Induction Pump Research Articles

Performance evaluation of ALIP applying fully enclosed slot

ABSTRACT In nuclear energy systems, annular linear induction pump (ALIP) is regarded as an ideal device for transporting liquid metal. Developed pressure and efficiency are crucial indicators for evaluating performance of an ALIP, and enhancing these fac- tors is of utmost importance. This paper presents a 2D axisymmetric finite element method (FEM) model for efficiently predicting the performance of ALIP and a 3D FEM model to explore the implementation of a fully enclosed slot structure. The accuracy of the proposed models is validated by comparing the results with experi- mental data, complemented by empirical formulas in the post-processing phase. The continuous and discontinuous conditions of the pole pieces are analyzed using the 3D FEM, demonstrating that the fully enclosed slot structure can significantly enhance both developed pressure and efficiency, thereby improving the overall performance of the ALIP.

Analysis of power system frequency and active power based on wind-storage combined frequency modulation system

Abstract To solve the problem of frequency and active power regulation of power systems, this paper proposes a wind-storage combined frequency modulation strategy. The mathematical models of doubly-fed induction machines, pump turbines, and wind turbines are established. Based on wind power frequency modulation, the doubly-fed variable-speed pumped storage unit is added to establish a combined frequency modulation system, and a simulation model on Simulink to analyze the participation of different parts of the combined system in frequency modulation and the active power output of the unit when the load changes. The simulation results show that when the load increases or decreases, the addition of a doubly-fed variable speed pumped storage unit can effectively improve the frequency modulation performance of the system, reduce the fluctuation numbers and amplitude, and reduce the deviation after stabilization. By changing its active power output, a new balance of the system power can be reached, which is conducive to the secure and steady functioning of the power system.

Liquid metal-enhanced thermoelectric generator for high-temperature thermal harvesting

It is a challenge to achieve high output power of the thermoelectric generator (TEG) for high-temperature waste heat recovery due to the working fluids with low thermal conductivity (such as air) or low tolerance of temperature (water or oil). In this paper, the gallium-based liquid metal (LM) with a high boiling point (>1000 ℃) and thermal conductivity (>20 W/mK) are introduced to significantly enhance heat charging and discharging at the hot/cold sides of TEG. We also developed an electromagnetic induction pumping method for the effective LM-driven flow at high temperatures. A three-dimensional coupling multi-parameter optimization simulation model of LM-based TEG was developed to reveal the internal heat transfer and power generation mechanism for clarifying the impact factors of the performance. The results have shown that the power generation capacity can be effectively improved by increasing the inlet temperature (Thot-in). It is worth noting that the temperature difference (ΔT) of the TEG module is severely limited by the thermal resistance (Rcapacity) of the LM heat capacity, such as, when the flow rate of 2 L/min, the Rcapacity accounts for 90.6 % (0.020 ℃/W). It is easier to achieve a larger open circuit voltage by increasing the height of the thermoelectric leg, but the Pmax is constantly weakened. Compared with Xceltherm 600 and Solar salt, LM heat transfer fluid has more obvious advantages in enhancing the power generation performance of the system. The LM-based TEG experiment platform was established to study heat transfer and power generation characteristics. The results have demonstrated that good consistency was proved by comparing experimental and numerical data. And the Pmax of the LM-based TEG system is 0.16 W/cm2 at ΔT of 136 ℃. LM-based TEG can open new perspectives for broad applications in high-temperature waste heat recovery.

Active Flow Control of the Magnetohydrodynamic Flow in an Annular Linear Induction Pump by Modifying the Driving Electromagnetic Field

The strong coupling between fluid and electromagnetic field in the annular linear induction pump (ALIP) can gradually amplify small disturbance in the fluid field into large-scale vortices. The appearance of the vortices seriously affects the efficiency and reliability of the pump. An active flow control method based on the modification of the driving electromagnetic field is proposed to improve the flow stability. A simplified numerical model of the ALIP is established to simulate the three-dimensional flow in the annular flow channel, and the internal electromagnetic field is modified by using the modulated surface current. The influences of the active flow control method on the flow behavior, pressure pulsation, and energy conversion are, respectively, investigated based on the simulation results. The results show that the modulated surface current can accelerate the vortical evolution. The size and strength of the vortices are suppressed in the modified electromagnetic field. The pressure pulsation low frequency at the ALIP’s outlet is significantly reduced when the modulated surface current density reaches a certain level. The surges in the processes of energy conversion become more gentle within the control method, and the overall energy efficiency is slightly reduced even at the highest modulated surface current density.

Effectiveness of perioperative low-dose esketamine infusion for postoperative pain management in pediatric urological surgery: a prospective clinical trial

BackgroundPostoperative pain is common in pediatric urological surgery. The study assess the impact of perioperative intravenous infusion of low-dose esketamine on postoperative pain in pediatric urological surgery.MethodsPediatric patients (n = 80) undergoing urological surgery were randomized into four groups. Patients in the control group were administered an analgesic pump containing only hydromorphone at a dose of 0.1 mg/kg (Hydromorphone Group 1, H1) or 0.15 mg/kg (Hydromorphone Group 2, H2). Patients in the experimental group were injected intravenously with 0.3 mg/kg of esketamine (Esketamine group 1, ES1) or equal volume of saline (Esketamine Group 2, ES2) during anesthesia induction. Esketamine 1.0 mg/kg and hydromorphone 0.1 mg/kg were added to the analgesic pump. Face, Leg, Activity, Crying, and Comfort (FLACC) scale or the Numerical Rating Scale (NRS) and adverse effects were recorded at 2, 6, 24, and 48 h postoperatively. Additionally, total and effective PCA button presses were recorded.ResultsIn comparison to the H1 group, the pain scores were notably reduced at all postoperative time points in both the ES1 and H2 groups. The ES2 group exhibited lower pain scores only at 24 and 48 h postoperatively. When compared to the H2 group, there were no significant differences in pain scores at various postoperative time points in the ES2 group. However, the ES1 group demonstrated significantly lower pain scores at 6, 24 and 48 h postoperatively, and these scores were also significantly lower than those observed in the ES2 group. The total and effective number of PCA button presses in the ES1, ES2 and H2 group were lower than that in the H1 group (P < 0.001). The incidence of adverse effects within 48 h after surgery was 15% in ES1, 22% in ES2, 58% in H1, and 42% in H2, respectively (P = 0.021).ConclusionsThe use of low-dose esketamine infusion in analgesia pump can effectively alleviates postoperative pain in pediatric urological patients, leading to a significant reduction in the number of analgesic pump button press. The combined approach of perioperative anesthesia induction and analgesia pump administration is recommended for optimal pain management in these patients.Trial registrationChinese Clinical Trial Registry- ChiCTR2300073879 (24/07/2023).

Coupled Numerical Simulation of Electromagnetic and Flow Fields in a Magnetohydrodynamic Induction Pump

Coupled Numerical Simulation of Electromagnetic and Flow Fields in a Magnetohydrodynamic Induction Pump

Design and Analyses of Miniature, Submersible Annular Linear Induction Pump for Test Loops Supporting Development of Advanced Nuclear Reactors

A submersible annular linear induction pump (ALIP) design with an outer diameter of 66.8 mm with appropriate materials is developed for circulating molten lead and alkali liquid metals of sodium and sodium-potassium-78 (NaK-78) alloy in test loops at temperatures up to 500°C. These loops investigate the compatibility of these liquid coolants with nuclear fuel and structure materials to support the development of advanced, Generation IV nuclear reactors. The present ALIP, which employs high-temperature ceramic-insulated coil wires and Hiperco-50 center core and stators, fits in Type 316 stainless steel, 2.5-in. standard schedule 5 pipe. This pipe, considered for the riser tube of the Versatile Test Reactor (VTR) in-pile test cartridge loop, has an inner diameter of 68.8 mm permitting 1.0-mm radial clearance for the present ALIP. An improved equivalent circuit model (ECM) is developed to analyze the performance of the present ALIP design. The accuracy of the model predictions is successfully validated using reported experimental measurements by other investigators for a low liquid sodium flow ALIP at 200°C and 330°C. The improved ECM calculates the performance characteristics of the present ALIP design and investigates the effects of varying the terminal voltage, current frequency, winding wire diameter, center core length, width of the liquid flow annulus, and working fluid properties and temperature on the pump operation. For circulating molten lead, the calculated peak efficiency of the present ALIP design of 6.7% occurs at a flow rate of 9.5 kg/s and pumping pressure of 263 kPa. The calculated peak efficiency for circulating liquid sodium is much higher, 26.3%, and occurs at a lower flow rate of 2.2 kg/s but a higher pumping pressure of 364 kPa. The calculated peak efficiency for circulating NaK-78 (23%) is lower than for sodium and occurs at a lower flow rate and pumping pressure of 1.9 kg/s and 310 kPa, respectively.

Performance evaluation of a high flow rate annular linear induction pump using a simple equivalent circuit model taking into account dynamic end effects

ElectroMagnetic Induction Pumps are a relevant technical solution for the transportation of alkali metals in applications where safety and reliability are fundamental. Especially, Annular Linear Induction Pumps (ALIPs) are preferred when high flow rates are required. In the early stage design of an ALIP, simple analytical models are convenient to get an estimate of performances. Equivalent circuit models are often used to this purpose. Their accuracy has been found variable, depending on pumps configuration and operating conditions. To assess the relevance for high flow rate applications, circuit models are applied to the ALIP of PEMDyn facility, in CEA Cadarache research centre. The simplest equivalent circuit model for a LIM is tested. Then, a modification to account for dynamic end effects is added. Results are compared to experimental measurements. The correction for dynamic end effects allows a significant reduction of the relative error, especially for the range of highest flow rates.

Design, Modeling, and Analysis of a Compact-External Electromagnetic Pumping System for Pool-Type Liquid Metal-Cooled Fast Reactors

Current pool-type Liquid Metal-Cooled Fast Reactors (LMCFRs), either under development or operational, immerse main reactor components in the primary coolant, (i.e. sodium), that includes heat exchangers, shielding structures, and pumping systems. Proposed main pumping systems, for some reactors that are under development, use electromagnetic pumps (EMPs) for primary coolant circulation. Annular linear induction pumps (ALIPs) are the preferred type since they are known for their advantages over mechanical centrifugal pumps (MCPs) when used to circulate liquid metals. This is due to ALIPs’ absence of moving parts such as shafts and impellers, seals and bearings, auxiliary lubrication systems, and simplicity of flow and pressure control mechanism. The immersion of reactor components in the primary sodium in the reactor vessel minimizes the likelihood of radioactive coolant leakage and loss of coolant accidents. However, since there is only one access point to reactor components, the immersion of ALIPs prevents additional potential advantages. Online pump inspection and replacement, reduction of negative effects on pump components due to the high temperature and radiation environment, an additional heat removal mechanism for self-cooled ALIPs, and simple decommissioning procedures are some possible advantages. This paper discusses a study conducted to investigate the possibility of using large EMPs, ALIP type, that are located outside the reactor vessel and connected in parallel, instead of in vessel sodium immersed ones for pool-type LMCFRs. The large, outside-vessel EMP idea is tested on a liquid metal-cooled test reactor design using an experimentally validated multiphysics finite element analysis tool. Specifically, the steady state reactor’s primary circuit cooling and pressure requirements are used to design two, in-vessel ALIPs and then two outside-vessel ALIPs. The two pumping systems are compared in terms of their geometries, performance characteristics, and impact on overall reactor design. It is found that the outside-vessel EMP design provides the same performance requirements and offers additional advantages compared to the in-vessel pump with only minimal reactor vessel modification and a slight drop in efficiency.

Electromagnetic pump with rotating permanent magnets operation at low inlet pressures

This study aimed to investigate the performance of an electromagnetic induction pump with rotating permanent magnets under different inlet pressure conditions. The tested cylindrical-type pump was placed in the test loop to test its parameters while pumping liquid sodium. The measurements of the pump characteristics were carried out at the different inlet pressure values. The inlet pressure was varied, changing initial overpressure in the loop's expansion tank from 0,1 to 1,75 bars. Inlet pressure influenced the cavitation occurrence in the pump channel, and thus, the maximal flow rate varied from 15,2 to 73 l/s. In addition to the pressure-flow rate characteristics, various data were collected during the experiments, such as drive unit power, vibration data, and acoustic signals. Analysis of these parameters showed a clear correlation between the inlet pressure and the apparent cavitation process in the pump channel. This study aimed to establish the operational limits for the electromagnetic induction pump with rotating permanent magnets. The results indicate that the pump can safely operate within the range of inlet pressure values of 0,6 bar and cavitation number values of 3,2.

Pumping Options for Versatile Test Reactor Molten Lead In-Pile Test Cartridge

The Extended Length Test Article–Cartridge Lead is a test assembly for conducting in-pile research in the Versatile Test Reactor to support the advanced molten lead–cooled reactor under development at the Westinghouse Company. This work investigates four pumping options for circulating molten lead at 500°C and develops an integrated thermal-hydraulic model to estimate the demand curves. The four pumping options fit within cartridge riser tubes that are 57.0 and 68.8 mm in diameter. These options are (1) gas lift pumping, (2) the miniature submerged annular linear induction pump, (3) the miniature submerged direct-current electromagnetic pump, and (4) the miniature axial-centrifugal flow mechanical pump. Gas lift pumping is the simplest and is fully passive with no heat dissipation, but it generates the lowest pumping pressure and flow rate. The mechanical pump and direct-current electromagnetic pump generate the highest pumping pressures, flow rates, and average velocities of molten Pb in the test article of three-fuel rodlets in a triangular lattice. The mechanical pump designs provide the highest flow velocities in the test article and the slowest decrease in pumping pressure with increased flow rate at low thermal power dissipation. The optimized electromagnetic pump designs with no moving parts and elevated temperature ALNICO-5 permanent magnets meet or exceed the target flow velocities in the test article but at higher rate of heat dissipation than the mechanical pump designs.

Healthy-State and Time-To-Failure Assessment of Induction Motors and Pumps for Maintenance Scheduling Using Cloud-Enabled Fault Prediction and Reporting System with Machine Learning Scheme

Every industry relies heavily on electrical machines. When these machines fail without giving a signal or warning, there is unplanned downtime and unanticipated deployment of maintenance staff which may affect or lower production if machines are serving as important assets. Some failures can lead to greater damage, instead of one machine or item being replaced a lot of resources will be needed to repair once a machine fails and assets will have a shorter life expectancy. There are also safety issues associated with running a machine to failure. Running a machine to failure also increases labour costs and safety costs. Therefore, this paper proposes a Cloud-Enabled Fault Prediction and Reporting System with Machine scheme for Healthy-State and Time-To-Failure Assessment of Induction Motors and Pumps for Maintenance Scheduling. This system uses sensors to extract data (current, speed, temperature, vibrations). The extracted data is then conditioned and compared to the values related to the healthy state of the equipment using machine learning algorithms, manufacturer specifications, and historical readings to identify performance non-conformities or items that require action and display the asset health report which will help schedule a proper maintenance procedure based on analysis.

Single dipole permanent magnet induction pump for liquid metals

Electromagnetic liquid metal induction pumps can be used in different technological processes, such as dosing, mixing, crystallization and others. Contactless devices are of special importance in metallurgical processes because high temperature metals are chemically aggressive and erode most materials over time. Additionally, induction pumps with permanent magnets are more efficient and cheaper than AC electromagnetic induction alternatives, thus allowing for a wider application range. A single dipole permanent magnet rotor magnetized perpendicular to the axis of rotation induces a travelling magnetic field and is used to demonstrate the effectiveness of the liquid metal pump. Non-dimensional parameters are analysed to upscale the experimental results to an industrial size dispenser. Tables 1, Figs 6, Refs 9.

Growth rate of azimuthal perturbation modes in an ideal annular linear induction pump

This study is aimed at investigating the growth rate of azimuthal perturbation modes in an ideal annular linear induction pump model. The positive growth rate of azimuthal perturbation modes is associated with the unstable behaviour of the annular linear induction pump and is known in the literature as MHD instability characterized by strong low-frequency oscillations of magnetic field, flowrate, and pressure. A linear stability analysis of a height-averaged quasi-stationary main flow in the ideal annular linear induction pump has been conducted, where only temporally evolving azimuthal modes of the axial velocity and magnetic field perturbations were considered. The obtained results predict damped or damped oscillating perturbations in a stable regime as a function of Rm, Rms, N and κm. In the studied parameter range, an amplification of perturbations without oscillations was observed above the instability threshold. It can be concluded that the analysed model of the ideal annular linear induction pump cannot predict experimentally and numerically the observed low frequency oscillations. Figs 4, Refs 17.

Experimental cavitation investigation of the electromagnetic PbBi pump with rotating permanent magnets

Electromagnetic induction pumps with rotating permanent magnets (EMP) are used mostly in experimental setups, where operation safety and reliability are crucial. Such pumps can face flow parameter decrease when operating at a low inlet pressure compared with those gained at higher inlet pressure values. The pump's developed flow rate increase does not correspond to the magnetic rotor rotation rate increase at the lower inlet pressure caused by the cavitation process at the pump’s inlet tract. The study focuses on critical cavitation numbers at several inlet tract sections under severe cavitation conditions which prevent the flow rate increase. The current study is an experimental approach to characterize the pump operation parameters using cavitation numbers and comparing them with the literature data. Figs 7, Refs 13.

Numerical study of a centrifugal electromagnetic induction pump with zero flowrate

The objective of the present study is to develop a numerical model of the centrifugal electromagnetic induction pump to predict the developed pressure in the case of zero flowrate. This is done using the COMSOL Multiphysics software in a 2D space with a time harmonic approach. A good agreement with previously reported experimental results was obtained. Based on the developed model, a study of the linear electromagnetic induction pump is also carried out and the obtained results are compared with those for the centrifugal electromagnetic induction pump. It is shown that with a low interaction parameter, the centrifugal pump can develop a significantly higher pressure than the linear pump. Figs 12, Refs 5.

High heat flux thermal management through liquid metal driven with electromagnetic induction pump

High heat flux thermal management through liquid metal driven with electromagnetic induction pump

MHD pump with rotating permanent magnets: inlet pressure influence on P-Q curves

The research is aimed at investigating the influence of the cavitation process on the performance of the electromagnetic induction pump with rotating permanent magnets operating in the circulation loop, where low pump inlet pressure values are maintained. Data on the inlet pressure influence on pressure-flow rate curves were obtained by an experimental approach using a disc-type pump with SmCo permanent magnets in experiments. The pump was placed in the test loop operating with liquid sodium, and measurements of the pump characteristics were made. The inlet pressure variation from 0.1 to 3.0 bar influences the maximum flow rate, thus varying it from 2 to 12 l/s. Figs 7, Refs 7.

An idea of employing a superconducting cylindrical linear induction pump for the nuclear power system

Molten salt reactors have the potential to be employed as the power system for space exploration machines due to their advantage in the scale and power density. One essential technology associated with the reactor is the pump which circulating molten salts. Since the electric resistivity of molten salts is three orders of magnitude higher than ordinary metals, more compact magnetic fields are required to drive the molten salts to prevent their stagnation in the pipe. To solve this problem, a type of induction pump made of superconducting coils has been designed and analyzed in this article. Considering the large temperature difference between liquid molten salts and the operating temperature of superconducting coils, the pump stator has been specially designed to ensure the heat transfer efficiency in the system. Meanwhile, studies of induced current density of the molten salts have been carried out. Furthermore, driving force of the molten salt have been analyzed as well. Results show that the pumping system has feasible thermal insulation properties, perfect electromagnetic properties and better propulsion abilities, which illustrate its potential in the application field of molten salt reactors. In addition, analysis of the Multi-physics phenomena in this article lead to a better understanding of magneto–hydrodynamics and instabilities in the pump.

Numerical study of the magnetohydrodynamic flow instability and its effect on energy conversion in the annular linear induction pump

A numerical model of annular linear induction pump with a full-scale pump channel is created to study the scale-dependent instability of the magnetohydrodynamic flow. The magnetic-fluid coupling effect is implemented by modifying the underlying governing equations and constraints. The model authenticity is validated by comparing the simulated pressure difference, as well as the pressure pulsation, with the previous experimental data. The flow patterns at different flow rates corresponding to different magnetic Reynolds numbers are depicted from both the azimuthal and meridian viewpoints, and the periodicity of the occurring vortex flows is found in the pump. By analyzing the different mechanisms contributing to the fluid kinetic energy, it is found the competition between the axial components of the Lorentz force and pressure gradient dominates the flow evolution in the pump channel. The magnetic-fluid coupling effect is found to amplify the disturbances in either the magnetic field or the fluid field. It is even effective within the uniform externally imposed magnetic field and inlet velocity only if a disturbance exists in the initial flow. Increase in the cycle number of disturbance can enhance the flow stability and induce smaller vortex flows. Finally, different mechanisms of energy conversion in the pump are analyzed and it is found that the sudden occurrence of vortex flows can induce large current density, which significantly increases the Ohmic dissipation and decreases the efficiency of energy conversion from magnetic field into the fluid. The relatively large Ohmic dissipation in the fluid is the main reason for the low efficiency of such a device.