Linear Pumps Research Articles

Development of a three-dimensional magnetohydrodynamics code for electromagnetic pumps

Annular linear induction pumps (ALIPs) are one of the electromagnetic (EM) pumps, which drive liquid metal using EM force, for fast reactors and have been developed in many countries. An ALIP mainly consists of multiple coils, iron cores and an annular flow channel. We have calculated the developed pressure of ALIPs using a two-dimensional magnetohydrodynamics (MHD) code. There are some reports in which pressure drop and fluctuation were observed in EM pump operations near the top of the pressure and flow rate relation (P–Q) curve. For fear of this phenomenon, the EM pump design is sometimes too conservative. To simulate the pressure drop and fluctuation occurrence conditions, we have developed a new three-dimensional (3D) MHD code. Clarification of this condition and its phenomena in the sodium flow will enable design of a new structure or determination of operation conditions that preclude this pressure drop and fluctuation and, thereby, achieve high efficiency. In this paper, the model of our new 3D MHD code, the accuracy of the code, simulation results focusing on pressure drop and fluctuation by radial and circumferential vortices are reported.

Design, in-sodium testing and performance evaluation of annular linear induction pump for a sodium cooled fast reactor

Annular linear induction pumps (ALIPs) are used for pumping electrically conducting liquid metals. These pumps find wide application in fast reactors since the coolant in fast reactors is liquid sodium which a good conductor of electricity. The design of these pumps is usually done using equivalent circuit approach in combination with numerical simulation models. The equivalent circuit of ALIP is similar to that of an induction motor. This paper presents the derivation of equivalent circuit parameters using first principle approach. Sodium testing of designed ALIP using the equivalent circuit approach is also described and experimental results of the testing are presented. Comparison between experimental and analytical calculations has also been carried out. Some of the reasons for variation have also been listed in this paper.

Conceptual Design and Composition Principles Analysis of a Novel Collaborative Rectification Structure Pump

In order to provide a solution of active rectification for linear pumps in pump control system, a novel collaborative rectification structure is conceptually designed in this paper. The fundamental subsystem is the direct drive pump cell (DDPC). A DDPC consists of a cylinder and a valve, and the piston rod and the valve spool are integrated together. The DDPC could be driven by a linear oscillating motor directly. The DDPC working process is logically modeled as a state machine. Certain theorems are given and proved to illustrate the composition principles of a pump system with collaborative rectification. The kinematic flow rate of the collaborative rectification pump is studied. According to the comparison to the existing linear pumps, the novel pump has more structure compactness and control flexibility.

Modeling of fully coupled mhd flows in annular linear induction pumps

The paper studies specific pumping characteristics of the Annular Linear Induction Pumps (ALIP) with travelling field for liquid sodium. The present work is focused on the analysis of very large electromagnetic pumps able to provide high flow rates. The magnetic Reynolds number is quite large, therefore, it is necessary to take into account the full magnetohydrodynamic interaction between the electromagnetic field and the liquid metal flow inside pump channel. We couple the electromagnetic aspects with the hydrodynamic ones by means of two commercial softwares. The geometry considered here is 2D axisymmetric. It is found that in such induction pumps the effect of convection is very important. Two main effects have been put forth. Firstly, due to the magnetic entrainment significant end effects are observed for large velocities. This leads to the existence of regions where the axial force is negative. Secondly, a Hartmann effect occurs near the walls. The electric current and the corresponding forces are confined near the wall in Hartmann layers. Global stability of e. m. pump is also analysed.

Sodium flow rate measurement method of annular linear induction pumps

Abstract The present paper proposes a method for measuring sodium flow rate of annular linear induction pumps. The feature of the method lies in measuring the leaked magnetic field with measuring coils near the stator end on the outlet side and in correlating it with the sodium flow rate. This method is verified through an experiment and a numerical analysis. The data obtained in the experiment reveals that the correlation between the leaked magnetic field and the sodium flow rate is almost linear. The result of the numerical analysis agrees with the experimental data. The present method will be particularly effective to sodium flow rate monitoring of each one of plural annular linear induction pumps arranged in parallel in a vessel which forms a large-scale pump unit.

Radial flow electroosmotic pump

This paper presents a radial frit geometry electroosmotic pump with a soft, semi-permeable gas venting membrane top. Radial pumps exhibit more than three times the average open flow rate per applied voltage and four times the average flow rate per sourced power than linear pumps for a given pump package volume. The radial pump can operate over a 16 h period with varying load.

Electroactive Elastomeric Actuator for All-Polymer Linear Peristaltic Pumps

This paper describes the concept of a lightweight and deformable structure with intrinsic distributed electromechanical actuation, potentially suitable to develop soft linear peristaltic pumps for incompressible fluids. The proposed system is represented by a series of radially expanding flexible tubular modules, made of dielectric elastomers (DEs), as one of the most promising classes of electroactive polymers for actuation. Each module consists of a cylindrical hollow DE actuator, working in purely radial mode with specific boundary constraints. The static electromechanical transduction performance of such a module was investigated analytically, numerically, and experimentally. For this purpose, predictions obtained from an analytical model, derived in the hypothesis of linear elasticity, were compared with those provided by a finite-element method. Both models were validated by means of a comparison with experimental data, obtained from a silicone-made prototype module. Results permitted to obtain a simple tool of simulation, suitable to predict the performance of the system in terms of both displaced volume and driving pressure, as a function of the material elastic modulus and the applied voltage.

리니어 펌프 구동용 하이브리드 전자기 리니어 엑츄에이터 해석 및 설계

리니어 펌프 구동용 하이브리드 전자기 리니어 엑츄에이터를 해석하고 설계하였다. 솔레노이드 엑츄에이터는 기계적인 에너지 변환장치가 필요하지 않기 때문에 공간을 많이 차지하지 않는 이점으로 인해 널리 사용되고 있다. 또한 에너지 손실이 매우 낮고 소음이 발생하지 않는 장점을 가지고 있다. 하지만, 솔레노이드 엑츄에이터는 전력소비가 크다는 단점을 가지고 있다. 이런 단점을 보완하여 전력소비를 줄이기 위하여 영구자석을 활용한 새로운 하이브리드 전자기 리니어 엑츄에이터를 제안하고 향상된 성능을 검증하기 위해 동적 유한요소 분석을 통해 시뮬레이션을 수행하였다. The purpose of this paper is to analyze and design a new hybrid electromagnetic linear actuator for linear pumps. Solenoid linear actuator is widely used because it occupies small space due to no mechanical energy conversion system. In addition, the energy loss is very low and it has no noise. Conventional solenoid linear actuator, however, has the critical drawback of high power consumption. In this research, we present a new hybrid electromagnetic linear actuator using a permanent magnet in order to reduce power consumption. The enhanced performance of the hybrid linear actuator was verified by dynamic finite element analysis.

ANALYSES OF ANNULAR LINEAR INDUCTION PUMP CHARACTERISTICS USING A TIME-HARMONIC FINITE DIFFERENCE ANALYSIS

The pumping of coolant in a liquid metal fast reactor may be performed with an annular linear induction electro-magnetic (EM) pump. Linear induction pumps use a traveling magnetic field wave created by poly-phase currents, and the induced currents and their associated magnetic field generate a Lorentz force, whose effect can be the pumping of the liquid metal. The flow behaviors in the pump are very complex, including a time-varying Lorentz force and pressure pulsation, because an induction EM pump has time-varying magnetic fields and the induced convective currents that originate from the flow of the liquid metal. These phenomena lead to an instability problem in the pump arising from the changes of the generated Lorentz forces along the pump's geometry. Therefore, a magneto-hydro-dynamics (MHD) analysis is required for the design and operation of a linear induction EM pump. We have developed a time-harmonic 2-dimensional axisymmetry MHD analysis method based on the Maxwell equations. This paper describes the analysis and numerical method for obtaining solutions for some MHD parameters in an induction EM pump. Experimental test results obtained from an induction EM pump of CLIP-150 at the STC "Sintez," D.V. Efremov Institute of Electro-physical Apparatus in St. Petersburg were used to validate the method. In addition, we investigated some characteristics of a linear induction EM pump, such as the effect of the convective current and the double supply frequency (DSF) pressure pulsation. This simple model overestimated the convective eddy current generated from the sodium flow in the pump channel; however, it had a similar tendency for the measured data of the pump performance through a comparison with the experimental data. Considering its simplicity, it could be a base model for designing an EM pump and for evaluating the MHD flow in an EM pump.

New representation for linear diaphragm pumps

New representation for linear diaphragm pumps

Comparison of computer codes for evaluation of double-supply-frequency pulsations in linear induction pumps

The paper describes and compares three computer codes that are able to estimate the double-supply-frequency (DSF) pulsations in annular linear induction pumps (ALIPs). The DSF pulsations are the result of interaction of the magnetic field and induced in liquid metal currents both changing with supply-frequency. They may be of some concern for electromagnetic pumps (EMP) exploitation and need to be evaluated at their design. The results of computer simulation are compared with experimental ones for annular linear induction pump ALIP-1.

More power options added to mobile vacuum pump range

The linear pumps in the Series 6000 from Rietschle Thomas can now be specified with 12 V and 24 V DC power options. In addition, there is also a new 24 V AC-version available to end-users in the scientific community who utilise battery power. Typical applications for the new range include fuel cells, portable gas analysers, portable aspirators and most other mobile applications in the laboratory. Visit www.worldpumps.com for the latest pump industry news

Two dimensional model for analysis of cylindrical linear induction pump characteristics: model description and numerical analysis

The paper describes a two dimensional numerical model for analysis of the local and integral characteristics of linear electromagnetic pumps, such as magnetic field distribution, pressure developed, amplitude of pressure pulsation with double supply frequency and distribution of liquid metal velocity over the azimuth. Numerical results are compared with experimental ones.

Configurations of a Flow Injection System for Perfusion Studies of Adherent Cells

This paper describes three configurations of a flow injection apparatus designed to be the fluidic drive for perfusion studies of cultured adherent cells. The apparatus was coupled to a flow-through perfusion chamber that was specifically designed for live cell perfusion using fluorescence microscopy as the detector. The instrument consists of two linear syringe pumps and a multiposition selector valve which, under computer control, allowed sequential injection, fluid switching, and flow injection to be performed with minimal system reconfiguration. When the apparatus is coupled to a dual inlet perfusion chamber, target cells can be exposed to very steep reagent pulses, while the traditional single inlet perfusion chamber allows more flexibility and provides a more gradual increase in reagent concentration. The most significant salient feature of the system is the ability to generate very steep pulses--a desirable feature for cell perfusion studies.

Accuracy of Intravenous Infusion Pumps in Continuous Renal Replacement Therapies

Most extracorporeal continuous renal replacement therapies (CRRT) require inflow pumping of either dialysate, filtrate replacement solution, or both. Outflow of spent dialysate and ultrafiltrate can be accomplished by gravity drainage or pump. Intravenous infusion pumps have been commonly used for these purposes, although little is known about the accuracy of these pumps. To evaluate accuracy of two different types of intravenous infusion pumps used in CRRT, we studied flow rates at nine different pressure variations in three piston type and three linear peristaltic pumps. The results showed that error of either pump was not different for flow rates of 4 and 16 ml/min. Both types of pumps were affected by fluid circuit pressures, although pressure conditions under which error was low were different for each pump type. The linear peristaltic pumps were most accurate under conditions of low pump inlet pressure, whereas piston pumps were most accurate under conditions of low pump pressure gradient (outlet minus inlet) of 0 or -100 mmHg. The magnitude of error outside these conditions was substantial, reaching 12.5% for the linear peristaltic pump when inlet pressure was -100 mmHg and outlet pressure was 100 mmHg. Error may be minimized in the clinical setting by choosing the pump type best suited for the pressure conditions expected for the renal replacement modality in use.

NEW ELECTROMAGNETIC PUMP BASED ON THE EFFECT OF MAGNETIC FLUX CONCENTRATION

Eddy currents, being of either positive or negative nature, have recently gained more and more importance in their positive aspects. New devices that may be called “eddy current based” have been worked out in recent years. This paper intends to present a quite new application of eddy currents which is an electromagnetic pump of novel design. The pump can be employed to transport liquid sodium for the Fast Breeder Reactor or other conducting materials, like melted metals. Eddy currents are used here for two pur‐poses: the first one is the typical usage to create electromagnetic force (as in tube‐type linear motors or conventional electromagnetic pumps) while the second one is just newly invented. Normally, in linear motors or conventional electromagnetic pump the air gap is relatively big which makes the leakage flux increase. Then the electromagnetic force is strongly reduced. To overcome this negative influence of the air‐gap, i.e. to minimize the leakage flux a conducting plate of special structure is inserted into the exciting coil. The first idea of it was given by K. Bessho for high magnetic field generation. Although the purpose of the application presented here is different from the initial one the idea is common and it is likely to be used for other purposes too. The basic features of the pump resulting from both numerical and experimental investigations are presented in the paper.

Helically Wound Linear Induction Pump for Molten Nonferrous Metals

The topology and characteristics of the basic categories of linear induction pumps are reviewed, and the concept, design, and performance of a novel type of pump for molten nonferrous metals are presented-the helically wound linear induction pump (HWLIP). The configuration is such that the windings follow a helical path about the axis of the pump, and three-phase excitation produces a bore field having both rotational and translational components. A HWLIP was designed to maximize the thrust component and was constructed with a set of six 5000-A solid copper water-cooled helical coils in a stack of laminations. The magnetic, electrical and mechanical characteristics were experimentally evaluated. It is shown that molten metal is essentially under no-load conditions in rotation, and if high angular velocities are allowed to occur, the performance of the pump is seriously degraded. An electromagnetic or mechanical means of spin suppression is required to make the HWLIP a useful molten metal pump for industrial applications.

Analysis of magnetic field in linear induction pumps with extended teeth

Conformal transformation is used to obtain the magnetic field of special type of linear induction pumps with long teeth and short coils. For the analysis, the teeth are assumed to be have semi-elliptical profile. Results indicate that both the propulsion and the leakage field increase with increasing tooth length. Due to the rapid increase of the leakage field optimum performance is expected when the length of the tooth equals the half tooth width.

An axisymmetric Stokes flow: application to linear induction pumps

One of the main problems in theoretical analyses of linear induction pumps is the derivation of the induced flow profiles. We consider the steady-state incompressible flow of a viscous fluid due to an assumed axisymmetric body force. The Stokes solutions obtained may be employed to discuss some of the design points for those linear induction pumps where this force approximates the exact induced Lorentz body force. The neglected inertia terms indicate that the linear solutions remain valid for sufficiently small source currents.

A comparison of distributed and concentric windings in linear induction pump for liquid metals

In this paper a calculation of the driving force in linear induction pumps is presented. The model used for the pump consists of an array of single turn coils which carry balanced polyphase currents. The coils have rectangular shape such that their dimension along the array length is much smaller than their dimension along the transverse direction. The metal is considered to be at rest and the secondary reaction is neglected. Closed form expression is obtained for the driving force. Results are presented for the force as a function of the air gap for a number of array lengths. The behaviour of the concentric windings is compared to that of the distributed windings. The calculations show that the force decays more rapidly with the air gap when the dominant wave length of the field-waves is smaller. The concentric windings have a smaller force than the distributed windings.