Magnetic Pump Research Articles

Preliminary Analysis of Liquid Metal MHD Pressure Drop in the Blanket for the FDS

Preliminary analysis and calculation of liquid metal Li17Pb83 magnetohydrodynamic (MHD) pressure drop in the blanket for the FDS have been presented to evaluate the significance of MHD effects on the thermal-hydraulic design of the blanket. To decrease the liquid metal MHD pressure drop, Al2O3 is applied as an electronically insulated coating onto the inner surface of the ducts. The requirement for the insulated coating to reduce the additional leakage pressure drop caused by coating imperfections has been analyzed. Finally, the total liquid metal MHD pressure drop and magnetic pump power in the FDS blanket have been given.

Wave phase conjugation of the second harmonic in a focused ultrasonic beam

Wave phase conjugation of the second-harmonic component generated nonlinearly in a focused beam of ultrasound is investigated experimentally and theoretically. The incident field in this case is radiated from an extended volume of the fluid between the acoustic source and the phase conjugation system. A tone burst of frequency f=3 MHz was radiated into water and focused at a point midway between the source and the conjugator. Phase conjugation of the second harmonic 2f was performed inside a magnetostrictive ceramic modulated by a magnetic pump field at frequency 4f. The conjugate beam at frequency 2f reproduces quite accurately the incident second-harmonic beam everywhere between the focal plane and the conjugator. The agreement deteriorates somewhat between the focal plane and the acoustic source, because it is mainly in this region where second-harmonic generation occurs. Experimental observations are supported by analytical and numerical results. Phase conjugation using the nonlinearly generated second harmonic possesses some advantages over conventional phase conjugation of the sound beam at the source frequency. The obtained results may provide a basis for applications employing phase conjugation of harmonics in acoustic imaging and nondestructive evaluation, such as second harmonic imaging in tissue. [Work supported by RFBR, CRDF, and ONR.]

A high-capacity magnetic pump for gas circulation in closed systems

This note describes a new pump designed primarily to recirculate gas in a closed-loop system. The pump consists of a main pump body and an exterior check-valve bridge. The main body, consisting simply of a cylinder and magnetic piston, drives gas in two directions, while the exterior check-valve bridge rectifies the flow to one direction. Large flow rates of up to 7 L/min can be obtained with the prototype pump. The design can easily be scaled to produce pumps for larger or smaller flow rates.

1929 流動鉛ビスマス条件下における SS316 のコロージョン・エロージョン特性

Corrosion-erosion properties of type 316 austenitic stainless steel were investigated at 458℃. The study aims at developing ADS, accelerator driven system, for nuclear transmutation of long lived activated nuclei to shorter ones. After 3000 hrs flow of eutectic 45Pb-55Bi loop tubes were cut and analyzed by optical microscope, SEM, EDX, WDX and TEM. It is concluded that corrosion-erosion depth is maximally 0.1mm per 3000 hrs and Cr-Fe crystals were precipitated in the lower temperature of flowing channel. Further more inspection results of Electro Magnetic Pump, Electro Magnetic Flow meter and controlling value were also reported. Output signal from EMF was stable after certain time duration. In this experiment oxygen content in Pb-Bi was not actively controlled but Pb-Bi was covered by 4N Argon gas.

Superconducting 7 T Wave Length Shifter for BESSY-II

A superconducting 3-pole Wave Length Shifter (WLS) with a maximum field of 7 T was fabricated and tested by BINP in collaboration with BESSY-II. The radiation point is fixed in the center of WLS at any field level by using two correctors. The magnetic field is stabilized with an accuracy of 10 −4 at 7 T by a feedback system based on NMR probes and magnetic flux pumps. Persistent current operation mode is enabled by using superconducting persistent keys. The magnetic field homogeneity of 10 −4 at 7 T is obtained as a result of shimming in the aperture of the magnet. A protection system based on cold diodes and dump resistors prevents the destruction of superconducting coils during the quench. Two screens with temperatures of 20 and 60 K cooled by cooling machine, two recondensers, HTSC current leads and cevlar suspensions of helium volume are used to decrease liquid helium consumption. The main features and operating mode of the WLS are described.

A New Magnetic Coupling Axial Flow Pump and its hydrodynamic and hemolysis performances

A New Magnetic Coupling Axial Flow Pump and its hydrodynamic and hemolysis performances

Condensing Heat Transfer Characteristics of R-22 and R-134a in Small Diameter Tubes

Condensing heat transfer coefficients of R-22 and R-134a were measured in smooth, horizontal copper tubes with inner diameters of 1.77mm, 3.36mm, and 5.35mm, respectively. The experiments were conducted in the closed loop, which was driven by a magnetic gear pump. Data are presented for the following range of variables : mass velocity from 200 to 500kg/.s and quality from 0 to 1.0. The heat transfer coefficients in the small diameter tubes (ID

( Vapour + liquid ) equilibrium measurement and correlation of the refrigerant ( propane + 1,1,1,3,3,3-hexafluoropropane) atT = ( 283.13, 303.19, and 323.26) K

(Vapour + liquid) equilibrium (v.l.e.) data were measured for the refrigerant {propane (R290) + 1,1,1,3,3,3-hexafluoropropane (R236fa)} atT= (283.13, 303.19, and 323.26) K, using forced recirculation of the vapour through the liquid by means of a magnetic pump. The composition of both phases was determined by gas chromatography. Due to the presence of more than negligible amounts of impurities in the R290, two sets of data are presented and correlated: the first was determined disregarding the impurities in the composition measurement, assuming that the mixture was binary; the second set was obtained assuming that the mixture was quaternary, considering the two impurities detected { n -butane (R600) and isobutane (R600a)} as components of the mixtures. The results were correlated using the Carnahan–Starling–De Santis equation of state. The experimental findings show a strong positive deviation from Raoult’s law and the presence of an azeotropic composition at high R290 concentrations. Applying the homomorph concept, the hydrogen-bonding energy in (dimethyl ether + R236fa) was estimated using previously published results and those presented here. The v.l.e. of the system are not reported elsewhere in the literature.

Coaxial probe and apparatus for measuring the dielectric spectra of high pressure liquids and supercritical fluid mixtures

A probe and apparatus were developed for measuring the dielectric spectra (complex permittivity) of high pressure liquids and supercritical fluid mixtures. The probe consisted a 2.2 mm semirigid coaxial cable that was cut off flat and mounted into a high pressure tube. The apparatus for measuring complex permittivity consisted of the dielectric probe, cell, densimeter, piston for varying the system density at constant composition, and magnetic pump for agitation and recirculation, all of which were housed in a constant temperature air bath. The probe is simple, robust, inexpensive, and further, its design allows for quick connection to high pressure systems. Probe accuracy is estimated to be ±0.5 in ε′ and ±0.5 in ε″ from 200 MHz to 18 GHz based on replicate measurements of calibration and 2σ deviations over the interval. Dielectric spectra were measured over the 200 MHz–20 GHz range for methanol+carbon dioxide mixture at 323.2 K and a pressures up to 18 MPa.

New structure of the magnetic fluid linear pump

In this paper, we developed a new structure of the magnetic fluid linear pump. The magnetic field could be focused effectively in the tube by using permalloy yoke. The magnetic reluctance could be reduced remarkably so that we could reduce device size up to 37.8% and increase pumping pressure up to 144.8%. The optimum width of the yoke was designed and compared with measurements.

Solubility of C. I. Disperse Red 60 and C. I. Disperse Blue 60 in Supercritical Carbon Dioxide

Solubility of two disperse dyes (C. I. Disperse Red 60 and C. I. Disperse Blue 60) in supercritical carbon dioxide was measured at pressures up to 35 MPa and temperatures between 313 K and 423 K in a closed-loop equilibrium apparatus equipped with a magnetic pump. The solubility increased with pressure at the same temperature. Solubility isotherms were straight and parallel to each other when the logarithm of solubility was plotted versus density of the fluid, whereas the slope of each isotherm decreased with increasing temperature when it was plotted versus the logarithm of density. The experimental data were successfully correlated using two semiempirical equations.

Magnetic systems depending on three or two variables; thermodynamic analysis and some existing and possible applications

Until quite recently, the theory of continuous media dealt mainly with diamagnetic and paramagnetic fluids. The researchers did not consider strongly magnetizable fluids, probably because such media had not yet been discovered in natural conditions and did not exist until recently as manufactured products. However, in the early 1960 s, magnetic fluids (MF) could be synthetically prepared, and then, technological interest in MF grew rapidly. Besides, magnetic refrigeration has been used for over 60 years as a technology to achieve temperatures below 1 K, employing the magnetocaloric effect of some solid materials. However, in the last 20 years, the technology has been developing for refrigeration applications above 1 K up to and including heat pumps above room temperature. The work has been multinational in scope and has focussed on the analysis of magnetic thermodynamic systems, investigation of magnetic materials suitable for refrigerants and development of prototype refrigerators. After a synthetic review of the basic properties of MF, of magnetic refrigerators and heat pumps and of magnetic properties of living matter, the aim of this paper is a thermodynamic examination of these systems in comparison with the relations usually applied to fluids. Three independent variables are generally considered, whereas usually only two variables have been considered until now for what is known to the authors. Also, in the case of only two independent variables, some results are obtained which are original. Furthermore, some applications of MF are taken into account, in particular, possibilities of converting thermal into mechanical energy are examined.

Characteristics of Exciting Power Lead-less Superconducting Magnet by Multi Magnetic Flux Pump

For exciting superconducting magnets has been used conventional power supply and power lead system. This way has some problems: heat leak into the cryogenic parts, occurrence of Joule loss in the power leads, etc. To cope with such problems, the use of superconducting magnetic flux pump has been studied. The magnetic flux pump can serve a large persistent current in superconducting magnets without switch and power leads, keeping to supply large current. However, the design method of the flux pump has not been well-known yet. Therefore, we have developed aa small size magnetic flux pump for analysis purposes to investigate its characteristics and actual performances when exciting a superconducting magnet. Furthermore, we set up a new type equipment which can connect many flux pumps compactly, so we have theoretically and experimentally examined the method to improve performances of the flux pump. As a result, we additionally derived some new important design parameters. This paper also gives a comparison between theoretically-calculated and experimental results for the case of parallel and multi-connected flux pump devices, respectively. Further it is clarified that the multi connection of the flux pump can improve performances.

Design of magnetic fluid linear pump

In this paper, the magnetic fluid linear pump is designed. Inside the small tube, magnetic fluid is constrained in the thin rubber. The magnetic fluid activated by traveling pulses of magnetic field drags the water inside the pump. The iterative algorithm for the computation of magnetic fluid shape is presented by using nonlinear finite element method and Navier-Stokes equations. The computed curvature of fluid under the magnetic field and the gravitational force agrees well with the photographic image. The dimensions and magnetic fields of the magnetic fluid linear pump are optimized and the computed pumping volumes are compared with measurements.

Output Power Limit and Excitation Method Effect Comparison in Trial Fully Superconducting Generator

A study on efficient excitation system would be important to enhance potentials of superconducting AC generators. Based on such a concept, we have fabricated an experimental machine for actually generating the electricity with a brushless exciter system which consists of a superconducting dynamo or “magnetic flux pump”. The fully superconducting generator has also been studied, in which both of armature and field windings are made of superconductors.We made tests for actual power generation and estimated its static electrical characteristics, resulting in 20kVA class available with not only the conventional excitation system, but also the novel brushless excitation system.The paper presents a comparison of elctrical characteristics in using the brushless excitation method and the external DC current source through brush-slipring system. And the results suggest that the brushless superconducting generator could yield higher output as compared with the conventional excitation.

A recirculation apparatus for vapor–liquid equilibrium measurements of refrigerants. Binary mixtures of R600a, R134a and R236fa

An apparatus for the measurement of vapor–liquid equilibria ( P– T– x– y) data of refrigerant systems was designed, built and tested. The recirculation method was used and the vapor phase was forced through the liquid phase by a magnetic pump. The thermodynamic equilibrium was reached in a visual cell with an internal volume of 50 cm 3. The compositions of the phases were analyzed by a gas chromatograph connected on-line with either FID or TCD detectors. The operating temperature and pressure in the apparatus, as tested before delivery to the laboratory [R. Stryjek, personal communication], range from 240 to 350 K and from 0.1 to 10 MPa, respectively. The estimated accuracy of the measured data was ±0.01 K for temperature, ±0.8 kPa for pressure and 0.001 in mole fraction for liquid and vapor compositions. Vapor–liquid equilibria data were obtained for the following systems: 1,1,1,2-tetrafluorethane+isobutane (R134a+R600a) at 293.66 and 303.68 K; 1,1,1,2-tetrafluorethane+1,1,1,3,3,3-hexafluoropropane (R134a+R236fa) at 283.62 and 303.68 K; and isobutane+1,1,1,3,3,3-hexafluoropropane (R600a+R236fa) at 303.68 K. The thermodynamic consistency of the experimental results was tested.

(Vapour + liquid) equilibrium measurements and correlations of the refrigerant mixture {dimethyl ether (RE170) + 1,1,1,3,3,3-hexafluoropropane (R236fa)} at the temperatures (303.68 and 323.75) K

(Vapour+liquid) equilibrium (VLE) data were measured for the refrigerant mixture {dimethyl ether (RE170)+1,1,1,3,3,3-hexafluoropropane (R236fa)} at the temperatures (303.68 and 323.75) K. The VLE data were obtained using forced recirculation of the vapour through the liquid by means of a magnetic pump. The composition of both phases was determined by gas chromatography. The experimental VLE data are regressed using the Carnahan–Starling–De Santis equation of state, which was chosen for its ability to represent the volumetric properties along bubble and dew point curves. The experimental data show negative deviations from Raoult's law that can be attributed to hydrogen bonding between oxygen in RE170 (proton acceptor) and hydrogen (evidently a proton donor, judging from our measurements) in R236fa. VLE data of the studied system are not available elsewhere in the literature.

Observation of the amplification of spin-wave envelope solitons in ferromagnetic films by parallel magnetic pumping

The propagation of envelope solitons of microwave-frequency spin waves in a spatially periodic field oriented parallel to the magnetic pump has been investigated experimentally. In a pulsed pumping regime with amplitude much greater than the threshold for parametric excitation of spin systems, amplification of spin-wave envelope solitons exceeding their natural damping was obtained.

Fluid Dynamic Characteristics of Monopivot Magnetic Suspension Blood Pumps

A monopivot magnetic suspension blood pump is a centrifugal pump under development with a magnetic suspension and a ceramic pivot to support the impeller with minimum contact. The pump size has been reduced by implementing a direct impeller drive mechanism in place of a magnetic coupling and motor. Flow visualization studies revealed that high shear, which seems to be closely related to hemolysis, concentrates in boundary layers near the walls. This implies that fluid dynamic shear can be reduced not by widening the gap, but by reducing the impeller velocity. Therefore, compared with the results of the previous semi-open curved vane impeller model, impeller velocity was reduced by 30% with a closed impeller having radial straight vanes, and smaller impeller/housing gaps. The volute shape around the impeller tip was also changed such that the outflow from the impeller enters along the center plane of the volute. To examine the effect of the improvements, hemolysis testing was conducted and found that the newly developed closed impeller model generated a lower level of hemolysis than the previous semi-open impeller model.

Electrical characteristics of a fully superconducting brushless generator equipped with a magnetic flux pump

Electrical characteristics of a fully superconducting brushless generator equipped with a magnetic flux pump