Pump Casing Research Articles

Poor state of irrigation statistics in India: the case of pumps, wells and tubewells

Groundwater is the main source of irrigation in India, but there is a huge uncertainty about the number of groundwater structures. This paper compares data from four government sources on wells and tubewells, diesel pumps and electric pumps for time periods from the mid-1980s to the mid-2000s. There is a wide divergence in data, which is not attributable to mere time lags or definitional differences. This is a cause for concern, because lack of reliable estimates of these numbers affects realistic calculations of important variables such as groundwater extraction, electricity subsidies, and the carbon footprint of agricultural groundwater use.

Simultaneous effects of magnetic field and space porosity on compressible Maxwell fluid transport induced by a surface acoustic wave in a microchannel

Peristaltic motion induced by a surface acoustic wave of a viscous, compressible and electrically conducting Maxwell fluid in a confined parallel-plane microchannel through a porous medium is investigated in the presence of a constant magnetic field. The slip velocity is considered and the problem is discussed only for the free pumping case. A perturbation technique is employed to analyze the problem in terms of a small amplitude ratio. The phenomenon of a “backward flow" is found to exist in the center and at the boundaries of the channel. In the second order approximation, the net axial velocity is calculated for various values of the fluid parameters. Finally, the effects of the parameters of interest on the mean axial velocity, the reversal flow, and the perturbation function are discussed and shown graphically. We find that in the non-Newtonian regime, there is a possibility of a fluid flow in the direction opposite to the propagation of the traveling wave. This work is the most general model of peristalsis created to date with wide-ranging applications in biological, geophysical and industrial fluid dynamics.

Modelling dynamic behaviour and noise generation in gear pumps: Procedure and validation

The paper presents a methodology for noise and vibration analysis of gear pumps and its application to an external gear pump for automotive applications. The methodology addresses the use of a combined numerical model and experimental analyses. The combined model includes a lumped-parameter model, a finite-element model and a boundary-element model. The lumped-parameter (LP) model regards the interior parts of the pump (bearing blocks and gears loaded by the pressure distribution and the driving torque), the finite element (FE) model regards the external parts of the pump (casing and end plates), while the boundary element (BE) model enables the estimation of the emitted noise in operational conditions. Based on experimental evidences, attention has been devoted to the modelling of the pump lubricant oil: the fluid–structure interaction between the oil and pump casing was taken into account. In the case of gear pumps all these important effects have to be considered in the same model in order to take their interactions into account. The model has been assessed using experiments: the experimental accelerations and acoustic pressure measured in operational conditions have been compared with the simulated data coming from the combined LP/FE/BE model. The combined model can be considered a very useful tool for design optimisation.

Research on Rapid Manufacturing Technology of Complicated Casting Mold without Pattern

In 21th century, the product upgrading becomes faster and faster. The development of varieties of production needs rapid manufacturing technology. The rapid fabrication of sand mold & core is the key of rapid casting. In this paper, the rapid manufacturing technology without pattern was applied to produce the complicated sand molds & cores of pump case. The digital precision forming technology without pattern casting was selected to mill the outer sand mold. And the Selective Laser Sintering (SLS) technology was used to print the sand core. So the complicated sand molds and cores were fabricated rapidly without pattern. As a typical digital manufacturing technology, the rapid manufacturing technology without pattern has a variety of benefits such as short cycle, low cost, flexibility and so on. The technology that combines the sand milling and SLS provides a high-efficiency method for the Single and small batch castings.

Parametric Amplification and Cascaded-Nonlinearity Processes in Common Atomic System

For the first time, we study the parametric amplification process of multi-wave mixing (PA-MWM) signal and cascaded-nonlinearity process (CNP) in sodium vapors both theoretically and experimentally, based on a conventional phase-conjugate MWM and a self-diffraction four-wave mixing (SD-FWM) processes, which are pumped by laser or amplified spontaneous emission (ASE), respectively. For laser pumping case, SD-FWM process serves as a quantum linear amplifier (a CNP) out (inside) of the resonant absorption region. While for ASE case, only the CNP occurs and the output linewidth is much narrower than that of the MWM signal due to the second selected effect of its electromagnetically induced transparency window. In addition, the phase-sensitive amplifying process seeded by two MWM processes is discussed for the first time. Theoretical fittings agree well with the experiment. The investigations have important potential applications in quantum communication.

Second harmonic generation in isotropic media: six-wave mixing of optical vortices

Optical vortex light can be up-converted into a second harmonic output in an isotropic medium, in which such conversion is normally forbidden, through six-wave mixing. The involvement of orbital angular momentum is tackled for the case of a Laguerre-Gaussian pump comprising l = 1 photons. By calculating quantum amplitudes for the emergent radiation states, utilizing a state-sequence method, the analysis identifies the characteristics of the emission and an entangled distribution of conserved orbital momentum. A distinctive conical spread affords a potential means of resolving the individual angular momentum content.

The Spiral Groove Bearing as a Mechanism for Enhancing the Secondary Flow in a Centrifugal Rotary Blood Pump

The rapid evolution of rotary blood pump (RBP) technology in the last few decades was shaped by devices with increased durability, frequently employing magnetic or hydrodynamic suspension techniques. However, the potential for low flow in small gaps between the rotor and pump casing is still a problem for hemocompatibility. In this study, a spiral groove hydrodynamic bearing (SGB) is applied with two distinct objectives: first, as a mechanism to enhance the washout in the secondary flow path of a centrifugal RBP, lowering the exposure to high shear stresses and avoiding thrombus formation; and second, as a way to allow smaller gaps without compromising the washout, enhancing the overall pump efficiency. Computational fluid dynamics was applied and verified via bench-top experiments. An optimization of selected geometric parameters (groove angle, width and depth) focusing on the washout in the gap rather than generating suspension force was conducted. An optimized SGB geometry reduced the residence time of the cells in the gap from 31 to 27 ms, an improvement of 14% compared with the baseline geometry of 200 μm without grooves. When optimizing for pump performance, a 15% smaller gap yielded a slightly better rate of fluid exchange compared with the baseline, followed by a 22% reduction in the volumetric loss from the primary pathway. Finally, an improved washout can be achieved in a pulsatile environment due to the SGB ability to pump inwardly, even in the absence of a pressure head.

A plan for safety and integrity of research reactor components

Safety and integrity of a research reactor that has been operated over 40 years requires frequent and thorough inspection of all the safety-related components of the facility. The need of increasing the safety is the need of improving the reliability of its systems. Diligent and extensive planning of in-service inspection (ISI) of all reactor components has been imposed for satisfying the most stringent safety requirements. The Safeguards Officer's responsibilities of Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code ASME Code have been applied. These represent the most extensive and time-consuming part of ISI program, and identify the components subjected to inspection and testing, methods of component classification, inspection and testing techniques, acceptance/rejection criteria, and the responsibilities. The paper focuses on ISI planning requirements for welded systems such as vessels, piping, valve bodies, pump casings, and control rod-housing parts. The weld in integral attachments for piping, pumps, and valves are considered too. These are taken in consideration of safety class (1, 2, 3, etc.), reactor age, and weld type. The parts involve in the frequency of inspection, the examination requirements for each inspection, the examination method are included. Moreover the flaw evaluation, the plan of repair or replacement, and the qualification of nondestructive examination personnel are considered.

Effect of Magnetic Field and Porosity on Peristaltic Flow of Micropolar Fluid

In this paper, the peristaltic flow of micropolar fluid in a flexible tube with viscoelastic is studied under effect of magnetic field and porosity. The Runge-Kutta method is used to solve the governing equations of motion resulting from a perturbation technique for small values of amplitude ratio. The time mean axial velocity profiles are presented for the case of free pumping and analyzed to observe the influence of porosity and magnetic field for various values of radial r and wave numbe. The numerical results of the time mean velocity profile are discussed in detail for homogeneous fluid under effect of magnetic field and porosity for different cases by figures. The results indicate that the effect of porosity and magnetic field are very pronounced. Numerical results are given and illustrated graphically.

Long-range parametric amplification of THz wave with absorption loss exceeding parametric gain

Optical parametric mixing is a popular scheme to generate an idler wave at THz frequencies, although the THz wave is often absorbing in the nonlinear optical material. It is widely suggested that the useful material length for co-directional parametric mixing with strong THz-wave absorption is comparable to the THz-wave absorption length in the material. Here we show that, even in the limit of the absorption loss exceeding parametric gain, the THz idler wave can grows monotonically from optical parametric amplification over a much longer distance in a nonlinear optical material until pump depletion. The coherent production of the non-absorbing signal wave can assist the growth of the highly absorbing idler wave. We also show that, for the case of an equal input pump and signal in difference frequency generation, the quick saturation of the THz idler wave predicted from a much simplified and yet popular plane-wave model fails when fast diffraction of the THz wave from the co-propagating optical mixing waves is considered.

Strength Analysis of Decompression Tower Bottom Pump's Pump Casing Based on Fluid-solid Coupling

Decompression tower bottom pump is the important equipment in oil refining equipment.The finite-element analysis based on fluid-solid coupling is used to check pump casing' reliability.The three-dimensional models include pump casing and fluid domains in pump are made by Pro/Engineer.The meshes of fluid domains in pump are made by ICEM-CFD.The steady flow field inside pump which include front pump cavity and back pump cavity is calculated numerically by CFX.The flow field and pump casing are singly fluid-solid coupling calculated by CFX and ANSYS Workbench.Every panel point's coordinate,stress and total deformation are exported by the post processing tool of ANSYS Workbench.The pump casing's stress distribution cloud pictures and the pump body's total deformation distribution cloud pictures in five working conditions of different flows are gotten.The maximum stress point's location and the maximum total deformation's location in five working conditions of different flows are comparisoned through table.The maximum stress,the minimum stress,the maximum strain,the minimum strain and the maximum total deformation are compared through table.The result show that the pump casing's stress distribution and strain distribution is scarcely changed in different flows.The maximum stress of the pump casing is less than 2Cr13's limit strength.Pump casing fit the strength requirement.

Numerical Simulation on the Performance of a Mixed-Flow Pump under Various Casing Structures

With regard to the reactor coolant pump and high flow-rate circulating pump, the requirements on the compactness of the structure, safety, and hydraulic performance are particularly important. Thus, the mixed-flow pump with cylindrical casing is adopted in some occasions. Due to the different characteristics between the special cylindrical casing and the common pump casing, the influence of the special casing on a mixed-flow pump characteristics was numerically investigated to obtain better performance and flow structure in the casing. The results show that the models with cylindrical casing have much worse head and efficiency characteristics than the experimental model, and this is caused by the flow in the pump casing. By moving the guide vanes half inside the pump casing, the efficiency gets improved while the low pressure zone at the corner of outlet pipe and pump casing disappeared. When the length of pump casing increases from the size equal to the diameter of outlet pipe to that larger than it, the efficiency drops obviously and the flow field in the outlet pipe improved without curved flow. In addition, the length of the pump casing has greater impacts on the pump performance than the radius of it.

Six Sigma Implementation to reduce rejection rate of Pump Casings at local Manufacturing Company

Six Sigma is being Implemented all over the World as a successful Quality Improvement Methodology. This article provides a description of Six Sigma Project implemented at Local manufacturing Company. The Company Manufactures Pump Casings where it was receiving high nonconformance rate that resulted in to Rejection of Product. This study deals with Six Sigma DMAIC methodology implementation and gives a frame work of how the non-conformance rate was first monitored and then brought in to acceptance limits. A complete Coverage of the statistical analysis performed during the study is given and results are shown to describe that how Six Sigma helped the Project members to Improve Quality of Pump casings at manufacturing facility. Keywords: Statistical Process Control (SQC), Process Capability Indices, Six Sigma, Variable control chart, Pareto charts, Standard deviation, Critical to Quality (CTQ), Analysis of Variance (ANOVA), DMAIC, Total quality Management (TQM)

Study on key technologies of energy-saving and environment-protective pumps

To meet energy-saving and environment-protective purpose, a series of plastic pumps are developed by composite molding. There are four key techniques involved, firstly, plastic hydraulic components with light-weight; secondly, steel barrel as a pump casing and a connection component as well; thirdly, floating impeller strategy where impeller is drifting freely along shaft; and lastly, a self balancing impeller technique which can totally keep axial force balancing. The manufacturing process is energy-saving, and the components can be recycled, which have great potentials for conservation of environment.

Solar Application for Transfer of Technology - A Case of Solar Pump

Agriculture requires energy as an important input to production. Agriculture consumes about 35 per cent of the total power generated through electrically operated pump sets. It is expected that about 30 per cent of savings is possible through appropriate technology. Agriculture uses energy directly as fuel or electricity to operate machinery and equipment, to heat or cool buildings, and for lighting on the farm, and indirectly in the fertilizers and chemicals produced off the farm. Agricultural technology is changing rapidly. Farm machinery, farm building and production facilities are constantly being improved. Agricultural applications suitable for photovoltaic (PV) solutions are numerous. These applications are a mix of individual installations and systems installed by utility companies when they have found that a PV solution is the best solution for remote agricultural need such as water pumping for crops or livestock. A solar powered water pumping system is made up of two basic components. These are PV panels and pumps. The smallest element of a PV panel is the solar cell. Each solar cell has two or more specially prepared layers of semiconductor material that produce direct current (DC) electricity when exposed to light. This DC current is collected by the wiring in the panel. It is then supplied either to a DC pump, which in turn pumps water whenever the sun shines ,or stored in batteries for later use by the pump. The aim of this article is to explain how solar powered water pumping system works and what the differences with the other energy sources are.

Application Research on Power Plant Heat Pump Regenerative Thermal System

To recycle waste heat from circulating water, the model of the power plant heat pump regenerative thermal system is put forward, and the indexes of the system are analyzed. It is indicated in the specific case that the absorption heat pump has an advantage over the compression heat pump. Using the extraction steam of the low pressure cylinder as its driving heat source, economize on coal can be realized in the condition that the coefficient of performance(COP) of the heat pump is above the critical COP. For the case of the compression heat pump, the fuel efficiency is improved a little, but on the other hand, as the station service power is increased, the power supply coal consumption is increased too.

Numerical simulation on dimension decrease for annular casing of one centrifugal boiler circulation pump

Primary formulation derivation indicates that the dimension of one existing centrifugal boiler circulation pump casing is too large. As great manufacture cost can be saved by dimension decrease, a numerical simulation research is developed in this paper on dimension decrease for annular casing of this pump with a specific speed equaling to 189, which aims at finding an appropriately smaller dimension of the casing while hydraulic performance and strength performance will hardly be changed according to the requirements of the cooperative company. The research object is one existing centrifugal pump with a diffuser and a semi-spherical annular casing, working as the boiler circulation pump for (ultra) supercritical units in power plants. Dimension decrease, the modification method, is achieved by decreasing the existing casing's internal radius (marked as "Ri0") while keeping the wall thickness. The research analysis is based on primary formulation derivation, CFD (Computational Fluid Dynamics) simulation and FEM (Finite Element Method) simulation. Primary formulation derivation estimates that a design casing's internal radius should be less than 0.75 Ri0. CFD analysis indicates that smaller casing with 0.75 Ri0 has a worse hydraulic performance when working at large flow rates and a better hydraulic performance when working at small flow rates. In consideration of hydraulic performance and dimension decrease, an appropriate casing's internal radius is determined, which equals to 0.875 Ri0. FEM analysis then confirms that modified pump casing has nearly the same strength performance as the existing pump casing. It is concluded that dimension decrease can be an economical method as well as a practical method for large pumps in engineering fields.

Dissipative dynamics of a driven two-level quantum dot interacting with a structured reservoir with two-peaked spectrum

In this paper, we investigate the dissipative dynamics of a driven two-level quantum dot weakly coupled with a structured reservoir that is characterized by a double-peaked spectral function. We discuss the time-dependent dissipation coefficients and the Bloch vector by using a time-local non-markovian master equation. It is shown that the decay rates display temporarily negative values that can be manipulated by the distance between the two peaks in the spectral function. For the strong pumping case, the nonsecular effect gives rise to the non-markovian dynamics of the Bloch vector. However, for the weak pumping case, the non-markovian dynamics show up when contributions from secular and nonsecular terms are comparable. In the long time limit, the signature of non-markovian dynamics disappears and the behavior obeys Fermi’s golden rule.

Development and Application of Repairing and Protection Technologies for Desulfurization Pump

Gypsum and slurry with high content of Cl- lead to the damage of desulfurization pump caused by erosion and corrosion. Gas tungsten arc welding (GTAW) and shield metal arc welding (SMAW) were employed to develop weld repairing technology. High-velocity oxygen fuel (HVOF) spraying was employed to prepare NiCr cermet coating and WC cermet coating against erosion and corrosion. Microstructures and mechanical properties of the weld and the protective coatings were tested. The mechanical properties of the weld joints with duplex microstructure were in accordance with related standards. The technology of HVOF sprayed NiCr cermet coating was selected to prolong the service lifetime and was applied on the pump casing and impeller repaired by using the weld repairing procedures developed in this study. The integrity of the pump parts after 30 months in-field service confirmed the reliability of the repairing technology and the protection technology.

Enhanced neutral depletion in a static helium helicon discharge

Laser-induced fluorescence (LIF) measurements of plasma opacity are used as a novel diagnostic to determine the absolute density of a metastable state of neutral helium atoms in a helicon plasma. The absorption scale length at a wavelength of 587.725 nm (vacuum) is determined from measurements of fluorescence intensity as a function of distance along the laser path. With a collisional–radiative model of the state populations, the absolute ground state neutral helium density is estimated from the metastable state density measurement. This paper expands upon previous work through measurements of neutral density, temperature and flow at different radial positions. The measured neutral density decreases by two orders of magnitude from the edge of the plasma to the axis of the plasma source. When the helicon source is operated in a static mode (i.e. no active gas pumping) the on-axis neutral density decreases by 69% from the pumping case and the on-axis plasma density increases by 42%; yielding an ionization fraction of approximately 90%.