SC 003 - Quench

This example is part 3 of the superconductor (SC) tutorial series. Check out the previous parts below:

• SC 001 - HTS tape AC loss
• SC 002 - Twisted superconductor AC loss

In this example, the quench event is simulated in a superconducting YBCO tape.

This example corresponds with the demo project Quench - Hello World Demo.

Model definition

The tape model has a 0.8 mm YBCO core with a 0.2 mm copper coating.

To initiate quench, a high resistivity area is modeled in the YBCO core. This is done by adding an aluminium cylinder at the mid-section of the core.

Element	XYZ dimensions [mm]	Aligned with axis
Copper box	12 x 1.2 x 50	Z
YBCO box	11.6 x 0.8 x 50	Z

Element	Radius [mm]	Height [mm]	aligned with axis
Air cylinder	40	50	Z
Aluminium cylinder	0.4	11.6	X

The center point of each element listed here is at the origin, (0, 0, 0).

Simulation setup guide

Here, you’ll find a simplified guide on setting up this simulation in Quanscient Allsolve.

Step 1 - Create the geometry

In the Geometry section, build the copper box, YBCO box, air cylinder and aluminium cylinder as detailed in the Model definition.

Step 2 - Define variables

Go to the Common sidebar.

• Define variables:

  Name	Description	Expression
  Tc	Critical temperature [K]	92
  Top	Operating temperature [K]	77

Step 3 - Define the physics, materials and apply boundary conditions

Proceed to the Physics section.

Assign the Copper, YBCO superconductor, Aluminium and Air materials to their corresponding volumes.

In this example, we need to make slight changes to the YBCO superconductor material properties, as the predefined YBCO_PowerLaw(j,T) function has the constant current density YBCO_Jc.

• In a quench simulation, the current density must be a function of temperature, as the resistivity of the YBCO tape increases with temperature.

• Change the YBCO_PowerLaw(j) function to use the current density JcT(T) instead:

  max(min(JcT(T)/YBCO_Ec * pow(norm(j)/JcT(T), 1.0-YBCO_n), 1e15), 1e6)

  Add T to the powerlaw function arguments.

  • The function is now called as YBCO_PowerLaw(j,T). Remember to pass T to the function also in YBCO material properties, where the function call is made.

• Define the function JcT(T) as:

  YBCO_Jc*ifpositive(T-Tc,1e-3,(Tc-T)/(Tc-Top))

In the Physics section, add the following physics.

Under Magnetism φ, the Constraint target is a top edge point on the air cylinder. The Lump I/V cut target is a loop along the top outer edge of the copper box.

Under Magnetism H, H-φ coupling must be enabled.

Under Heat solid, the Joule heating target is the whole tape volume, with the copper box, YBCO box and aluminium cylinder included.

Step 4 - Set up the simulation, run and plot

Proceed to the Simulations section and add a mesh that suits your needs.

Add a new simulation and choose options. See Superconductor AC loss tutorial for reference. Run the simulation.

Plot Time step in X axis and max T in YBCO in Y axis to see joule heating results.