抄録
A fundamental study for frost formation around a single cold cylinder was conducted using an experimental and numerical method. We focused on the mass transfer around the cylinder under the condition where phase change of the vapor in the flow occurs. By the experimental study, the mass transfer rate on the cold surface of the cylinder at a constant surface temperature (200–250K) was measured. The results show that the mass transfer rate decreases according to the decrease of the wall temperature below 230K, while it increases above 230K. This phenomenon can not be expressed by the common equation of Sherwood number in which the phase change of the vapor (condensation) is excluded. In the numerical study, we calculated the flow around the cylinder including the phase change of the vapor. The scheme for compressible flow was modified to be able to solve lower speed flow. As a result of the calculation we obtain same tendency as that of the experiment that the mass flux decreases at low temperatures where the phase change occurs.
