| The cryogenic stability of a superconducting magnet depends upon the heat transfer characteristics of the composite conductor and its cooling channels. A normal zone created in a superconducting magnet following a mechanical disturbance will either grow or collapse, depending on the heat transfer rate from the conductor to the adjacent cooling channels. It is important to design a large superconducting magnet with cooling channels sufficiently large so that vapor locking will not occur under both steady state and transient conditions.;It is found that the critical burnout heat flux for the transition from nucleate boiling to film boiling is in inverse proportion to the thickness of insulation; that the pumping effect of cooling channel improves the heat transfer characteristics during the recovery transition from film boiling to nucleate boiling; that the vapor flow biasing either improves or deteroriates the heat transfer depending on the flowing speed and vapor fraction.;This study investigates the effects of heat transfer and vapor formation on the cryostable superconductors. One factor that affects the heat transfer rate is the amount of vapor accumulated in the cooling channel. The experiments have involved the effects of the channel dimension, the channel orientation, the coil-layer structure, the vapor accumulation, the vapor flowing, the thermal conduction through insulation, and of the gas-only cooling. The effects under the steady state, transient and transient with steady state biases have been studied. |
