Boiling heat transfer from a horizontal flat plate in a pool of liquid hydrogen

摘要

Heat transfer from a flat plate facing upward immersed in a liquid hydrogen pool was measured for thepressures from atmospheric to 1.1 MPa. The flat plate heater used was 10 mm in width, 100 mm in lengthand 0.1 mm in thickness. Critical heat fluxes (CHFs) in saturated boiling increased with the increase inpressure up to around 0.3 MPa and then decreased with further pressure increase. The CHFs under sub-cooled condition at each pressure increased with the increase in sub-cooling. Discussions were made onthe experimental results by comparing with those of the other cryogenic liquids and also the Kutate-ladze's equations under saturated and subcooled conditions. The experimental CHFs were much smallerthan the Kutateladze's equation for higher pressure up to critical. The heater surface temperature wasfound to reach the critical temperature before the occurrence of hydrodynamic instability and jump tothe film boiling regime at the lower heat flux in the higher pressure range. It was suggested that the CHFsare determined not by the heat flux but by the temperature in the higher pressure range.