The accurate prediction of AC losses in High- Temperature Superconducting (HTS) tapes has been widely discussed in the literature, as both homogenized and multi-scale models have been proposed using different magnetodynamic finite-element (FE) formulations. In this work, we discuss numerical considerations to be taken into account when coupling magnetic and thermal FE models. The validity of...
In this contribution is demonstrated how to evaluate in T-A formulation the “macroscopic” voltage in turns of HTS magnet energized by AC current. Decomposing the local electric field into the vector-potential induced and the electrostatic-charges initiated part allows to integrate the latter along the whole length of conductor, and compute in this way the voltage signal that will appear at the...
To improve the understanding of High-Temperature Superconducting (HTS) devices in electrical systems, it's important to couple Finite Element Models (FEM) with Electrical Circuits (EC). This coupling should consider superconducting behavior and how HTS devices affect electrical systems. Some HTS devices shift from the superconducting state to the normal resistive state, like fault current...
3D thermal-hydraulic and electric modelling of quench propagation in HTS conductors for fusion
Andrea Zappatore
Energy Department
Politecnico di Torino
Turin, Italy
andrea.zappatore@polito.it
Abstract—A fully three-dimensional multi-physics model to simulate quench propagation in HTS conductors for fusion applications is presented. It accounts for thermal, electric and fluid...
In perspective of 20 T+ field magnet and more compact layouts for fusion reactors, the high temperature superconductors are the alternative which can allow high transport current at very high field, guaranteeing at the same time a higher stability. Among them, the Rare-Earth Barium Copper Oxide (ReBCO ) coated conductors are a promising option due to their high critical temperature and the...
Although thermomagnetic instability can deteriorate its performances, MgB$_2$ has been proved to be one of the most promising superconductors for magnetic shielding. For this reason, finding solutions to reduce or prevent thermomagnetic instabilities is mandatory. A numerical approach can be a powerful tool for predicting the occurrence of such phenomena, thus facilitating the development of...
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\title{Impact of porosity on trapped...
The design of REBCO high temperature superconducting (HTS) ultra-high-field magnets requires fast and accurate multi-physics modelling (electromagnetic, thermal and mechanical). This contribution presents a novel computationally-efficient multi-physics method that takes screening currents into account. We apply this method to a REBCO insert within a 19 T / 150 mm bore low-temperature...
We present a finite element model for a single-layer CORT cable composed of three coated conductors wound around a tube and carrying an AC current. We use a coordinate transformation that takes into account the helicoidal symmetry of the cable and enables the problem to be studied with an equivalent two-dimensional model. We show that this model correctly captures the full three-dimensional...
AC losses, current density and the magnetic field are important variables for designing high-temperature superconducting (HTS) devices. The preferred method to compute those parameters is the finite element method. In this framework, most of the computational effort has been carried out in the time domain even though the interest may lay in the steady-state regime. For the latter, it is...
Superconductors have revolutionized magnet technology, surpassing the limitations of traditional coils and permanent magnets. Relying on the results of trapped field measurements carried out on MgB$_2$ discs, in this paper we numerically investigate the field trapping ability of hybrid layouts where ferromagnetic (FM) structures were added to a superconducting (SC) disc. To this aim, through...
We present the latest progress within the
BELFEM project, with a focus on the electromagneticthermal
modeling of high-temperature superconducting
cables and magnets. We discuss a recent validation and
benchmark against COMSOL and GetDP, and provide a
brief outlook onto current fields of research.
A primary challenge encountered in the accurate modeling
of such systems is the...
HTS coils are used in various applications, however, it is complicated and time-consuming to model their multiphysics behavior. We have developed a simple homogenized method to accurately simulate HTS coils, in the context of electrothermal quench. Different numerical models are benchmarked for these computations, and they show very good agreement for different configurations of homogenized method.
We introduce a H-phi magneto-thermal model to predict the dynamics of quench nucleation in HTS tapes by finite-element simulations. This superconductor model uses an original interpolation regime between the usual power-law model and the normal state resistivity, based using Bezier curves to allow a smooth transition between these two regimes. It is shown that this explicit modeling of the...
Due the integration of superconducting technologies into electrical networks around the world, its precise simulations in power grids are increasingly becoming a desirable outcome. Sophisticated methods have been used to model superconducting power cables and, in this way, predict its behavior under different conditions. Most of the available models, however, are not advisable to be used and...
Fast and scalable Superconductor simulations in the cloud with Quanscient Allsolve
Dr. Valtteri Lahtinen, Chief Scientist and Co-Founder
Dr. Janne Ruuskanen, Application Engineer and Superconductor Modeling Expert
The so-called Conductor On Round Core (CORC) and the Twisted Stacked-Tape conductor (TSTC) are both the most compelling candidates for the development of high temperature superconducting (HTS) cables, both with the high current carrying capabilities required for the future development of fusion projects, with the CORC cross-sectional design being generally larger than its TSTC counterpart. In...
Abstract— High-temperature superconducting (HTS) tapes, represented by Rare Earth-Barium-Copper-Oxide (REBCO) conductors, are promising for high energy and high field superconducting applications. However, practical applications subject HTS conductors to various stresses and strains, including residual stresses due to thermal mismatch and tensile stresses from Lorentz forces. This can result...
Abstract— In this work, a new topology of an inductor of axial flux synchronous machine is presented and tested. It is executed by combining superconducting (SC) bulks and six solenoids. It consists of six superconducting solenoids connected in series stuck in a non-magnetic disc and supplied by direct current. The presence of two SC bulks which by their magnetic field screening property,...
China Fusion Experimental Reactor (CFETR), European Fusion Reactor (EU DEMO), and US Fusion Reactor (SPARC) are all actively developing high-temperature superconducting magnet (HTS) design schemes to effectively improve the magnetic field strength of future fusion reactors and increase fusion power. The resulting fusion nuclear heat effect brings great challenges to the stability of...
Homogenization techniques are appealing in reducing the computational cost of simulating structures with many stacked high temperature superconductor (HTS) tapes. In this contribution, the foil conductor model is extended to HTS applications with insulated conductors. The model is derived in 2-D with the A−formulation and allows directly imposing the current in the conductors. Preliminary...
This abstract presents the magnetic field dynamics of a
large-scale prototype of a HTS insert when powered with a
constant transport current. The use of a 2D electromagnetic model
helps to identify the contribution of the changes of current
distribution inside the superconducting layers affecting the
stability. The existence of coupling currents dumping through
resistive interfaces...
Superconductors play a crucial role in the advancement of high-field electromagnets used for particle accelerators, magnetic resonance imaging, fusion reactors, and many other high-end technological applications. Unfortunately, their performance can be compromised by thermomagnetic instabilities, wherein the interplay of rapid magnetic and heat diffusion can result in catastrophic flux jumps...
HTS coils used for high field magnets are usually made of several metal-insulated or non-insulated HTS pancakes. Quench modeling of these coils requires time-dependent simulation of current distribution inside each pancake. Partial element equivalent circuit is well-known method of modelling HTS coils, however due to large number of magnetically coupled elements, it can be time and memory...
Aviation electrification is at the center of attention in reducing CO2 emissions. Aircraft are responsible for around 2.4 % of the annual global carbon emissions. This is the motivation behind the development of fully electric, zero-emission aircraft. The advantages of superconductivity, including compactness, lightweight, and high efficiency, make this technology a promising choice to...
The no-insulation (NI) coil technique has proven to be robust for realizing high-field magnets with REBCO high-temperature superconductors (HTS). While the stable operation and charging delay — both originating from the inter-turn current transfer — on one hand, ensure the success of NI coils, on the other hand, they limit their application scenarios. A possible solution to the charging delay...
This work presents the 3-D modelling and measurements of the sorting of a 10 cm long high-temperature superconducting bulk undulator. We use the H-ϕ formulation together with the matrix method to produce an inverse analysis of the trapped field potential of each bulk. The simulation results are then used to sort the bulks in order to reduce the field error. A factor of 1.8 error reduction was...
Various quench detection methods are under development at EPFL Swiss Plasma Center, aiming at the detection response determined solely by temperature and not affected by EM noise or mechanical strain. This can be especially useful when applied to HTS coils. Currently, the promising options are twisted-pair SQDs (essentially, co-wound insulated superconducting wire), thermocouple chains and...
Alternative technologies for transmission cables have gained both scientific and industrial interest in recent years. In fact, global electricity production is planned to increase, causing grid nodes to be very much congested. Therefore, these alternative conductors might efficiently transport relevant amounts of power between the nodes. In such a context, superconducting cables are considered...
The multi-scale method for calculating AC loss of large-scale REBCO-based coils has been proposed for several years. I am one of the researchers contributing to the development of the multi-scale method to enhance its calculation capability. In this presentation, the development of the multi-scale method will be introduced, in which one can find the detailed modelling strategy of the method...
Producing accurate computational models that forecast the alternating current losses associated with cold-dielectric conductors is pivotal for power grid investors, what in turn can influence the designing and manufacturing of lightweight superconducting cables aspiring to reach high engineering current densities whilst maintaining a compact structure. By utilizing the so-called H-formulation...
Superconducting devices are likely to play a crucial role in the energy transition addressing power generation, transmission, distribution systems, transportation and even quantum computing. Therefore, developing models that enable fast and highly accurate simulations is important for advancing the technology. This work introduces the \textbf{T}-\textbf{A}-$\phi$ and...
This work presents a PGRML model for predicting superconducting tape temperature profiles during a quench. The model accurately forecasts the nonlinear dynamics involved in a drastically reduced computational time with respect to finite element models.
Halbach arrays made of bulk melt-textured YBa2Cu3O7-δ superconductors are very promising systems to generate magnetic flux density gradients exceeding those given by classic Halbach arrays using permanent magnets. When assembling an array made of bulk superconductors, the challenge is to prevent a reorganization of induced currents in the superconductors and their subsequent demagnetization....
In this communication, we demonstrate numerically and experimentally the remarkable DC magnetic screening ability of hybrid superconducting screens combining a 30 mm-diameter disk-shaped superconducting bulk with different closed superconducting loops made from coated conductors. The loops are placed coaxially with the bulk. The axial, DC and inhomogeneous field to be screened is produced by...
This study delves into the application of sparse sensor placement, a data-driven approach that hinges on identifying an optimal orthogonal basis for representing the angular dependency of high-temperature superconducting tapes and other devices. The proposed method offers the potential to expedite measurements and computations substantially by acquiring data at select locations and...
Please see the attachment for the abstract
Filamenting is crucial for reducing AC losses in superconducting coated conductor tapes and cables. However, the metallic stabilizing layer can lead to additional energy dissipation due to coupling currents. Estimating AC losses in such cases is challenging due to the complex geometry of the cable. We demonstrate a FEM numerical model suitable for estimation of the AC losses in different...
This work presents the modelling done to
optimize the pole geometry to be used in the planned high
temperature superconducting bulk undulator in PSI. The H-ϕ
formulation is used to model the undulator field and the
magnetic forces inside the poles. A T-shaped pole with a width
of 10 mm and height of 8 mm was found to be optimal to
maximize the peak undulator field. This model was...
This work presents a 2D FEM modeling approach for a straight soldered ReBCO stack cable within Comsol Multiphysics, focusing on high magnetic field environments. The model incorporates a detailed structure of the ReBCO tapes, including properties like resistivity for the electromagnetic model, as well as the solder shell surrounding the tapes. Critical current dependence on magnetic field...
The development of compact REBCO HTS coils (Rare-EarthBiCaCuO High Temperature Superconductor) with large energy densities face two issues. The first is destructive thermal runaway induced by local dissipative zones, the second is dynamic field homogeneity. The first issue, thermal runaway, may be solved by using a non-insulation or partial insulation technique. These techniques however affect...
Abstract—CERN’s next generation particle accelerator, the Future Circular Collider (FCC), aims to reach center-of-mass collision energies of 100 TeV with a 91 km tunnel where charged particles are accelerated and collided. One of the key devices in circular accelerators is the beam screen, responsible for shielding the steering and focusing magnets from the synchrotron radiation generated by...
