Patent Document ID: 9672303
Application ID: 13869868
Patent Flag: 1

Claim One:
1. A method of predicting initial cooling of a superconducting magnet, comprising the steps of: setting influence factors for predicting initial cooling of a superconducting magnet on the basis of an electronic device including the superconducting magnet and a cooling apparatus for cooling the superconducting magnet; setting at least one control volume on the basis of constituents of each device involved in the cooling of the superconducting magnet; checking the influence factors with respect to each of the control volumes and then inducing governing equations with respect to a thermal shield region, a first thermal anchor region, a magnet region, a second thermal anchor region, a radiation shield and a superconducting magnet using the checked influence factors; and predicting the initial cooling of the superconducting magnet using the governing equations, wherein the influence factors may include region factors set by spatially dividing the influence factors, and constituent factors set by dividing constituents influencing the region factors, wherein the region factors include: high-temperature region factors influenced by thermal energy transferred from a vacuum container of the cooling apparatus to a radiation shield disposed therein; and low-temperature region factors influenced by thermal energy transferred from the radiation shield to a conduction link provided therein with the superconducting magnet, and the constituent factors are classified into conduction heat factors and radiation heat factors according to heat transfer mode, wherein the governing equations are: temperature change per unit time in the thermal shield region is represented by ⅆ E s ⅆ t = Q H - Q A ⁢ ⁢ 1 - Q L = ⅆ ⅆ t ⁢ ( ρ ⁢ ⁢ VC p ⁢ T ) s [superscript S means radiation shield, Q H is an amount of thermal energy externally flowing into the radiation shield, Q A1 is amount of thermal energy transferred from the radiation shield to the first thermal anchor, Q L is amount of thermal energy transferred from the radiation shield to the superconducting magnet, ρ is density, V is volume, C P is thermal capacity, T is absolute temperature], temperature change per unit time in the first thermal anchor region is represented by ⅆ E A ⁢ ⁢ 1 ⅆ t = Q A ⁢ ⁢ 1 - Q C ⁢ ⁢ 1 = ⅆ ⅆ t ⁢ ( ρ ⁢ ⁢ VC p ⁢ T ) A ⁢ ⁢ 1 [subscript A1 means the first thermal anchor, Q C1 is amount of thermal energy discharged to the ultralow-temperature refrigerator after being heat-exchanged in the first thermal anchor], temperature change per unit in time in the magnet region is represented by ⅆ E M ⅆ t = Q L - Q A ⁢ ⁢ 2 = ⅆ ⅆ t ⁢ ( ρ ⁢ ⁢ VC p ⁢ T ) M [subscript M means superconducting magnet, Q A2 is amount of thermal energy transferred from the superconducting magnet to a second thermal anchor], temperature change per unit in time in the second thermal anchor region is represented by ⅆ E A ⁢ ⁢ 2 ⅆ t = Q A ⁢ ⁢ 2 - Q C ⁢ ⁢ 2 = ⅆ ⅆ t ⁢ ( ρ ⁢ VC p ⁢ T ) A ⁢ ⁢ 2 [subscript A2 means second thermal anchor, Q C2 is amount of thermal energy transferred from the superconducting magnet to the second thermal anchor], total amount of thermal energy transferred from the outside to the radiation shield (Q H ) is represented by 
 Q H =Q k1 +Q r1 +Q l1 +Q g1 [Q k1 is amount of conduction thermal energy transferred from the outside to the radiation shield through the support, Q r1 is amount of radiation thermal energy transferred from the outside to the radiation shield, Q l1 is amount of conduction thermal energy transferred from the outside to the radiation shield through current lead, Q g1 is amount of radiation thermal energy transferred to the radiation shield by residual gas existing between the vacuum container and the radiation shield], total amount of thermal energy transferred from the radiation shield to the superconducting magnet(Q L ) is represented by: 
 Q L =Q k2 +Q r2 +Q l2 +Q g2 [Q k2 is amount of conduction thermal energy transferred from the radiation shield to the superconducting magnet through the support, Q r2 is amount of radiation thermal energy transferred from the radiation shield to the superconducting magnet, Q l2 is amount of conduction thermal energy transferred from the radiation shield to the superconducting magnet through the current lead, Q g2 is amount of radiation thermal energy transferred to the superconducting magnet by residual gas existing in the radiation shield,] Q k1 and Q k2 are represented by Q k = N · A L ⁢ ∫ T L T H ⁢ k ⁡ ( T ) ⁢ ⁢ ⅆ T [N is number of supports, A is section area of the support, L is length of the support, k is thermal conductivity of the support, T H is temperature of a hot portion, T L is temperature of a cold portion, the subscripts ‘1’ and ‘2’ are respectively the outside and inside of the radiation shield,] Q r1 and Q r2 are represented by Q r = γ ⁡ ( T H 4 - T L 4 ) 1 - ɛ H ɛ H ⁢ A H + 1 A L ⁢ ( 1 ɛ L + 2 ⁢ ⁢ N ɛ ⁢ ⁢ N - N ) [ε is the emissivity of the radiation shield, A is the surface area of the radiation shield, N is number of radiation shields (number of layers), the subscript ‘H’ is a high-temperature region, the subscript ‘L’ is a low-temperature region, the subscripts ‘1’ and ‘2’ are respectively the outside and inside of the radiation shield,] Q I1 and Q I2 are represented by Q 1 = 2 · A L ⁢ ∫ T L T H ⁢ k ⁡ ( T ) ⁢ ⁢ ⅆ T [A is section area of the current lead, L is length of the current lead, k is thermal conductivity of the current lead] Q g1 and Q g2 are represented by Q g = a 0 ⁢ PA 4 ⁢ γ + 1 γ - 1 ⁢ 2 ⁢ ⁢ R π ⁢ ⁢ M ⁢ T H - T L T [P is a pressure of residual gas, A is a radiation area, τ is a thermal expansion coefficient of residual gas, R is a thermal constant of residual gas, M is a molecular weight of residual gas] a 0 is represented by a 0 = a 1 ⁢ a 2 a 2 + ( A 2 / A 1 ) ⁢ ( 1 - a 2 ) ⁢ a 1 [A 1 and A 2 are respectively inflow area and outflow area of thermal energy transferred by residual gas, a 1 and a 2 are accommodation coefficients of residual gas to A 1 and A 2 ].