serving only one year in a 1000 MW nuclear power plant, was carefully investigated. In order to find out the root cause of the failure, material identification, metallographic inspection, mechanical property test, wear and fractographic observation, micro-zone analysis and mechanism analysis were carried out. The obtained results indicated that triple stress concentration, caused by the small transition arc radius, surface defects and the aggregation of inclusions, was the primary reason. It resulted in the nucleation and coalescence of micro-cracks and consequently lead to the premature fracture. Countermeasures were then put forward to solve corresponding problems.

МODERNIZATION TECHNOLOGY REPAIRING ACENTRIFUGAL WATER PUMP

The article provides an overview of the principle of the pump D630-90, as well as methods for studying the real conditions of technical support to improve maintainability and optimize technological processes and systems. A technological process for the restoration of the shaft of a centrifugal water pump has been developed and an algorithm for managing it has been proposed, on the basis of which the system for energy-efficient management of the recovery area has been implemented. Also in the article some questions of use, metal-filled compound SK812, and also application of ultrasonic processing of a surface of a shaft of the centrifugal water pump of mark D630-90 are mentioned and considered. The developed technological process of pump shaft restoration showed that it is characterized by simplicity, it fits well into the production process of repair and can be widely used in repair shops.

An experimental study of the wave effect in fuel equipment using hydrogen additives to diesel fuel

The object of research is the hydrodynamic wave effects in the fuel equipment of high pressure diesel engines. One of the most problematic phenomena when using hydrogen additives to diesel fuel is the change in the maximum fuel injection pressure, which leads to deterioration of fuel separation parameters. For research on the nature of hydraulic oscillations in the fuel equipment, an experimental booth has been created that allows the study of the wave effect with the use of small additives of hydrogen to the main fuel. In the development of an experimental stand, modern precision measuring instruments were used. According to the results of experimental studies, it is established that in the high pressure fuel line a characteristic «wave effect» of oscillations appears. This effect is caused by the landing of the pressure valve on the saddle in the fuel pump of high pressure, as well as the landing of the needle nozzle. The nature of the oscillation depends on factors such as the length of the pipeline between the pump and the nozzle, the maximum injection pressure of diesel fuel, the speed of propagation of the pressure wave. This speed, in turn, depends on the frequency of rotation of the crankshaft of the engine. The frequency of rotation of the fuel pump shaft is changed with the help of an inverted regulator and frequency meter of the drive motor. As a result, the fuel injection characteristics are obtained, which reflect the nature of the change in the pressure wave, depending on the presence of hydrogen additive. It is determined that the hydrogen additive in the amount of 0.1 % of the cycle fuel supply (by mass) leads to the suppression of wave oscillations and the shortening of the oscillation region by 12...20. The characteristics of absorption of hydrogen by diesel fuel are obtained. The amount of hydrogen additive depends on the pump rotation frequency, the injection pressure and the supply pressure of the additive. This kind of hydrogen consumption is explained by the time frame of the restriction of the absorption process, the difference in the minimum value of the «pressure wave» of the excess pressure of the additive. The resulting data can be used to confirm the mathematical model of hydrogen absorption when used as an additive to the fuel line.

Simulation of Modified TRIGA-2000 with Plate-Type Fuel under LOFA Using EUREKA2/RR-Code

The TRIGA-2000 research reactor in Bandung, Indonesia, has operated for over 50 years. Recently, the problem of fuel availability arises, since its fuel is no longer produced. A modification of reactor core with new plate-type fuel has been suggested . The study of the neutronic assessment of plate-type fuel elements reactor core had been done. The next assessment that needed to be done was thermal-hydraulic analysis. The purpose of this study is to simulate the thermal-hydraulic characteristics of major parameters, such as reactor power, fuel cladding temperature, and departure from nucleate boiling ratio (DNBR) due to LOFA transient, using EUREKA2/RR code. During steady-state condition, downward flow forced convection mode for core coolant system is operated. The upward flow occurs when the natural circulation mode takes place. Hottest core channels temperature during LOFA conditions was considered. The reactor core was modeled as three channels, i . e ., the hottest channel, the average channel, and the channel for control assemblies, respectively. The s imulation was based on the steady-state condition of 2 M W t reactor power, cooling mass flow rate of 63.5 kg/s , and inlet coolant temperature to the core of 3 5.5 °C. The result shows that the hottest fuel cladding temperature does not cause a nucleate boiling. During LOFA, the residual heat was removed by natural circulation flow that occurred slowly. In order t o have larger inertia force , provision of the flywheel in the shaft of primary coolant pump is suggested.

Preliminary results of the study of the effect of a multi-cycle load on the hardness of a high-pressure fuel pipe

Investigation of the effect of internal pressure on the distribution of hardness in the fuel pipe wall was conducted. In the high pressure circuits of Common Rail systems, the fuel pressure is much higher than the pressure level in conventional fuel systems. Thas is why it is of practical interest to change the mechanical properties of the component materials during operation. In the present work, an attempt was made to evaluate the influence of the multi-cycle loading of the fuel pipe with a high internal pressure on the hardness of the material from which the fuel line was made. The loading was carried out under the conditions of a non-motorized test bench with a pressure of diesel fuel of 160 MPa. The test duration was 500 hours. With the selected pump shaft speed and the response frequency of the electrohydraulic control valves this was equivalent to approximately 96x106 cycles. Before and after the tests, hardness measurements were made in the cross section of the fuel lines. The distributions of hardness values are obtained, which testify the existence, under the given loading conditions of a self-hardening process of the material. In the initial state, fuel lines are characterized by a certain anisotropy of hardness and, accordingly, strength characteristics. In this case, the inhomogeneity of the field of values of hardness decreases with decreasing radius of location of the material layer. Dispersion of hardness values takes place both along the axis of the fuel pipe and in the circumferential direction. Loading of fuel pipes of the Common Rail type with pulsating hydraulic pressure leads to a redistribution of the hardness values in the fuel pipe wall. It is found that in the layers of material located closer to the central channel of the fuel pipe, the hardness equalization occurs to a greater extent as it is used, than in layers located far from the central channel. In general, the hardness is increased, which can be interpreted as the hardening of the fuel line during operation.

Vibration Mode and Influence Analysis of Rotary Shaft for 200kW Tubular Pump

The pump rotary shaft’s vibration will influence pump unit’s work situation. The rotary shaft of 2200kW tubular pump is proceeded 3D FEM’s modeling analysis in this paper. Some benefit results are obtained by researching the vibration mode, resonance oscillation frequency and deformation. It will help design and apply the tubular pump, own the practical value.

Design and experimental verification of a port plate in a gerotor pump to reduce pressure pulsation

In a gerotor pump, pressure pulsation occurs in a chamber through contact with the internal and external rotors. This causes an overhung load on the pump shaft bearing and cavitation, which affect the durability and noise of the pump. In this study, relief grooves on the port plate were designed to reduce pressure pulsation and verified experimentally. The opening areas between the port plate and chamber with and without relief grooves were obtained. The relation between the pressure pulsation and relief grooves was examined through a simulation and verified experimentally. The results indicated that the relief grooves were very effective at reducing and stabilizing the pressure pulsation of the pump outlet and in the chamber. Thus, installing relief grooves on the port plate can improve the durability of the pump and allow the size of the motor coupled with the pump to be reduced.

Simulation of loss-of-flow transient in water cooled fission blanket of Fusion-fission Hybrid Energy Reactor (FFHER)

Fusion-fission hybrid reactor takes advantage of the best of both domains, fusion and fission, without needing a full development of fusion reactor, and without critical safety issues of fission reactor. However, decay heat still exists in fission blanket of hybrid rector in shutdown state, which will menace the safety of rector if it cannot be smoothly carried out. To testify the passive safety characteristics of fission blanket, the reactor coolant pump shaft seizure accident in fission blanket of FFHER, a fusion-fission hybrid reactor, is simulated. The model of passive residual heat removal system, as well as reactor coolant system, are built using software SCDAP/RELAP5 4.0. The analysis shows that the simulated system response is reasonable. In the SG domination stage, the peak fuel temperature keeps always below the limiting value. In the PRHR domination stage, three cases are simulated and compared to choose appropriate parameter. It is found that PRHR circulation can be rapidly established and transfer enough heat from blanket. The transition from SG domination to PRHR domination is smooth. From the simulation results, it can be concluded that PRHRS can provide sufficient blanket cooling capability in LOFA.

Failure Analysis of Shaft Circulating Water Pump (CWP) used in Power Plant

Pump shafts are generally exposed to the liquid being pumped either on a continual basis or at certain locations along the length of the shaft. The shaft material is austenitic stainless steel, description ASTM AU 79 TY 316. The purpose of this study is to determine the failure of the water pump shaft used in the power plant. Metallography is the study of structure metal shaft can used as a means for CWP metal pelleting (Circulating Water Pump), for the purpose of damaged or deeply degraded areas. SEM test is used to know the beginning of the crack (crack initiation). EDS test is used to chemical composition and Vikers hardness test is also used to know the hardness material. These three tests to support in analyzing the failure of the pump shaft. The conclusion of this failure analysis is the shaft material has porosity. Fatigue cracking comes from the outer surface area.

Effects of Arcor Nitrocarburizing Process on the Case Chemistry and Morphology of AISI 1018 Low-Carbon Steel

Industrial modern machinery components, such as gears, bolts, and shafts, are always subjected to continuous frictional wear. The wear resistance and cost of material are the two most important factors while selecting a material for such components. The conventional materials are costly, and there is always a quest for inexpensive materials. The designers mostly choose the low-cost, low-carbon steels. AISI 1018 is one such low-cost, low-carbon grade, which has been used extensively in high-volume screw machine parts applications and is commonly employed in spindles, pins, rods, sprocket assemblies, axles, bolts, connecting rods, motor shafts, hydraulic shafts, pump shafts, and machinery parts. However, the wider applications are restrained by their relatively poor wear and surface properties. This necessitates the need for research on these low-carbon, low-cost materials to address the problem. For decades, surface treatments have been performed to enhance the tribological properties of these components. Salt bath nitrocarburizing is one of the oldest methods and an economical method to improve the tribological properties, as well as the mechanical properties of materials. Unfortunately, in the present literatures, there is not much attention paid on treating AISI 1018 low-carbon steel. A nontoxic salt bath surface modification process nitrocarburizing (Arcor) in ferritic state is investigated on AISI 1018 low-carbon steel. It has been observed that with the increase in nitrocarburizing time and nitrocarburizing temperature, a significant enhancement in mechanical properties, like the hardness of the work material, has been found. Field Emission Scanning Electron Microscope (FESEM) investigations identified compound and diffusion regions on the surface of steel along with line scan elemental intensities.

A Brief Review on Machining of Inconel 718

Inconel 718 is a novel material introduced in the field of hard to machine material. As it has the ability to withstand tremendous environmental conditions, it is commonly used in combustors, turbocharger rotor and seals, heat exchangers, nuclear reactors, turbine blades, electric submersible well pump and motor shaft and high-pressure vessels. Due to its high strength to weight ratio it is also used in aeronautical and aerospace industry. In recent decade there is a growing demand for cost efficient and eco-friendly machining, many researcher are taking keen interest in development of more advance machining processes. During machining of hard to machine materials, the proper selection of machining processes and cooling conditions plays a vital role which affects the machining performance. This present review paper focuses on the brief description of different machining operations (turning, milling, and drilling) during machining of Inconel 718. In addition, comparison between different cooling environments (Dry, MQL and Cryogenic) and different aspects of cooling fluids are Presented. Experimental and theoretical observations for tool wear, surface roughness and machining temperature using different types of cutting inserts and cooling environments have been discussed.

Multiobjective Optimization Design and Performance Prediction of Centrifugal Pump Based on Orthogonal Test

In order to improve the hydraulic performance of the centrifugal pump, based on the original model, the optimization mathematical model with the four indexes head, efficiency, shaft power, and pump net positive suction head as objective function was established, and the multiobjective optimization design of the centrifugal pump was carried out by orthogonal test. Based on the L16(44) orthogonal table, 16 sets of orthogonal test schemes were made by selecting the four parameters impeller outlet width, blade inlet angle, blade outlet angle, and cape angle; the flow field numerical simulation was carried out by computational fluid dynamics technique; and the influence order of geometric parameters on optimization indexes was obtained by range analysis. The weight of each test factor on the optimization index was calculated by weight matrix, and a set of optimal schemes was obtained. Based on the external characteristic experimental bench of the IH 65‐60‐190 chemical centrifugal pump, the simulation values and test values of the prototype pump and the optimization pump were obtained under different working conditions. Under the rated flow, the head was reduced by 17.00%, the efficiency was increased by 9.14%, the shaft power was reduced by 21.50%, the pump net positive suction head was reduced by 16.69%, the curve hump was eliminated, the performance of centrifugal pump was improved, and the feasibility of the weight matrix optimization method was verified. The particle image velocimetry measurement system was used to measure the relative velocity of the internal media in the centrifugal pump. The results showed that the optimization pump had no obvious “jet‐wake” flow structure, its maximum velocity was less than the prototype pump, the area of low‐speed zone was larger than the prototype pump, the efficiency of the centrifugal pump was improved, and the shaft power and pump net positive suction head were reduced. The reason of the head decrease was analyzed from the internal flow situation, and the accuracy of the design optimization process was proved.

Fracture analysis of a cooling water pump shaft

Six shaft failures were encountered in a centrifugal water pump, part of the engine cooling system of a container ship. The last two failed pieces were received for analysis. A detailed study was carried out to determine the cause of the component failures. Historical data was collected, visual inspection was performed and a photographic file was created. The pieces were measured in order to record their general features and a 3-D model was generated. Hardness measurements were carried out. Microstructure was examined by means of light microscopy. A finite element simulation was conducted in order to determine the stress topology and to identify possible critical areas. Chemical analysis was carried out. The shafts were manufactured onboard, from AISI 304 stainless steel. The low hardness of both pieces indicates insufficient mechanical properties. Microstructural examination showed characteristic microstructure of coarse austenite. The presence annealing process derived twins and limited grain-boundary carbide precipitates were verified. The shafts failed due to torsional fatigue. Fracture initiated at the keyway on the propeller side as it was predicted from the finite elements analysis. Material selection material has and poor machining were found to be the main cause of failure. Appropriate recommendations were provided.

Numerical investigations of the flow induced oscillation of a torque converter

The flow induced oscillation of a three-element torque converter was investigated numerically under various operational conditions. A two-way coupling fluid–structure interaction simulation was performed using ANSYS-Fluent along with the ANSYS Transient Structural module. The fluid pressure excitation and the dynamic structure response were investigated at various turbine/pump rotation speed ratios . The maximum pressure blade load and structural deflections were observed in the stall condition, corresponding to the highest torque transmission ratio. The pressure pulsations and structure oscillations were monitored at locations selected on the basis of time-averaged distributions. The turbine oscillations were dominated by the frequency of pump blade passing at . The stator always oscillated under impact from the upstream flow with the dominating pump shaft frequency. Both the time-averaged and instantaneous features revealed that the pump oscillations were almost independent of SR.