Abstract
We discuss the film flow of liquid lithium planned for the target and coolant of BNCT (Boron Neutron Capture Therapy) using accelerators which makes tumors curable with cell-level selections. We treat of the centrifugal instability to be generated in the boundary layer of the film flowing down on a concave guide plate. The object of our research is the thin film flow in a vacuum because of the ambiance using accelerators, and they serve both as a target of accelerators and as a coolant for the target itself. The latter role requires high-speed film flow for sufficient removals of proton beam heating. In this paper, we predict that the above centrifugal instability will give rise to the transition to turbulent flow in the boundary layer of the film flow.
