HEAT-TRANSFER OF A LARGE COPPER-PLATE TO LIQUID-HELIUM APPLICABLE TO LARGE-SCALE SUPERCONDUCTORS

Heat transfer characteristics of a copper plate (18 mm x 76 mm) to liquid helium have been measured by changing the heat surface orientation and the channel width of liquid helium. We observed that the critical heat flux depends on the heat surface orientation, and the critical heat flux has the maximum at the angle of 15 degrees - 30 degrees, where the angle is taken from the horizontal axis. On the other hand, the minimum heat flux has less dependence on the heat surface orientation. The channel tends to degrade the heat transfer characteristics compared with the open surface at all surface orientations, especially at 0 degrees.