Temperature evolution in the 6 m long cable of assumed three turn Magnet Coil. From the figure one can see that the estimated hot-spot temperature at 1s is ∼ 50 K. The steep slope in the curves represents the quench-front positions. The rate at which the quench fronts move along the x-coordinate is the measure of longitudinal quench propagation and the rate at which the other subsequent peaks emerge in the graph is the measure of the transverse quench propagation. At 1s, the farthest quench front position from origin is at ∼ 3.2 m, almost the entire length of the innermost cable turn i.e., Ω ⊂ [0, 2m], is quenched, and there is no steep rise of the curves in the outermost cable turn i.e., Ω ⊂ [4m, 6m], meaning the entire length of the outermost turn is still in the superconducting state. The dipole magnet coil consists of altogether 150 cable turns each of length ∼15 m. The total length of the cable is 2.25 km [2]. In the Chapter 3 it was concluded that without using adaptive mesh feature the optimal choice to discretize the cable domain is in the scale of 1 cm. Which means there will be altogether 225 thousand computation cells for the entire magnet coil and the analysis can be computationally expensive. It is for this reason that we use adaptive mesh refinement feature and start the model analysis with a mesh size of 15 cm, i.e., 15000 number of computational domains. To represent the initial condition properly we added a few more nodes at the quench initiation position. The mesh-adaptation parameters used are the same as were used in the 1D FEM model of the superconducting wire. During the analysis COMSOL evaluates the error at specified sample points and refines the mesh according to a defined error estimate. Figure 5 shows the solution obtained at different times. The blue curve represents the initial imposed temperature profile. The graph has a axis in the horizontal direction. The peak values at x = 0 m represent hot-spot temperatures.

Contexts in source publication

Context 1

... current, magnetic-field, and the parameters defining the helium cooling are the same as listed in the Table 1. Figure 4 shows the imposed initial profile and the solution obtained at different time. The graph is a logarithmic plot in the vertical direction. ...

Context 2

... current, magnetic-field, and the parameters defining the helium cooling are the same as listed in the Table 1. Figure 4 shows the imposed initial profile and the solution obtained at different time. The graph is a logarithmic plot in the vertical direction. ...