Liquid Metal Fluid Flow Research Articles

Effect of nano-coating on corrosion behaviors of DCLL blanket channel

The corrosive behaviors of liquid metal fluid flow on the channel wall of Dual Coolant Liquid (DCLL) blanket of fusion reactor were simulated by imposing the discrete phase model (DPM) under different magnetic field strength, inlet velocities and neutron heat sources while considering blanket channel walls with and without non-wetting nanomaterial coating conditions. Results showed that regardless of the external environment of the blanket (except in the absence of magnetic field), the corrosion of the inner walls of the blanket channel declined significantly after employing nano-coatings in comparison to that of uncoated wall. For the uncoated condition, channel wall corrosion rate increased exponentially with time, various parameters have significant influence on channel corrosion, and the effect of magnetic field intensity is highest among them. In contrast, the corrosion rate of the channel walls with nanomaterial coating increased linearly with time, and unlike uncoated wall there is little difference on the corrosion rate of the channel walls for different parameters. Hence, these minute alterations in the corrosion of the channel walls with varying parameters indicate that the nanomaterial coating layer has a substantial protective effect on the blanket wall structure.

Research on Flow Field of Double-Nozzles Bottom Blowing CAS Process with Properties of Liquid Metal through Numerical Simulation

The Fluid Flow of Liquid Metal in Ladles of CAS-OB Refining Process Is a Complicated Turbulent Transmission Process. it Behaves much More Complicated than in Traditional Ladle because of Immersion Snorkel. this Paper Describes Properties of Liquid Metal Based on Full Buoyancy Model. the Author Analyzes the Characteristics of Flow Field in Single and Double-nozzles Bottom Blowing Condition through Numerical Simulation Method. Double-nozzles Bottom Blowing Could Improve Blending Effect in the Region where Is Weak Mixing. this Paper Also Draws an Empirical Formula which Tells how Gas Blowing and Immersion Depth Influence Mixing Time in CAS-OB Ladle through Dimensionless Analysis.

LIQUID METAL FLOW CONTROL BY DC ELECTROMAGNETIC PUMPS

The cooling system of high-density thermal power requires fluids of high thermal conductivity, such as liquid metals. Electromagnetic pumps can be used to liquid metal fluid flow control in cooling circuits. The operation of electromagnetic pumps used to flow control is based on Lorentz force. This force can be achieved by magnetic field and electric current interaction, controlled by external independent power supplies. This work presents the electromagnetic pump operational principles, the IEAv development scheme and the BEMC-1 simulation code. The theoretical results of BEMC-1simulation are compared to electromagnetic pump operation experimental data, validating the BEMC-1 code. This code is used to evaluate the DC electromagnetic pump performance applied to Mercury flow control and others liquid metal such as Sodium, Lead and Bismuth, used in nuclear fast reactors.

A PARAMETRIC STUDY AND PERFORMANCE EVALUATION OF DC ELECTROMAGNETIC PUMPS WITH BEMC-1 CODE

Electromagnetic pumps are used to control liquid metal fluid flow in cooling loops. The principle of operation of an electromagnetic pump is based on Lorentz’s force. This is obtained by interaction of the magnetic field and the electrical current, imposed and adjusted by independent external electric power sources. In this work are presented the continuous current electromagnetic pumps, their basic equations and the BEMC-1 code, developed for design and performance evaluation of a DC electromagnetic pump. The main objective of this paper is a parametric study for magnetic induction, static pressure, fluid flow and performance evaluation of the pump. The theoretical results are compared with the experimental data to get adjust factors to be used in the BEMC-1 code. In this way the BEMC-1 code can be validated and used in the evaluations and projects of DC electromagnetic pumps.

Numerical analysis of fluid flow with free surface and phase change under electromagnetic force

In this study, fluid flow of liquid metal with free surface and melting of metal under electromagnetic force was investigated numerically. The computational code was developed by the authors based upon a finite difference method to simulate the free surface flow and the eddy current simultaneously. The VOF method was introduced to treat the free surface, and magnetic vector potential was used for eddy current analysis. The free surface shape predicted by the code agreed with that obtained experimentally. Furthermore, the code was improved to calculate the phase change (melting) of solid metal by Joule heating due to eddy current. Numerical results of melting of metal were also demonstrated.

Effect of Swirling Flow on Electro-magnetic Flow Meters.

In general, liquid metal fluid flow in externally applied magnetic fields produces induced currents. A study was carried out on the electro-magneto-hydraulic effect of the induced currents on the characteristics of liquid metal electro-magnetic flow meters. Both theoretical analysis and corresponding experimental measurements have been conducted to investigate swirling flow profiles which are produced by upstream arrangements of pipes and bends. The results showed that these arrangements produced two types of flow profiles ; single swirling and double swirling. Based on such flow profiles, the distortion of a potential field was evaluated and the influence on voltage output was estimated with the two-dimensional electro-magnetic analysis code FALCON-2D developed for this study. The analyis showed that the single swirling flow had a larger effect on the voltage output than the double swirling flow.

Analysis of Liquid Metal MHD Fluid Flow and Heat Transfer Using the KAT Code

A new computer code has been developed with the capability to model laminar liquid metal fluid flow and heat transfer in relatively complex geometries at parameter values greater than previously possible with a transient 3-D “full” numerical solution of the MHD equations. The full solution method, which includes viscous and inertial terms, provides an exact solution for boundary layers and is valid over a wide range of flow parameters. Previous attempts at numerically solving the full MHD equations have been limited in the range of magnetic field strengths (B) and Reynolds number (Re) which could be accurately modelled. Numerical techniques for treating problems at high B and Re are implemented in this code, named KAT.The KAT code is written in rectangular coordinates, with a sophisticated mesh generator and boundary condition input routines. Single-duct and multiple-duct geometries can be modelled with arbitrary wall conductivity and magnetic field variation throughout the solution domain. The code has been tested and benchmarked against analytical solutions and fully-developed very highly accurate numerical solution obtained by 2-D finite element method (FEM). The KAT solutions are in very good agreement with analytic and FEM solutions. The KAT code was applied to a right-angle rectangular bend problem with inclined B-field. Finally, the capabilities of the code and future applications are discussed.

Heat transfer-solidification kinetics modeling of solidification of castings

A close examination of the recent developments in the field of computer simulation of solidification process reveals that a combination of both macroscopic and microscopic models is necessary in order to accurately describe the solidification of castings. Currently available macroscopic models include models that describe heat transfer from metal to mold, fluid flow of liquid metal during mold filling, and stress field in the casting. At the microscopic level, the models should include more intricate issues such as solidification kinetics and fluid flow in the mushy zone. Although significant progress has been accomplished over the years in each field, the task of including all of these models into a comprehensive package is far from being complete. This paper describes the state of the art on coupling the macroscopic heat transfer (HT) and microscopic solidification kinetics (SK) models and introduces thelatent heat method as a more accurate method for solving the heat source term in the heat conduction equation. A new method for calculation of fraction of solid evolved during solidification based on computer-aided cooling curve analysis (CA-CCA), as well as a method based on nucleation and growth kinetics laws, is discussed. A new nucleation model based on the concept of instantaneous nucleation, which is used to describe equiaxed eutectic solidification of commercial alloys, has been introduced. It is demonstrated that the instantaneous nucleation model agrees well with the experimental results in terms of cooling curves and of evolution of the fraction of solid during solidification. Validation results are also shown for SK models that are based on CA-CCA coupled with HT models for eutectic Al-Si and gray cast iron alloys.

Modeling, analysis and experiments for fusion nuclear technology

Selected issues in the development of fusion nuclear technology (FNT) have been studied. These relate to (1) near-term experiments, modeling, and analysis for several key FNT issues, and (2) FNT testing in future fusion facilities. A key concern for solid breeder blankets is to reduce the number of candidate materials and configurations for advanced experiments to emphasize those with the highest potential. Based on technical analysis, recommendations have been developed for reducing the size of the test matrix and for focusing the testing program on important areas of emphasis. The characteristics of an advanced liquid metal MHD experiment have also been studied. This facility is required in addition to existing facilities in order to address critical uncertainties in MHD fluid flow and heat transfer. In addition to experiments, successful development of FNT will require models for interpreting experimental data, for planning experiments, and for use as a design tool for fusion components. Modeling of liquid metal fluid flow is a particular area of need in which substantial progress is expected, and initial efforts are reported here. Preliminary results on the modeling of tritium transport and inventory in solid breeders are also summarized. Finally, the thermo-mechanical behavior of liquid-metal-cooled limiters is analyzed and the parameter space for feasible designs is explored. Because of the renewed strong interest in a fusion engineering facility, a critical review and analysis of the important FNT testing requirements have been performed. Several areas have been emphasized due to their strong impact on the design and cost of the test facility. These include (1) the length of the plasma burn and the mode of operation (pulsed vs. steady-state), and (2) the need for a tritium-producing blanket and its impact on the availability of the device.

Variables affecting the nature of the chill zone

Structures and substructures in the chill zone have been studied in Al-Cu alloys as a function of the following solidification conditions at the substrate chill: a) heat sink capacity; b) surface microprofile; c) nature of the liquid metal fluid flow as it makes substrate contact. The parameters taken in account both experimentally and analytically are: heat transfer coefficient of the metal/mold interface, surface rugosity of the mold walls, and the Reynolds number of the liquid metal fluid flow. The results obtained show definite correlations between the structural characteristics of the chill zone and the values of the studied parameters.