Liquid Metal Pump Research Articles

Design of an ultrahigh temperature liquid metal centrifugal pump for thermal energy storage

Liquid metals serve as efficient heat transfer fluids due to their exceptional thermal conductivity and broad temperature range, rendering them well-suited for demanding applications such as nuclear reactors and thermal energy storage. Nevertheless, designing liquid metal pumps poses significant challenges, including chemical compatibility with the containment vessel and various thermomechanical issues. This study focuses on elucidating these challenges and proposing potential solutions through the example of a centrifugal pump designed for handling liquid tin at an extreme operating temperature of 2400°C. To address chemical compatibility concerns, graphite is adopted as both the containment and pump material, presenting novel mechanical hurdles. Key obstacles include accommodating thermal expansion and navigating the intricacies of working with features approaching the grain size of graphite.

A system for fluid pumping by liquid metal multi-droplets.

The transportation and control of microfluidics have an important influence on the fields of biology, chemistry, and medicine. Pump systems based on the electrocapillary effect and room-temperature liquid metal droplets have attracted extensive attention. Flow rate is an important parameter that reflects the delivery performance of the pump systems. In the systems of previous studies, cylindrical structures are mostly used to constrain the droplet. The analysis and quantitative description of the influence of voltage frequency, alternating voltage, direct current voltage bias, and solution concentration on the flow rate are not yet comprehensive. Furthermore, the systems are driven by only one droplet, which limits the increase in flow rate. Therefore, a pump with a cuboid structure is designed and the droplet is bound by pillars, and the flow rate of the pump is increased by more than 200% compared with the cylindrical pump. For this structure, the mechanism of various factors on the flow rate is analyzed. To further enhance the flow rate, a pump system with multi-droplets is proposed. Moreover, the expression of flow velocity of the solution on the surface of each droplet and the relationship between the flow rate, alternating voltage, and the number of droplets are deduced. Finally, the potential of applying the multi-droplet cuboid pump system in drug delivery and analytical chemistry is demonstrated. Additionally, the core of the pump, the droplet area, is modularized, which breaks the overall structural limitations of the liquid metal pump and provides ideas for pump design.

Effect of inlet/outlet height difference on P-Q characteristics of an electromagnetic pump for heavy liquid metals

A permanent magnet based electromagnetic pump (EMP) has been designed and fabricated for high temperature heavy liquid metals. It has features of being bi-directional in operation and non-intrusive in technique. The EMP has been characterized by generating its pressure developed vs flowrate (P-Q) curve in a high temperature experimental set up. Usually, the pressure developed by the pump is measured by taking the difference of pressure at discharge and suction ends. In contrast our experiment shows that the measured pressure difference between the suction and discharge end is different from that of the actual pressure developed by the pump. This may be due to the existing height difference between the suction and discharge end of the pump. A systematic study has been performed to analyse the effect of gravity on P-Q curve of such pumps. A method has been proposed to accurately generate the P-Q curve for such pumps for heavy liquid metals. The generated P-Q curve has been compared with available analytical expressions and found to match well with Hvasta et al.

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.

Numerical investigation on the performance of gas-lift pump with large density ratio of liquid to gas

Heavy liquid metals such as sodium and liquid lead-bismuth eutectic (LBE) have excellent heat transfer capability and receive increasing attention as the primary coolant in fast reactors and accelerator driven systems (ADS). In ADS system, coolant system is designed as natural circulation, to simplify the primary system, improve the compactness of reactors and most important of all is to increase the inherent safety of reactor. Because the electromagnetic pump that drives the flow of liquid metal is eliminated in the coolant natural circulation system. In such situation, gas-lift technique named gas-lift pump could be adopted to enhance the coolant natural circulation capacity. The open research on the performance of gas-lift liquid metal pump is much less than that of air- lift water pump. The physical properties of large density ratio of liquid to gas, small kinematic viscosity and high surface tension of liquid metal is believed to have effects on the performance of gas-lift liquid metal pump. The present paper carries out some preliminary numerical simulation work on the two-phase flow characteristics of argon-liquid LBE in the up-riser tube and the performance of gas-lift liquid metal pump. Eulerian-Eulerian two-fluid model is used to describe the two-phase flow. Some interphase momentum transfer models from literature are used to account for the interfacial momentum transfer between liquid and gas phases. SST k-ω model with mixture treatment is used to compute the turbulence parameters of the homogeneous mixing phase in the present study. The influence of such parameters as argon injection superficial velocity, submergence ratio and diameter of up-riser tube on the discharged LBE mass flow rate and pressure drop of gas-lift pump are checked. The results could be helpful for the design of the gas-lift liquid metal pump.

Bilateral liquid metal pump with permanent magnets

Bilateral liquid metal pump with permanent magnets

Artificial Heart Based on Electrically Controlled Non‐Toxic Liquid Metal Pump

A novel approach is introduced to realize an artificial heart based on redistribution of charges on the surface of liquid metal droplets. The unique feature is that liquid metal droplets can be shaped into various forms when a driving voltage is applied at a specific condition. In addition, the deformed liquid metal droplets are easily restored to their original spherical shape by eliminating the driving voltage. The motions of electrically controlled liquid metal droplets make it possible to mimic the heartbeat. The heartbeat motions are precisely controlled by the modulation of the driving voltage amplitude and frequency. The maximum flow rate is ≈70 µL min−1 at 1.5 Vpp and 2 Hz square wave. To the best of our knowledge, this is the instance mimicking the artificial heart based on the electrically controlled liquid metal droplets. The experimental results reveal that the proposed deformation mechanism creates new opportunities in the field of soft robotics.

Numerical modelling of liquid metal electromagnetic pump with rotating permanent magnets

In this work, we study rotating permanent magnet based liquid metal pump. Full 3D model of the pump is created and different approaches to electromagnetic force computation are investigated. First, we seek a possibility to model the permanent magnet block consisting of many separate magnets as a single block with equivalent analytically prescribed magnetization. Second, different approaches regarding coupling of electromagnetic field to fluid dynamics simulation are considered. Main results show that for pump integral parameter calculation, time-dependent coupling is not necessary, although it can lead to different velocity and turbulent structure distribution in the channel.

Maintainability of the helical reactor FFHR-c1 equipped with the liquid metal divertor and cartridge-type blankets

The maintenance scheme in the compact helical fusion reactor, FFHR-c1, equipped with the liquid metal divertor, REVOLVER-D (Reactor-oriented Effectively VOLumetric VERtical Divertor) and the cartridge-type molten salt blankets, CARDISTRY-B (CARtridges Divided and InSerTed RadiallY − Blanket), is investigated. The magnetic configuration of the compact variant FFHR-c1 is similar to that of the Large Helical Device (LHD), while the device size is 2.8 times enlarged from LHD and a strong magnetic field strength of ∼8 T at the plasma center is adopted. The maintenance of the REVOLVER-D is simpler than that of the helical divertor with a complicated structure as seen in the LHD. In the REVOLVER-D, showers of molten tin are injected into the ergodic layer at 10 inner ports. To circulate the molten tin, 10 sets of the shower system including a liquid metal pump, ducts, a showerhead, a pool, and a heat exchanger, are installed. These can be replaced with simple up/down motions. The CARDISTRY-B consists of 320 tritium breeding blanket cartridges, which are toroidally segmented every two degrees. These cartridges are maintained by using heavy manipulators with a simple 4DOF motion at a constant toroidal angle.

The History of Liquid Metal Pump Development in India

In a fast breeder reactor, the liquid sodium coolant is circulated through the core using vertical centrifugal pumps. These pumps are critical equipment for reactor operation and they have many unique design features. Indigenous development of pumps is vital for the demonstration and expansion of fast reactor technology which constitutes the critical second stage of our three-stage programme. Indigenous design and development of vertical centrifugal sodium pumps was taken up more than two decades ago in close collaboration with Indian industry. This article provides an account of the work done in the areas of pump hydraulics, mechanical design and testing, and manufacture.

Conceptual design of a liquid metal limiter/divertor system for the FFHR-d1

A new liquid metal divertor system named the REVOLVER-D (Reactor-oriented Effectively VOLumetric VERtical Divertor) is proposed for the helical fusion reactor FFHR-d1. The REVOLVER-D is composed of molten tin shower jets stabilized by internal flow resistances of wire/tape/chain. These shower jets are inserted into the ergodic layer surrounding the main plasma. Tin is selected as the liquid metal because of its low melting point, low vapor pressure, low material cost, and high safety. The liquid metal pumps, cryopumps, and turbo molecular pumps are installed in the central vacuum vessel connected to the main vacuum vessel via 10 inner ports equipped with maze neutron shields. Central solenoid coils made of high-temperature superconductors are installed inside the central vacuum vessel to shield the pumps from the strong magnetic field. The REVOLVER-D has a good possibility to satisfy important characteristics required for the divertor system in a fusion reactor, that is, high heat load tolerance, high maintainability, sufficient vacuum pump speed, high level of safety, and a small amount of radioactive wastes.

The stress analysis of a heavy liquid metal pump impeller

Lead-based coolant reactor is a promising Generation-IV reactor. In the lead-based coolant reactor, the coolant is liquid lead or lead-bismuth eutectic. The main pump in the reactor is a very important device. It supplies force for the coolant circulation. The liquid metal has a very large density which is about ten times of the water. Also, the viscosity of the coolant is small which is about one sixth of the water. When the pump transports heavy liquid, the blade loading is heavy. The large force can cause the failure of the blade when the fatigue stress exceeds the allowable stress. The impeller fraction is a very serious accident which is strictly prohibited in the nuclear reactor. In this paper, the numerical method is used to simulate the flow field of a heavy liquid metal pump. The SST k-w turbulent model is used in the calculation to get a more precise flow structure. The hydraulic force is obtained with the one way fluid solid coupling. The maximum stress in the impeller is analyzed. The stress in the liquid metal pump is compared with that in the water pump. The calculation results show that the maximum stress of the impeller blade increases with increase of flow rate. In the design of the impeller blade thickness, the impeller strength in large operating condition should be considered. The maximum stress of the impeller blade located in the middle and near the hub of the leading edge. In this position, the blade is easy to fracture. The maximum deformation of the impeller firstly increase with increase of flow rate and then decrease with increase of flow rate. The maximum deformation exists in the middle of the leading edge when in small flow rate and in the out radius of the impeller when in large flow rate. Comparing the stress of the impeller when transporting water and LBE, the maximum stress is almost one-tenth of that in the LBE impeller which is the same ratio of the density. The static stress in different medium is proportional to the pressure distribution because a large percentage of the total stress is caused by hydraulic pressure.

Electromagnetic rotation of a liquid metal sphere or pool within a solution

A liquid metal electric motor including a pair of concentric ring electrodes, permanent magnet and electrolyte solution is demonstrated. A liquid metal galinstan sphere, along with a NaOH solution, is stimulated to rotate centrifugally around the central electrode and the rotating speed increases with the voltage. The NaOH solution serves to rapidly remove the oxide on the liquid metal surface, reduce the motion friction and provide impetus to the liquid metal. As the mass of the liquid metal is increased to 12.16 g to form a kidney-like body, its rotating speed appears more controllable and the effect of the electrolytic action in the NaOH solution becomes weak in the range of 0–1.82 V. As the mass of the liquid metal is increased to 18.20 g to form a circular ring-shaped body, the ideal voltage range for controlling the rotating motion of the liquid metal is 0–0.81 V. The metal fluid rotates at a speed of 1.9 r.p.m., even at an extremely low voltage of 0.03 V. The liquid metal electric motor established here can find important applications in chip cooling, liquid metal pumps, material mixing, soft machine realization, etc.

Conceptual Study of Central Receiver Systems with Liquid Metals as Efficient Heat Transfer Fluids

Abstract Concentrated Solar Power plants (CSP) provide several advantages to other energy conversion concepts. However, they are still not competitive in price, compared to conventional power plants. But there is still potential to reduce the cost. The higher heat conductivity of liquid metals leads to very high heat transfer coefficients – ten times higher as with molten salts. This big advantage could increase the efficiency and lower the cost of CSP plants. In order to optimize such a power plant regarding efficiency and cost, detailed information of each component of the system is necessary. This paper shows several system concepts in which liquid metals can be used as heat transfer fluid. In addition, several liquid metal pump types are investigated as well as thermal energy storage concepts. With the assumptions and boundary conditions taken in this model, direct thermal energy storage with liquid metal is prohibitive. But some innovative indirect storage systemswith liquid metals show costs in the same range as with a 2-Tank molten salt storage.

Bearing Pumps for Heavy Liquid Metals for Fast Reactors

At the present time, specialists in Russia are engaged in designing the BREST-OD-300 fast neutron lead-coolant reactor plant. There is currently no experience in designing and operating axial pumps of lead-coolant reactor plants, including one of their major units – bearing unit.

Harvesting biomechanical energy in the walking by shoe based on liquid metal magnetohydrodynamics

A liquid metal magnetohydrodynamics generation system (LMMGS) was proposed and demonstrated in this paper for collecting parasitic power in shoe while walking. Unlike the conventional shoe-mounted human power harvesters that use solid coil and gear mechanism, the proposed system employs liquid metal (Ga62In25Sn13) as energy carrier, where no moving part is requested in magnetohydrodynamics generators (MHGs). While walking with the LMMGS, the foot alternately presses the two liquid metal pumps (LMPs) which are respectively placed in the front and rear of the sole. As a result, the liquid metal in the LMPs (LMP I and II) is extruded and flows through the MHGs (MHG I and II) in which electricity is produced. For a comparison, three types of LMMGSs (LMMGS A, B and C) were built where all the parts are the same except for the LMPs. Furthermore, performances of these LMMGSs with different volume of injected liquid metal were tested respectively. Experimental results reveal that both the output voltage and power of the LMMGS increase with the volume of injected liquid metal and the size of the LMPs. In addition, a maximum output power of 80mW is obtained by the LMMGS C with an efficiency of approximately 1.3%. Given its advantages of no side effect, light weight, small size and reliability, The LMMGS is well-suited for powering the wearable and implantable micro/nano device, such as wearable sensors, drug pumps and so on.

Development, Visualization, and Application of the ARIES Systems Code

The ARIES research program has utilized its comprehensive ARIES systems code (ASC) and a new graphical user interface for visualizing the parameter space as important tools in its analysis of fusion power plant designs. Recently, the ASC has undergone modifications to accommodate different divertor designs, each having unique pumping powers, helium and liquid-metal pump thermal heat recovery, and the latest material, fabrication, and costing algorithms. The modifications and changes made to the code have been documented and verified by members of the ARIES team to ensure accuracy of implementation and self-consistency of design. The code has also been modified to display a wider range of input and output files, formulas, and algorithms for a greater degree of transparency and verification. After the changes to the code were completed and the version was locked, the ASC was employed to scan the physics and technology operating space for relevant power plant designs. Four corners of aggressiveness and conservativeness in both physics and technology serve as the boundaries for the scans within which a range of possible tokamaks exist. The Visual ARIES Systems Scanning Tool (VASST) has been used in parallel with the ASC scans to visualize the tremendous amounts of data resulting from these detailed systems scans. Displaying the data in a colorful and intuitive visual environment and giving the user explorative and visual interaction have helped extract meaningful relationships and trends from the data. Initially, broad scans from the ASC and VASST indicated areas of interest where additional detail was needed. Further scans of higher fidelity helped enhance and further refine the database. After the final scans were completed, VASST facilitated in displaying and filtering the large database to choose two “strawmen” data points at two of the four corners of the aggressive/conservative operating space. These points now serve as reference designs, so more detailed design and calculations can be done. The results of the in-depth designs assist the ASC by feeding back information into the code that can then be generalized for a wider range of operating scenarios relevant to the scanning range. This substantiates the ASC and helps mesh simple formulas with detailed design.

Liquid metal corrosion/erosion investigations of structure materials in lead cooled systems: Part 1

In future lead cooled nuclear power systems the heavy liquid-metal pump will be placed in the hot temperature region of the reactor. This combines corrosion problematic at elevated temperatures with erosion at the impeller of the pump. Several steels designed for conventional mechanical high loaded pumps and the SiSiC have been tested in oxygen containing stagnant lead (10 −6 and 10 −8 wt%) at 550 and 600 °C for 2000 and 4000 h in the COSTA-facilities. Only SiSiC shows no influence by the liquid metal. No dissolution attack occurs at cast iron steels but inner oxidation takes place. NORILOY shows no dissolution attack. All other steels are attacked by liquid lead at one of the conditions. To evaluate the erosion–corrosion attack a new test facility allowing velocities of the lead of up to 20 m/s was designed and constructed. With a CFD-code the behaviour and flow velocity of the lead are simulated.

Cooling of high-power-density microdevices using liquid metal coolants

High electrically conducting fluids such as liquid metals offer a unique solution to the current and future cooling needs of high power density heat sources. The two principal advantages of developing single phase cooling systems based on liquid metals lie in their superior thermophysical properties and in the ability to pump these liquids efficiently with silent, nonmoving pumps. Closed loop systems based on liquid metals and liquid metal pumps enable gravity independent high performance cooling systems. Analytical and experimental work is presented showing heat transfer coefficients on the order of 10W∕cm2∕K and miniature pumps operating at greater than 8kPa maximum pressure rise and 1% maximum efficiency.

Emittance measurements for a thin liquid sheet flow

The Liquid Sheet Radiator (LSR) is an external flow radiator that uses a triangular-shaped flowing liquid sheet as the radiating surface. It has potentially much lower mass than solid wall radiators such as pumped loop and heat pipe radiators, along with being nearly immune to micrometeoroid penetration. The LSR has an added advantage of simplicity. Surface tension causes a thin (100-300 microns) liquid sheet to coalesce to a point, causing the sheet flow to have a triangular shape. Such a triangular sheet is desirable since it allows for simple collection of the flow at a single point. A major problem for all external flow radiators is the requirement that the working fluid be of very low (approx. 10(sup -8) torr) vapor pressure to keep evaporative losses low. As a result, working fluids are limited to certain oils (such as used in diffusion pumps) for low temperatures (300-400 K) and liquid metals for higher temperatures. Previous research on the LSR has been directed at understanding the fluid mechanics of thin sheet flows and assessing the stability of such flows, especially with regard to the formation of holes in the sheet. Taylor studied extensively the stability of thin liquid sheets both theoretically and experimentally. He showed that thin sheets in a vacuum are stable. The latest research has been directed at determining the emittance of thin sheet flows. The emittance was calculated from spectral transmittance data for the Dow Corning 705 silicone oil. By experimentally setting up a sheet flow, the emittance was also determined as a function of measurable quantities, most importantly, the temperature drop between the top of the sheet and the temperature at the coalescence point of the sheet. Temperature fluctuations upstream of the liquid sheet were a potential problem in the analysis and were investigated.