Induction Electromagnetic Pump Research Articles

Research on high heat flux cooling technology of a liquid metal driven by a compact induction electromagnetic pump

Research on high heat flux cooling technology of a liquid metal driven by a compact induction electromagnetic pump

One dimensional analytical model considering end effects for analysis of electromagnetic pressure characteristics of annular linear induction electromagnetic pump

A one-dimensional analytical model with the finite magnetic core length and conductive duct wall thickness of annular linear induction electromagnetic pump (ALIP) is established in this paper. Based on this model considering both the end effects and the conductive duct wall effect, the explicit analytical expressions of the electromagnetic and force fields are deduced. At the same time, the influence of end effects and the conductive duct wall effect on electromagnetic field and force field is analyzed and the components of magnetic field, induced eddy current and force field which are produced because of the existence of end effects are separated. Then, the explicit analytical expression of the developed pressure is obtained with the introduced fluid loss. Finally, to verify the feasibility and accuracy of the analytical model, the performance of a small three-phase ALIP under different frequency and current conditions are calculated analytically and the calculated results are verified by experiments data from the experimental test loop.

The Improved Equivalent Circuit Models Considering End Effects of Annular Linear Induction Electromagnetic Pump for Space Nuclear Power Supply

The improved equivalent circuit models considering the end effects are put forward to predict the performance of annular linear induction electromagnetic pump (ALIP) based on the one-dimensional analytical model built in this paper. First, the one-dimensional physical model of ALIP is established, and the analytical expressions of electromagnetic fields are deduced and the impact of the end effects on it is analyzed. Then, two equivalent circuit models including the model only considering the end effects and the model fully taking the end effects and the difference of synchronous velocity among the end effect traveling waves and the fundamental wave into account are developed. Meanwhile, the key impedance parameters in the equivalent circuit models are obtained and the correction coefficients of the impedance generated by the end effects are abstracted. Furtherly, the performances of a small designed ALIP are calculated by the conventional and two improved equivalent circuit models respectively, the results obtained from them are compared with measured data to validate the rationality and feasibility of the models proposed.

A 50 kW Liquid-Lithium Target for BNCT and Material-Science Applications

A compact Liquid Lithium Target (LiLiT) has been operating at SARAF for several years with beam power of several kW (1.9-2.5 MeV, up to 2 mA). When bombarding the lithium with low energy protons neutrons are generated. The neutron source, mainly used for nuclear astrophysics research, was decommissioned in 2016 towards an upgraded model - with possible applications to Boron Neutron Capture Therapy (BNCT) and material-science studies. The improved version has been designed to sustain 50 kW proton beam power (2.5 MeV, ~20 mA) to provide sufficient neutron flux required for clinical BNCT application. The new model has a 50 mm wide lithium jet to enable dissipation of the higher beam power and an improved heat exchanger to remove the power to a secondary cooling loop. A new Annular Linear INduction electro-magnetic pump (ALIN) has been designed and built to provide the required lithium flow rate. Other mechanical improvements facilitate the maintenance of the system and the robustness of operation. Radiological risks due to the 7Be produced in the reaction are reduced by using an integrated lead shielding of the lithium reservoir. An integrated neutron moderator is being designed to adjust the neutron energy to the spectrum best suited to BNCT. A low power (6 kW) model of the new design with a narrower nozzle (18 mm wide) and a rotating-magnet electro-magnetic pump is operating at SARAF to support the ongoing astrophysics and nuclear research program [1], [2]. To fulfill clinical BNCT, the upgraded LiLiT model will require an accelerator of appropriate energy and intensity. The design features of the new system are presented in this paper.

Optimization of outer core to reduce end effect of annular linear induction electromagnetic pump in prototype Generation-IV sodium-cooled fast reactor

An annular linear induction electromagnetic pump (ALIP) which has a developed pressure of 0.76 bar and a flow rate of 100 L/min is designed to analysis end effect which is main problem to use ALIP in thermohydraulic system of the prototype generation-IV sodium-cooled fast reactor (PGSFR). Because there is no moving part which is directly in contact with the liquid, such as the impeller of a mechanical pump, an ALIP is one of the best options for transporting sodium, considering the high temperature and reactivity of liquid sodium. For the analysis of an ALIP, some of the most important characteristics are the electromagnetic properties such as the magnetic field, current density, and the Lorentz force. These electromagnetic properties not only affect the performance of an ALIP, but they additionally influence the end effect. The end effect is caused by distortion to the electromagnetic field at both ends of an ALIP, influencing both the flow stability and developed pressure. The electromagnetic field distribution in an ALIP is analyzed in this study by solving Maxwell's equations and using numerical analysis.

Design optimization analysis of a large electromagnetic pump for sodium coolant transportation in PGSFR

An annular linear induction electromagnetic pump (ALIP) with a flow rate of 0.86 m3/s and a developed pressure of 3.6 bar is designed by conducting an optimization analysis of its geometrical, electromagnetic, and hydrodynamic variables. The purpose of the ALIP involves circulating liquid sodium in the intermediate heat transport system of the Prototype Generation-IV Sodium-cooled Fast Reactor (electric output: 150 MWe) that is currently under development in Korea. The efficiency and developed pressure of the ALIP are derived as a function of its design variables and include the core length, flow gap, number of poles, flow velocity, pole pitch, input frequency, and input current. In terms of electromagnetic variables that can be controlled during its operation, hydraulic efficiency is maximized at an input frequency of a few tens of Hertz. The P–Q characteristics of the optimized ALIP are analyzed and verified via a theoretical comparison with an extremely large ALIP.

Design and preliminary test of an annular linear induction electromagnetic pump for a sodium-cooled fast reactor thermal hydraulic experiment

ABSTRACTAn annular linear induction electromagnetic pump (ALIP) with a flow rate of 2265 L/min and a developed pressure of 4 bar was designed and fabricated to test the performance of the components of a sodium-cooled fast reactor (SFR) in a sodium thermal hydraulic experimental loop. The design characteristic of the ALIP was calculated using the electrical equivalent circuit method typically used for analyzing linear induction machines. Preliminary tests, such as verification of the moving function using an annular Al pipe, were carried out. The linearity between the input voltage, current, and magnetic flux density was verified. The developed force demonstrated an increase proportional to the square of the input current, whereas the velocity was linearly proportional to the input current. The main design variables of the pump were calculated theoretically for the SFR thermal hydraulic experimental loop. The pump was optimized for the design variables including input frequency, and the characteristics of the optimized pump were compared with those of the pump at the commercially used frequency of 60 Hz.

Periodic magnetohydrodynamic natural convection flow of a micropolar fluid with radiation

This article is concerned with the problem of periodic magnetohydrodynamic (MHD) natural convection boundary-layer flow of a radiating micropolar fluid near a vertical surface. Such type of problems are posed by induction electromagnetic pumps and generators. The governing equations are reduced to a convenient form by the introduction of stream function formulations and are simulated by the implicit finite difference method along with the Keller-box scheme. The results of the surface shear stress, rate of heat transfer, distribution of couple stress, velocity profile, temperature profile and angular velocity profile are shown graphically for a range of parameters. Excellent agreement is found when present solutions are compared with the previous studies. It is shown that the heat transfer rate remains insensitive when magnetic field parameter, micropolar parameter and micro-inertia density parameter increases. Further, the micropolar parameter, K, has dominant effect on skin friction coefficient and couple stress coefficient.

The basic approach to the performance test of the ALIP for GENIV sodium fast reactor

The annular linear induction electromagnetic pump (ALIP) with the flowrate of 900 L/min and the developed pressure of 4 bar has been designed by electric equivalent circuit analysis. It was fabricated by the consideration of materials compatible to the sodium environment of high temperature. Basic characteristic test of the ALIP was carried out in advance for its installation to the integral effect TEst Loop for safety simuLation and Assessment (STELLA) loop to confirm the sodium-thermo-hydraulic components. The test showed that the magnetic field had been linearly increased when the input current was increased, where input current and voltage had represented linear relation each other. The generated electromagnetic force was proportionate to the square of the applied current. The velocity of the aluminium pipe was proportionally increased when the input current was increased. It was verified that the basic characteristic of the ALIP showed a good accordance with the theoretical calculation.

A liquid aluminum alloy electromagnetic transport process for high pressure die casting

For the electromagnetic transport (EMT) of liquid aluminum alloy during high pressure die casting (HPDC) by the plane induction electromagnetic pump (EMP), how to improve EMT efficiency and control EMT stationarity are key problems. Magnetic-flow coupling analysis was used to reveal effects of structural design and transport process parameters on EMT efficiency and stationarity. The output pump height of plane induction EMP was optimized by matching of iron core width W, coil width W′ and pump ditch width b, i.e., b values of bopt corresponding to 90% of the maximum output pump height, bopt/W=1.27 and bopt/W′=1. Both EMT efficiency and stationarity are achieved under the optimum transport current 32A. With the increase of the transport height from 350mm to 500mm, the EMT flow rate decreases from 4.28kg/s to 3.59kg/s, and the fillings of shot sleeve are always stationary. The transport tubes suffer a maximum positive pressure of 1.8×104Pa and a minimum negative pressure of −1.42×104Pa during EMT. For the liquid aluminum alloy soup occasions of 4.5kg, 6.5kg and 12.0kg, the transport time could be shortened significantly from manipulator’s 16s, 22s and 38s to EMT’s at most 2.195s, 2.75s and 4.28s, respectively. The developed EMT process with plane induction EMP for HPDC is a process with low cost, high transport efficiency and stationarity.

Instability in electromagnetically driven flows. II

In a previous paper, we have reported numerical simulations of the magnetohydrodynamic flow driven by a travelling magnetic field in an annular channel, at low Reynolds number. It was shown that the stalling of such induction pump is strongly related to magnetic flux expulsion. In the present article, we show that for larger hydrodynamic Reynolds number, and with more realistic boundary conditions, this instability takes the form of a large axisymmetric vortex flow in the (r, z)-plane, in which the fluid is locally pumped in the direction opposite to the one of the magnetic field. Close to the marginal stability of this vortex flow, a low-frequency pulsation is generated. Finally, these results are compared to theoretical predictions and are discussed within the framework of experimental annular linear induction electromagnetic pumps.

MHD design analysis of an annular linear induction electromagnetic pump for SFR thermal hydraulic experimental loop

The design variables of an annular linear induction electromagnetic pump (ALIP) for SFR thermal hydraulic experimental loop were analysed magnetohydrodynamically. The theoretical model of ALIP was configured for magnetohydrodynamic (MHD) analysis. Mathematical equations for the developed pressure, generated by Lorentz electromagnetic force and hydraulic efficiency were derived. The developed pressure was found to be a function of design variables, including the geometrical variables of pump core length, inner core diameter and flow gap, and the electromagnetic ones of turns of coils, frequency and input current. The developed pressure from the MHD analysis was compared and identified with the developed pressure derived by an equivalent circuit method leading to Laithewaite’s standard design formula for a linear induction electromagnetic pump. The design characteristic of the electromagnetic pump was analyzed according to the change of the pump’s geometric and electromagnetic variables, taking into account hydraulic friction pressure loss in the narrow annular gap of the pump. The design specification of ALIP with a flow rate of 900L/min and a developed pressure of 4.5bar was drawn from the characteristic analysis of the variables.

Effect of electromagnetic transport process on the improvement of hydrogen porosity defect in A380 aluminum alloy

The hydrogen solubility in liquid A380 aluminum alloy was determined. When comparing with the conventional No EMT casting condition, hydrogen porosity defect improving amplitudes of 33.8%, 57.9% and 51.2% at casting temperatures 670 °C, 700 °C and 730 °C were observed in A380 ingots casted by the experimental electromagnetic transport (EMT) prototype with plane induction electromagnetic pump (EMP). Negative pressure zone minus normal atmosphere was found in the rectangular pump ditch of the plane induction EMP by electromagnetic-flow coupling analysis. The electromagnetic separation of hydrogen pores preformed in the negative pressure zone decreases the hydrogen solubility before solidification, and the electromagnetic purification of inclusions and the non-entrainment of surface bi-films weaken the heterogeneous nucleation of hydrogen pores during solidification, which result in the improvement of hydrogen porosity defect under the EMT process. Further analysis indicates that the engineering EMT prototype with higher rectangular pump ditch aspect ratio and more negative pressure zone possesses more prominent hydrogen porosity defect improving effect. The EMT process with plane induction EMP is a promising way to transport liquid aluminum alloys during casting with both high casting efficiency and excellent hydrogen porosity defect improving effect.

Coupling analysis of the electromagnetic transport of liquid aluminum alloy during casting

Electromagnetic transport (EMT) process with plane induction electromagnetic pump (EMP) was developed for the transport of liquid aluminum alloy during casting. The temperature rise of liquid aluminum alloy when flowing into and out of the pump ditch of the EMP during the EMT process was gained by magnetic-thermal coupling analysis. The flow field and the effects of structural design and transport technological parameters on the transient and stable EMT performance of the engineering EMT prototype were obtained by magnetic-flow coupling analysis. The extra temperature rise effect accompanied with the EMT process can be neglected since the EMP induced local maximum and average temperature rises corresponding to a common sojourn time of 1.16s are only 1.3°C and 0.6°C, respectively. Two recirculation zones distribute symmetrically along both sides of the central main flow in the pump ditch and the transition transport tube. Sequential air exhaust and outflow appear when the cross-sectional area shrunken ratio from the rectangular pump ditch to the circular transport tube is 0.472. The stable outlet flow rate increases with the diameter of the circular transport tube (d) due to the weakening of recirculation zones, and it increases linearly with the transport current (I), while it decreases with the initial transport height. The morphology of the stable flow field is not affected by I.

Simulative and Experimental Study on Electromagnetic Pump Supplying Liquid Alloys during Casting: Modeling and Effects of Design Parameters on Pump Height

The pump height (ΔH) of liquid A356 alloy by the plane induction electromagnetic pump supplying liquid aluminum alloys during casting was measured, and the experimental values agreed with 3D simulation results. It was found that the relationship between ΔH and frequency was relevant with structural design parameters, and the increase of ΔH versus frequency started to deviate from linearity when the width of the pump ditch (b) was higher than that of the iron core (W). ΔH was found to be always proportional to the square of the current and irrelevant with frequency and structural design parameters. It was also found that ΔH decreased significantly with the magnetic gap and increased with W and the thickness of the iron core, while ΔH was not affected by the polar distance. In addition, ΔH increased first rapidly and later slowly with b till the maximum was reached, after which ΔH started to decrease slowly with b.

3D simulation of plane induction electromagnetic pump for the supply of liquid Al–Si alloys during casting

The distribution and evolution of the magnetic flux, the induced current and the electromagnetic force in liquid A356 alloy in the pump ditch were revealed by the transient analysis. The magnetic flux was mainly along the height direction of the pump ditch and changed direction every interval of half cycle (T/2). The induced current formed two or three groups of swirl rings alternately along the length direction (X) of the pump ditch. The electromagnetic force contained the effective component (FMAGX) along +X direction and the invalid component that was centrosymmetric along the width direction of the pump ditch, and its change cycle was T/2. The magnetic flux, the induced current and the electromagnetic force all traveled along +X direction periodically. The effects of electromagnetic and structural design parameters on FMAGX and the pump height (ΔH) of the pump were obtained by the harmonic analysis. FMAGX and ΔH increased nearly linear with the frequency while decreased significantly with the magnetic gap, and they were proportional to the square of the current. FMAGX increased with the width (b) and the height (h) of the pump ditch, and ΔH first increased and later decreased with b while decreased monotonically with h.

MHD stability analysis of a liquid sodium flow at the annular gap of an EM pump

A stability analysis of a viscous, incompressible, and electrically conducting liquid sodium flow in an annular linear induction electromagnetic pump for sodium coolant circulation of a Sodium Fast Reactor (SFR) was carried out when transverse magnetic fields permeate the sodium fluid across the narrow annular gap. Due to a negligible skin effect and the presence of a magnetic core outside the gap, radial magnetic field is assumed to be constant over the narrow channel gap, and the steady state solution of the axial velocity is obtained as a function of radius. Small perturbations for MHD fields were considered in sinusoidal form as a function of the angular frequency and wave number, and the resulting equations were linearized. The solutions of the perturbed equations were sought in the form of a linear combination of independent orthogonal functions in a non-dimensional radial interval (0,1), and each orthogonal function was chosen to satisfy the boundary conditions of adhesion to the solid walls of the channel. Under the assumption that solutions of the equations were not oscillated rapidly according to the radial coordinate, finite numbers of orthogonal polynomials were considered. As a result, simultaneous equations with coefficients of steady-state solutions were arranged, and dispersion relations between angular frequency and wave number of perturbed state were sought. The imaginary part of the angular frequency was taken into consideration from the condition of existence of a nontrivial solution of the system, which leads to the relation between critical Reynolds number (Recr) and Hartmann number (Ha). In the present study, critical Reynolds number and wave numbers were plotted against the Hartmann number for a long wave perturbation; thus, it was shown that a magnetic field has a significant stabilizing effect on liquid sodium flow.

A design and characteristic experiment of the small annular linear induction electromagnetic pump

A small-scale annular linear induction electromagnetic pump (ALIP) of the externally-supported-in-pipe type with a flowrate of 60L/min and a developed pressure of 1.3bar was developed for the circulation of sodium liquid metal. The developed pressure and the efficiency of the pump were analyzed on the change of the pump-design variables by using an equivalent circuit method. The pump designed was manufactured with the consideration to the material and functional requirements of a chemically-active sodium environment. The silicon–iron steel plates with high magnetic permeability and alumina-dispersion-strengthened-copper bands were used as cores and coils of the pump electromagnet for operating in a high temperature. Each turn of the coil was insulated by an asbestos band to protect against an electrical short at a high temperature. Stainless steel compatible with sodium was selected as a structural material. The completed pump was installed in the sodium experimental loop system. At temperatures of 150°C and 350°C, the performance of the ALIP (including the P–Q characteristic) was tested by changing the electrical input. The measurements showed that the pumping flowrate and the developed pressure were increased as the input current, voltage and power increased. On the other hand, the developed pressure was decreased with the increase of the flowrate. At the nominal input current and voltage, the developed pressure was 1.25bar with the relative error of 3.8% compared with the prediction of 1.3bar at 150°C, where the flowrate was 54L/min. The test on the pump showed good agreement with the theoretical calculation with some experimental errors.

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.

Analysis of a novel laminated coil using eddy currents for AC high magnetic field

The analysis and performance of an eddy current type laminated coil for a high AC magnetic fields are described. It is usually difficult to obtain a high AC magnetic field using an air-gap coil because of eddy currents. The present coil circumvents this limitation by making use of the magnetic shielding effect of eddy currents. Two different realizations of the coil are proposed to provide design flexibility. The field distributions are analyzed by the two-dimensional finite-element method. The coils can also be applied to an induction electromagnetic pump.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>