Pressure Drop Of Two-Phase Helium Flowing In A Large Solenoidal Magnet Cooling Path And A Long Transfer Line

The pressure drop of two-phase helium flowing in a 64 m cooling path of a magnet and a 58 m connecting transfer line was investigated. A large thin superconducting solenoidal magnet, which was developed for the SDC detector (Solenoidal Detector Collaboration for the former SSC project), was used for this experiment. The magnet is 3.8 m in diameter, 2 m in length with a total cold mass of 4.5 tons. It was cooled by two-phase helium flow passing through a serpentine cooling path. The pressure drops of single-phase gas helium flow during cool down and two-phase helium flow in steady cooling were measured and compared with predictions. The measured pressure drop of single-phase helium agreed well with the prediction; however, the measured pressure drop of two-phase helium was much larger than the predictions based on separated and homogeneous flow models. In the high mass-flow region of two-phase flow, slight pressure oscillations were observed in the inlet, outlet and differential pressures of the magnet. The magnet temperature was stable and not affected by those oscillations.