Abstract
The surface orientation dependence of heat transfer characteristics in liquid helium was discussed based on previous studies. Judging from their discussions and experimental data, the critical heat fluxes of our measurements come from the upper limit of the heat flux in the regime of continuous vapor columns and patches. To compensate the surface orientation dependence, we modified the gravitational force term in a theoretical equation for the critical heat flux with a horizontal surface. Then, the evaluations by the modified equation were compared with our experimental results. Film boiling heat transfer coefficient with the variation of surface orientation was also discussed based on two-phase boundary layer treatment of free convection film boiling. It was confirmed that our experiments were consistent with the theory.
